The Effects Of No Tillage And Straw Returning Continuously On Soil Fertility And Yield Of Wheat And Rice

As a new type of cultivation nutrients,no tillage and straw returning can change the soil nutrients of farmland,affecting the growth and grain yield of crops.In order to investigate the effects of continuous no tillage and straw returning on soil physical and chemical properties and yield of wheat and rice, the field study was based on the experimental location platform of protective tillage of wheat/rice cropping system for 10 years in Yangzhou University Key Laboratory of Crop Genetics and Physio logy,during the two growing seasons of 2014 and 2015.Yangmai 13 was the wheat variety and Nanjing 9108 was the rice variety used in this study.The study was arranged in a randomized block design with eight treatments with three replicates. The eight treatments included no-tillage and straw returning (NTS), no-tillage and high stubble returning (NTH), no-tillage in wheat and convention tillage in rice (RNT), convention tillage in wheat and no-tillage in rice (RCT), convention tillage and full straw returning (CTS1), convention tillage and half-amount straw returning (CTS2), convention tillage and straw burning (CTB), and convention tillage (CT). The effects of these eight treatments on physical and chemical properties,soil fertility,wheat growth and yield of rice and wheat.It reveals nutrition absorption and growth of wheat and rice plants. As a reference for no tillage and straw returning to increase wheat and rice production.The main results were as follows.1.The amounts of soil organic matter were all increased under consecutive no tillage (NTS; NTH) and CTS (CTS1 and CTS2).The content of soil organic matter was maintained at a high level both after rice harvest and rice sowing,where CTS1 worked best.The dynamic trend of total nitrogen content was similar to that of organic matter,but how much the amount of straw returning has little effect on the dynamic trend of total nitrogen content. No tillage could increase the content of alkali-hydrolyzable in soil surface. Straw Returning increased the content of alkali-hydrolyzable in all the soil layers.The effects on the content of available phosphorus were not apparent.Both NTS and CTS1 increased the amount of available potassium.The amount of soil organic matter, total nitrogen, alkali-hydrolyzable and available potassium all increased under RNT and RCT,but the effect was less than no tillage and straw returning.It showed that returning straw in two seasons could have more significant effect on fertilize soil than one season. After wheat-rice two seasons condition, the amount of soil organic matter, total nitrogen, alkali-hydrolyzable and available potassium all increased.Compared with CT(conventional tillage+no straw returning,), the amplitude increases were 13.69%-31.97%、2.08%-17.71%、 9.46%-19.71%、4.42%-10.31%, the effects on the content of available phosphorus were not apparent.The average content of soil organic matter and total nitrogen under no tillage and straw returning in ten years were higher than CT,the amplitude increases were 6.45%-22.01%、 5.49%-21.98%,with convention tillage and straw returning (CTS1 and CTS2) as high.2.The height of rice was lower and dry matter accumulation was decreased, because of no seedling and the interference of wheat stubble in NTS. Rice grew rapidly in the later stages in treatments with straw returning, which increased the danger of rice lodging, and influenced the accumulation of dry matter. Due to the interference of rice stubble in NTS, dry matter accumulation was decreased and the height of wheat in no tillage was lower.The ability of lodging resistance was improved.The height of wheat in CTS was higher,which increased the possibility of lodging.The treatments of no tillage,rotation tillage and straw returning all increased the area of the three leaves on the upper part of wheat plant.The wheat in CTS was maintained a relatively high dry matter accumulation during the whole growth period,provided with high yield.With the advance of the growth period, NPK content of wheat plant gradually decreased.CTS2 could not only help to improve the content of NPK plant but also to improve the absorption rate of NPK plant.3.By viewing the 10 years yield of wheat and rice,no tillage in one season could increase wheat yield,RNT and CTS1 were better than other treatments.CTS was beneficial to the high-yielding rice. The rice yield could reach high level under no tillage and directly seeding condition,but continuous no tillage is lower.CTS2 got the highest annual yield, RNT took the 2nd place, and CTS1 was relatively higher. RCT and NTH were equal to CT, only NTS was lower than CT, resulting from lower rice yield under continuous no tillage in interplanting or direct sowing conditions.No tillage and rotation tillage with straw returning combined with sustainable farming technology system,might help to improve oil fertility and increase crop yields.It might conducive to sustainable development of agriculture.