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Introduction: Previous studies have proven that different tillage measures have significant different effects on soil structure, hydrology properties and soil erosion. However, few studies have clarified the dynamic changes in soil aggregate stability and infiltration properties during crop growth under four tillage measures. Methods: Four field plots (150 m x 15 m) managed by four tillage methods including wide ridge tillage (DT), no-tillage (NT), contour ridge tillage (CT) and traditional tillage (CK) were built in 2021 to evaluate their effects on dynamic changes of soil structure and water conductivity during crop growth. Soybean was the seasonal crop. Soil bulk density, soil porosity, soil aggregate stability and soil infiltration characteristics were measured to assess dynamic changes in soil aggregate stability and infiltration from June to October 2022. Results: The results showed that NT significantly increased soil bulk density by up to 21.62% compared with CK, while DT did not show significantly increase in soil bulk density. DT, NT and CT could greatly increase the capillary porosity and proportion of capillary porosity to total porosity. DT and NT also improved the stability of soil water-stable aggregates by 3.37% and 10.6%. In terms of soil infiltration properties, all three tillage methods increased the initial, stable and average infiltration rates by 8.4%-52.94%, of which the DT and NT showed the greatest improvement. The soil infiltration process of four tillage measures could be better fitted by Horton model than Kostiakov and Philip models. Soil saturated hydraulic conductivity (SHC) of CK exhibited a significant negative correlation with soil bulk density and capillary porosity, and showed a positive correlation with total porosity and geometric average diameter of water-stable aggregate (GMD), whereas the other three treatments only displayed a significant correlation with the stability of soil water-stable aggregate. Conclusion: The results suggest that DT, NT and CT have potential to improve soil structure and infiltration capacity compared with CK, and contribute to preventing and controlling soil erosion in sloping farmland of Northeast China. [ABSTRACT FROM AUTHOR]

The application of organic materials contributes to the sustainable development of agriculture. Increased manure inputs have a fundamental effect on the composition and dynamics of soil organic carbon (SOC). In this study, we conducted a 10-year field experiment in Changchun, Jilin, Northeast China, to investigate the effects of manure addition on soil organic carbon components and soil microorganisms. Specifically, we established four treatments: (i) chemical fertilizer or no addition of manure (CK), (ii) pig manure with chemical fertilizer (ZF), (iii) cow manure with chemical fertilizer (NF), and (iv) chicken manure with chemical fertilizer (JF). The results showed that the JF treatment significantly increased the soil organic carbon (SOC), dissolved organic carbon (DOC), and readily oxidized organic carbon (ROC) content by 20.36%, 105.9%, and 61.32%, respectively, relative to CK. The microbial biomass carbon (MBC) content in JF, ZF, and NF treatments were significantly higher than that of CK, which increased by 107.24%, 116.45%, and 96.71%, respectively. The particulate organic carbon (POC) content in NF and JF treatments differed significantly, increasing by 25.61% and 19.01%, respectively, relative to CK. Redundancy analysis showed that continuous manure application had a positive effect on soil microbial community diversity and abundance, which was favorable for the accumulation of soil carbon. We also found that soil fungi were more sensitive than bacteria to changes in soil carbon composition following manure application. In conclusion, adding different organic materials can better support biodiversity conservation and realize ecosystem services of surface carbon storage and soil conservation. Our results reveal the importance of microbial fixation in soil carbon dynamics according to the different distribution of active organic carbon pools, which will help enhance our understanding of the carbon cycle. [ABSTRACT FROM AUTHOR]

