Screening Of Salt Tolerant Green Manure And On Effect Of Green Manure On Cotton Fields

The research was conducted to screen salt tolerance green manure and clear the contribution ofgreen manure in agriculture production. These experiments evaluated salt tolerant of green manurecrops in northern China, determinated the sowing date of Vicia villosa Roth and Orychophragmusviolaceus(L.) in different salinity soils, researched the influence of green manure on cotton fields. Theseconclusions were gotten:1The evaluation of salt tolerant green manure crops in northern China. Vicia villosa Roth andalfafa have a weak salt tolerance, and they can obtain more than90%of the biomasses in the soil with asalinity content of3g/kg Orychophragmus violaceus(L.) and Astragalus adsurgens Pall. have amoderate salt tolerance, and they can obtain nearly85%of biomasses in the soil with a salinity contentof4g/kg; Beta vulgaris, G.soja.Sieb.et Zucc and Sorghum bicolor(L.) moench×S.Sudanense(L.)Stapfhave a strong salt tolerance, and they can obtain nearly85%of yields or biomasses in the soil with asalinity content of5-6g/kg; Sesbania cannabina Pers has a extremely strong salt tolerance, and it canobtain90%of biomass. in the soil with a salinity content of5-6g/kg. Growing and overturning greenmanure in saline-alkaline soil can reduce the salinity in topsoil and improve the organic matter content.(2) The determination of Vicia villosa Roth and Orychophragmus violaceus(L.) sowing date indifferent salinity soils. The fresh biomass of Orychophragmus violaceus(L.) is mainly influenced bysowing date in mild and middle saline-alkali soil. Its fresh biomass sowed in September10is twicemuch as fresh biomass sowed in September20. Orychophragmus violaceus(L.) can be as green manurein mild and middle saline-alkali soil. In mild saline soil, sowing date has not much influence on Viciavillosa Roth fresh biomass. The biomasses were essentially identical in different sowing dates. But thesoil salinity content has a big influence on fresh biomass of Vicia villosa Roth, its biomass beinginhibited in middle saline-alkali soil, Vicia villosa Roth can be as green manure in mild saline-alkalisoil.3The influence of green manure applying on cotton growth and fertilizer use efficiency. Growingand overturning green manure can increase SPAD values of cotton leaves significantly. In thisexperiments, two treatments of overturning Orychophragmus violaceus(L.) and Vicia villosa Roth haveSPAD values of42.9and44.6, and they are higher significantly than the treatment of no green manure,which has the SPAD value of39.9. The influence of green manure on cotton agronomic charactersfocus on productive bulls, however, fruit nodes and fruit bearing branches have no significant difference.Green manure overturning is helpful to the absorption of cotton’s nitrogen, phosphorus and potassium.The application of green manure matching with70%inorganic fertilizers has no effect on cottonnutrients absorption. In this experiment, the two treatments of overturning green manure have a highernutrient accumulation than the treatment of on green manure, the N, P, K accumulations ofOrychophragmus violaceus(L.) treatment is higher than Vicia villosa Roth treatment.The seed cotton yields of green manure incorporated treatment increased about30%than the singlefertilizer treatment. The seed cotton yields of treatment overturning Orychophragmus violaceus(L.) ishigher than treatment overturning Vicia villosa Roth. Combined application of green manure matching with inorganic fertilizers can significantly increase the cotton’s Fertilizer contribution rate(FCR) andAgronomic efficiency(AE). In this experiment, FCR of two green manure treatments (Orychophragmusviolaceus(L.) and Vicia villosa Roth)are17.04%and9.98%higher than no green manure treatment, andAE of two green manure treatments(Orychophragmus violaceus(L.) and Vicia villosa Roth) are145.04%and95.76%higher than the no green manure treatment. FCR and AE of treatment Orychophragmusviolaceus(L.) are higher than treatment Vicia villosa Roth.4The influence of green manure on soil nutrient in cotton field. Applying green manure canincrease soil N, P, K and organic matter contents significantly. Reducing30%fertilizer, soil nutrient didnot reduce significantly. In this experiment, the total N, available P, available K and organic matter oftreatment Orychophragmus violaceus(L.) reached0.85g/kg11.63mg/kg149.93mg/kg12.66g/kg, thesecontents are higher than treatment no green manure; the total N, available K and organic matter oftreatment Vicia villosa Roth reached0.85g/kg10.41mg/kg144.21mg/kg12.64g/kg, these contents arehigher than treatment no green manure, but available P content is relatively low. The soil nutrientcontents of treatment Orychophragmus violaceus(L.) are higher than treatment Vicia villosa Roth..