Primary Study On High Yield And High Efficiency Planting Techniques Of Green Manure Grass In Agricultural Areas Of Lower Yangtze River

For select the suitable species and provide more choices for the planting of green manure grass in agricultural areas of lower Yangtze river,this research adopted the field experiment,pot experiment and investigation to compare chinese milk vetch(Astragalus sinicus L.),light leaf vetch(Vicia villosa Rothvar.),hairy vetch(Vicia villosa Roth.)and other 18 species green manure grass in agricultural areas of lower Yangtze river of growth,nutrient content,disease and insect resistance,nitrogen fixation capacity,landscape effect and the changes of soil fertility after returning green manure grass to field.Meanwhile,the planting techniques of green manure grass suitable for high-yield and high-efficiency cultivation in agricultural areas of lower Yangtze river were studied,and the effects of sowing date,sowing amount,planting methods and stubble height of rice(Oryza sativa L.)on the growth of green manure grass were explored,which provided technical support and theoretical guidance for high-yield and high-efficiency cultivation,and provided experience and reference for sustainable agricultural development.This research mainly draws the following conclusions:1.There are obvious differences in growth and development among green manure grass species.Fifteen species of succeeding crops,such as light leaf vetch,hairy vetch,common vetch(Vicia sativa L.),alfalfa(Medicago sativa L.)grew relatively well in the intercropping with rice;showy crotalaria(Crotalaria spectabilis Roth.),crownvetch(Coronilla varia L.)and standing milkvetch(Astragalua adsurgens Pall.)grew relatively poor.The highest yield of fresh grass is light leaf vetch,followed by hairy vetch,common vetch and italian ryegrass(Lolium multiflorum Lam.),grass yield the lowest is standing milkvetch.the six species of the genus vetch and clover are the most resistant to disease and insects,and the disease and insects resistance of chinese milk vetch,sainfoin(Onobrychis viciaefolia Scop.)and crownvetch is the weakest.Vicia genus,chinese milk vetch and orychophragmus violaceus(Orychophragmusviolaceus L.)have the better landscape effect,with early flowering,longer flowering period,more flowers and more beautiful colors.showy crotalaria,sainfoin,california burclover(Medicago hispida Gaertn.),yellow sweetclover(Melilotus officinalis Desr.),white clover(Trifolium repens L.)and alfalfa have high nitrogen-fixing ability.2.The 18 green manure grass tested can increase soil nutrient content after returning to the field,improve soil fertility,and increase soil organic matter content by 1.01～4.52 g·kg-1,total nitrogen 0.02～0.45 g·kg-1,and total phosphorus 0.04～0.19 g.kg-1,total potassium 0.05～0.52 g·kg-1,ammonium nitrogen 0.44～3.61 mg·kg-1,available phosphorus 1.10～3.89 mg·kg-1,available potassium 10.24～36.34 mg·kg-1.Among them,the fertilization effect of light leaf vetch was the best among the green manure grass.3.Sowing date significantly affected the growth and development process,morphology,yield and nutrient content of green manure grass.Among the five sowing dates of green manure grass tested,the growth process of sowing date on October 11 was closely related to the stubble degree of rice,with high yield.According to the varieties tested,the suitable sowing amount is 37.5-45.0 kg·hm-2.4.The interplanting chinese milk vetch is the most productive and efficient planting method,the fields can reach 35.7 kg·hm-2,which is 5.82%higher than that of shallow-rotation seedling after harvest and 18.81%higher than stubble seedling after harvest.5.Under "rice—chinese milk vetch" rotation mode,different stubble height of rice had significant effects on the growth period,overwinter rate,morphological index,yield and field landscape effect of chinese milk vetch.30 cm stubble height of rice can promote the growth and development of chinese milk vetch,increase the yield of chinese milk vetch,and the field landscape effect is better.