The Influence On Rice Growth And Soil Nutrients Of Various Depth Of Tillage

Continuous years of unreasonable soil management has made the paddy soil rise many problems including the plough layer shoaling,soil hardening,plow pan thickening and soil porosity decreasing,which lead the ventilation and water permeability of the soil to reduce,affect the penetration and growth of root and reduce the activity of soil microbe and influence the yield and quality of the rice.By the methods such as increasing the depth of farming or breaking the plow sole,the soil physical and chemical properties can be improved so as to be helpful to the growth of rice and transformation of soil nutrients and rising of yield.This paper takes the paddy field testing ground as the research object to study the effects of different tillage depth treatment(14cm,17cm,20cm respectively)on the growth of rice and nutrients of soil,to explore the feasible tillage depth of littoral saline paddy soil in order to provide a theory reference and data support for increasing the yield and quality of rice and constituting reasonable plough layer index system of paddy field.The main research results are as follow:(1)It can be seen that the total root length,root surface area and root volume of the tillage depth treatment of 20cm from the morphological index of root.The tillage depth in each growing period of rice is higher than 14cm and 17cm,it reflects that 20cm tillage depth treatment could promote the growth of root and boost the absorption range of root.(2)From three treatments of rice yield and its component factors,the treatment of 20cm tillage depth is greater than the treatment of 17cm tillage depth which is greater than the treatment of 14cm tillage depth,their outputs are 12.09t/hm~2,12.97t/hm~2,13.13t/hm~2.It can be seen that the output of rice increases with the increase of tillage depth.The plant height,panicle length,kernels per spike,setting percentage and other index of the treatment of 20cm tillage depth are superior to the treatment of 14cm tillage depth and the treatment of 17cm tillage depth.(3)At tillering stage,the total absorption of nitrogen,phosphorus and potassium of rice all is that the treatment of 20cm tillage depth is greater than the treatment of 17cm tillage depth which is greater than the treatment of 14cm tillage depth,and their total absorption of the nitrogen are respectively 30.44 kilograms per square hectometer,28.19 kilograms per square hectometer,24.85 kilograms per square hectometer;and the total absorption of phosphorus are 2.26 kilograms per square hectometer,1.80 kilograms per square hectometer,1.70 kilograms per square hectometer;and the total absorption of potassium are 72.34kilograms per square hectometer,59.57 kilograms per square hectometer,47.43 kilograms per square hectometer.It can be seen that the treatment of 20cm tillage depth is more favorable for rice to absorb nutrients.(4)After the rice was harvested,the content of the alkali-hydrolyzale nitrogen,the available phosphorus and the rapidly available potassium in soil are the treatment of 20cm tillage depth is the minimum,their content value are 42.58 milligrams per kilometer,10.63milligrams per kilometer,122.99 milligrams per kilometer respectively.The treatment of tillage depth of 20cm could boost the transformation of available nutrient and enhance the ability of plant to absorb and utilize the available nutrient.Taken together,the treatment of tillage depth of 20cm could quicken the transformation of soil nutrient and increase the total nutrient absorption of rice plants.The treatment of tillage depth of 20cm could improve the soil characteristics,boost the growth of rice roots and increase the yield of rice.