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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]

Soil available nutrients and soil salt ions are considered to play a significant role in soil fertility. A two-year field experiment was conducted to investigate the effects of different agricultural organic wastes on soil available nutrients and soil ions in a primary saline soil, located in the west of Jilin Province, China. The treatments were granular corn straw (GS), coarse corn straw (CS), sheep manure (SM), fodder grass (FG), and control (CK). The results showed that agricultural organic wastes effectively decreased soil pH by 1.28%-3.83%. The application of agricultural organic wastes also improved soil available nutrients, of which the available nitrogen (AN) increased by 23.64%-32.54%, the available phosphorus (AP) increased by 16% −19.93%, and the available potassium (AK) increased by 2.78% – 8.42%. In contrast, the content of soil salt ions decreased significantly with the exception of potassium ions. Linear dependence suggests that, with the decrease of soil pH, the soil available nutrient content was higher. From the correlation analysis, the relationship between other salt ions and soil available nutrients showed an extremely significant negative correlation with the exception of potassium (K+). The redundancy analysis (RDA) showed that calcium (Ca2+) and potassium (K+) are the main factor affecting soil available nutrient content in 2a (about 12 months after organic wastes were applied) and 3a (about 24 months after organic wastes were applied), respectively. In conclusion, treatment GS is recommended for improving soil available nutrients and decreasing the pH and content of soil salt ions in primary saline-alkali soils. CK: control without orgaanic material; GS: granular corn straw; CS: coarse corn straw; SM: sheep manure; FG: fodder grass; AN: available nitrogen; AP: available phosphorus; AK: available potassium; RDA: redundancy analysis; 1a: before the application of organic wastes; 2a: about 12 months after organic wastes were applied (first year); 3a: about 24 months after organic wastes were applied (second year). [ABSTRACT FROM AUTHOR]

In order to evaluate the effects of different maize straw returning modes on humus composition and humic acid (HA) structural, a field experiment was designed to have five treatments, i.e. Treatment CK (no straw returned), Treatment EIS (straw incorporated evenly into the soil using the crashing-ridging technique), Treatment SP (straw plowed into the soil), Treatment SM (straw returned as mulch) and Treatment SG (straw returned as pellets). Our results showed that Treatment EIS significantly increased the content of soil organic carbon (SOC), soil humus substances (HEC), soil humic acid carbon (HAC) and fulvic acid carbon (FAC) by 27.8%, 47.6%, 63.3% and 33.8%, respectively, as compared with CK. Among all the straw returning treatments, Treatment EIS was the most significant in effect of increasing the content of HEC, HAC and FAC. Moreover, Treatment EIS altered the composition of humus more significantly than all the other treatments, by increasing the proportion of alkyl C and the ratio of aliphatic C/aromatic C. These results suggest that straw returning accelerated the accumulation of soil organic C and various components of humus, significantly improved the structure of soil HA, with the practice of EIS in particular. [ABSTRACT FROM AUTHOR]