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Soil tillage is widely acknowledged to affect soil characteristics and agricultural productivity. This research investigates the short‐term effects of various tillage methods on soil physical properties and crop yields at a Central German field site with a dry climate (mean temperature 9.5°C; annual precipitation 470 mm). Three tillage approaches were evaluated: conventional plough tillage (25 cm depth), cultivator tillage (18 cm depth), and double‐layer plough tillage (15 and 30 cm depth). We assessed soil physical properties through standard laboratory analyses, compression tests, soil pore structure via X‐ray computed tomography (X‐ray CT) and crop yields over 3 years. The results indicate that cultivator tillage approach increased soil bulk density relative to conventional tillage, especially in the second year, though this effect diminished over time. Double‐layer plough tillage emerged as a viable short‐term alternative to conventional tillage, achieving comparable soil bulk density. Saturated hydraulic conductivity values were generally higher for soils under conventional tillage or double‐layer plough tillage than for cultivator tillage, highlighting their soil loosening effect. Classical soil analysis methods combined with X‐ray computed tomography provided valuable insights into tillage induced changes to soil structure. Cultivator tillage resulted in a distinct pore structure with reduced macroporosity and pore connectivity. Despite notable soil property variations, crop yields remained consistent across the tillage methods. Overall, double‐layer plough tillage presents a sustainable option, moderately improving soil physical properties while maintaining crop yields. This study highlights the need to assess the short‐term effects of tillage on soils and contributes to the broader dialogue on optimizing tillage strategies for effective soil management and crop production. [ABSTRACT FROM AUTHOR]

Microbial necromass is a crucial contributor to the formation of soil aggregates and serves as a key source of stable soil organic carbon (SOC). However, how tillage practices regulate microbial necromass accumulation within aggregate fractions at different soil depths remains unclear. Thus, a 20‐year field experiment was carried out to identify how microbial necromass carbon (MC) is distributed in aggregates and its contribution to SOC under no‐till (NT) and plow tillage (PT) in a rice‐wheat rotation system. The results showed that NT significantly increased bacterial and fungal necromass carbon (C) concentrations in both macro‐ and micro‐aggregates (>0.25 and <0.25 mm), and enhanced the contribution of MC to SOC compared with PT at 0–5 cm topsoil depth. However, NT decreased SOC concentration in micro‐aggregates by 12.4% mainly attributed to lower bacterial and fungal necromass C in micro‐aggregates by 21.6% and 27.6% compared with PT at 5–15 cm subsoil depth. There was no significant difference for SOC mineralization per unit SOC concentration between NT and PT, which can be attributed to the equilibrium between microbial necromass C and labile C (e.g., dissolved organic C). Random forest and partial least squares path model demonstrated that soil total nitrogen, available NH4+, and NO3− positively regulated β‐glucosidase activity, and thus affected MC and SOC concentration. NT decreased soil nitrogen concentration and β‐glucosidase activity in micro‐aggregates, and thus lowered MC formation at 5–15 cm depth. Our findings highlights that NT reduced subsoil organic carbon due to decreased microbial necromass in micro‐aggregates. [ABSTRACT FROM AUTHOR]

A field experiment was conducted in northeast China to examine the response of nitrogen cycling enzymes, that is, protease, N‐acetyl‐β‐D‐glucosaminidase (NAG), amidase, urease, and peptidase, as well soil organic nitrogen (SON) fractions and their relationships to RT (no maize residue application), NT (no tillage with maize residues placed on the surface), TT (plow maize residues into the soil at 0–35 cm depth in the first year, 0–20 cm in the second year, and 0–15 cm in the third year), and PT (plow maize residues into soil at 0–35 cm depth). The results have shown that NT significantly enhanced the activities of protease and NAG at 0–10 cm soil depth in comparison with other treatments. NT and TT significantly enhanced the activities of protease compared to RT and PT at 10–20 cm soil depth. TT significantly enhanced the activities of NAG in comparison with RT at 10–20 cm soil depth. TT and PT significantly enhanced the activities of NAG and peptidase compared to RT and NT at 20–35 cm soil depth. PT significantly increased the activities of protease in comparison with RT at 20–35 cm soil depth. NT, TT, and PT significantly enhanced the activities of peptidase compared to RT at 10–20 cm soil depth. NT significantly increased the concentration of hydrolyzable NH4+‐N$$ {\mathrm{NH}}_4^{+}\hbox{-} \mathrm{N} $$ in comparison with other treatments at 0–10 cm soil depth. PT significantly enhanced the concentration of hydrolyzable NH4+‐N$$ {\mathrm{NH}}_4^{+}\hbox{-} \mathrm{N} $$ and amino acid N compared to other treatments at 20–35 cm soil depth. Redundancy analysis showed that protease played a crucial role in the cycling of SON under RT and NT, whereas peptidase and NAG played a significant role in the cycling of SON under TT and PT, respectively. This study provided a comprehensive understanding of crop residue return methods for regulating soil N cycling. [ABSTRACT FROM AUTHOR]

Conservation tillage (CT) is a ploughless tillage with a reduced number of operations, and its positive effect on soil functions and health is widely known. Multivariate analyses are required to choose indicators that adequately characterize the changes in soil health. However, there is little research on the comprehensive analysis of the full spectrum of soil physical, chemical and biological properties. Therefore, we examined 21 soil parameters in a long-term CT experiment conducted in Hungary. Four pairs of similarly sized CT and conventional ploughing tillage (PT) plots were set up in 2003 on Luvisols. The soil samples were collected after 17 years. The total organic carbon (TOC) increased significantly in the 0-15 cm layer at CT sites compared to those in PT, indicating a total increase of 5.22 tha-1 TOC stock. In addition, the increasing biological activity and improved soil structure were the most important processes at the CT sites. Furthermore, more complex humic substances with higher molecular weights are characteristic of water-extractable organic matter (WEOM) as a result of CT. The potentially available nitrogen, phosphorus and potassium were also measured with a relatively high response ratio. Slowly changing parameters, such as cation exchange capacity and base saturation, are important soil physical and chemical parameters, but are not good indicators of the impact of tillage practices. Based on principal component analysis, we suggest the use of water-extractable organic C, amino-nitrogen, water-stable aggregates, available P and K and photometric analysis of WEOM to identify the soil improving processes. [ABSTRACT FROM AUTHOR]

Efficient management of fertilizer phosphorus (P) is crucial for enhanced resilience of agro‐ecosystems. We assessed five rates (0, 5, 10, 15, and 20 kg P ha−1) of starter P fertilizer on silage corn (Zea mays L) yield in high‐P manured soils at eight sites in 2020 and 2021 in the Fraser Valley, Canada, monitoring soil phosphate concentrations using anion exchange membranes (AEM‐P). At the V3 and V6 (3‐ and 6‐leaf) stages, corn dry matter (DM) weight response to starter P was not significant, except at one site where the critical rate was 5 kg P ha−1. At maturity, corn DM yields were in the optimum provincial range (20–25 Mg ha−1), with the exception of two sites, one with low initial soil P concentrations and the other with waterlogged soils. These results indicate that during the growing season, phosphate supply from manure application alone was sufficient for silage corn growth. Root length and diameter were not affected by starter fertilizer, while root surface area, volume, and root DM weight decreased with increasing starter fertilizer at the V3 stage in 2020. In addition, AEM‐P increased with starter P only during the first week after application. We conclude that starter fertilizer P, at any application rate, in high‐P manured soils does not improve silage corn yield; farmers applying manure at plowing in soils with high P concentrations can reduce or eliminate starter fertilizer P without impacting silage corn yields, decreasing reliance on off‐farm P inputs, and reducing potential P loss to the environment. Core Ideas: Response of silage corn to starter fertilizer phosphorus (P) in high‐P manured soils was not consistent across eight sites.Critical starter fertilizer P rate was maximum 5 kg P ha−1 in one responsive site.Mature silage corn yield was not increased by starter fertilizer P across sites.Anion Exchange Membrane‐P mimicked starter P rates only during the first week.Mineral starter P has no benefit in fields with high soil test P receiving manure. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) transformation is susceptible to tillage practices. Conservation tillage is known to optimize soil structure, improve microbial community diversity and increase SOC storage. However, how soil aggregate distribution and microbial community structure and function within aggregates affect SOC transformation under long‐term conservation tillage remains unclear. In this study, SOC mineralization dynamics were studied in situ and under laboratory conditions to examine the mechanisms by which C functional genes within soil aggregates of different sizes (i.e., mega‐, macro‐, and micro‐aggregates) influence SOC mineralization under long‐term tillage (i.e., zero, chisel, and plow tillage) in a dryland. The results indicated that in the winter wheat and summer maize rotation cropping system, SOC‐derived CO2‐C emissions were 143.99 and 133.29 g CO2‐C m−2 h−1 lower under chisel and zero tillage than that under plow tillage, respectively. Moreover, after 180 days of laboratory incubation, SOC mineralization in micro‐ and macro‐aggregates was 1.98 and 1.63 mg CO2‐C g−1 d−1 higher than that in mega‐aggregates, respectively. The aggregate‐associated differential modules of bacterial co‐occurring networks may be directly governed by bacterial community diversity and composition, which might play critical roles in driving SOC mineralization in response to different tillage intensities. Moreover, aggregate‐associated functional genes involved in labile and recalcitrant C compositions, which were determined by shotgun metagenomic sequencing, were associated with SOC mineralization and were significantly affected by the legacy effect of tillage intensity and aggregate size. Particularly, partial least squares path modeling revealed that genes involved in simple sugar metabolism exerted significantly positive effects on SOC mineralization, except for the effects of tillage intensity and aggregate size. Overall, this study showed that decreased abundances of labile C decomposition‐related functional genes within aggregates and community composition changes, as elucidated by the differences in bacterial network modules, under conservation tillage inhibit SOC mineralization. These findings may help in the development of adaptive soil tillage strategies for reducing carbon emissions in agroecosystems. [ABSTRACT FROM AUTHOR]

