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Taking tuber sciences and their histories as a case study, this essay hinges on materiality, both as a condition shaping thing–human relations and as a vector for producing knowledge and generating theory. It explores how people have made knowledge about some very earthy, solid, rooted, underground things: namely, tuber crops—yams, sweet or white potatoes, manioc, and taro. Unlike the waving seas of wheat and other grand global crops that sustained the rise of our modern world, tubers were almost invisible in history of science and technology until very recently. Anthropologists, however, have been thinking with tubers, recording how humans understand and work with them, and building theories about materiality and society from these observations for over a century—and they continue to be a vibrant source of inspiration to anthropologists of materiality today. The essay discusses the contexts in which different ways of knowing-through-tubers, vernacular and academic, have been formulated and asks what inspiration these tuber tales might offer to historians of science. [ABSTRACT FROM AUTHOR]

Nitrogen (N) fertilization has been repeatedly reported to strongly influence soil properties and crop growth. However, there is little information about the combined effects of soils and crops on soil CO 2 fluxes under N fertilization. In this study, in situ soil respiration, soil physicochemical properties, microbial communities and crop properties were measured for eight years (2008 to 2016) on the Loess Plateau. Five rates of N fertilization were applied to different plots to compare the soil respiration rate and its temperature sensitivity (Q 10). Nitrogen fertilization significantly increased mean annual cumulative soil respiration (R cum) by 25%–44%. R cum had a positive correlation with grain yield, and the carbon emission efficiency (grain yield produced per unit of carbon emission) under N-fertilized plots was 1.62–2.52 times that of unfertilized plots. R cum also had a positive correlation with root biomass and the root N concentration but showed a negative correlation with the root C/N ratio. The Q 10 values under N-fertilized plots decreased by half at a diurnal scale, but had a smaller reduction (i.e. , 0.04–0.09) at an annual scale compared to unfertilized plots. The decreased Q 10 values under N-fertilized plots also resulted from the lower aromaticity of dissolved carbon (SUVA 254) (7.40 vs. 10.53 L mg C−1 m−1). In addition, the altered R cum and Q 10 values were affected by the varied bacteria community derived from N fertilization, which was related to Acidobacteria , Chloroflexi , Proteobacteria and Bacteroidetes. Therefore, N fertilizer applications regulate the combined effects of soil and crop parameters on soil respiration and the Q 10 value. This study suggests that, due to the lower carbon emission efficiency and higher SOC concentration under N-fertilized plots, N fertilizer applications may be used to sustain crop yields and increasing SOC storage while minimizing carbon emission impacts to the environment on the Loess Plateau. • Nitrogen fertilizer application increased soil respiration rate (SR) but decreased Q 10. • Variation in SR and Q 10 was resulted from altered photosynthetic rate, C/N, SUVA 254 , and bacteria community. • Nitrogen fertilizer application increased carbon emission efficiency. [ABSTRACT FROM AUTHOR]

Using 12 long-term (of 15 to 42 years duration) experiments with different cropping systems under various soils and agro-climatic conditions, we studied how different (inorganic and integrated) nutrient management practices influenced boron (B) availability in soils, and its nutrition of nine crops. To this end, four nutrient management practices viz., NPK (recommended dose of N, P and K), NPK + FYM (farmyard manure), control and fallow, which were common in all the experiments, were selected and their effects on B availability in soils were tested using four commonly used methods viz., hot-CaCl 2 (HCC), KH 2 PO 4 (PDP), mannitol-CaCl 2 (MCC) and hydrochloric acid (HCl) in relation to B nutrition of wheat, rice, cowpea, sorghum, sesame, mustard, groundnut, soybean and lentil. Amounts of B extracted by the four different methods followed the order HCC = HCl > MCC > PDP across the tested soils. Averaged over the extractants, long-term nutrient management practices with NPK + FYM resulted in 15% increases in available B in soil over the control, which produced 20% increase in plant tissue B concentration. Such increases with integrated (NPK + FYM) nutrient management practices maintained available B in soils and plant tissues above its critical limits that supplied adequate amounts of B for nutrition of all the tested crops grown intensively for so many years. A B balance study in six experimental sites showed a net B accumulation over time as irrigation water contained and supplied (130–296 g B ha−1 year−1) more B than removed by harvested crops. Of the four methods used, HCC was the best for assessment of availability of B in soils under long-term cultivation. • 15–42 years integrated NPK supply maintained adequate B in soils and in plants. • Long-term nutrient management caused a positive balance of B in soils. • Hot-CaCl 2 was the best extractant in capturing changes in B availability in soils under LTFE. • B-rich irrigation water and to a lesser extent FYM caused B accumulation in soils. [ABSTRACT FROM AUTHOR]

This study assessed the concentrations of potentially harmful elements (Cu, Pb, Zn, Mo, Ni, Co, Cd, Cr, Mn and As) in agricultural soils and plants (tubers, fruity and leafy vegetables) and their possible health risk implications on human in the lead-zinc mining districts of Ishiagu, Nigeria. The concentration of potentially harmful elements in the soils varies according to the order Pb > Mn > Zn > Co > Cu > Ni > Cr > Cd > As > Mo. The potential ecological risk assessments show that the agricultural soils are contaminated by Pb, Zn and Cd and exceeded recommended limits. The concentration of Pb and to some extent Zn, Cr and Cd are higher in the leafy vegetables compared to the tubers and exceeded EU and WHO/FAO maximum allowable limits. Plant concentration factor (PCF) was identified to be higher in Cd, followed by Zn > Cu > Mo > Cr > Ni > Pb > Mn > Co > As. The Daily In-Take of Metals (DIM) values for the PHEs through the ingestion of tubers, fruit, and leafy vegetables were generally below 1; the sequence of DIM values for adults and children for all the plants studied in the order: Zn > Mn > Pb > Cu > Cr > Ni > Cd > As; also, the DIM values were higher for the children compared to the adults, in consistent with the observation of previous workers. The DIM values for Pb, Mn and Cd for all the plants exceeded the USEPA IRIS (2006) threshold limits. The health risk indices indicate that Pb, Mn and Cd contamination in the food crops have greater potential to pose serious health risk to the consumers, including decrease in immune system and dysfunction of vital organs, rise in Pb levels in the blood of children, kidney damage and development of carcinogenic cells in the body, with more prevalence in the leafy vegetables. Development and implementation of effective monitoring and regulation of the activities of mining industries and land use types in the area, massive sensitization campaign for the inhabitants and miners on mining best practices, are recommended for reducing these negative effects of mining in the environment; application of lime-rich soils can be adopted to limit the mobility of the PHEs to some extent. • Potential ecological risk assessment indicates evidences of serious soil metal contamination. • Metal transfer is higher in the leafy vegetables compared to the tubers. • The soils and foodcrops contain significant amount of potentially harmful elements. • The concentration of Pb, Zn, Cd and Mn in the agricultural soil exceeded CCME and EU Standards in 70% samples. • The ingestion of Pb, Mn and Cd through contaminated plants may pose health risk in the area. [ABSTRACT FROM AUTHOR]

There is a lack of information on how to determine N-use efficiency and monitoring and diagnosing N losses in irrigated potato (Solanum tuberosum L.) production. This study was conducted to determine and validate a simple model to estimate inorganic N leaching losses (Nlosses) from gravitational water and to determine Nlosses thresholds using the soil N and canopy sensor tests. We conducted field experiments (n = 6) from 2008 to 2012 to evaluate the effects of N rates and/or managements and gravitational water on tuber yield, crop N uptake (Nuptake) and Nlosses on the cultivar Innovator in the Argentinean Pampas. The N nutrition index (NNI), normalized chlorophyll meter reading (NNI-CM), relative chlorophyll meter reading (CMr), and relative normalized difference vegetative index (NDVIr) were determined 70 d after planting. Tuber yield, residual N, and Nlosses varied from 40.8 to 70.3 t ha-1, 23.2 to 78.7 kg N ha-1 and 6.4 to 219.4 kg N ha-1, respectively. The Nlosses were directly associated with the amount of gravitational water in the soil profile (r2 = 0.79). Threshold values of 255 kg N ha-1 for N available, 1.0 for NNI, 1.03 for NNI-CM, 0.94 for CMr and 0.98 for NDVIr were defined. We determined linear increases in Nlosses above these thresholds (r2 = 0.75, 0.35, 0.53, 0.40, and 0.46, respectively). High N rates and gravitational water increased the N losses in potato crops under irrigation. This information could be useful to adjust N fertilizer recommendation and monitoring the Nlosses in potato crops under irrigation. [ABSTRACT FROM AUTHOR]

