The Effect Of No-tillage And Straw Return On Soil Ecological Environment And Rice Growth

As a new type of conservation tillage,no tillage and straw returning influence the soil environment and quality,thus indirectly affect the growth of crops.This experiment is a long-term field location test conducted at the experimental farm of Yangzhou University and it is the double cropping systems of rice and wheat.A total of six treatments are set up in this experiment,they are No-tillage and straw mulching(NTS),Rotation tillage that convention tillage in wheat and no-tillage in rice(RT1),Rotation tillage that convention tillage in rice and no-tillage in wheat(RT2),Convention tillage and full straw returning(CTS),Minimum convention tillage and half straw returning(MTS)and Convention tillage(CT).The aim is to further study the influence of no-tillage and straw returning on soil ecological environment and rice growth and yield,provide theoretical and technical support for light weight and efficient cultivation of rice.The results of the study show that organic matter,total nitrogen,available phosphorus and other elements show the obvious stratification in the soil.Its regularity is:there are high content of nutrient elements in the upper layer of soil,the middle is the second and the lowest level is the lowest.The stratification of no-tillage treatment is more obvious and no-tillage contributes to the enrichment of elements on the surface of the soil.No-tillage and convention tillage and full straw returning(CTS)or minimum convention tillage and half straw returning(MTS)can significantly improve the content of soil organic matter,and the CTS treatment is the best.Total nitrogen enrichment in the upper layer of soil under continuous no-tillage treatment,the content of total nitrogen is lower in the lower layers of the soil,it is not conducive to the improvement of total nitrogen in the layers of the soil,but convention tillage and full straw returning(CTS)or minimum convention tillage and half straw returning(MTS)has a certain effect on the content of total nitrogen in soil.Continuous no-tillage can enrich the available nitrogen on the surface of the soil,straw returning can improve the content of nitrogen in the whole soil layer.Continuous no-tillage or plowing and straw returning have no obvious effect on the content of available phosphorus in soil,but rotation tillage(RT1?RT2)can help to improve the content of available phosphorus in the soil layer.No-tillage contributes to the enrichment of available potassium on the surface of the soil,while the content of available potassium in each soil layer is high under the tillage treatment.Bulk density and respiration intensity are important indicators for measuring ecological environment of soil.Soil bulk density is lower after ploughing while it is higher after continuous no-tillage,but it does not affect the growth of rice or wheat.Respiration intensity of each treatment after the harvest of rice is:MTS>CTS=RT2>RT1>NTS>CT.Soil respiration intensity of convention tillage and full straw returning(CTS)or minimum convention tillage and half straw returning(MTS)is greater than no-tillage(NTS)and convention tillage(CT),the main reason is that there are more microbial biomass and activity in the soil of MTS or CTS treatments.In addition to influence soil environment and nutrient contents,no-tillage and straw returning also affect the growth of rice plants,thus affecting the yield of rice.In the whole growth period of rice,direct seeding rice of no-tillage has a lower plant height.Compared with other treatments,the dry matter accumulation is low.The plowing and straw returning treatments have a higher nitrogen content in the late stage of rice growth,and it is conducive to improve the rice production.The content of nitrogen,phosphorus and potassium in plant is not high under the continuous no-tillage treatment,straw returning and rotation tillage can help the accumulation of nitrogen,phosphorus and potassium in rice plants.From the jointing stage to the mature period,this test founded that the increase of nitrogen,phosphorus and potassium in rice plant is quickest under the RT2 treatment and reach a higher level and RT2 treatment has a high yield.The number of real grains of no tillage direct seeding rice is less,although the number of spikes and thousand-grain weight is slightly larger,the yield is still low.The yield is 6.0%-19.4%lower than the contrast,the yield of continuous no-tillage rice is the lowest.The plowing and straw returning treatments influence rice yield,minimum convention tillage and half straw returning(MTS)in favor of increasing rice production and increasing income,and there is no significant difference between the convention tillage.Therefore,we can turn over or carry on minimal tillage in good time after continuous no-tillage,and it is helpful to increase rice yield by combining with straw returning and rotation tillage.