Ratoon rice is resource efficient to produce economically sound and environmentally sustainable rice production. However, there is no more information on the relative impact of soil tillage practices on soil physical and chemical properties, microbial biomass, and enzymatic activity, and grain yield in a rice–ratoon rice cropping system remains to be tested. Systematic study of soil under ratooning rice model is a problem to be solved in the development of ratooning rice model. This study primarily investigated the long‐term (from 2014 to 2020) changes in soil bulk density (BD), soil organic carbon (SOC) concentration, total nitrogen (TN) concentration, microbial biomass, β‐glucosidase activity (BG), urease activity (UR), and yield under four treatments: no‐tillage (NT), no plowing tillage + rotatory tillage (RT), plowing tillage in winter + rotatory tillage (PTW), and plowing tillage in spring + rotatory tillage (PTS). NT increased BD by 9.65%–12.97%, and RT increased the 20–40 cm soil layer BD by 8.80% in 2020, compared with the baseline initial value (in 2014). Plowing tillage (PT) time had no significant effect on BD. All tillage methods decreased the SOC concentration in the 0–20 cm soil layer, and only RT increased the TN concentration. PT was the only treatment that increased the SOC and TN concentrations in the 20–40 cm soil layer. Both the main‐season rice yield and the ratoon season rice yield ranked PTW > PTS > NT > RT, in which the main‐season rice yield increased by 28.15% and the ratoon season rice yield increased by 25.19% in PTW. Overall, the PTW treatment had the highest microbial biomass, enzyme activity, and grain yield compared with the other tillage methods. In conclusion, plowing tillage in winter + rotatory tillage is a more suitable tillage method under the mode of ratooning rice. [ABSTRACT FROM AUTHOR]

Retention of crop biomass is widely recommended to improve soil organic carbon (SOC). However, the magnitude of contribution of above‐ground residues and below‐ground roots from C3 and C4 crops to SOC is unclear.Data from a 10‐year field experiment and a 60‐day laboratory incubation were synthesized to identify the respective contribution of C3 (e.g., wheat) and C4 (e.g., maize) residues and roots to SOC, as well as its underlying mechanisms under no‐till (NT) using 13C labelling trace in wheat‐maize rotations.The field experiment showed that residue retention significantly increased SOC accumulation, and SOC derived from wheat was 126.0% higher than that from maize. Conversion to NT promoted SOC derived from wheat and thus accumulated 17.6% higher SOC stock compared with plough tillage (PT) under residue returning at 0–20 cm soil depth (p < 0.05). The data from laboratory incubation revealed the mechanisms that lower priming effects at 0–10 cm depth decreased total mineralization by 91.8% after inputs of wheat residues and roots compared with that of maize residues and roots, especially under NT compared with PT. Priming effects were negatively correlated with enzyme activities associated with the C recycle, SOC, and total nitrogen (TN) contents (p < 0.01). NT increased enzyme activities, SOC, and TN contents and thus reduced priming effects and improved residual carbon.Synthesis and applications. These results suggested that wheat may contribute more to SOC accumulation than maize, and carbon increment efficiency in farmland could be enhanced by considering the crucial roles of C3 crops in SOC accumulation. NT practice sustains the benefits of C3 crops to SOC sequestration in the upper soil depths. [ABSTRACT FROM AUTHOR]

Rotation of grass ley with periods of annual crop production can be a means to increased farming system productivity, sustainability, and profitability. This research review offers interpretations of rotation research results for future African agriculture. Some rotation studies were with naturally generated and severely over‐grazed fallows consisting primarily of annual plant species but other studies were with planted and well‐managed perennial grass ley. Generally, the rotations increased annual crop yields with soil improvement. System benefits were similar or greater for ley compared with fallow with generally higher fodder yields with ley. Surface crusting of sandy soil in the Sahel is a major concern that may be worsened by fallow due to the deposition of clay and silt particles. Ley and fallow were terminated in all studies with inversion plow tillage with more tillage for subsequent crops while the rotation benefits may be greater with less tillage. Most studies did not have fertilizer use but annual crop yield response to fertilizer was greatly increased following ley in one study and with no system by fertilizer interaction effect in three studies. The profitability of ley rotations will vary with fodder demand which is rapidly increasing, especially near urban areas. Strip cropping, for example, alternate ley with annual crop strips of 5–20 m width and rotation cycles of 6–10 yr, may often be optimal for erosion control and sediment trapping, protection from uncontrolled grazing, and nearby supply of vegetative planting material for ley re‐establishment. Rotation management can be improved through experiential learning and experimentation. [ABSTRACT FROM AUTHOR]

In residue return farming, ploughing and zero‐tillage (syn. no‐till or minimal tillage) rotation may regulate soil physicochemical properties and help reduce erosion and improve productivity; however, the soil physicochemical properties and soil productivity response to ploughing and zero‐tillage rotation remain unclear. This present study evaluates the effects of ploughing and zero‐tillage rotation on soil physicochemical properties and crop productivity based on an 11‐year experiment (2007–2018) on a typical erodible area of the Loess Plateau. Three tillage methods were included: ploughing and zero‐tillage rotation with 1‐year ploughing tillage and 1‐year zero tillage (PZT), ploughing tillage with moldboard plough (PT), and zero tillage (ZT); crop residue was returned in all treatments. After 11 years' we tested, the PZT method showed significantly lower soil water storage in key maize growth stages, less soil organic carbon (SOC) and total nitrogen (N) storage (0–10 cm), and poorer soil structure stability (0–10 cm) when compared with ZT. However, PZT showed significantly higher SOC and N storage (4.5%, 6.5% and 16.3%, 8.6%, respectively) in the 10–20 cm and 20–40 cm soil layers, compared with ZT. In addition, when compared with ZT and PT, PZT significantly decreased soil penetration resistance in 0–10 cm, 10–20 cm, and 20–40 cm soil depths and significantly increased yield of maize by 10.9 and 7.8%, respectively, and of wheat by 11.2 and 9.8%, respectively. This study highlights that combining ploughing and zero tillage with return of crop residue changed soil physicochemical properties and can provide an effective method to improve soil productivity in an erodible field. [ABSTRACT FROM AUTHOR]