• The study evaluate the impact of cover cropping in soil properties on the long term. • Soil water content was continuously monitored during 10 years by capacitance probes. • Soil hydraulic properties were estimated yearly inverting WAVE hydrological model. • Minimum tillage and cover crop affected macro-micro porosity and hydraulic properties. • Water depleted by cover crops was compensated with a larger water retention capacity. Cover cropping in agriculture is expected to enhance many agricultural and ecosystems functions and services. Yet, few studies are available allowing to evaluate the impact of cover cropping on the long term change of soil hydrologic functions. We assessed the long term change of the soil hydraulic properties due to cover cropping by means of a 10-year field experiment. We monitored continuously soil water content in non cover cropped and cover cropped fields by means of capacitance probes. We subsequently determined the hydraulic properties by inverting the soil hydrological model WAVE, using the time series of the 10 year monitoring data in the object function. We observed two main impacts, each having their own time dynamics. First, we observed an initial compaction as a result of the minimum tillage. This initial negative effect was followed by a more positive cover crop effect. The positive cover crop effect consisted in an increase of the soil micro- and macro-porosity, improving the structure. This resulted in a larger soil water retention capacity. This latter improvement was mainly observed below 20 cm, and mostly in the soil layer between 40 and 80 cm depth. This study shows that the expected cover crop competition for water with the main crop (evapotranspiration) can be compensated by an improvement of the water retention in the intermediate soil layers and a reduction of drainage loses. This may enhance the hydrologic functions of agricultural soils in arid and semiarid regions which often are constrained by water stress. [ABSTRACT FROM AUTHOR]

Tembotrione is an herbicide with a high persistence in soil, a characteristic that affects the growth and development of susceptible cultures in succession. In this sense, the objective of this research was to evaluate the residual effects of tembotrione on production and quality of potato tubers in a tropical soil. A field experiment (2014/2015) with randomized blocks design with four replications was conducted. The treatments consisted of five doses of tembotrione (0, 8.4, 16.8, 33.6, and 50.4 g a.i. ha−1) incorporated into the soil before planting the potato cultivar Atlantic. At 115 days after herbicide application were evaluated: total solids (%), dry matter content (DMCT %), nitrogen and potassium of the tubers, total yield and classification. The productivity of normal tubers decreased as doses of tembotrione were increased. The percentage of class I tubers was reduced at doses of 33.6 and 50.4 g a.i. ha−1. The increase in the doses increased the percentage of class II tubers and did not influence the percentage of class III and discard. The appearance of cracked tubers increased with increasing herbicide doses. Tembotrione affected the productivity of potato tubers and caused cracks in the tubers, which are dependent on the applied doses. [ABSTRACT FROM AUTHOR]

Wheat stem base disease (WSD) is an important disease complex which can be caused by various pathogens with variable life cycles, ecological requirements and sensitivities to fungicides. Agronomic practices are considered important tools to control this disease complex and influence the spectrum of fungal communities in infected wheat stems. The aim of the present study was to determine the impact of crop rotation schemes and soil tillage methods on the development of WSD and to elucidate the spectrum of causal agents of this disease. The development of WSD was assessed in a two-factorial (soil tillage practice and crop rotation) experiment. The incidence of WSD was evaluated at the BBCH growth stages 83–85. Causal agents of WSD and other fungi were identified using molecular methods. The soil tillage method did not influence the development of WSD, but the impact of crop rotation was significant, and the cropping system where oilseed rape, barley and faba beans were included decreased disease levels. Members of the genera Oculimacula and Fusarium were the most prevalent fungi associated with WSD. Moreover, fungi from other taxonomic groups were detected, with Phaeosphaeria spp. being prevalent. An increasing occurrence of Microdochium spp. was also observed. In conclusion, agronomic practices influenced the level of WSD, but no distinct impact on the fungal spectrum was identified. Further investigation is required to clarify the roles that pathogens and fungi from other taxonomic groups play in the fungal–wheat relationship. [ABSTRACT FROM AUTHOR]

Abstract Recently biochar has attracted attention as a soil amendment and soil organic carbon source which can be used to modify soil quality. Although the effects of biochar on individual soil quality parameters are well established, the impacts on soil quality indexes are rather limited or less known. Soil samples were collected from a two year controlled experiment treated with various levels of biochars (0, 4 and 8 Mg ha−1) obtained from three locally available materials (cotton straws, pistachio shells and corn cobs) and two different irrigation regimes 100% (FC100) and 65% of field capacity (FC65). Soil samples were collected and analyzed for important soil quality indicators; soil organic matter, aggregate stability, bulk density, porosity, available water content, hydraulic conductivity and total nitrogen. A Soil Quality Index (SQI) of multiple measured soil parameters for each parcel was obtained using both linear and non-linear scoring functions. Biochar application improved all soil quality parameters investigated and soil quality indexes and these improvements were more prominent in FC65 parcels than those in FC100 parcels. Soil quality indexes were significantly increased with a synergistic impact of biochar applications with a range from 3.9% to 138.5% depending on treatments and scoring function used. The results from these field studies showed that carbon rich biochars obtained from locally available plant residues can be applied to improve soil qualities on the degraded, low organic matter soils of the Harran Plain. Highlights • Biochars obtained from the residues of locally grown crops can improve the quality of field soils • Biochars obtained from pistachio shells were more effective in impacting soil quality parameters • Improvements of soil quality variables in soils with deficit irrigation were more pronounced • Biochar application can increase the soil quality index of degraded soils • Soil quality indexes are useful for demonstrating the synergistic effects of biochar on multiple soil quality parameters [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi can enhance plant resistance particularly against soil-borne pathogenic fungi. However, little is known about the effects of Funneliformis mosseae on the community composition of rhizosphere fungi in soybean (Glycine max [L.] Merr.) continuous cropping soil. Here, the disease index of soybean root rot was analyzed, and high throughput sequencing technology was applied to investigate whether F. mosseae could change the composition of fungal communities in the rhizosphere of continuous cropping soybean during seedling period. The results indicated that the disease index of soybean root rot decreased significantly after inoculation of F. mosseae. The root rot disease index was also affected by the increasing of continuous cropping regimes. Furthermore, the relative abundance of fungal community in soybean rhizosphere soil and root samples was influenced after inoculation. Ascomycota was the dominant phylum in most samples. Basidiomycota was the second dominant phylum in all the soil samples, but Olpidiomycota was the second phylum in most root samples. At the genus level, both inoculation and continuous cropping regimes had significant effects on the dominant genus and their relative abundances in all the samples. The relative abundance of some plant pathogenic fungi such as Fusarium in the inoculated root samples was lower than those in the non-inoculated root samples in the same continuous cropping regime. The results can provide new insights into the interactive effects of AM fungi and rhizosphere fungi, and also provide theoretical evidence on biological solutions to alleviate the obstacles of soybean continuous cropping. [ABSTRACT FROM AUTHOR]

• Study on Spent Microbial Biomass distribution network in Eastern Tennessee of U.S. • Application and delivering N rich industrial coproduct to crop field. • Solved for optimal distribution routes and storage facility characteristics. • Results suggest on-farm storage minimizing material transport and storage costs. Advancement of a sustainable bioeconomy requires strategic planning and development of new markets for coproducts. This research develops a least cost transportation model to deliver Spent Microbial Biomass (SMB) to farm fields as a soil amendment and fertilizer substitute. SMB is a coproduct resulting from the production of Bio-PDO™ – a certified biobased 1,3-propanediol made from corn glucose. SMB is bulky, but high in organic matter and other important plant nutrients. Distribution of SMB requires storage sites and truck transportation. The location of storage sites and serviceable coverage area are important factors determining supply logistic costs. This case study focuses on a Bio-PDO™ processing facility in East Tennessee. Stochastic programming and Monte Carlo simulation were used to evaluate the least-cost distribution of SMB under uncertain farmer demand. Farmer interest and participation rates affect the number and location of storage facilities, the system's total storage capacity and costs, and transportation costs. The results suggest that on-farm storage of SMB minimizes material transport and storage costs. [ABSTRACT FROM AUTHOR]