Returning organic materials is recognized as an effective practice to alter soil organic carbon (SOC) content, in which microorganisms play a critical role. The objective of this study was to evaluate the effects of different kinds of animal manure combined with stover (AM-S treatments) on labile organic C fractions and soil microbial community. The two-year experiment involved four treatments: maize stover only (S), maize stover plus ox manure (SO), maize stover plus chicken manure (SC), and maize stover plus pig manure (SP). In 2018 and 2019, AM-S treatments increased the levels of SOC, dissolved organic carbon (DOC), easily oxidized carbon (EOC), microbial biomass carbon (MBC), and maize yields. Maize stover plus ox manure treatment could provide better accumulation of MBC, and enhance bacterial and fungal richness and diversity. Maize stover plus pig manure treatment enhanced the contents of DOC and maize yield and also recorded the highest percentage of Proteobacteria (57.6%). Also, the EOC contents were 13.0% and 21.5% higher than SO and SC respectively. In all, our findings suggested that the application of maize stover plus pig manure was the most effective treatment for enhancing labile SOC fractions and improving the microbial community. [ABSTRACT FROM AUTHOR]

The structures of soil humus (HS) amended with organic wastes (OWs) were closely related to properties of OWs-derived humus-like substances (HSL). This work evaluated the properties of HSL isolated from mushroom residue (MR), chicken manure (CM), sheep manure (SM), tree leaves (TL), maize straw (MS) and fodder grass (FG) and studied the structures of soil humic acid (HA) and fulvic acid (FA) amended with these OW. FTIR results showed that the relative intensities at 1,640 cm−1 peaks of TL-, FG- and SM-derived HAL were higher than other CM-, MS- and MR-derived HAL (p < 0.05), while the 2,930/1,640 ratios were lower (p < 0.05). Relatively lower E4/E6 ratios and ΔlogK values of TL-, FG- and SM-derived HAL were recorded (p < 0.05). Relative intensities at 1,620 cm−1 peaks of soil HA and soil FA amended with TL, FG and SM were higher than other OWs, while the 2,930/1,620 ratios were significantly lower (p < 0.05). The 2,930/1,620 ratio of soil HA and soil FA amended with MS and CM was the highest, respectively. In conclusion, the properties of OWs-derived HSL play important roles in functional groups of soil HS amended with these OWs. [ABSTRACT FROM AUTHOR]

Poor soil fertility conditions limit agricultural production and development in saline-alkali areas. At the same time, in order to solve the problem of environmental pollution caused by agricultural wastes, agricultural wastes are used for organic fertilization of saline-alkali soils. In this study, the amount and structure of soil dissolved organic carbon after the application of different organic wastes was assessed. The results showed that the content of dissolved organic carbon in each component increased significantly (p <.05), while treatment GS recorded the highest content of dissolved organic carbon in each organic carbon component. The UV-visible spectrum of soil dissolved organic carbon recorded different results after the application of organic materials. For water-soluble organic carbon (WSOC), treatment CS was most effective in increasing the molecular weight of soil WSOC while treatment GS was most beneficial in improving the hydrophobicity and aromaticity of soil WSOC. For thermal hydrolyzed organic carbon (THOC), treatment GS was most effective for increasing the molecular weight and hydrophobicity, while treatment SM was most beneficial for increasing aromaticity. For hydrochloric acid and hydrolyzed organic carbon (HHOC), treatment SM was most effective in increasing molecular weight, while treatment FG and GS were most beneficial in improving the hydrophobicity and aromaticity of HHOC. For Alkali hydrolysis of organic carbon (AHOC), treatment GS was most beneficial for increasing the molecular weight, aromaticity, and hydrophobicity of AHOC. Amongst all the treatments the organic material treatments increased the aromaticity, hydrophobicity, molecular weight, and humification degree of soil soluble organic carbon compared with CK. [ABSTRACT FROM AUTHOR]

The degradation characteristics of polypropylene carbonate (PPC) mulch film and ordinary mulching film in soil were studied through the field net bag landfill experiment. The results showed that in 0~1,50 days, the PPC film in the soil broke gradually due to the degradation reaction. Moreover, the degradation rate increased gradually and the highest degradation rate was 39.67%, while the surface of the common mulch film did not change and the degradation rate did not increase, with the highest degradation rate for the common mulch film only 1.52%. The absorption peaks of methylene C-H, C=O, C-O-C antisymmetric stretching, C-OH, and C-O decreased in the chemical structure of the PPC film. In 0~150 days, the elongation at break and tensile strength of the PPC film and common mulch film decreased, and the mechanical properties of the PPC film were always lower than that of common mulch film. At 150 d, the tensile strength and elongation at break of the PPC film were 4.08 MPa and 114.17% respectively, while those of the common mulch film were 10.79 MPa and 190.15% respectively. The findings indicated that the degradation rate of PPC film has a power exponential relationship with its mechanical properties, and the mechanical properties will be reduced with an increase in the degradation rate. [ABSTRACT FROM AUTHOR]