Reduced tillage systems have been argued to provide several potential benefits to soil, environment and to farm incomes. In England, while many farms have partially adopted such practices, a large proportion of arable farmers do not undertake reduced tillage in any form. This paper analyses the rationale for and uptake of different cultivation techniques, including analysis of the barriers to adoption of reduced tillage, aiming to benefit policymakers and researchers and increase the spread of smart agricultural practices. Based on a postal questionnaire, we estimated that 47.6% of English arable land is cultivated using minimum‐tillage and 7% under no‐tillage. As farm size increased, so did the probability of reduced tillage uptake. Furthermore, farms growing combinable crops were more likely to utilize reduced tillage approaches than other farm types. Soil type, weed control and weather conditions were noted as the main drivers for 'strategic' and 'rotational' ploughing, constraining continuous reduced tillage use. To effect greater reduced tillage uptake, greater communication between researchers and farmers is needed to facilitate the implementation of sustainable soil management solutions, supported by current legislation permitting responsible herbicide use in arable production. Financial support to access reduced tillage machinery may also be required for farmers operating smaller holdings. Adopting reduced tillage is a continuous learning process requiring ongoing training and information gathering; supporting a network of reduced tillage 'farmer champions' would facilitate practical knowledge exchange, allow farmers to observe soil improvements, understand transition phase barriers and ultimately encourage increased reduced tillage uptake. [ABSTRACT FROM AUTHOR]

Tillage is an important agricultural practice, influencing the physical, chemical and biological soil characteristics. In this paper the influence of various tillage systems combined with or without a cover crop under different nitrogen fertilization levels on silage maize yield and soil fertility was investigated. Based on a field trial in Bottelare (Belgium), during the period 2007–2015, it was concluded that for each tillage system higher nitrogen levels resulted in a higher yield. In addition, the highest yield was achieved for the conventional tillage system, the yield gain for mouldboard ploughing varied between 13% (2015) and 71% (2012) compared to zero tillage. In case reduced tillage was adopted, the yield loss compared to mouldboard ploughing varied between 6% (2013 and 2015) and 24% (2012). Furthermore, it seemed that the accumulated temperature during the growing season and rainfall around flowering were decisive in determining maize yield. Additionally, rainfall in the period 60 days post sowing was significantly negatively correlated with the yield from the zero tillage plots, whereas in case tillage was adopted no correlations with rainfall 60 days post sowing were detected. Concerning the soil organic carbon content and the amount of earthworms, no clear trends could be observed. Zero tillage resulted in high weed pressure and caused soil compaction. So, in this trial, under humid conditions, the less labor intensive zero tillage system did not result in competitive maize yields. In conclusion, reduced tillage methods offer opportunities for maize cultivation in Belgium. This method of farming resulted in a lower yield, however, the difference with mouldboard ploughing was not significant. Therefore, adopting a reduced tillage system can be seen as a valid alternative for ploughing as this tillage system ensures a sustainable environment. [ABSTRACT FROM AUTHOR]

Grassland renovation can be done physically by ploughing or chemically using herbicides, but information on influences of grassland renovation on soil structure is scarce. Our objective was to compare physically and chemically renovated grasslands and to quantify temporal variations of soil organic carbon (SOC) stocks, water‐stable aggregates and SOC stored in different aggregate fractions. Soil samples were taken on a sandy soil before (T0), 6 days (T6_days), 2 (T2_mo), 7 (T7_mo) and 12 months (T12_mo) after grassland renovation and in permanent grassland. Neither grassland renovation practice led to SOC losses in 0–10 cm after 12 months. The physical renovation led to an increase in microaggregates (53–250 μm) in the surface soil between T0 and T6_days and to highest microaggregate concentrations in T2_mo and T7_mo. Therefore, ploughing seems to have direct negative effects on macroaggregates (10 mm–250 μm) followed by indirect longer‐lasting negative effects which were nullified after 1 year. Chemical renovation resulted in no different aggregate distribution than permanent grassland. Strong temporal variations in aggregate distribution were found especially for large macroaggregates with lowest concentrations in T6_days and 6.7‐ to 10.2‐fold higher concentrations in T2_mo. A linear regression suggested that the soil gravimetric moisture content might have caused this observation. [ABSTRACT FROM AUTHOR]

Annual grass weeds such as Apera spica-venti and Vulpia myuros are promoted in non-inversion tillage systems and winter cereal-based crop rotations. Unsatisfactory weed control in these conditions is often associated with a poor understanding of the emergence pattern of these weed species. The aim of this study was to investigate, understand and model the cumulative emergence patterns of A. spica-venti, V. myuros and Poa annua in winter cereals grown in three primary tillage regimes: (i) mouldboard ploughing, (ii) pre-sowing tine cultivation to 8-10 cm soil depth and (iii) direct drilling. Direct drilling delayed the cumulative emergence of A. spica-venti and V. myuros (counted together) in contrast with ploughing, while the emergence pattern of P. annua was unaffected by the type of tillage system. The total density of emerged weed seedlings varied between the tillage systems and years with a higher total emergence seen under direct drilling, followed by pre-sowing tine cultivation and ploughing. The emergence patterns of all species were differently influenced by the tillage systems, suggesting that under direct drilling, in which these species occur simultaneously, management interventions should first and foremost consider that A. spica-venti and V. myuros emerge over a longer period to avoid control failures. [ABSTRACT FROM AUTHOR]

This study investigated the effects of plowing on the vertical migration of radioactive Cs, air dose rate, and soil physicochemical properties in temperate pastures after radioactive pollution from the 2011 Fukushima Daiichi Nuclear Power Plant accident. The study area consisted of three plowed pastures (decontamination treatment) and one non-plowed pasture at the Kawatabi Field Science Center of Tohoku University, 150 km north of the nuclear power plant. Air dose rate was measured at the top, middle, and bottom of the slope of each pasture. A profile pit (1 m × 3 m) was excavated at each location. Plants, litter and soil samples (from 0 cm to the parent material layer) were collected from all locations during the summer of 2014 to determine the radioactive Cs concentration. Particle size distribution and bulk density of the soil samples were also measured. Air dose rate was higher on the non-plowed (0.090-0.097 μSv h−1) than that on the plowed (0.047-0.073 μSv h−1) pastures. Radioactive Cs concentration was high in the litter layer (207-475 Bq kg−1 dry matter [DM]) and the topsoil (0-2.5 cm depth; 412-1139 Bq kg−1 DM) in the non-plowed pasture. In the plowed pastures, these variables did not differ within the 0-40 cm layer. In the non-plowed pasture, there were high sand (37.0%) and low silt (61.4%) proportions at 10-20 cm and the topsoil had a high bulk density. In the plowed pastures, these variables were similar within the 0-20 cm layer. The bulk density ( P < 0.001) and organic matter content ( P < 0.05) had significant relationships with the concentration of radioactive Cs. These results indicate that plowing reduced air dose rate. [ABSTRACT FROM AUTHOR]

The frequency and distribution of plowzone artifacts are compared with the timing and duration of two plow modes at two study locales on the Delmarva Peninsula, United States. Our results indicate that historic moldboard plowing created a maximum plowzone of ca. 0.30 m, in which artifacts were retained over time. Later, soil-conservative chisel plowing mixed the top ca. 0.15 m of soil, creating a shallow, minimum plowzone. With time and repeated plowing, our data suggest that the number of artifacts at the surface diminished via a combination of vertical mixing and/or degradation, physical and chemical weathering, and avocational collecting. When moldboard plowing is reapplied to fields after decades of chisel plowing, the historic maximum plowzone is inverted and the surface is re-saturated with artifacts. This inverted maximum plowzone retains an inherent pattern of artifact transport from moldboard plowing, which supports other studies that have measured such displacements over time. Our results suggest that the frequency of artifacts observed at the surface of agricultural fields, or lack thereof, is a likely outcome of natural and mechanical processes, and removal within the minimum plowzone. This inevitable depletion of artifacts may have negative repercussions for many research designs that systematically sample the plowzone. [ABSTRACT FROM AUTHOR]