Pinellia ternata is a traditional Chinese herb that has been shown to suffer from continuous cropping. Deterioration in continuous P. ternata cropping soils and the effect of alteration of crop rotation on the soil were evaluated by using Illumina high‐throughput sequencing technology. Soil physicochemical properties and fungal diversity were significantly lower in continuous P. ternate cropping soil compared with those of uncultivated soil. In contrast, significant increases in soil factors and fungal diversity were detected after the continuous cropping soil was subjected to rotational cropping treatments, indicating a remediation effect of crop rotation on continuous cropping soil. Moreover, with the extension of wheat cropping in the rotations, fungal richness and most physicochemical properties exhibited a significantly increasing trend, suggesting that the remediation effect of crop rotation could be enhanced by extending the cropping of break crops. Furthermore, compared with those of continuous cropping soils, microbes that were potentially beneficial to P. ternate were enriched in the rhizosphere by rotational cropping, whereas micro‐organisms that supposedly lead to soil deterioration were suppressed. Redundancy analysis indicated that Podospora and Alternaria were the major microbes that were responsible for increasing soil physicochemical properties; by contrast, the deterioration in soil fertility was mainly attributed to Fusarium micro‐organisms. Significance and Impact of the Study: Knowledge of deterioration in continuous Pinellia ternate cropping soils and how crop rotations alter the deteriorated soil is still limited, especially regarding the presence of fungi and soil fertility. This research found remediation effects of crop rotation on continuous P. ternate cropping soils and indicates that these effects could be enhanced by extending the cropping of break crops. Community shifts between the continuous and rotational cropping soils and the associated changes in soil fertility will have a considerable impact on the diagnosis of obstacles to continuous P. ternate cropping and enhancement of the remediation effects of crop rotation. [ABSTRACT FROM AUTHOR]

Highlights • A dynamic soil endmember spectrum selection approach for rice residue cover estimation. • Use soil moisture and soil spectral reflectance model to modify soil endmember spectra. • RRC estimation accuracy improved for a soil moisture content lower than 20%. • Distribution of SM in farmland was crucial for RRC estimation. Abstract Crop residue deposited on the soil surface helps protect against water and wind erosion, improve soil quality and increase soil organic matter and soil carbon storage. Linear spectral mixture analysis (LSMA) is an important technique in field crop residue estimation. Traditionally, only one single or fixed standard crop residue and soil endmember spectrum is performed for each of the presented endmember classes or field. Because the variation in soil endmember spectrum signatures significantly changes with soil moisture (SM), spectral unmixing with fixed endmember spectra can lead to poor accuracy of the abundance of the spectral constituents of pure crop residue. Herein, this paper presents a dynamic soil endmember spectrum selection approach for improving the performance of soil and rice residue spectral unmixing analysis in rice residue cover (RRC) estimation. This new approach uses SM and soil spectral reflectance model to modify soil endmember spectra in each spectral unmixing analysis. Two validation datasets computed results have verified the feasibility and correctness of the dynamic soil endmember method. Results indicated that the distribution of SM in farmland was crucial for RRC estimation. Compared with traditional fixed min and fixed mean soil endmember spectrum methods, the results of the method developed herein showed this method significantly improved RRC estimation accuracy for an SM content lower than 20% (volumetric water content) over the traditional methods tested. Therefore, our proposed approach can be used to improve RRC estimation accuracy in harvest field. [ABSTRACT FROM AUTHOR]

The effects of land use on soil organic and inorganic phosphorus (P) stocks were assessed in the Pampas, Argentina. Three hundred and eighty-six paired sites widely distributed over an area of ca. 50 Mha were sampled. Land use types included soils under trees, uncropped soils, cropped soils at the pasture phase of a mixed rotation, cropped soils at the crop phase of a mixed rotation, and flooded soils. Slight differences in organic P stocks were found among land uses. Organic P was 21–35% lower in flooded soil than in the other treatments in the 0–100 cm depth. Inorganic P was significantly lower (ca. 27%) in pasture and cropped soils than in the uncropped controls at 0–25 cm depth. The ratios of organic P/inorganic P and organic C/organic P decreased with depth and did not significantly differ among the sites. The influence of cultivation on inorganic P to a depth of 100 cm depended on the initial phosphorus content of the soil. Soils rich in phosphorus lost substantial amounts of their phosphorus stocks, in some cases losses were as high as 70%, whereas phosphorus-poor soils presented only small changes in their inorganic P levels. [ABSTRACT FROM AUTHOR]

Although fertilization plays an important role in determining the contents of soil dissolved organic matters or water-extractable organic matter (DOM, WEOM), knowledge regarding the dynamics, biodegradability, and microbial community shifts of WEOM in response to different fertilization treatments is very limited, particularly in rice–wheat cropping soil. Thus, in the present study, we performed biodegradation experiments using WEOM extracted from samples of soil that had been subjected to four different fertilization treatments: unfertilized control (CK), chemical fertilizer (CF), 50% chemical fertilizer plus pig manure (PMCF), and 100% chemical fertilizer plus rice straw (SRCF). UV spectrum and fluorescence 3D excitation–emission matrix analyses applied to investigate the chemical composition of WEOM revealed that all examined WEOMs were derived from microbial activity and the dominant portion comprised humic acid-like compounds. After the incubation, 31.17, 31.63, 43.47, and 33.01% of soil WEOM from CK, CF, PMCF, and SRCF treatments, respectively, were biodegraded. PMCF- derived WEOM had the highest biodegradation rate. High-throughput sequencing analyses performed to determine the microbial community before and after the incubation indicated that Sphingomonas , Bacillus , and Flavisolibacter were the predominant bacterial genera in the original inoculum derived from the four fertilization treatments. Following biodegradation, we observed that the dominant bacteria differed according to fertilization treatments: Curvibacter (43.25%) and Sphingobium (10.47%) for CK, Curvibacter (29.68%) and Caulobacter (20.00%) for CF, Azospirillum (23.68%) and Caulobacter (13.29%) for PMCF, and Ralstonia (51.75%) for SRCF. Canonical correspondence analysis revealed that, shifts in the microbial community were closely correlated with pH and specific UV absorbance at 254 nm. We speculated that the inherent traits of different WEOM and the properties of soil solutions under different fertilization treatments shaped the soil microbial community structure, thereby influencing the biodegradation of WEOM. Image 1 • The dominant portion of the tested WEOM were humic acid-like compounds. • Fertilization influenced the dynamic and biodegradability of WEOM. • PMCF-derived WEOM had the highest biodegradation rate. • Diverse dominant bacteria utilized recalcitrant C from various fertilizer treatments. The paper revealed how fertilization treatments affect the decomposition of soil dissolved organic matters and the associated bacterial community. [ABSTRACT FROM AUTHOR]

Soil tillage is an agricultural practice that directly affects the global carbon cycle. Our study sought to assess the implications of adopting sunn hemp cover crops with different tillage practices on CO2 emissions for two soil types (clayey and sandy soil) cultivated with sugarcane in Brazil. The experimental design was a split‐plot with randomized blocks, with the main plots being with cover crop or fallow and sub‐plots being under conventional or minimum tillage. Our results indicate that during the first 50 days after soil tillage, the variation in soil CO2 emissions was stimulated by cover crop and soil tillage, while after that, it became dominated by the root respiration of sugarcane plants. We also found that over the first 97 days after the tillage, the clayey soil showed differences between minimum tillage with cover crop and fallow. Conversely, for sandy soil over the first 50 days following, there were differences between the tillage systems under cover cropping. Emissions from sugarcane rows were found to be greater than those from inter‐row positions. We concluded that soils under different textural classes had distinct patterns in terms of soil CO2 emissions. The correct quantification of CO2 emissions during the sugarcane renovation period should prioritize having a short assessment period (~50 days after soil tillage) as well as including measurements at row and inter‐row positions. [ABSTRACT FROM AUTHOR]