Crop straw is of great significance in improving farmland ecological environment, soil fertility, and enhance crop quality and yield. The application of decomposed livestock manure into soil can not only provide a good breath environment and energy for microorganisms, but also have a short growth cycle of microorganisms, and livestock manure can cause rapid changes in microorganisms. Taking the typical dark brown soil cultivated land in Liaoyuan City, Jilin Province, as the experimental area, the characteristics of in-situ strip composting of livestock manure and corn straw in the field by nylon mesh bag landfill method was studied. Four treatments were set up in the experiment: corn straw (CS), corn straw + pig manure (SPM), corn straw + chicken manure (SCM), corn straw + cow dung (SCD). The samples were collected at 30 d, 60 d, 90 d, 120 d and 150 d after bag burying and the mass loss rate and nutrient release rate of corn straw under each treatment were measured. The results showed that by 150 days after the end of the experiment, the mass loss rate of corn straw under the four treatments increased rapidly in the early stage and slowly increased in the later stage, and the cumulative mass loss rate of corn straw ranged from 42.48%~53.28%. At the same time, the cumulative release rates of carbon, nitrogen, phosphorus and potassium in corn straw under the four treatments were 56.87%~66.95%, 41.01%~46.15%, 44.92%~48.94%, 94.14%~96.24%, respectively. The addition of livestock manure accelerated the decomposition of corn straw, and increased the mass loss rate and nutrient release rate of straw. The best performance was SCM treatment, and the difference between SCM treatment and other treatments was significant (P<0.05). In addition, the cumulative mass loss rate was SCM>SPM>SCD>CS, and the cumulative release of nutrients was K>C>P>N. In conclusion, corn straw in situ strip composting combined with different livestock manure is beneficial to the decomposition of corn straw and promotes the release of carbon, nitrogen, phosphorus and potassium in corn straw, and the straw returning to the field with chicken manure being the best. [ABSTRACT FROM AUTHOR]

The application of agricultural wastes to the soil does not only improve soil fertility but also helps in the recycling of agricultural waste resources. However, the effects of agricultural organic materials on soil physicochemical properties in primary saline and alkaline lands unsatisfactory. In this study, the effects of different organic materials on the physicochemical properties of primary saline-alkali soil were studied in the west of Jilin province for two consecutive years. The organic materials included: grass (FG), sheep manure (SM), coarse corn straw (CS), and granular corn straw (GS). Soil pH, EC, total salt content, CEC, exchangeable sodium, ESP, organic matter, field capacity, water immersed bulk density, sedimentation coefficient, hardness and the morphological characteristics of soil aggregates were measured by conventional methods. CEC, SOM, and the physical properties varied significantly among the different treatments, whereas pH, EC, total salt content and exchangeable sodium did not. Moreover, the morphology of the organic materials significantly affected pH, EC1 : 5, total salt content, SOM and physical properties of the soil however, it did not affect the CEC, exchangeable sodium and ESP. Comparing granular corn straw with coarse corn straw, granular corn straw increased the SOM and field capacity by 48.5 and 17.0% respectively and decreased the pH, EC1 : 5, total salt content, water immersed bulk density, sedimentation coefficient and soil hardness by 2.6, 2.4, 3.7, 11.3, 6.2 and 7.7% respectively. In conclusion, the application of organic materials effectively improved the physical and chemical properties in the saline-alkali soil however did not cause a complete change in the saline-alkaline nature of the soil. The morphology of the organic materials also significantly affected soil properties, with granular corn straw having a better effect than the other treatments. [ABSTRACT FROM AUTHOR]