Archaeological remains are very often buried under uneven soil of agricultural fields crossed by rather parallel furrows and ridges. Consequently, ploughing in a magnetic survey might produce a repetitive, quite regular, linear noise in the data, which could impede optimal recovery of the archaeological magnetic anomalies; depending on the acquisition line orientation, this noise may show as an oblique, vertical or horizontal pattern in the magnetic maps. Several studies have tested and verified methods for oblique ploughing minimization, but, to our knowledge, no procedures regarding the vertical and horizontal types of noise have been published. The present research proposes a procedure to filter each type of ploughing effect through an algorithm working in the wavenumber domain. The procedure produces images with a considerable reduction of the noise in any direction, resulting in enhanced visibility and readability of the archaeological anomalies. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Subsoils play an important role within the global C cycle, since they have high soil organic carbon (SOC) storage capacity due to generally low SOC concentrations. However, measures for enhancing SOC storage commonly focus on topsoils. This study assessed the long-term storage and stability of SOC in topsoils buried in arable subsoils by deep ploughing, a globally applied method for breaking up hard pans and improving soil structure to optimize crop growing conditions. One effect of deep ploughing is translocation of SOC formed near the surface into the subsoil, with concomitant mixing of SOC-poor subsoil material into the 'new' topsoil. Deep-ploughed croplands represent unique long-term in situ incubations of SOC-rich material in subsoils. In this study, we sampled five loamy and five sandy soils that were ploughed to 55-90 cm depth 35-50 years ago. Adjacent, similarly managed but conventionally ploughed subplots were sampled as reference. The deep-ploughed soils contained on average 42 ± 13% more SOC than the reference subplots. On average, 45 years after deep ploughing, the 'new' topsoil still contained 15% less SOC than the reference topsoil, indicating long-term SOC accumulation potential in the topsoil. In vitro incubation experiments on the buried sandy soils revealed 63 ± 6% lower potential SOC mineralisation rates and also 67 ± 2% lower SOC mineralisation per unit SOC in the buried topsoils than in the reference topsoils. Wider C/N ratio in the buried sandy topsoils than in the reference topsoils indicates that deep ploughing preserved SOC. The SOC mineralisation per unit SOC in the buried loamy topsoils was not significantly different from that in the reference topsoils. However, 56 ± 4% of the initial SOC was preserved in the buried topsoils. It can be concluded that deep ploughing contributes to SOC sequestration by enlarging the storage space for SOC-rich material. [ABSTRACT FROM AUTHOR]

The adoption of no-tillage systems in semi-arid cereal fields in northern Europe has resulted in difficulties in controlling Bromus diandrus. However, in some fields, lower densities are observed in continuous long-term no-tillage management than in other reduced tillage systems. A cumulative effect on the seedbank could promote changes in the period of seedling emergence and in population demography. This study evaluated the effect of long-term mouldboard plough (MbP), chisel plough (ChP), subsoiler ( SS) and no-tillage ( NT) on the population dynamics of B. diandrus. The work was carried out in a barley ( Hordeum vulgare)-wheat ( Triticum aestivum)-barley rotation during three seasons where these soil management systems had been applied for the last 22 years. Cumulative emergence ( CE) and densities of B. diandrus followed a gradient of ChP > SS > NT > MbP. This cumulative effect over time resulted in significant differences in population demography. A previous hydrothermal emergence model developed for this species estimated the percentage of emergence prior to the date of sowing to be: 71%, 92% and 53% for the seasons 2008-2009, 2009-2010 and 2010-2011 respectively. Furthermore, the reduction in CE observed was on average 53% in SS, 92% in NT and 98% in MbP in comparison with that recorded in ChP. The long-term effect of different tillage systems tended to cause changes to soil characteristics (photo-inhibition of germination, soil temperature, water availability) affecting B. diandrus demography, reaching equilibrium in weed densities over years, which were significantly lower in MbP and NT than in ChP or SS. [ABSTRACT FROM AUTHOR]

Without herbicides, the control of Elymus repens relies on intensive tillage, often in the form of repeated post-harvest stubble cultivations followed by ploughing. This is costly and time-consuming and also increases the risk of nitrogen leaching. Our aim was to quantify the controlling effect on E. repens of single and repeated cultivation and differing time of cultivation in relation to spring cereal harvest. A 2-year experiment was conducted at two sites in the south and east of Sweden in 2011-2012 and 2012-2013. We compared no, single and repeated tine cultivation followed by mouldboard ploughing; the single cultivation was performed directly after harvest or 20 days after harvest; when repeated, the first cultivation was performed immediately or 5 days after harvest, followed by a second cultivation 20 days after harvest. Tine cultivation in combination with mouldboard ploughing resulted in 50-70% lower rhizome biomass, and increased average subsequent cereal yields by 0-130% compared with ploughing alone. Large E. repens populations appeared to be more efficiently reduced by tine cultivation than smaller populations. A single tine cultivation 20 days after harvest tended to result in a higher E. repens shoot density and more rhizome biomass in the subsequent year than tine cultivation directly after harvest. Additional cultivation 20 days after harvest did not improve control of E. repens or the subsequent cereal grain yield, compared with a single cultivation conducted directly after harvest. In conclusion, preventing the growth of E. repens during the early part of the post-harvest autumn period was more important than starving rhizomes with repeated cultivations. [ABSTRACT FROM AUTHOR]

Many process-oriented erosion prediction models reproduce rill erosion as affected by site-specific parameters, as for example, rill erodibility, and thus, their practical application requires the measurement of these parameters or their estimate. The aim of this paper was establishing a method for indirectly measuring field rill erodibility. A simple mathematical approach based on a known soil detachment equation and accounting for the rill erosion dynamic process is applied. Field measurements carried out for seven natural rainfall events occurring at the plots of the Sparacia experimental station, southern Italy, are used for indirectly measuring the rill erodibility of the investigated soil. This method needs only the knowledge of the geometric characteristics of the rills at the end of the erosion event and the event duration. The method was also tested by using the Water Erosion Prediction Project database, and this analysis showed that a reliable value of rill erodibility can be obtained by the proposed Equation . The proposed method has the following advantages: (i) to be applicable at field scale, being more realistic than the laboratory scale because the soil structure is not destroyed, and (ii) to avoid the disadvantages of field experiments such as the cumbersome experimental set-up and the large volume of water inflow needed. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Nitrogen (N) loss from agriculture impacts ecosystems worldwide. One strategy to mitigate these losses, ecologically based nutrient management (ENM), seeks to recouple carbon (C) and N cycles to reduce environmental losses and supply N to cash crops. However, our capacity to apply ENM is limited by a lack of field-based high-resolution data on N dynamics in actual production contexts. We used data from a five-year study of organic cropping systems to investigate soil inorganic N (SIN) variability and nitrate (NO3-) leaching in ENM. Four production systems initiated in 2007 and 2008 in central Pennsylvania varied in crop rotation, timing and intensity of tillage, inclusion of fallow periods, and N inputs. Extractable SIN was measured fortnightly from March through November throughout the experiment, and NO3-N concentration below the rooting zone was sampled with lysimeters during the first year of the 2008 start. We used recursive partitioning models to assess the importance of management and environmental factors to SIN variability and NO3- leaching and identify interactions between influential variables. Air temperature and tillage were the most important drivers of SIN across systems. The highest SIN concentrations occurred when the average air temperature three weeks prior to measurement was above 218C. Above this temperature and within 109 days of moldboard plowing, average SIN concentrations were 22.1 mg N/kg soil; 109 days or more past plowing average SIN dropped to 7.7 mg N/kg soil. Other drivers of SIN dynamics were N available from manure and cover crops. Highest average leachate NO3-N concentrations (15.2 ppm) occurred in fall and winter when SIN was above 4.9 mg/kg six weeks prior to leachate collection. Late season tillage operations leading to elevated SIN and leachate NO3-N concentrations were a strategy to reduce weeds while meeting consumer demand for organic products. Thus, while tillage that incorporates organic N inputs preceding cash crops can promote synchrony of N mineralization and crop demand, late or post-season tillage promotes NO3- leaching by stimulating SIN pulses that are asynchronous with plant uptake. [ABSTRACT FROM AUTHOR]

Knowledge of the effects of agricultural practices on weed seedbank dynamics is essential for predicting future problems in weed management. This article reports data relative to weed seedbank structure after 18 years of continuous application of conventional tillage ( CT, based on mouldboard ploughing) or no tillage ( NT) within three crop sequences (continuous wheat, WW; wheat-faba bean, WF; and wheat-berseem clover, WB). Tillage system did not affect the size of the total weed seedbank, but altered both its composition and the distribution of seeds within the soil profile. In particular, the adoption of CT favoured some species (mainly Polygonum aviculare), whereas the continuous use of NT favoured other species ( Papaver rhoeas, Phalaris spp. and Lactuca serriola). The effects of tillage system on weed seedbank size and composition were less pronounced in the WB cropping system than in either the WW or WF. Compared with WF and WB, WW resulted in an increase in total weed seedbank density (about 16 000 seedlings m−2 in WW, compared with 10 000 and 6000 seedlings m−2 in WF and WB, respectively) and a reduction in weed diversity, with a strong increase in some species (e.g. Polygonum aviculare). Our results for the effect of NT application on weed seedbank size and composition suggest that farmers should only apply such a conservative technique within an appropriate crop sequence. [ABSTRACT FROM AUTHOR]