Quantification of soil CO2 emission under different cropping designs and relating it to the climate parameters can help better understanding the main mechanisms controlling its magnitude and mitigating its release to the atmosphere. Wheat and corn are the most produced crops worldwide contributing highly to total CO2 emissions from agricultural lands to atmosphere. Long term fluctuations in the soil CO2 emissions under continuous wheat and corn cropping and bare land were monitored for 509 weeks from 2009 to 2018 in semi arid conditions in the Harran Plain located in southeastern Turkey. The soil CO2 emissions were modeled for each cropping seasons separately using available meteorological parameters (air temperature (AT), soil temperatures (ST), relative humidity (RH) and rainfall) and field soil moisture (SM) data. The quantity of long term soil CO2 emission were following order; corn, wheat and bare land and it was around 38% higher (574 vs 792 kg ha-1 week-1) in soils under field crops than bare soils. Overall there were n increasing trends in seasonal, yearly cumulative and average weekly soil CO2 emissions over the years. The weekly soil CO2 emission values were positively correlated with AT and ST but negatively with RH and SM. The linear models were able to explain variations in the long term weekly soil CO2 emissions obtained during wheat, corn cultivations and bare land up to 77%, 55% and 50%, respectively. [ABSTRACT FROM AUTHOR]

In this study, we determined the activity concentrations of naturally occurring radioactive nuclides in plant crops and the corresponding soil collected from greenhouses and agricultural fields in Erbil city in the Iraqi Kurdistan Region by using a high purity germanium detector. The soil-to-plant crops transfer factors were determined for radioactive nuclides. The results showed that the activity concentration ranges for 226Ra, 232Th, and 40K in agricultural soils were (11.94–18.24) Bq/kg, (8.80–12.36) Bq/kg and (247.65–338.26) Bq/kg, respectively. The activity concentrations ranges for 226Ra, 232Th, and 40K in plant crops were (0.20–1.45) Bq/kg, (0.11–0.48) Bq/kg, and (68.07–1355.36) Bq/kg, respectively. The transfer factors from soil to plant crops for 226Ra, 232Th and 40K were in the ranges of (0.011–0.087), (0.011–0.046), and (0.201–5.130), respectively. The annual effective doses from consuming plant crops were also estimated. The values obtained were comparable to the internationally recommended values. • Natural radioactive nuclide level examined in Erbil, Iraqi Kurdistan. • Activity concentrations of 226Ra, 232Th, and 40K determined in soils and plant. • Measurements used to determine soil-to-plant crop transfer factors. • Annual effective doses from plant crop consumption. [ABSTRACT FROM AUTHOR]

The thermal-based Two-Source Energy Balance (TSEB) model partitions the evapotranspiration (ET) and energy fluxes from vegetation and soil components providing the capability for estimating soil evaporation (E) and canopy transpiration (T). However, it is crucial for ET partitioning to retrieve reliable estimates of canopy and soil temperatures and net radiation, as the latter determines the available energy for water and heat exchange from soil and canopy sources. These two factors become especially relevant in row crops with wide spacing and strongly clumped vegetation such as vineyards and orchards. To better understand these effects, very high spatial resolution remote-sensing data from an unmanned aerial vehicle were collected over vineyards in California, as part of the Grape Remote sensing and Atmospheric Profile and Evapotranspiration eXperiment and used in four different TSEB approaches to estimate the component soil and canopy temperatures, and ET partitioning between soil and canopy. Two approaches rely on the use of composite T rad , and assume initially that the canopy transpires at the Priestley–Taylor potential rate. The other two algorithms are based on the contextual relationship between optical and thermal imagery partition T rad into soil and canopy component temperatures, which are then used to drive the TSEB without requiring a priori assumptions regarding initial canopy transpiration rate. The results showed that a simple contextual algorithm based on the inverse relationship of a vegetation index and T rad to derive soil and canopy temperatures yielded the closest agreement with flux tower measurements. The utility in very high-resolution remote-sensing data for estimating ET and E and T partitioning at the canopy level is also discussed. [ABSTRACT FROM AUTHOR]

Purpose: According to the specific conditions of the region, we sought to determine appropriate soil materials for improving soil conditions after the reclamation of hollow villages into cultivated land and for quickly restoring agricultural production. Materials and methods: The test plot consisted of seven treatments with an area of 5 m × 6 m (30 m2) each, and each treatment included three replicates. The plot was filled with raw soil (old wall soil) from an abandoned homestead in Yuzihe Village, Yaotou Town, Chengcheng County, Shaanxi Province, China. The test design was completely randomised with seven treatments: fly ash (T1), organic fertiliser (chicken manure) (T2), improver (ferrous sulphate) (T3), fly ash + organic fertiliser (T4), improver + organic fertiliser (T5), fly ash + improver (T6) and no fertilisation measures (T0). The modified materials were mixed evenly with raw soil then applied to a depth of 0–30 cm onto the test plot. Results and discussion: After adding the various modified materials, the soil bulk density decreased by 6.52–14.49% and total soil porosity, capillary porosity and non-capillary porosity increased by 7.09–15.75%, 3.14–12.67% and 15.57–38.47%, respectively. The soil permeability coefficient increased by 5.75–10.75×. Organic matter, total nitrogen, available phosphorus and available potassium in reclaimed hollow village soil increased by 12.50–66.44%, 15.15–20.00%, 6.58–64.62% and 18.24–26.82%, respectively, relative to that of T0. Only T4, T2, T6 and T5 significantly increased maize yield and water use efficiency compared with T0. The other treatments did not significantly improve maize yield or water use efficiency. Conclusions: Organic fertiliser and fly ash composite was an appropriate amendment for improving reclaimed soil in a hollow village in a loess hilly gully region. [ABSTRACT FROM AUTHOR]

Proposal: A 12-year field experiment was conducted to assess straw mulch effects on soil organic carbon fractions, the carbon pool management index (CPMI) at different depths, and crop yield under a no-till rice-wheat rotation system on the Chengdu Plain, southwestern China. Materials and methods: There were two treatments in the experiment: no-till without straw mulch (CK) and no-till with straw mulch (SM). The soil was sampled at 0–5, 5–10, 10–20, and 20–30-cm depths. Soil total organic carbon (TOC), the labile organic carbon fractions, including particulate organic carbon (POC), dissolved organic carbon (DOC), microbial biomass carbon (MBC), and permanganate-oxidizable carbon (KMnO4-C), and the CPMI were analyzed. The crop grains were measured between September 2013 and May 2018. Results and discussion: Between 2013 and 2018, rice and wheat grain yields under SM were comparable to CK, except there were higher rice yields in 2016 and higher wheat yields in 2017 under SM. The soil organic carbon decreased as soil depth increased in both treatments. Soil TOC, POC, and KMnO4-C concentrations at 0–5 and 5–10 cm, CPMI at 0–5 and 5–10 cm, and DOC at 0–5, 5–10, and 10–20-cm soil depths were significantly greater under SM than under CK, whereas the MBC at 0–5 and 5–10 cm under SM was lower than CK. The POC/TOC, KMnO4-C/TOC, and DOC/TOC ratios were greater under SM in the 0–5 and 5–10 cm, 0–5 cm, and 5–10 and 10–20-cm layers than CK, respectively, whereas the MBC/TOC ratio decreased under SM at 0–5, 5–10, and 10–20-cm depths. Conclusions: The results showed that straw mulching should be adopted when a no-till rice-wheat cropping system is used in southwestern China because it leads to effective improvements in SOC sequestration while still maintaining normal crop yields. [ABSTRACT FROM AUTHOR]

Polynesians introduced the tropical crop taro (Colocasia esculenta) to temperate New Zealand after 1280 CE, but evidence for its cultivation is limited. This contrasts with the abundant evidence for big game hunting, raising longstanding questions of the initial economic and ecological importance of crop production. Here we compare fossil data from wetland sedimentary deposits indicative of taro and leaf vegetable (including Sonchus and Rorippa spp.) cultivation from Ahuahu, a northern New Zealand offshore island, with Raivavae and Rapa, both subtropical islands in French Polynesia. Preservation of taro pollen on all islands between 1300 CE and 1550 CE indicates perennial cultivation over multiple growing seasons, as plants rarely flower when frequently harvested. The pollen cooccurs with previously undetected fossil remains of extinct trees, as well as many weeds and commensal invertebrates common to tropical Polynesian gardens. Sedimentary charcoal and charred plant remains show that fire use rapidly reduced forest cover, particularly on Ahuahu. Fires were less frequent by 1500 CE on all islands as forest cover diminished, and short-lived plants increased, indicating higher-intensity production. The northern offshore islands of New Zealand were likely preferred sites for early gardens where taro production was briefly attempted, before being supplanted by sweet potato (Ipomoea batatas), a more temperate climate-adapted crop, which was later established in large-scale cultivation systems on the mainland after 1500 CE. [ABSTRACT FROM AUTHOR]

