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The return of straw and manure to agricultural fields can impact soil organic carbon (SOC) and biological properties. However, there is a lack of research on how to use swine manure, maize straw, and various conditioners together affects soil bacterial and fungal populations. This study aimed to investigate six treatments, namely, only maize straw (S00), maize straw combined with swine manure (S0Z), maize straw combined with biochar and swine manure (SCZ), maize straw combined with boron slag and swine manure (SBZ), maize straw combined with biological agent and swine manure (SJZ), and maize straw combined with bio-organic fertilizer and swine manure (SFZ). The results showed that after the two-year return, all treatments increased the SOC content in 2023, which was 12.55–26.89% higher than S00. And the SCZ treatment significantly increased the soil organic carbon (SOC), dissolved organic carbon (DOC), easily oxidizable carbon (EOC), particulate organic carbon (POC), and microbial biomass carbon (MBC) content by 26.89%, 25.44%, 56.88%, 16.08%, and 43.54%, compared to S00. A redundancy analysis (RDA) showed that the continuous application of manure, maize straw, and conditioners has a positive impact on the diversity and abundance of soil microbial communities, enhancing the accumulation of soil carbon. Furthermore, our research revealed that soil fungi exhibited higher sensitivity in soil carbon composition following the addition of manure, straw, and conditioners to agricultural fields than bacteria. In conclusion, the addition of different conditioners to the fields is beneficial to biodiversity conservation from the perspective of achieving soil carbon storage and soil protection. Our findings suggested that the combination of maize straw, biochar, and swine manure was been proven to be the most effective treatment for increasing labile organic carbon fractions and enhancing the microbial community. [ABSTRACT FROM AUTHOR]

The purpose of this study was to observe the changes in soil nitrogen pools (active organic and inorganic nitrogen fractions) after applying organic materials under drip irrigation with film mulching in a semi-arid soil. The two-year field experiment included four fertilization treatments: maize straw, fodder grass, sheep manure, and a control treatment with no organic material applied (CK). The results showed that the application of maize straw and sheep manure significantly increased the soil total nitrogen content by 9.02~13.33% and 11.02~17.27%, respectively, while no significant improvement was found with the use of fodder grass. Compared with CK, returning organic materials to the field increased the soil active nitrogen pools, except for ammonium nitrogen content. Meanwhile, the content of particulate organic nitrogen was significantly increased by 42.11~78.85% under the application of organic materials, which took the highest proportion of active nitrogen pools and was sensitive to fertilization treatments. Among the three organic materials, maize straw and sheep manure increased the soil active nitrogen content the most. In conclusion, both maize straw and sheep manure are the optimum organic materials, which could be applied for improving soil nitrogen storage under drip irrigation with film mulching within semi-arid areas. [ABSTRACT FROM AUTHOR]

Plastic pollution in farmland soil has become a significant concern for scientists studying farmland ecosystems. However, the current research focus on the environmental impacts of plastics in soil overlooks crucial factors such as sources, distribution, and persistence. In this study, we examined the distribution of residual film after eight years of film mulching in mid-April 2018. We also assessed changes in spatial distribution from 2018 to 2020. Our findings reveal that eight years of film mulching significantly increased the quantity of agricultural mulch film residues in the soil. The size of residual film fragments varied from 0.25 cm2 to 109 cm2, and the average size, number, and quantity of residues were influenced by soil depth. There was a noticeable downward trend in the quantity of agricultural mulch film residues, decreasing annually by 0.525 kg·ha−1. In contrast, the number of residual films showed an average annual growth rate of 2.13 × 105 p·ha−1. Importantly, we observed a substantial accumulation of residual film fragments below the 10 cm soil layer over time. Fragments ranging from 1–5 cm2 were the most abundant and gradually accumulated in deeper soil layers, enhancing mulching film recovery efficiency. This study provides valuable insights into the influence of mulch cycles on farmland soil profiles, identifying the key locations and size-to-shape ratios of residual films. These findings serve as a theoretical foundation for implementing effective measures to control mulch film pollution in agricultural practices. [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]