Ridge and furrow planting (RFP) is a rainwater harvesting system that improves the yield and water use efficiency (WUE) of alfalfa (Medicago sativa L.) and other crops. Field experiments were performed to study the effects of RFP under non- or single-irrigated (NI and SI) alfalfa production on yield, WUE, evapotranspiration (FT), soil water, and forage growth from 2010 to 2011. Three planting treatments were used, flat bed, bare ridge, and plastic mulch ridge in the NI and SI fields that were referred to as FPNI, BRNI, and MRNI; and FPSI, BRSI, and MRSI, respectively. For the NI field, BRNI and MRNI significantly increased the total forage yield in the 2 yr combined by 14 and 53%; and WUE by 17 and 74% compared with FPNI, respectively. The MRNI significantly increased the 2-yr combined yield by 34% and WUE by 55% compared with BRNI. There were no significant differences in the ET over the 2 yr among the three treatments. For the SI field, BRSI and MRSI significantly increased the total forage yield over the 2 yr by 53 and 107%; and WUE by 54 and 120% compared with FPSI, respectively. The MRSI significantly increased the yield over the 2 yr by 34% and WUE by 44% compared with BRNI. Only the ET value from the MRSI treatment was significantly lower than that from the FPSI or BRSI. Therefore, MRSI could improve the yield and WUE in alfalfa, with MRNI another option under rain-fed conditions. [ABSTRACT FROM AUTHOR]

High levels of nitrate leaching losses from potato rotation systems have caused concerns for both drinking water quality and aquatic ecosystem protection in Prince Edward Island ( PEI). Paired-field experiments were carried out in commercial fields to evaluate the potential of delayed plowing forages within potato rotation from fall to spring on reducing nitrate leaching at two separate sites in PEI during 2010 and 2013. Monitoring showed that fall plowing resulted in elevated tile-drain nitrate concentrations compared to spring plowing, probably mainly due to crop residue mineralization during fall which was hastened by earlier herbicidal termination of forage (i.e., herbicidal killing) at Site 1. A similar trend was also observed regarding nitrate concentrations of shallow groundwater at Site 2 during the forage phase. The practice of delaying the plowing of forages and/or associated earlier herbicidal termination of forage until spring reduces forage-phase nitrate leaching loss by 20 to 61%, and should therefore be encouraged for nitrate mitigation. The study also demonstrated that only a small fraction (9.6 to 22%) of the fall plow-down forages decayed during the forage phase and a large portion was retained in the soil into the next season. Growers should consider accounting for some of the carried-over N for the subsequent crops regardless implementing fall or spring plowing. [ABSTRACT FROM AUTHOR]

This study investigated changes in soil organic carbon ( SOC) in a poorly drained clay loam soil under (i) permanent grassland ( PG) over 7 years and (ii) after PG renovation over 2·5 years. The experimental area was divided into four blocks with four paddocks per block. Composite soil samples from each PG block were taken to 30-cm depth on five occasions between 2004 and 2011. In June 2008, one paddock per block was renovated by ploughing and reseeding and sampled as above on the latter four occasions. Renovation decreased SOC ( P < 0·05) by 32·2 t ha−1 in the 2·5 years following ploughing; the difference developed almost entirely (86%) in the first four months. Renovation had no effect on above-ground productivity, standing root and stubble phytomass or on dissolved organic matter leaching. Therefore, soil respiration was considered to be a single potential pathway responsible for the SOC loss from renovated grassland. Although a simple linear regression indicated a tendency for PG to accumulate SOC, there was no evidence of recovery in SOC to previous levels following renovation during the study period. These results could have implications for greenhouse gas inventories in countries where PG is an important land-use type. [ABSTRACT FROM AUTHOR]

The first full greenhouse gas ( GHG) flux budget of an intensively managed grassland in Switzerland (Chamau) is presented. The three major trace gases, carbon dioxide ( CO2), methane ( CH4), and nitrous oxide (N2O) were measured with the eddy covariance ( EC) technique. For CO2 concentrations, an open-path infrared gas analyzer was used, while N2O and CH4 concentrations were measured with a recently developed continuous-wave quantum cascade laser absorption spectrometer ( QCLAS). We investigated the magnitude of these trace gas emissions after grassland restoration, including ploughing, harrowing, sowing, and fertilization with inorganic and organic fertilizers in 2012. Large peaks of N2O fluxes (20-50 nmol m−2 s−1 compared with a <5 nmol m−2 s−1 background) were observed during thawing of the soil after the winter period and after mineral fertilizer application followed by re-sowing in the beginning of the summer season. Nitrous oxide (N2O) fluxes were controlled by nitrogen input, plant productivity, soil water content and temperature. Management activities led to increased variations of N2O fluxes up to 14 days after the management event as compared with background fluxes measured during periods without management (<5 nmol m−2 s−1). Fluxes of CO2 remained small until full plant development in early summer 2012. In contrast, methane emissions showed only minor variations over time. The annual GHG flux budget was dominated by N2O (48% contribution) and CO2 emissions (44%). CH4 flux contribution to the annual budget was only minor (8%). We conclude that recently developed multi-species QCLAS in an EC system open new opportunities to determine the temporal variation of N2O and CH4 fluxes, which further allow to quantify annual emissions. With respect to grassland restoration, our study emphasizes the key role of N2O and CO2 losses after ploughing, changing a permanent grassland from a carbon sink to a significant carbon source. [ABSTRACT FROM AUTHOR]

Attention is being paid to the use of different tillage regimes as a means of retaining soil organic carbon ( SOC) and sequestering more SOC. Alongside earlier measurements of total SOC stocks under different tillage regimes, we have examined the distribution of nitrogen ( N), microbial activity and the structure of the soil bacterial community from differently tilled plots under continuous barley. The plots were established 5 yr before sampling and have been maintained annually under conventional tillage ( CT; moldboard ploughing to 20 cm and disking), deep ploughing ( DP; ploughing to 40 cm and disking), minimum tillage ( MT; disking to 7 cm) or zero tillage ( ZT). Our earlier work showed there was no difference in SOC contents down to 60-cm depth between the treatments, but now we report that there were significant differences in the total N and active microbial biomass (substrate-induced respiration) contents of the same soils. The N contents of the CT, DP and MT treatments were not significantly different, but the ZT contained significantly more N, indicating either greater N retention under the ZT treatment or preferential loss from the more intensively tilled treatments, or a combination of both. The microbial biomass content was greater for the CT and DP treatments than for the MT and ZT treatments, indicating greater sensitivity to treatment effects of the microbial biomass pool than the total C pool, consistent with its more dynamic nature. Terminal restriction fragment length polymorphism ( T- RFLP) analyses of the soil bacteria DNA (a method of assessing the bacterial community structure) enabled the samples to be distinguished both according to SOC content, which is to be expected, and to tillage regime with the greatest differences in community structure occurring in the ZT treatment and the least in DP and CT treatments, reflecting the degree of homogenization or disturbance resulting from tillage. [ABSTRACT FROM AUTHOR]