Grassland silage management is generally semi-organised with no conscious attempt to re-use wheel ways as with arable fields. The total number of machine passes can be 15 or more with normal traffic (NT) systems resulting in potentially large areas of a field suffering from direct damage to the crop and soil. Literature suggests there can be grass dry matter yield reductions of 5 to 74% under NT through compaction and sward damage, with a mean of 13% in the UK. Commercially available grass forage equipment with widths of 3 to 12 m set up for controlled traffic farming (CTF) could reduce trafficked areas (which is typically 90% to 80% for NT) to 40% to 13% for CTF. This study compared grass dry matter yield between CTF and NT for a three-cut silage system based on a 9 m working width in a permanent silage field in the southwest of Scotland, UK in 2015. Results showed a 13.5% (0.80 t ha−1) increase in yield for CTF for the 2nd and 3rd cuts combined. The CTF trafficked area covered was 57% less than the NT system (30.4% compared to 87.4%) over the three silage cuts. An economic analysis based on a 13% increase in dry matter yield (for 2- and 3-cut systems) and a reduction in trafficked area from 80% (for NT) to between 45% and 15% (for CTF), increased the yield by between 0.53 t ha−1 and 1.36 t ha−1 for 2- and 3-cut systems, respectively with an equivalent grass value of between £38 ha−1 and £98 ha−1. Introducing CTF for a multi-cut grass silage system is cost-effective by increasing yields due to a reduction in compaction and sward damage. [ABSTRACT FROM AUTHOR]

Peat reserves of the Russian Federation are estimated at more than 170.0 billion tons, it makes more than one-third of the world resources. The use of peat as a component for the preparation of composts is an important factor in increasing the productivity of agricultural ecosystems. During two cycles of four-course crop rotation 'potatoes - barley - annual grasses - winter wheat', we studied the influence of lowland peat, composted peat-poultry manure, cattle manure, their combined application with mineral fertilizers on soil physicochemical properties, nitrifying and cellulosolytic activity of soil and productivity of crop rotation. Application of cattle manure and composted peat-poultry manure contributes to the increase in the content of humus in soil by 0.07-0.16%, when combined with mineral fertilizers - by 0.14-0.22%, respectively. On average, the highest yield was noted in the variants with cattle manure and composted peat-poultry manure - 10.75-12.13 t ha-1 of grain units (g.u.), while in the check (without fertilizers) it was 8.03 g.u. (t ha-1). That is why peat is more profitable to use in the form of composts, especially as a component of composted peat-poultry manure. [ABSTRACT FROM AUTHOR]

An ontology-based knowledge representation scheme thrives by establishing relations between different terms belonging to the underlying domain. However, automating the identification of all possible relations that may exist between the different terms pertaining to a vast domain, such as agriculture, is quite challenging. One of the major challenges comes from extracting the inter-subdomain relations which are quite common in the agriculture domain. This present work proposes a knowledge-based scheme for extraction of inter-subdomain relations. In particular, it deals with three such cases, viz. crop and soil, crop and disease, soil and region. A baseline system has been designed by analysing official documents retrieved from different repositories. In an improved version of the proposed scheme co-reference resolution techniques have been used to achieve much higher success with average precision and average recall more than 75% and 85%, respectively. [ABSTRACT FROM AUTHOR]

Purpose: Microbial nitrification plays an important role in nitrogen cycling in ecosystems. Nitrification is performed by ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and nitrite-oxidizing bacteria (NOB) including complete ammonia oxidizers. However, the relative importance of nitrifiers in autotrophic nitrification in relation to soil pH is still unclear.Materials and methods: Combining DNA-based stable isotope probing (SIP) and molecular biological techniques, we investigated the abundance, structure, and activity of AOA, AOB, and NOB along a pH-gradient (3.97-7.04) in a vegetable cropped soil.Results and discussion: We found that AOA abundance outnumbered AOB abundance and had a significantly negative relationship with soil pH. The abundances of NOB Nitrospira 16S rRNA, nxrB gene, and Nitrobacter nxrA gene were affected by soil pH. Incubation of soil with 13CO2 and DNA-SIP analysis demonstrated that significant 13CO2 assimilation by AOA rather than by AOB occurred in the acidic soils, whereas the labeled 13C level of AOA was much less in the neutral soil than in the acidic soils. There was no evidence of 13CO2 assimilation by NOB except for Nitrobacter with NxrB gene at pH 3.97. Phylogenetic analysis of AOA amoA gene in the 13C- and 12C-labeled treatments showed that the active AOA mainly belonged to Nitrososphaera in the acidic soils.Conclusions: These results suggested that the main performer of nitrification was AOA in the acidic soils, but both AOA and AOB participated in nitrification in the neutral soil with low nitrification activity. NOB Nitrospira and Nitrobacter did not grow in the soils with pH 4.82-7.04 and other populations of NOB were probably involved in nitrite oxidation in the vegetable cropped soil. [ABSTRACT FROM AUTHOR]

The acting forces between soil and potatoes in the process of harvesting by vibration loads are complicated. In order to study the effect of the exciting forces for the dynamic characteristics of potato conveying and vibration separation system, taking potatoes with soil on them and equivalent viscoelastic material as a whole, a mechanic model was establish for the potato conveying and separation system considering the sectional material forces between the potatoes, the soil and the shaker chain in the conveying, separating, crushing and screening process, and then analysis of the model was conducted by asymptotic method numerical integration. The results show that the dynamic characteristic of the conveying and separation system is more complicated under specific conditions, and the system motion is chaotic. The test further shows that the rational use of vibration can improve the separation rate of potato and soil, and improve the harvest quality. [ABSTRACT FROM AUTHOR]

In many areas of China, agricultural land is subject to heavy metal contamination from mining activity. This study investigates an in situ remediation program suitable for the recovery of heavy metal-contaminated agricultural soil around mining areas. A 1-year field experiment was conducted in a gold mining area of Tongguan, Shaanxi Province, China, to evaluate the effectiveness of engineering remediation measures, including adding a layer of noncontaminated soil, or soil homogenization to 40 cm and 80 cm depths, and three crop rotation systems, including rye-corn rotation, wheat-corn rotation, and potato-adzuki bean rotation on ameliorating heavy metal pollutants from contaminated agricultural soil around mining areas. The results showed that soil treatment and crop rotation significantly decreased soil heavy metal concentrations, with 80 cm homogenization and wheat-corn rotation being most effective. After 1 year of in situ remediation using this combination, the concentrations of Hg, Cd, and Pb in topsoil (0–20 cm) were 71.7%, 82.4%, and 21.8% lower, respectively, than before remediation. The single and Nemero indexes of the edible parts of wheat and corn were both <1, indicating they were safe for consumption. The results provide a solution for the in situ remediation of heavy metal-contaminated agricultural soil in mining areas. [ABSTRACT FROM AUTHOR]

The salts have the ability to accumulate often in the soil of different crops, as a result of water and fertilizers used. A greenhouse experiment was carried out with the objective of studying the response of the vegetative phases of quinoa plants (Chenopodium quinoa Willd) at ascending concentrations of sodium chloride (NaCl). The seeds of quinoa Soracá accession were sown in bags with soil from the municipality of Ventaquemada (Colombia). The soil of the bags was gradually salified with NaCl by the addition of 0.0; 0.1; 0.2 and 0.3 M. days were measured to six and eight true leaves, days to branching and appearance of panicle; besides measuring length of stem, number of leaves, number of ramifications, content of chlorophyll, fresh and dry matter of root, leaves and stems and pH and electrical conductivity; observing that the plants presented significant statistical differences in the phenological development as well as in the height, number of branches and electrical conductivity, concluding that doses close to or higher than 0.3M generate the death of the plants, however electrical conductivities lower than 15,2 dS.m-1 allows the plant to reach grain formation. [ABSTRACT FROM AUTHOR]