In order to test the short-term effects of straw amendment on soil organic C (SOC) stabilization, SOC protection mechanisms, and soil bacterial community, we examined which bacterial taxonomic groups were associated with protected C fractions via different soil depths. We conducted a 5-year field experiment including a total of four treatments: S0 (no straw amendment), S1 (0–20 cm straw-amended soil), S2 (0–40 cm straw-amended soil) and S3 (0–60 cm straw-amended soil). The core method was used for soil sampling, and 180 soil samples was collected. Our results showed that straw amendment significantly increased bulk soil C content, enhanced the constituents of physically separated fractions and their OC contents, and changed the soil bacterial community composition at different soil depths. SOC was more accelerated in macroaggregate-derived unprotected and microaggregate-derived physically protected fractions at soil depths of 0–20 cm. Physically protected and physico-biochemically protected fractions were the major C protection mechanisms at soil depths of 20–40 cm and 40–60 cm soil depths. Our study also provides evidence that straw amendment significantly increases the bacterial phyla abundance of Proteobacteria and Bacteroidetes at each soil depth. Moreover, straw amendment enhanced the relative abundances of Gemmatimonadetes and Nitrospirae at soil depths of 40–60 cm and have a positive correlation with physically and physico-biochemically protected C pools. These results indicate that straw amendment can regulate C sequestration processes by enhancing SOC physical protection and modulating bacterial community, especially in the deep soil. In addition, straw amendment in subsoil (0–40 cm or 0–60 cm) is more beneficial for C storage and stabilization. [ABSTRACT FROM AUTHOR]

Straw and animal manure are major organic waste materials from agricultural ecosystems. Different kinds of animal manure combined with straw (AM-S) may have varying effects on the decomposition, nutrient release, and structural changes of maize straw. Using the Humic Cambisols soil as the experimental area, the straw decomposition characteristics under the co-application of animal manure were studied following the nylon net bag landfill method. The experiment involved four treatments: maize straw only (S), maize straw plus ox manure (SO), maize straw plus chicken manure (SC), and maize straw plus pig manure (SP). The treatments with AM-S accelerated the decomposition of straw and increased the release rate of nutrients and organic components (cellulose, hemicellulose, and lignin). During the 240 days of the study, straw decomposition showed a trend of increasing rapidly in the first stages and then increasing slowly in the latter stages in all the treatments. At 240 d, the straw decomposition rates and carbon release rates of the AM-S treatments were 65.25–71.87% and 64.04–69.35%, respectively. At the end of the experiment, the order for the final release rates of nitrogen (N), phosphorus (P), and potassium (K) was K (93.25–96.56%) > P (42.25–55.08%) > N (40.01–52.23%). Moreover, scanning electron microscopy showed that SP treatment had the highest degree of structural changes of the maize straw compared with the other treatments. The purpose of this study was to screen the effective animal manure that can promote straw decomposition and provide a reference for the rational use of straw and animal manure management. In conclusion, the study suggested that the co-application of animal manure and straw should be adopted in agricultural systems, especially SP treatment, as it was more conducive to promoting the decomposition of maize straw and the release of nutrients. [ABSTRACT FROM AUTHOR]

A field experiment was designed to assess the impacts of various maize straw (stover) returning methods on the basic soil physicochemical properties and soil quality index in Jilin (NE China). The five treatments were no return of straw residues (CK), straw incorporated evenly into the soil using the crashing-ridging technique (EIS), straw mulching (SM), straw plowed into the soil (SP), and straw returned in granulated form (SG). Relative to the no straw return, EIS effectively reduced soil bulk density and penetration resistance, increased soil total organic carbon (TOC), macroaggregate-associated carbon content, and the accumulation of soil humus. Furthermore, EIS improved soil structure and soil aggregate stability and significantly increased the soil quality index. Among the various straw returning treatments, SM and SG significantly promoted soil macroaggregation and increased macroaggregate-associated carbon content by 23.69% and 21.70% at the soil surface, respectively (as compared with the control). Compared to SM, SP, and SG, EIS significantly enhanced the aliphaticity and hydrophobicity of soil organic carbon. These results suggested that EIS was the most efficient straw return mode to increase TOC and improve soil structure and fertility. [ABSTRACT FROM AUTHOR]

