The Effects Of No Tillage And Straw Returning On Soil Physical And Chemical Properties And Wheat Growth

No-till with straw returned technology is a developing new type of farming, aimed at solving some traditional farming problems. It can improve the soil environment and the content of organic matters, increase soil nutrients, and promote crop growth and improve the yield. In this experiment, two wheat varieties, Yangmai13and Yangmai16, were treated by eight different till treatments:NTS(No-tillage and straw returning test was set up continuous no-tillage and straw mulching); NTH(No-tillage and high stubble remaining); RNT(no-tillage in wheat and convention tillage in rice); RCT(Convention tillage in wheat and no-tillage in rice); CTS1(Convention tillage and full straw returning), CTS2(Convention tillage and half straw returning), CTB(Convention tillage and straw burning), CT(Convention tillage). The trial aimed to study the influences of different tillage cultivation methods on soil fertilizer, the growth and development, the yield and quality of wheat, revealing that soil and wheat fertilizer characteristics, and rhythm of wheat, and it showed that no-tillage and straw returned could improve the yield and quality of wheat. The main result s are as following:1. Because of different tillages, there were difference between the upper topsoil bulk density and lower, no-tillage treatments with slightly higher density in middle and lower soil layer. But,all the topsoil bulk density is not over1.35g/cm3,it would not impact the growth of crops next season. After the rice harvest and the wheat harvest, no-tillage treatment had the lowest soil respiration rate, maybe there were more microorganism after the soil ploughing. They released a large number of CO2. Treatment of no-tillage, rotation tillage and straw mulching treatments favored for improving SMBN. After the rice harvest or the wheat harvest, soil organic matter content kept a high level on the treatment of CTS1,CTS2,NTS and NTH. After the same cultivation method, the more straw returned, the higher soil organic matter content was. Treatment of no-tillage, rotation tillage and straw mulching also favored for improving soil total nitrogen and alkaki-hydrolyzable N, so we can reduce the fertilizer use properly. For available P,the increasing was not obvious; and to soil available K, treatment of continous no-tillage could enhance soil available K degree of enrichment, but it can’t increase totality content, straw returned could improve the soil available K in total.2. During earlier growing stage, straw returning improved the temperature of the top layer of soil. No-tillage and straw returning were good for wheat growing, but the wheat was thin and long, however, straw returning had litter influence on the height of wheat plant during later growing stage. The plant height with no-tillage treatment was very low during maturation stage, which was good for wheat lodging-resistance ability. The upper-three leaf areas of no-tillage, crop rotation and straw returning treatment were high, which could increase wheat yield. No-tillage and straw returning had enough nitrogen nutrition for anthesis, so their chlorophyll content was high. After elongation stage, dry matter of NTS and NTH treatments were affected. During late growth stage, dry matter accumulation were higher, however, on the whole growing stage, ploughing straw returned treatment had a higher dry matter accumulation, which created a foundation for high yield. During seeding, tillering and regreening stage, with the pushing forward of grow period, nitrogen rate, phosphorus rate and potassium rate of wheat were gradually dropping. Nitrogen rate, phosphorus rate and potassium rate of wheat were relatively higher during maturation stage with no-tillage treatment which was good for the wheat vigorous growth, and no-tillage was also in favor of absorption N, P, and K accumulation.3、Wheat yield was affected in treatments with continuous no-tillage treatments, the wheat’s actual production with NTS, NTH was slightly lower than CT, but the difference was not significant. CTS2>CTB>CT>CTS1, this showed straw returning were in favor of wheat yield increasing; RNT>RCT>CT, and they had significant difference, which showed rotation tillage were in favor of wheat yield increasing. With convention tillage and straw returning treatments increasing the contents of protein, gluten content and zeleny, it improved the quality of medium gluten of wheat. Peak viscosity, low viscosity and final viscosity of no tillage and straw returning treatments were no significant difference to CT treatment, moreover, their breakdown value were all higher than CT, these all showed that no-tillage and straw returning would not reduce wheat quality.