To investigate the effects of seed inoculation with phosphate affecting microorganisms on the quantitative and qualitative traits of two forage sorghum (Sorghum bicolor (L.)), genotypes were investigated during 2011 and 2012 field experiments. The experimental treatments consisted of chemical (triple super phosphate (TP)), and biological P fertilizers [mycorrhizal fungus (Rhizophagus intraradices) (AM) + Pseudomonas fluorescens strain 93 (PB)] as well as sorghum genotypes (Speedfed and Jumbo) factorially arranged on the basis of a randomized complete block design with three replications. The results revealed that seed inoculation by AM fungi and its combined inoculation with PB significantly influenced sorghum growth, P concentration and acid detergent fibre (ADF%). Rhizophagus intraradices appeared to be better adapted for association with sorghum than P. fluorescens strain 93 under the environmental conditions of the experiment. The significant differences in the quantity and quality of the two genotypes as affected by chemical and biological fertilization indicate the importance of selecting the right genotype, which results in higher growth and yields with a better forage quality. Although in most cases, the biological fertilization was the more recommendable, the use of chemical P fertilization up to some level was essential for the production of sorghum forage yield affecting crop quality. It is more beneficial to use the integrated beneficial microorganisms (AM + PB) instead of their single use to achieve better crop growth, yield and nutrient status for both plant and soil health. [ABSTRACT FROM AUTHOR]

The article presents the results of research on the occurrence of beneficial groups of microorganisms in the rhizosphere of carrot, parsley and potato plants after the application of: (1) a commercial product EmFarma Plus (Probiotics Polska), (2) a consortium called Skierniewickie Microorganisms (MS) (containing three strains of Klebsiella oxytoca, Pseudomonas fluorescens, Pseudomonas sp.), and (3) Consortium MS together with EmFarma Plus. The study estimated the populations of microscopic fungi and bacteria, including the groups of microorganisms considered to be beneficial, i.e., spore-forming bacteria, fluorescent bacteria of the genus Pseudomonas, diazotrophs and actinomycetes. Applications of Consortium MS and, to a lesser extent, the preparation EmFarma Plus together with Consortium MS resulted in a significant increase in the total population of diazotrophs isolated from the rhizosphere soil of the vegetable species included in the study. There was no significant impact of the application of EmFarma Plus on the population size of the analyzed groups of microorganisms in the rhizosphere soil. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Oil Crop Sciences is the property of Oil Crops Research Institute of Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • Fertilization increased copper and manganese concentrations in stover but not grain. • Zinc concentrations declined in all plant fractions with nitrogen fertilization. • Iron concentrations in the grain increased with fertilization. • Available and total soil micronutrients were not impacted by fertilization rates. • Available soil micronutrients closely followed soil organic carbon. Abstract Sustaining or increasing micronutrient concentrations in food and feed is essential for human and animal health, yet little research has quantified the relative importance of nitrogen (N) fertilization on maize micronutrient concentrations. Nitrogen fertilization could dilute some micronutrients while increasing others (i.e., biofortification). Nitrogen fertilization also influences the amount of residue returned to the soil, potentially altering soil organic carbon (SOC) and micronutrients. While changes in soil micronutrients under long-term production are sometimes attributed to export via harvest or import via fertilization, available micronutrients are also influenced by soil organic matter — changes in SOC could impact available micronutrients. Our objectives were to (1) examine the long-term effects (14 years) of different N rates (0, 68, 120,173, 232 kg ha−1) on the concentration ([]), uptake, and cycling of N and micronutrients (Fe, Zn, Cu, Mn) in no-till continuous maize and (2) assess whether nutrient removal via grain harvest, or residue return have resulted in depletion or accumulation of SOC and available and total micronutrients. Results showed a positive impact of fertilization on stover [N], [Cu] and [Mn], and increased grain [N] and [Fe]. However, fertilization decreased [Zn] in all plant fractions, indicating that maize [Zn] is susceptible to yield dilution. Total and available soil micronutrients were not impacted by fertilization, despite widely differing rates of nutrient harvest and return. Available Cu and Mn followed changes in SOC, which declined in all depths except the surface 0–7.5 cm. Available Zn increased in the surface 0–7.5 cm, with slight increases in deeper depths. Available micronutrients appear to be closely regulated by SOC in this system. These findings give additional insights into how N fertilization impacts maize micronutrient concentrations, and suggest that SOC contributes to micronutrient availability, underscoring the role of SOC in sustaining long-term soil fertility. [ABSTRACT FROM AUTHOR]

We have mapped the broad groups of crops grown each summer and winter, from 1987 to 2017, for a 300,000-km 2 region of Queensland, Australia. These maps are part of a legislated decision-making process for the protection of prime agricultural land. For summer, the two groups of crops are ‘Coarse-grain & Pulse’ and ‘Cotton’. For winter, the two groups of crops are ‘Cereal’ and ‘Pulse’. Non-crop groups, present in both summer and winter, are ‘Bare soil’ and ‘Other’ (comprising pastures, woody vegetation, and crop residues). The foundation of the maps is time-series modelling—specifically, applying the concepts of geostatistics in the temporal domain—to model the variation in land-surface phenology within a growing season. The time-series model is flexible, robust, parsimonious, parallelisable, and able to deal with irregular observations. We combined satellite imagery from the Landsat sensors, as well as, when available, Sentinel-2A and MODIS (with the last two reprojected to the 30-m grid of Landsat). We applied the time-series model pixel-wise across the study region, to three variables derived from satellite imagery gathered for an individual growing season: enhanced vegetation index, and the sub-pixel proportions of bare-ground and non-photosynthetic vegetation. Weekly-averaged predicted phenological metrics then served as explanatory variables in a tiered, tree-based classification model, for the prediction of the groups. The classification model comprised two expert rules and two random forests. Prior to fitting the classification model, geospatial object-based image analysis was used to change the scale of analysis from individual pixels to (approximately) field-based segments. From the perspective of a map-user, in any given growing season we predicted ‘Coarse-grain & Pulse’ correctly in 79% of cases; the values for ‘Cotton’, ‘Cereal’, and ‘Pulse’ were 90%, 84%, and 73%, respectively; ‘Bare soil’ was 72% in summer, and 88% in winter. ‘Other’ was the most accurately mapped group (98% correct in summer, and 99% correct in winter). [ABSTRACT FROM AUTHOR]

Aims: Root shrinkage in drying soil has been shown repeatedly. The aim of this study was to investigate the dynamics of root-soil contact and its relationship with plant water status during soil drying.Methods: The development of root-soil contact of Vicia faba L. during a drying period was studied. Plants (N = 4) were grown in cylinders filled with a sandy soil. Samples were repeatedly scanned with an X-ray CT scanner to visualize root-soil contact. Soil matric potential, transpiration rate, and stomatal conductance were measured daily.Results: Root-soil contact was lower in taproots than in lateral roots at any time. Transpiration rate and stomatal conductance decreased before roots started to shrink. Root-soil contact decreased significantly over the course of the drying period, starting at soil matric potentials below −20 kPa. Root shrinkage did not differ significantly between taproots and laterals.Conclusions: This study confirms previous findings with Lupinus albus roots in that roots shrink after transpiration rate decreases. The dynamics of root shrinkage are governed by soil water availability and transpirational demand. [ABSTRACT FROM AUTHOR]

