Advances in Germplasm Resources of Chinese Milk Vetch in China

Chinese milk vetch （Astragalus sinicus L. ） is a conunonly used green manure crop in paddy fields in southern China and it has the effect of fostering fertility and soil. This paper firstly sununarized advances in research of new high quality and yield varieties of germplasm resources of Chinese milk vetch. Then, on the basis of current situation, it came up with recommendations for collection, storage and promotion, as well as application in the current ecological agriculture, including establishing germplasm resource bank and improving germplasm resource evaluation system.

Effects of Long-term Return of Milk Vetch(Astragalus sinicus)on Soil Nutrients and Microorganism Communities in Double-rice Cropping Field

[Objectives]This study was conducted to investigate the effects of milk vetch(Astragalus sinicus)on soil nutrients and microorganisms in paddy fields after returning to the field.[Methods]Three treatments,no fertilization,single application of chemical fertilizers and milk vetch return combined with chemical fertilizers,were set up to determine soil nutrient contents and the quantity of microorganisms,respectively.[Results]The return of milk vetch combined with chemical fertilizers could significantly increase the contents of organic matter and total nitrogen in the paddy soil,while the contents of available potassium and available phosphorus decreased.Milk vetch return combined with chemical fertilizers could significantly increase the quantity of soil microorganisms in the paddy field.[Conclusions]The return of milk vetch can be used as a feasible measure to improve soil fertility.

Effects of rumen microorganisms on the decomposition of recycled straw residue

Recently,returning straw to the fields has been proved as a direct and effective method to tackle soil nutrient loss and agricultural pollution.Meanwhile,the slow decomposition of straw may harm the growth of the next crop.This study aimed to determine the effects of rumen microorganisms(RMs)on straw decomposition,bacterial microbial community structure,soil properties,and soil enzyme activity.The results showed that RMs significantly enhanced the degradation rate of straw in the soil,reaching 39.52%,which was 41.37%higher than that of the control on the 30th day after straw return.After 30 d,straw degradation showed a significant slower trend in both the control and the experimental groups.According to the soil physicochemical parameters,the application of rumen fluid expedited soil matter transformation and nutrient buildup,and increased the urease,sucrase,and cellulase activity by 10%‒20%.The qualitative analysis of straw showed that the hydroxyl functional group structure of cellulose in straw was greatly damaged after the application of rumen fluid.The analysis of soil microbial community structure revealed that the addition of rumen fluid led to the proliferation of Actinobacteria with strong cellulose degradation ability,which was the main reason for the accelerated straw decomposition.Our study highlights that returning rice straw to the fields with rumen fluid inoculation can be used as an effective measure to enhance the biological value of recycled rice straw,proposing a viable solution to the problem of sluggish straw decomposition.

Effects of hydrothermal carbonization temperature on carbon retention,stability,and properties of animal manure-derived hydrochar

Hydrothermal carbonization of animal manure is being increasingly recognized as a green process for hydrochar production.Temperature obviously affects the properties of hydrochar especially with respect to carbon retention and stability.These properties determine the carbon sequestration potential of hydrochar but related researches are limited.In this study,chicken,dairy,and swine manures were collected and hydrothermal carbonized under different temperature conditions,aiming to study the fuel characteristics,carbon retention,and stability of hydrochar influenced by temperature.Results show that high temperature led to low yield and declined H/C,O/C,and volatile matter of hydrochar.While high temperature caused high fixed carbon,fuel ratio,and heating value of hydrochar,indicating that animal manure hydrochar can be adopted as an alternative of fuel.After hydrothermal carbonization,less than half of carbon from animal manure was retained in hydrochar:22.70%-46.71%for chicken manure,39.36%-49.72%for dairy manure,and 36.24%-64.21%for swine manure.The carbon retention decreased with the increase of temperature.Conversely,high temperature improved the aromatic and strengthened the resistance to thermal oxidation of hydrochar,which was evidenced by FTIR and TGA analysis.Moreover,the carbon sequestration capacity of animal manure hydrochar was less than a third of total carbon(originated from animal manure)and relatively low temperature(no more than 250℃)was beneficial to produce hydrochar for carbon sequestration.