Returning straw plays an important role in protecting the environment and maintaining the sustainable development of agriculture. In this research, we explored the effects of returning granular corn straw on soil humus composition and humic acid structural characteristics in a typical saline-alkali soil. This study was conducted in Jilin province. A randomized block design consisting of nine plots with three treatments in three replicates was used for this study. The treatments were granular corn straw (GS), coarse corn straw (CS), and control (CK). The results show that treatments GS and CS both increased the contents of soil humus and its components in the soil compared to CK. However, treatment GS recorded the highest significant increase in soil humus carbon (HEC), fulvic acid carbon (FAC), and humic acid carbon (HAC) by 17.59%, 8.32%, and 26.51%, respectively. Comparing the two straw treatments, it was found that the relative intensities of treatment GS at 2920 and 2850 cm−1 were higher than treatment CS by 1.58% and 72.49%, respectively. The relative intensities of treatment GS at 1720 cm−1 and 1620 cm −1 were lower than treatment CS by 52.2% and 30.43%, respectively. Moreover, an analysis of soil humic acid (HA) through an infrared spectrum, fluorescence spectrum, and principal components analysis (PCA) showed that the application of straw makes the structure of HA aliphatic, simple, and younger, and also promotes the continuous renewal of humus. In this study, the application of granular corn straw effectively improved the soil humus content and humic acid structural characteristics and is thus highly recommended. [ABSTRACT FROM AUTHOR]

High salinity and low fertility have restricted crop production in primary saline-alkali soils. Soil organic carbon (SOC) and surface charge characteristics affect the soil fertility and soil colloid characteristics of primary saline-alkali soils, respectively. In this paper, the SOC and surface charge properties of primary saline-alkaline soil under organic wastes applications were assessed. Five treatments were involved in this experiment: chemical fertilizer combined with sheep manure (SM), corn straw (CS), fodder grass (FG), and granular corn straw (GS), while chemical fertilizer only was used as control (CK). The content of SOC was significantly different under different organic wastes application (p < 0.05). Treatment GS recorded the highest content of SOC compared with the other treatments. In addition, the content of each SOC density fraction increased after the application of organic wastes. Similarly, the application of organic wastes, increased the proportion of organic carbon in free light fraction (Fr-FLOC) and organic carbon in occluded fraction (Oc-FLOC) in the soil however the proportion of organic carbon in heavy fraction (HFOC) decreased. In this study, we found that treatment GS has a greater impact on soil surface charge properties than other treatments, and through redundancy analysis (RDA) the content of SOC and Fr-LFOC (F = 24.704, p = 0.004; F = 19.594, p = 0.002) were identified as the main factors affecting the surface charge properties of soil organic carbon. In conclusion, GS is the recommended organic waste for ameliorating primary saline-alkali soil, as compared to the other organic waste treatments. [ABSTRACT FROM AUTHOR]

Returning organic materials to fields is an effective management practice for improving soil quality in agroecosystems. In the case of scarce organic material resources, choosing the optimal material type for improving the quality of a soil type is an urgent problem to be solved. The objective of this study was to evaluate the temporal variations in the spectroscopic characterization of humic acids (HAs) over a period of 90 days after applying biotechnologically extracted fulvic acid (BFA), well-decomposed sheep manure (M), corn stover pellets (Ps) and corn stover powder (Pr) at equal C amount to a chernozem under laboratory conditions, measured by Fourier transform infrared (FTIR) spectroscopy and ultraviolet-visible spectrophotometry (UV–Vis). The results indicated that the BFA and Pr with higher C contents (68.9 and 59.8 g kg−1, respectively) were more beneficial to the C mineralization of HAs. M, applied in the largest amount, together with the highest available N, P, and K contents (575.4, 160.1, 478.9 mg kg−1, respectively), and its more easily consumed carbohydrates as well as well-decomposed status, was more likely to promote the condensation of HAs. BFA carried more hydrophilic groups into the HAs, while Ps did not introduce high levels of adsorbed H2O molecules and aromatic C=C (or C=O) groups. Ps did not affect the molecular structure of HAs after incorporation into the chernozem. At the equal C input amount, M had the greatest benefit, whereas the beneficial effect of Ps was the least, in improving the chernozem quality. [ABSTRACT FROM AUTHOR]