A 2-year study to evaluate the effect of four soil preparation techniques and four species compositions in a pine plantation with an admixture of broad-leaved trees on the species diversity and structure of ground beetle assemblages (Carabidae) was conducted. The soil preparation techniques were full shallow agricultural plowing (25 cm deep with three variants-plowing, plowing with ridge formation, and plowing with subsoiling) and full deep plowing (50 cm deep). The plantation species compositions were pine 7000/hectare, pine 5500/hectare + broad-leaved species 1500/hectare, pine 4000/hectare + broad-leaved species 3000/hectare, and pine 2000/hectare + broad-leaved species 5000/hectare. Carabidae were sampled monthly with pitfall traps in the plantation from May to November in 2003 and 2004-the fourth and fifth years after afforestation. Only the soil preparation technique affected species diversity. The mean number of carabid species and the Shannon-Wiener index were higher in the case of the full agriculture plowing with subsoiling treatment and the full agriculture plowing with ridge formation than in the full shallow agriculture plowing. The structure of the assemblages was dependent on the soil preparation technique, but not on tree species composition. In general, deep plowing and shallow plowing with subsoiling were conducive to an increase in the proportion of individuals representing late succession species, whereas shallow plowing favored early succession species. The results suggest that for effective plantation of a managed stand, deep plowing or shallow plowing with subsoiling is more beneficial for afforestation of fallow fields than typical shallow agricultural plowing. [ABSTRACT FROM AUTHOR]

Question The importance of silvicultural site preparation techniques in determining vegetation succession is increasingly recognized. We studied the effects of mechanical site preparation ( MSP) on post-fire vegetation regeneration within reforested sites in Mediterranean Israel. Location Upper Galilee region, Israel. Methods Vegetation cover and composition, ruderal species colonization and pine regeneration were monitored in four reforested sites for 3 yr following wildland fires that burned mature Pinus brutia and P. halepensis plantations. In each reforested site, a 50 m × 50 m monitoring area was assigned and measurements were conducted within five subplots (2 m × 50 m) encompassing three MSP patch types: ploughed patches ( P), unploughed patches ( UP) and planting mounds ( M) that combined ploughing, pit digging and wood-chip mulching. Results Recovery of vegetation cover (excluding pines) was rapid. The MSP patch type significantly affected vegetation cover in the first spring following the fire: cover was lowest on M, intermediate on P and highest on UP. However, these differences became minor by the third spring following the fire. Total woody species richness was not affected by MSP patch type, although there were minor effects on relative abundance of woody species. Two ruderal species were found, but their abundance became untraceable by the third year. Patterns of MSP effects on pine regeneration were similar for P. halepensis and P. brutia. Density of emerging seedlings of both pine species during the first year following the fire was significantly affected by MSP patch type: lower in P and M than in UP by more than 50% and 90%, respectively. However, emergence and/or survival during the following 2 yr was higher in P and M than in UP, with overall outcome of pine regeneration still about 50% lower in P and M than in UP. Conclusions The MSP treatments had only a minor, short-term effect on post-fire regeneration and colonization of vegetation, except for pine recruitment, which was more severely affected. [ABSTRACT FROM AUTHOR]

Unsuitable agricultural practices can cause loss in soil quality and erodibility to thus increase or trigger desertification under Mediterranean conditions. A field experiment was performed at the El Teularet-Sierra de Enguera Experimental Station (eastern Spain) to assess the influence during a 5-yr period of different agricultural practices on physical and chemical indicators of soil quality (total and water-soluble carbohydrates, glomalin-related soil proteins (GRSP), total organic carbon, aggregate stability (AS), vegetation cover and soil erosion). The management practices included residual herbicide use, ploughing, ploughing + oats, addition of oat straw mulch and a control (land abandonment). Adjacent soil under natural vegetation was used as a reference for local, high-quality soil and as a control for comparison with the agricultural soils under different management practices. Oat straw mulching led to higher levels of water-soluble carbohydrates, GRSP and AS and lower soil erosion rates, resulting in values similar to those in the soil under native vegetation. The lowest levels of carbohydrates and GRSP were for the plots that were treated with herbicide or were ploughed. The maintenance of and increases in stable aggregates promoted by the different agricultural management practices over the years were attributed to increases in labile organic fractions such as carbohydrates and to the GRSP content. The results demonstrate that land abandonment (control plot) or the use of a cover (plants or straw) contributes to increases in soil quality and reduces the risk of erosion. The research also shows that sustainable agricultural management allows soil to recover and that the use of straw mulching is the most effective management strategy. [ABSTRACT FROM AUTHOR]

Camelina (Camelina sativa L.), a member of the Brassicaceae family, can potentially serve as a low-input alternative oil source for advanced biofuels as well as food and other industrial uses. Winter annual camelina genotypes may be economically and environmentally advantageous for the northern Corn Belt, but little is known about their agronomic potential for this region. A 2-yr field study was conducted in western Minnesota to determine optimum fall sowing time for yield and oil content of two winter camelina cultivars in a no-tillage (NT) and chisel-plowed (CP) system. Seeding dates ranged from early September to mid- October. Plants reached 50% flowering as much as 7 d earlier in the NT than the CP system. Plant stands were generally greatest in the NT system, but yields were only greater than those in the CP system during the second year of the study, possibly due to differences in water logging of soil between tillage systems. Seed yield and oil content increased with sowing date up to early October. When sown in October, seed yield and oil content ranged from 419 to 1317 kg ha-1 and 282 to 420 g kg-1, respectively. Results indicate that camelina is a viable winter crop for the northern Corn Belt and that seed yields and oil content tended to be greatest when sown in early to mid-October. Moreover, fall-seeded camelina offered good weed suppression without the use of herbicide, supporting the contention that it can be successfully produced with low agricultural inputs. [ABSTRACT FROM AUTHOR]

The article presents a study regarding the impact of physical structure on fungal growth dynamics by combining a physiologically based model of fungal growth with digitized images of internal pore volume of samples of undisturbed soil with different management practices. It is investigated by measuring the pore geometries of the soil samples in chisel plow (CT) and no till (NT). Results of the study indicate the disadvantaged fungal invasion of the fragmented pore space in soils under NT.

Temporal changes in soil C content vary as a result of complex interactions among different factors including climate, baseline soil C levels, soil texture, and agricultural management practices. The study objectives were: to estimate the changes in soil total C contents that occurred in the past 18 to 21 yr in soils under agricultural management and in never-tilled grassland in southwest Michigan; to explore the relationships between these changes and soil properties, such as baseline C levels and soil texture; and to simulate C changes using a system approach model (SALUS). The data were collected from two long-term experiments established in 1986 and 1988. Geo-referenced samples were collected from both experiments before establishment and then were resampled in 2006 and 2007. The studied agricultural treatments included the conventional chisel-plow and no-till management systems with and without N fertilization and the organic chisel-plow management with cover crops. Total C was either lost in the conventional chisel-plowed systems or was only maintained at the 1980s levels by the conservation management systems. The largest loss in the agricultural treatments was 4.5 Mg ha-1 total C observed in the chisel-plow system without N fertilization. A loss of 17.3 Mg ha-1 occurred in the virgin grassland soil. Changes in C content tended to be negatively related to baseline C levels. Under no-till, changes in C were positively related to silt + clay contents. The SALUS predictions of soil C changes were in excellent agreement with the observed data for most of the agricultural treatments and for the virgin soil. [ABSTRACT FROM AUTHOR]

Topography is one of the major factors affecting soil C and N contents at the field/landscape level. However, topographical effects are likely to differ in magnitude in different agricultural systems. The objective of this study was to examine the interactions between topography and management systems on soil C and N. The study was conducted at the Kellogg Biological Station Long-Term Ecological Research (LTER) site in southwest Michigan. The studied treatments were chisel-plow (CT) and no-till (NT) with conventional chemical inputs and a chisel-plow organic management system with winter leguminous cover crops (CT-cover). At the 0- to 5-cm depth in both upperslope and valley positions total C and N contents of NT management were the highest followed by CT-cover and then CT. At 0- to 15-, 20- to 30-, and 30- to 40-cm depths, treatment effects varied depending on the landscape position. There were no differences among the treatments in upperslopes, while in the valleys total C and N tended to be the highest in NT and CT-cover followed by CT. The results indicated the importance of accounting for interaction between topography and management practices when assessing C sequestration across landscapes with varying topography. Total C stocks at the 0- to 30-cm depths were around 35,32, and 27 Mg C ha-1 soil (± 2Mg C ha-1standard error) in CT-cover, NT, and CT, respectively, across upperslopes and valleys. Overall, CT-cover was found to be as efficient in maintaining C and N content as no-till with conventional chemical inputs. Power analysis for C and N stocks at the 0-to 40-cm depth revealed that because of high variability in total C and N stocks at greater depths, the 10 to 30 samples per treatment available in this study were inadequate to detect differences in C and N stocks if thh differences were < 26Mg C ha-1. [ABSTRACT FROM AUTHOR]

The article presents a study on predicting the effect of tilling practices on wind erosion activity and the application of the Wind Erosion Prediction System in a sand drift area in The Netherlands. It states that the inland drift sand area in this location forms a unique ecosystem in northern Europe. It mentions that it is essential to investigate how the drift sand areas can be maintained, and how their immobilization by vegetation can be countered by establishing techniques that reactivate the aeolian processes. Four techniques, including rotary cultivator, disc harrow and excavator, and beach sand cleaner, were evaluated during an 8-month experiment at Kootwijkerzand, The Netherlands. The most effective method that was determined is the beach sand cleaner.