Abstract This study used a meta-analytic approach to systematically examine changes in greenhouse gas (GHG) emissions intensities (i.e., carbon footprints) between pulse-containing and pulse-free crop rotations in western Canada. A systematic literature review was conducted to identify published literature relevant to the goal of the analysis and meta-analysis was conducted to determine statistically significant differences in GHG emissions between pulse-free and pulse-containing crop rotations. Four pulse-free reference rotations (cereal-cereal [C C]; oilseed-cereal [O C]; oilseed-oilseed [O O]; and cereal-oilseed [C O]) were compared to rotations where the first crop in each two-year sequence was replaced with either dry pea (Pisum sativum L.) or lentil (Lens culinaris M.). Two scenarios were considered. The first scenario investigated the effects of dry peas and lentils when synthetic nitrogen (N) applied to cereal and oilseed crops grown after pulses was not reduced (i.e., no change) (N N). The second scenario (N CR) investigated the effect of dry peas and lentils when synthetic N application rates were reduced to the maximum extent possible (i.e., credit) to maintain subsequent crop yields. Pooled analyses demonstrated that, in general, cereal and oilseed crops grown after a dry pea or lentil crop had similar or reduced GHG emissions compared to those grown after a cereal or oilseed. The GHG emissions from cereal and oilseed crops grown after dry peas and lentils were higher in N N (888–987 kg CO 2 e/ha; 286–598 kg CO 2 e/t) than in N CR (311–978 kg CO 2 e/ha; 116–598 kg CO 2 e/t), suggesting that emissions were reduced to a greater extent when pulse crops offset the N fertilizer requirements of a subsequent crop compared to when they were used to provide N to maximize crop yields. In two-year rotations, the inclusion of pulses reduced GHG emissions compared to all reference rotations in both N N (savings of 475–719 kg CO 2 e/ha over two years [area basis]; 164–496 kg CO 2 e/t over two years [yield basis]) and N CR (savings of 489–1185 kg CO 2 e/ha over two years [area basis]; 335–610 kg CO 2 e/t over two years [yield basis]), mostly as a result of reduced synthetic N requirements of the whole rotation. The results of the analysis are presented by crop for each pulse-free and pulse-containing cropping sequence for each scenario to allow for flexibility in comparing GHG emissions from various rotations. Highlights • Meta-analysis used to examine effect of pulses on GHG emissions from crop systems. • Pulses reduce GHG emissions by reducing synthetic nitrogen requirements of rotations. • Reducing nitrogen application reduces GHGs to greater extent than maximizing yields. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aside from its use for improving soil properties, biochar is increasingly promoted as a direct nutrient provider for sustainable recycling of waste materials. However, incomplete understanding of the interacting factors that determine P release from biochar may limit the efficiency of P recycling from biochar to soil. In particular, the contrasting pH of biochar and soil need to be considered. In this study, soil-free biochar (rice [Oryza sativa L.] husk, 700°C) extractions were performed under different pH (4.6-9.9) and extractant conditions to test how solution composition affects biochar P release. When solution pH was in the range of 7.6 to 8.6 and excess Ca was present in the solution or in biochar, P release was low--only 1 to 7% of the total P was released compared with ~20% under most other conditions. Importantly, we demonstrate that biochar total Ca concentration is closely related to P availability (R² = 0.76) and could be used to predict biochar P release. The results suggest that for maximum P release, low Ca concentrations in biochar and (soil) solution are needed and/or a pH <7.5 at the soil-biochar interface. This novel understanding will help engineer sustainable biochar fertilizers optimized for P provision. [ABSTRACT FROM AUTHOR]

Purpose: Crop straws and animal manure have the potential to ameliorate acidic soils, but their effectiveness and the mechanisms involved are not fully understood. The aim of this study was to evaluate the effectiveness of two crop (maize and soybean) straws, swine manure, and their application rates on acidity changes in acidic red soils (Ferralic Cambisol) differing in initial pH.Materials and methods: Two red soils were collected after 21 years of the (1) no fertilization history (CK soil, pH 5.46) and (2) receiving annual chemical nitrogen (N) fertilization (N soil, pH 4.18). The soils were incubated for 105 days at 25 °C after amending the crop straws or manure at 0, 5, 10, 20, and 40 g kg−1 (w/w), and examined for changes in pH, exchangeable acidity, N mineralization, and speciation in 2 M KCl extract as ammonium (NH4+) and nitrate plus nitrite (NO3− + NO2−).Results and discussion: All three organic materials significantly decreased soil acidity (dominated by aluminum) as the application rate increased. Soybean straw was as effective (sometimes more effective) as swine manure in raising pH in both soils. Soybean straw and swine manure both significantly reduced exchangeable acidity at amendment rate as low as 10 g kg−1 in the highly acidic N soil, but swine manure was more effective in reducing the total acidity especially exchangeable aluminum (e.g., in the N soil from initial 5.79 to 0.50 cmol(+) kg−1 compared to 2.82 and 4.19 cmol(+) kg−1 by soybean straw and maize straw, respectively). Maize straw was less effective than soybean straw in affecting soil pH and the acidity. The exchangeable aluminum decreased at a rate of 4.48 cmol(+) kg−1 per pH unit increase for both straws compared to 6.25 cmol(+) kg−1 per pH unit from the manure. The NO3− + NO2− concentration in soil increased significantly for swine manure amendment, but decreased markedly for straw treatments. The high C/N ratio in the straws led to N immobilization and pH increase.Conclusions: While swine manure continues to be effective for ameliorating soil acidity, crop straw amendment has also shown a good potential to ameliorate the acidity of the red soil. Thus, after harvest, straws should preferably not be removed from the field, but mixed with the soil to decelerate acidification. The long-term effect of straw return on soil acidity management warrants further determination under field conditions. [ABSTRACT FROM AUTHOR]

The Western flower thrips, Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) is an invasive polyphagous pest with an expanding global range that damages a wide variety of crops. F. occidentalis was first reported in China from Yunnan province during 2000, and has rapidly expanded its range since then. It is currently distributed across at least 10 provinces in China and has become a particularly devastating pest, causing substantial damage and economic losses. At present, the still heavy reliance on frequent use of insecticides for control of F. occidentalis, has lead to a series of ecological problems stemming from insecticide resistance, interspecific displacement and non-target effects. Thus, integrated pest management (IPM) programmes, multiple complementary tactics, including preventive tactics, biological controls, and judicious use of insecticides will likely provide a viable IPM strategy for control of F. occidentalis in the near future. This review provides an overview for information gained during the 10+ years since the invasion of F. occidentalis into China, reviews lessons that have been learned enhancing our overall understanding of the biology and ecology of F. occidentalis and discusses IPM practices relative to this widespread invasive insect pest. [ABSTRACT FROM AUTHOR]

Studies on the effect of biochar on nitrate leaching are few. Hence, a laboratory column experiment was conducted using surface (0–20 cm) soil from three different land uses of a Vertisol, to investigate the effect of biochar amendment on leaching behaviour of nitrate and salts. The three selected land uses were: thick forest, agriculture land use with good soil fertility and good crop production history and agriculture land use with low soil fertility and poor crop production history. Biochar was added at 0, 0.5, 1.0 and 2.0% (w/w) to the soil in the upper half of the columns. The treatments were taken with three replications in a factorial completely randomized design. The PVC made columns (40 cm height and 11 cm internal diameter) filled with soil to a bulk density of 1.2 Mg m −3 were leached with deionized water once a week for 15 consecutive weeks. Nitrate in form of KNO 3 was added at the rate equivalent to 100 mg N kg −1 soil (220 kg ha −1 ) at each application in the 1st, 8th and 11th week. The forest soil showed significantly higher salt and NO 3 − -N leaching. Biochar amendment @ 0.5% or at higher level showed a significant reduction in NO 3 − -N leaching in the forest and good agriculture soil, whereas, in the poor agriculture soil, no significant effect was observed even at 2.0% biochar amendment level. With the highest level of biochar amendment (2%, w/w), reduction in NO 3 − -N leaching to the extent of 27% and 23% was observed in the forest and good agriculture soil, respectively. Biochar application significantly reduced salt leaching in the forest soil at 0.5% amendment level, and in the good agriculture soil at 1.0% level. At 2.0% biochar amendment, reduction in salt leaching to the extent of 18% and 16% was observed in the forest and good agriculture soil, respectively. [ABSTRACT FROM AUTHOR]

In this work observations were made related to the chemical and organic fertilization of the soil to the foliar fertilization and to the effects of these types of fertilization upon the number of stolons obtained from a hectare. The productions of the stolons is an important link in the technology of strawberry culture. The strawberry runners are set for a period of one year so during the vegetation period the soil needs to be extremely well supplied with nourishing elements so that the production of the stolons be a good one in what the quantity and the quality are concerned. The obtained results show the fact that both the chemical and organic fertilization as well as the foliar fertilization have positive effects upon the stolon production. [ABSTRACT FROM AUTHOR]

On-farm assessments of Miscanthus × giganteus growth and nutrient export across a wide range of management and environmental conditions are needed to determine and model how this crop performs and where it should be placed on the landscape. Therefore, Miscanthus growth and nutrient concentration and nutrient export at harvest were monitored during 2014 and 2015 at several landscape positions within 22 commercial production fields in central and southwestern Missouri and northeast Arkansas. Miscanthus shoot density and/or yield were best when it was grown: (i) following pasture converted to annual row crops or following row crops, (ii) on soils with colluvium parent material, (iii) on north-facing backslopes or footslopes, (iv) on soils with medium to fine texture, and (v) on well-drained/high runoff/low available water soils. Factors influencing nutrient concentrations varied by nutrient, but all concentrations consistently decreased as stands matured and most were more influenced by weather than were yield or nutrient export. Most effects on nutrient export were similar to effects on yield, but some nutrient exports were also influenced by manure history and weather conditions. Overall, cropping history prior to Miscanthus, landscape position, and soil properties such as parent material, soil textural class, and drainage class had the largest influence on Miscanthus growth and nutrient concentrations and exports. Weather conditions and inferior soils did not strongly influence Miscanthus production, but excessive soil moisture caused by various soil and weather factors often limited its growth. Thus, Miscanthus may be especially well-suited following annual crops on erosion-prone soils that drain well and have slope. These results will assist with the strategic cultivation of Miscanthus on Midwest landscapes. [ABSTRACT FROM AUTHOR]

