| Rice wheat rotation system is one of the important cropping systems in the Yangtze River Basin in china.However,due to years of drought and flood alternation and rotary shallow rotation operations,paddy soil tillage depth becomes shallower,the soil structure gradually deteriorated,resulting in a decline in the overall quality of the soil,is not conducive to wheat root and absorb the deep soil nutrients and water,greatly limiting rice stubble wheat production.Deep loosening by deep shovel breaking hard bottom soil plough layer,can be added for deep layer thickness but without soil turnover,reduce soil bulk density and compaction,so as to effectively promote the infiltration and crop root water fertilizer under the overall under the bar,raising the yield of crops.However,at present,the study on the effects of subsoiling on Soil and crop is mainly focused on the soil and crops in dry farming area.Therefore,this paper describes the physical properties of soil in paddy rice soil,explore the deep tillage of the energy input and the disturbance effect on soil,study of deep tillage on wheat soil physical properties,root growth and yield of the influence of comprehensive evaluation of paddy soil subsoiling effect on soil physical characteristics,input resistance wheat,root growth and yield of paddy soil in rice wheat cropping system design,equipment specification of subsoiling tillage,provide a theoretical basis for establishing reasonable soil management mode.The results are as follows:1.Soil physical properties of paddy soilUnder the long-term drought and operation effect of alternating rotary tillage,paddy soil layer is very shallow,roughly in 0～12 cm depth,the plough in 12～22 cm depth range,below 22 cm for the percogenic layer;compared to upland soil,paddy soil and soil is shallow,soil bulk density is larger,the average soil rice soil is 0-40 cm soil volume is more important than upland soil is higher than 0.1 g/cm3;with the increasing depth of the soil physical parameters showed a tendency of slow-sudden gentle ";the soil bulk density,compactness,cohesive force increases dramatically in the plow bottom layer,the porosity decreases sharply,resulting in decreased the soil water storage capacity,water content decreased rapidly,below 22 cm overall at a high bulk density,high compactness,high cohesion,low porosity,low moisture level,is not conducive to the root And crop growth,and difficult to break the hard soil,increase the difficulty of mechanical farming,machinery and equipment need to invest more energy.2.Paddy soil subsoiling tillage resistanceIn the paddy soil conditions,chisel deep shovel shovel,shovel compared to palm wings has advantages of small resistance,farming resistance small,can obtain optimum tillage efficiency,paddy soil subsoiling subsoiling shovel suitable;subsoiling tillage resistance with tillage depth growth was two order the fitting function of growth,when the tillage depth is not more than 20 cm,the subsoiling tillage resistance resistance is low,small,high efficiency cultivation.But the subsoiler tillage depth exceeds 20 cm,the deep tillage resistance increased,tillage resistance increases rapidly,the deep tillage efficiency is greatly reduced;due to changes in soil structure,soil crushing required deep tillage energy input is different.When the depth of the soil layer is less than 20 cm,the deep loosening resistance is relatively small when every cm thick soil layer is cut by 10.However,when the soil depth is more than 20 cm,the deep cutting resistance of each cm thick soil layer is increased by 10.3.The effect of soil deep looseningThe subsoiler intensity of soil disturbance varies with tillage depth,generally show"first increase and then decrease" trend;in depth 20 cm,subsoiler tillage depth increased in the process of gradually increasing the amount of soil disturbance,broken body size increases,surface uplift,and longitudinal cracking fluctuation aggravation,the overall degree of disturbance increases;when the depth is over 20 cm,more part of the deep loosening shovel at the critical depth(15 cm depth)below,the quantity of soil disturbance,broken body scale decreases,surface uplift,cracking and longitudinal fluctuation degree decreased,the overall decline in the degree of disturbance;therefore only consider tillage efficiency and soil disturbance degree under the premise of the research results,the physical properties of soil,paddy soil deep tillage resistance considering the paddy soil deep tillage with deep chisel Shovel is the best subsoiler tillage depth 20 cm was the best,the largest amount of soil disturbance,tillage resistance at a relatively low level of energy efficiency and meet the best farming,"breaking plow and loose plough layer below 5～15 cm" technology.4.Effects of different tillage methods on soil physical properties in wheat growth stageCompared with conventional tillage subsoiling and no tillage,the average soil bulk density of two winter wheat growth period decreased 0.04 g/cm3,0.11 g/cm3,was followed by 3%,7.8%;the average soil water content increased by 3.08%,2.61%,followed by an increase of 11.1%,9.3%.The average soil water holding capacity increased by 1.77%,2.79%,5.5%,followed by an increase of 8.9%;compared to conventional tillage and no tillage,subsoiling tillage can effectively break the hard plough layer,reduce the average soil bulk density of wheat growth period,the increase of soil receptivity precipitation,water conservation,especially the effect on the bottom 10 20～cm soil bulk density decreased,water storage capacity increased more significantly,thus creating the soil environment for crop root growth of good.5.Effects of different tillage methods on root distribution and yield of WheatSubsoiling treatment could promote the growth of wheat roots and the degree of the whole cutting,deepen the root growth space and increase the total amount of roots.The root system of no tillage and conventional rotary tillage was distributed in the soil layer of 0-25 cm,and the root system of subsoiling tillage was distributed in the soil layer from 0 to 35 cm.Compared with no tillage and conventional tillage,subsoiling and root biomass in turn increased by 18.3%and 19.4%,and the overall increase below the surface(below 10 cm)quantity distribution percentage of wheat roots,is conducive to the absorption of wheat in bottom soil water and fertilizer,promote the whole wheat growth and development,strengthening resistance to natural disasters,pests and diseases and lodging support ability.Compared with no tillage and conventional rotary tillage,the average yield of subsoiling increased by 211.40 kg/hm2 and kg/hm2 in the next two seasons,with an increase of the order of 3.9%and 12%. |