While the adoption of no-till (NT) usually leads to the accumulation of soil organic C (SOC) in the surface soil layers, a number of studies have shown that this effect is sometimes partly or completely offset by greater Soc content near the bottom of the plow layer under full-inversion tillage (FIT). Our purpose was to review the literature in which soc profiles have been measured under paired NT and FIT situations. Only replicated and randomized studies directly comparing NT and FIT for >5 yr were considered. Profiles of soc had to be measured to at least 30 cm. As expected, in most studies soc content was significantly greater (P < 0.05) under NT than FIT in the surface soil layers. At the 21- to 25-cm soil depth, however, which corresponds to the mean plowing depth for the data set (23 cm), the average soc content was significantly greater under FIT than NT Moreover, under FIT, greater soc content was observed just below the average depth of plowing (26-35 cm). On average, there was 4.9 Mg ha-1 more soc under NT than FIT (P = 0.03). Overall, this difference in favor of NT increased significantly but wealdy with the duration of the experiment (R2 = 0.15, P = 0.05). The relative accumulation of soc at depth under FIT could not be related to soil or climatic variables. Furthermore, the organic matter accumulating at depth under FIT appeared to be present in relatively stable form, but this hypothesis and the mechanisms involved require further investigation. [ABSTRACT FROM AUTHOR]

The soil C saturation concept postulates that there is an upper limit to the equilibrium soil C level of mineral soils even when soil C input is increased. To test this concept, we analyzed the relationship between steady-state soil C input and soil organic C (SOC) concentration in a temperate corn (Zea mays L.) agroecosystem experiment located in Lexington, KY. In this experiment, a gradient in plant productivity and consequent C input to the soil was produced with four N application rates (0, 84, 168, and 336 kg N ha-1 yr-1) under two disturbance regimes, no-till (NT) and moldboard plowing (MP). We examined whether physical protection of organic matter by soil aggregation and chemical protection by association with silt and clay particles led to SOC saturation. We used wet sieving to physically separate SOC pools that differ in C stabilization potential, and determined the C sequestration in each fraction. Total SOC was positively related to C input, and this was primarily due to C stabilization in small macroaggregates. In both tillage systems, however, microaggregate C and silt-plus-clay C did not increase with greater C input. Within the small macroaggregates, coarse particulate organic matter C and microaggregate C increased with C input, but there was no increase in silt-plus-clay C. Our results indicate that soil fractions with low C stabilization potential exhibit C saturation behavior. Apparent C saturation of some of the fractions indicates that SOC pools have a limited capacity to stabilize added C and that such a limit to C stabilization will constrain the ecosystem services provided by these SOC pools. [ABSTRACT FROM AUTHOR]

The article presents a study which quantified carbon dioxide fluxes over two fields in central Pennsylvania that has been managed as pastures for at least 35 years. The research utilized eddy covariance systems to quantify the fluxes. It relates the role of plowing in the depletion of organic carbon (C) stocks in many agricultural soils. The research determines the net ecosystem C exchange (NEE) and net biome productivity for the grazed pastures in the temperate region of central Pennsylvania. It outlines the C content of harvested forage and returned manure.

Increasing precipitation storage as plant-available soil water increases dryland crop yields on the semiarid southern Great Plains. The dominant soil in this region is a Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll), which features dense subsoil layers that limit infiltration and root proliferation. Deep (∼0.7 m) plowing may eliminate these layers, but the duration of treatment efficacy must be sufficient to recoup costs. Our objective was to quantify the long-term effects of deep plowing on soil bulk density (BD), penetration resistance (PR), ponded infiltration, and crop yield. In fall 1971, paired 24- by 460-m level conservation bench terrace plots at the USDA-ARS Conservation and Production Research Laboratory, Bushland, TX (35°11′ N, 102°5′ W) were moldboard plowed to 0.7 m or untreated and, subsequently, maintained with conventional sweep tillage. Grain sorghum [Sorghum bicolor (L.) Moench] was grown intermittently during the next 34 yr for 15 paired yield comparisons. Compared with the control, deep plowing significantly decreased BD and PR and increased water infiltration. Long-term mean grain yield of 2.86 Mg ha-1 with deep plowing was greater (P < 0.05) than the 2.61 Mg ha-1 yield in control plots. Approximately 89% of the 15-yr 3.75 Mg ha-1 cumulative yield increase with deep plowing occurred during 4 yr with large early growing season rains. We attributed this yield increase with deep plowing to greater internal drainage that reduced crop injury during infrequent floods and not greater root growth through the dense subsoil. Thirty years after deep plowing, high water intake suggests that flow-limiting subsoil layers had not yet redeveloped. The sustained deep-plowing benefit extends the period to recoup the 1971 plowing costs of US$160 ha-1. [ABSTRACT FROM AUTHOR]

The article provides information on the inception of horse pastoralism and its relationship with humans. It discusses the diversified roles of horses including transportation, herding, sports, plowing and haulage. It highlights the research on the Botai culture in northern Kazakhstan which provided evidence on the early history of the domestication of horses. According to the research, Botai has high number of tools for making rawhide thongs through the use of horse mandibles. Furthermore, it notes that evidence in Botai supports the argument that horses at the region were domesticated.

This article discusses the effects of compost additions and plowing on surface soil runoff and phosphorus losses. Inversion plowing of composted fields was found to significantly reduce runoff and total phosphorus losses compared to unplowed compost fields. Compared with unplowed compost treatments, sediment loss was increased with plowing but less than no-compost treatments. They concluded that plowing to invert high phosphorus surface soil losses effectively reduced runoff and dissolved reactive phosphorus loss.

This review presents the methods of fighting against silverleaf nightshade that have been employed in Morocco. Concerning competing crop methods, the use of a weed-choking crop like alfalfa (Medicago sativa L.) at the beginning of rotation can largely reduce the infestation of this weed because it cuts out competition and has an allelopathic effect on silverleaf nightshade. There are three mechanical methods that have demonstrated their effectiveness: deep plowing with a three disc plow, the sweep (a tool with a width of 2. 5 m made up of three V blades) and the small scythe (manual tool which cuts the plant on the level of the ground). Deep plowing (> 30 cm) and the sweep are recommended at the beginning of summer and following crop harvesting. Use of the small scythe, during 2 to 3 times each year at the flowering stage in various biotopes, allows the progressive weakening of the weed in the short term. Alfalfa planting, deep plowing and the sweep are advised for the infestations medium to high. Moreover, mechanical interventions combined with herbicides (glyphosate, sulfosate, aminotriazole and phytohormones) often are highly effective. The combination of these methods is highly desirable for the large surfaces where the infestation is average to strong. [TRANSLATION]

The period after ploughing of grass–clover leys within a ley-arable rotation is when nitrogen accumulated during the ley phase is most vulnerable to loss. We investigated how ploughing date and timing of cessation of grazing before ploughing affected nitrous oxide (N2O) losses of the first cereal crop. Ploughing dates were July and October for a winter wheat pilot study and January and March for spring barley in the main experiment. Timings of cessation of grazing (main experiment only) were October, January and March. Spring barley yield, nitrogen uptake and soil mineral nitrogen were also assessed. A separate large-scale laboratory incubation was made to assess the effect of temperature and rainfall on nitrous oxide emissions and nitrate leaching under controlled conditions. Nitrous oxide emissions in the 1- to 2-month period after autumn or spring ploughing, or sowing were typically between 20 and 150 g N ha−1 day−1 and increased with temperature and rainfall. Tillage for crop establishment stimulated N2O emissions with up to 2.1 kg N ha−1 released in the month after spring tillage. Cumulative nitrous oxide emissions were greatest (∼8 kg ha−1 over 17 months) after cessation of grazing in March before March ploughing, and lowest (∼5.5 kg ha−1) after cessation of grazing in January before January ploughing. These losses were 1.2–3.9% of the N inputs. In the laboratory study, winter ploughing stimulated nitrate leaching more than nitrous oxide emissions. The optimum time of ploughing appears to be early spring when the cold restricts nitrogen mineralization initially, but sufficient nitrogen becomes available for early crop growth and satisfactory N offtake as temperature increases. Early cessation of grazing is advantageous in leaving an adequate supply of residues of good quality (narrow C:N ratio) for ploughing-in. Restricting tillage operations to cool, dry conditions, being aware of possible compaction and increasing the use of undersown grass–clover should improve the sustainability of organic farming. [ABSTRACT FROM AUTHOR]

