Effects Of Maize Straw And Tillage Managements On Nutrition Absorption Of Peanuts And Soil Quality In Peanut Field

Peanut (Arachis hypogaea L.) as one of the most important oil crops, produces about 16.5 million tons of the yields per year in China, which accounts for 40% of the total peanut yields all over the world. Promoting the soil quality and peanut nutrition will provide the basis for high-yield and high-efficiency cultivation of peanut. In order to solve the problems of shallow soil layer, low soil fertility and low use efficiency of the fore-rotating crop straw, a typical brown soil site situated in Laixi Experimental Station of Shandong Peanut Research Institute was selected during April to October,2015. The experiment was used to investigate the changes in soil quality and peanut nutrient absorption under maize straw returning and various tillage treatments by determining soil fertility indexes, peanut growth traits, dry matter accumulation characteristics and nutrient absorption. Results showed as follows.(1) Tillage measure and maize straw returning exerted large effects on soil quality in peanut field. Compared with shallow plough, deep plough and deep loosing, no tillage decreased the soil bulk density by 10.1%,13.4% and 14.2%. Deep plough and deep loosing promoted the release of soil alkaline hydrolysable nitrogen (N), NH4F-HCl extractable phosphorus (P) and CH3COONH4 extractable potassium (K),which increased the total nutrient and organic matter content. Straw returning affected the soil physics, while soil bulk density was decreased slightly under the maize straw returning treatments.(2) All of the shallow plough, deep plough and deep loosing improved the growths of peanut, while the main stem height, branch length, branch number, leaf age, hundred pod weight, hundred kernel weight were increased significant compared with no tillage. The main stem heights and branch lengths under shallow plough and deep plough were of 20.3%-30.2% more than no tillage, while hundred pot weight and hundred kernel weight increased by 45%-54%. Under deep loosing, main stem height and branch length increased by 6.5% and 7.9% while hundred pot weight and hundred kernel weight increased by 30.1% and 30.2%. Straw returning combining with the deep plough and deep loosing have slightly positive effects on plant growth traits and pod traits, but there was no significant difference compared with no tillage.(3) Dry matter accumulation and peanut yield was promoted under tillage measure treatments while deep plough was better than shallow plough and deep losing. Tillage measures significantly increased the accumulation of dry matter in kernel part of peanut but no more accumulation in other parts within these three treatments. Under the maize straw returning, shallow plough increased the dry matter accumulation in vegetative organs whereas dry matter accumulation was decreased in vegetative organs but increased in kernel organs under deep plough and deep loosing. Compared with no tillage, peanut yields were increased respectively by 1621.0 kg/hm2,1523.8 kg/hm2,763.5 kg/hm2 under shallow plough, deep plough and deep loosing. Straw returning increased the yields under no tillage and deep loosing while no significant increase showed under shallow plough and deep plough. So far as the yield of all the treatments, deep loosing plus straw returning produced the highest yield, which increased 1700.6 kg/hm2 compared with no tillage.(4) There was obvious correlation between soil available nutrient and plant nutrient absorption amount. Under various tillage treatments, deep plough, deep loosing and shallow plough improved the total absorption amounts of N, P and K by the whole peanut part and the kernel. Straw returning could even increase the nutrient absorption under these three tillage treatments, while the ratio of these nutrients in kernel to the whole part was increased by straw returning. This indicated that straw help the nutrient transferring into the kernel of peanut.In conclusion, maize straw returning with 500 kg per mu combining the deep plough or deep loosing could promote the soil properties in the typical brown soil of peanut field (Laixi site). These two measures of deep tillage and straw returning increased the peanut growth, dry matter accumulation, nutrient absorption and yield. However, there was no significant difference among shallow plough, deep plough and deep loosing under the high soil fertility condition.