Purpose: Nanoparticles (NPs) have received increased attention in recent past due to their unique distinct properties. Metal-based NPs are widely used in chemical and allied sector. Most of the research is directed to study the efficiency of NPs in medicine and agriculture. The aim of this review is to explore the possible threats posed by toxicity of various NPs on plants and microbial diversity.Materials and methods: First, major sources of NPs to the environment were analyzed. The effects of metal-based NPs on the microbiota and plants are presented in this review. The results obtained by the authors during last 12 years of research are used.Results and discussion: The exposure of soil to nanoparticles causes a decrease in soil microbial biomass and enzymatic activity, which impacts microbial community composition including yeasts, bacteria, fungi, and biological diversity. The effects of NPs on plants result in various types of abnormalities. Nanoparticles can also pose risks to human health.Conclusions: Increased applications of NPs pose a threat to beneficial microbial communities as well as crops and soils. Thus, it is important to explore whether NPs could compromise crop yield, soil properties, soil organisms, and functional activities of soil. [ABSTRACT FROM AUTHOR]

Nodules harboring nitrogen-fixing rhizobia are a well-known trait of legumes, but nodules also occur in other plant lineages, with rhizobia or the actinomycete Frankia as microsymbiont. It is generally assumed that nodulation evolved independently multiple times. However, molecular-genetic support for this hypothesis is lacking, as the genetic changes underlying nodule evolution remain elusive. We conducted genetic and comparative genomics studies by using Parasponia species (Cannabaceae), the only nonlegumes that can establish nitrogen-fixing nodules with rhizobium. Intergeneric crosses between Parasponia andersonii and its nonnodulating relative Trema tomentosa demonstrated that nodule organogenesis, but not intracellular infection, is a dominant genetic trait. Comparative transcriptomics of P. andersonii and the legume Medicago truncatula revealed utilization of at least 290 orthologous symbiosis genes in nodules. Among these are key genes that, in legumes, are essential for nodulation, including NODULE INCEPTION (NIN) and RHIZOBIUM-DIRECTED POLAR GROWTH (RPG). Comparative analysis of genomes from three Parasponia species and related nonnodulating plant species show evidence of parallel loss in nonnodulating species of putative orthologs of NIN, RPG, and NOD FACTOR PERCEPTION. Parallel loss of these symbiosis genes indicates that these nonnodulating lineages lost the potential to nodulate. Taken together, our results challenge the view that nodulation evolved in parallel and raises the possibility that nodulation originated ~100 Mya in a common ancestor of all nodulating plant species, but was subsequently lost in many descendant lineages. This will have profound implications for translational approaches aimed at engineering nitrogen-fixing nodules in crop plants. [ABSTRACT FROM AUTHOR]

Multi-decadal regional projections of future climate change are introduced into a linear statistical model in order to produce an ensemble of austral mid-summer maximum temperature simulations for southern Africa. The statistical model uses atmospheric thickness fields from a high-resolution (0.5° × 0.5°) reanalysis-forced simulation as predictors in order to develop a linear recalibration model which represents the relationship between atmospheric thickness fields and gridded maximum temperatures across the region. The regional climate model, the conformal-cubic atmospheric model (CCAM), projects maximum temperatures increases over southern Africa to be in the order of 4 °C under low mitigation towards the end of the century or even higher. The statistical recalibration model is able to replicate these increasing temperatures, and the atmospheric thickness-maximum temperature relationship is shown to be stable under future climate conditions. Since dry land crop yields are not explicitly simulated by climate models but are sensitive to maximum temperature extremes, the effect of projected maximum temperature change on dry land crops of the Witbank maize production district of South Africa, assuming other factors remain unchanged, is then assessed by employing a statistical approach similar to the one used for maximum temperature projections. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) balance is an important component of the terrestrial carbon (C) budget. However, effect of cropland management changes on SOC dynamics has not been recently assessed in the tropics. Studies were compiled in the tropics where SOC stocks were measured in the topsoil (0–20 or 0–30 cm depth) after the adoption of management practices that are expected to enhance SOC stocks, including tillage reduction, crop rotation, exogenous organic amendments, restitution of crop residues, mineral amendments, and combinations of these practices. Random forest regression was used to identify the determinants of SOC accumulation rates (ΔSOC) depending on the climate, soil characteristics and changes in management practices. 214 cases were identified in 48 studies in 13 different countries. The average ΔSOC was 0.41 ± 0.03 Mg C ha −1  yr −1 (significantly greater than zero), for an average experiment duration of 13.6 ± 0.6 years. Although a large part of the variability remained unexplained due to methodological bias in the studies or a lack of relevant predictors. The strongest predictors of ΔSOC were C inputs, duration of the experiments, and the management practices, whereas neither soil characteristics (soil type, clay content, and initial SOC stock) nor climate variables (mean annual temperature and rainfall, aridity index) affected ΔSOC. The SOC accumulation rates increased linearly with C inputs, and the conversion rate of C inputs to SOC was 8.2 ± 0.8%. Given the competing uses of organic matter on many tropical farms, the benefits of using changes in management practices for climate change mitigation might be overrated. As ΔSOC decreased with the duration of the experiments, ΔSOC would probably be smaller if a period of 20 years were considered, as recommended by the IPCC guidelines. The management practice with the greatest ΔSOC was diversified crop rotation. Cropping systems where diverse practices were combined resulted in higher ΔSOC than individual practices such as reduced tillage and mineral fertilization on their own. The adoption of improved management practices that increase C inputs is still relevant for meeting the challenges of food security and adaptation to climate change. [ABSTRACT FROM AUTHOR]

Currently there is a shift from grassland based forage production towards maize systems in the Low Countries of north-west Europe. Breaking-up grassland and turning it into arable fields is associated with high nitrate leaching. Crop models can help to identify cropping strategies to reduce nitrate leaching by performing long-term simulation experiments. This study aimed: (i) to evaluate the crop model APSIM against field trial data, in particular nitrogen (N) balance components N-uptake, leaching and soil mineral N, and (ii) conduct a simulation experiment for assessing suitable management practices over a long period using historical records (1980–2015). Evaluation data consisted of two rotation types over two years (maize-maize and barley-mustard-maize) with two nitrogen (N) fertilizer schemes (zero and standard fertilizer: 160 for maize and 120 kg N/ha for barley) after the break-up of grassland. Experiments were carried out at three different sites with contrasting soils in north-west Germany. Results showed that APSIM was capable of simulating the crop rotations and fertilizer applications satisfactorily: Total biomass (n = 21) was reproduced with a root mean square error (RMSE) of 1139 kg/ha against an observed mean of 9915 kg/ha across crops. Total N uptake (n = 21) was simulated well with a RMSE of 22 kg/ha (against observed mean 144 kg/ha). Simulated soil mineral N in the top 0–30 cm (n = 253) and 0–90 cm (n = 33) showed a high index of agreement (IA) of 0.90 and 0.86, respectively. Comparisons observed vs simulated over time confirmed that APSIM was able to capture the N dynamics in the soil. Extractable soil water was also modelled well. Leached nitrate (n = 16) was simulated with a RMSE of 50 kg N/ha, whereby APSIM captured the high nitrate losses of up to 240 kg N/ha/winter period caused by the high mineralization and the fertilization. In the long-term the simulation experiment showed that fertilization of maize did not result in additional biomass, but in higher leaching losses. Mustard was effective in reducing nitrate leaching but is difficult to implement in practice. Finally, the study demonstrated that crop modelling complements conventional analysis very well in identifying environmentally sound and profitable management practices for complex situations in soil-crop systems such as grassland break-up. [ABSTRACT FROM AUTHOR]