One of the main effects of soil tillage is that it determines the distribution of crop residues in the soil profile. Little information is available on how this affects the distribution of carbon (C) and nitrogen (N) in the soil and more specifically in soil aggregates, as in general the contribution of other effects of tillage (i.e. mechanical disturbance) cannot be distinguished. A laboratory experiment was conducted with repacked soil columns to improve our understanding of the mechanisms of soil aggregate stabilization and storage of organic C in relation to residue location. Double-labelled oilseed rape residues (13C and 15N) were incorporated in the 0–10 cm soil layer or left on the soil surface. The soil columns were incubated for 33 weeks at 20°C. Artificial rain events followed by evaporation imposed several dry-wet cycles on the soil-residue system. Spatial separation of surface-placed residues from the soil slowed down the decomposition rate compared with incorporated residues. This resulted, in the short term, in a large fraction of residue fragments at the soil surface (equivalent to 52% of carbon applied). In contrast, initial crop residue location did not significantly affect incorporation of residue-C in soil aggregates (only 10–12% of carbon applied), as new C entered the aggregate fractions mainly as soluble C. However, concentrations of residue-derived C and N were greater and aggregation increased near the soil surface with mulch, which in the longer term can modify physical and biological properties of the upper cm of the soil. [ABSTRACT FROM AUTHOR]

Question: How has the terrain, namely elevation, slope and aspect, controlled the cultural modification of the forest-grassland transition in southern Alberta? Location: The aspen parkland region of the Rocky Mountains foothills southwest of Calgary, Alberta, Canada. Methods: Dominion Land Survey data, historical maps and a DEM (digital elevation model) were used to determine which decision rules settlers used to plough native grassland and parkland at the turn of the last century. Comparative measurements between historical and current vegetation patterns and GIS techniques were used to explore relationships between terrain, land use and the modification of the landscape. Results: Grassland at lower elevations, aspen park land at mid elevations and closed forest at higher elevations dominated the pre-settlement forest-grassland transition. Elevation, hillslope angle and aspect affected which parts of the landscape were cleared and ploughed for agriculture or left in their natural state. Clearing and ploughing occurred mostly on gentle hill-slopes (⩽ 6°). At higher elevations with fewer gentle hillslopes clearing and ploughing were limited. Ca. 90% of the original vegetation at lower elevations has been cleared or ploughed, compared to ca. 30% at higher elevations. Almost all of the grassland at lower elevations has been converted to cropland. In the mid-elevation parkland 48% of the tree cover and > 72% of the native grass have been converted to domesticated grass and cropland. Tree cover has expanded at the expense of grass on steep hillslopes and in ravines that presumably were burned frequently by wildfires in pre-settlement times. At higher elevations, the closed forest has remained more or less intact. Conclusions: Terrain structure has controlled the arrangement of suitable agricultural land and consequently deter-mined the current vegetation patterns in the forest-grassland transition zone in southern Alberta. Tree invasion into grass has been minimal, and has been restricted to hilly topography or wet areas, even though the parkland has expanded some-what in its distribution. Any effect the cessation of wildfires may have had on aspen expansion has been overshadowed by agriculture, which has converted vast areas of native grassland and aspen parkland to farmland. Thus, along this forest-grass-land transition, the strong elevation, slope and aspect have maintained wine of the regional variation in vegetation. [ABSTRACT FROM AUTHOR]

Current tillage erosion models account for the influence of tillage direction in the magnitude of the soil transport coefficient. It is argued that a re-modelling of tillage erosion is preferable in which the influence of tillage direction is separated from the soil transport coefficient, which is a measure of tillage intensity. This has been achieved here by developing a two-dimensional tillage erosion model that incorporates tillage direction in the measure of slope and uses soil transport coefficients that are independent of tillage direction and based on relationships between transport and the slope in the direction that bisects tillage direction and the overturning direction. Mean tillage erosion, associated with a single pair of opposing tillage directions and pair of overturning directions, can be described by a two-dimensional diffusion-type equation if the dimensions are defined as the tillage direction and the direction perpendicular to tillage. Application of the model to a real-world case allows quantification of the potential soil conservation benefits associated with optimization of tillage direction. The scope for amelioration is related to the ratio between the coefficients for transport in the direction of tillage and perpendicular to tillage. As this ratio approaches unity, the potential for amelioration reduces towards zero. For the study site investigated, use of the experimentally derived ratio of 0.66 indicated that a 12% reduction in tillage erosion could be obtained by ploughing across the dominant field slope as compared to ploughing up and down the dominant slope. For an implement with a coefficient ratio of 0.2 the reduction in tillage erosion intensity, associated with optimizing the tillage direction, reaches 28%. Nevertheless, such benefits must be considered in the context of other management considerations. The tillage direction that minimizes erosion is associated with lateral slopes of 10o, or more, over 20% of the field. To the land-user this disadvantage may outweigh the soil conservation benefits. [ABSTRACT FROM AUTHOR]

On the volcanic soils of the uplands of the French West Indies, banana monocropping has been practised since about 1980, mostly with large inputs of chemicals and replanting every three to five years after ploughing. However, in Guadeloupe less intensive cropping systems with only few added chemicals are still being used. The effects of the intensive practices on the physical, chemical and biological attributes of soils were evaluated on 34 farmed fields, which were selected to include the diverse soils and management practices found in the uplands of South Basse-Terre. Management was classified into four groups to differentiate effects of fertilizers, nematicides and tillage over at least 10 years. The population of the parasitic nematode Radopholus similis was, on average, greater 3 months after the application of nematicides. Thus, the use of nematicides increases the dependency of yield on nematicides. Ploughing decreased soil organic matter in the 0-10 cm layer as well as microbial respiration and earthworm biomass, but increased banana root infestation by R. similis. Ploughing was also associated with a change in soil structure, as revealed by the decrease in soil water content at -1 kPa potential and the increased infiltration rate of water into the 0-10 cm layer. The use of fertilizers has advantages for the maintenance or increase of soil reserves of K. However, due to the decreasing of negative electrical charges in the lower layers of andosols, where pH remains low, the majority of the cations supplied by fertilizers, mainly potassium, are prone to leaching. [ABSTRACT FROM AUTHOR]

Two field experiments were carried from 1999 to 2001 to assess the effectiveness of autumn, winter and spring application of straw-based farmyard manure (FYM). The soil was a sandy loam containing 106 g clay kg-1 situated in the temperate coastal climate of Denmark. The FYM was applied manually to experimental plots at a target rate of 300 kg N ha-1. The manure was incorporated by three initial tillage strategies (harrowing, rotavating or no-tillage) prior to ploughing. All combinations of tillage strategies were also carried out without manure application. Spring barley (Hordeum vulgare L.) was grown, followed by ryegrass (Lolium perenne L.). The results suggest that, as far as circumstances permit, FYM should be applied in spring to achieve the optimum use of nitrogen in the manure. Further, yield and nitrogen uptake did not benefit from harrowing or rotavating the manure before ploughing. When manure was not applied, soil tillage prior to ploughing did not significantly affect grain yield or nitrogen uptake. [ABSTRACT FROM AUTHOR]

Determines the effect of plowing on the concentration and forms of phosphorus in soils highly stratified with respect to phosphorus, as a result of continual, long-term application of manure. Effect of mixing high phosphorus surface and low phosphorus subsurface soil to simulate field plowing; Effect of the one-time plowing of phosphorus-stratified soils on the long-term loss of phosphorus in overland flow.