The Mechanism Of High Yieid Farmland Soil Structure And Deep Tillage And Straw Returning Regulation In Spring Maize

For the study of the system of spring corn high yield field law of annual variation of soil structure, this research through the maize straw manure returning fixed-point test for five consecutive years, the ratio of different biological carbon soil water capacity simulation experiment, and the frequency of different frozen soil freezing and thawing alternation of simulation experiment. Determination of soil structure, water capacity and pore properties and corn upper leaves, dry matter accumulation and yield index, Correlation analysis of various index.Exploring deep plowing of maize straw manure reductive degradation annual variability effects on soil structure, providing a reference for create and establish a system for high yielding spring maize planting patterns.Through the test is Setting the spring shallow rotary tillage 15cm and the fall of the commune 40cm spring maize straw crushing returning full amount processing, the average annual amount of straw returned to spring maize is 2924.84kg/667m2. Spring shallow rotary tillage for five years is written for CK; The Falling Deep Tillage one year and Spring shallow rotary tillage for five years is written for SFI; The Falling Deep Tillage two years and Spring shallow rotary tillage for five years is written for SF2; The Falling Deep Tillage three years and Spring shallow rotary tillage for five years is written for SF3; The Falling Deep Tillage four years and Spring shallow rotary tillage for five years is written for SF4; The indicators of these five pieces of yielding spring maize soil structure are analyzed, and Each field is 115 meters long,4.5 meters wide. To analyze the soil structure index.1.Different in the commune time (SF1～SF4) processing, the Soil bulk density and soil rigidity are significantly lower than CK at 0-40 centimeters soil layer. The mechanical aggregate of SF4 which includes R0.25 are obviously lower than CK in the 0-20 centimeters soil layer. SF3 and SF4 are obviously smaller than the Mean Weight Diameter (MWD) of CK. SF4 is obviously smaller than the Geometric Mean Diameter (GMD) of CK. SFI is obviously smaller than the Percentage of Aggregate Disruption(PAD) of CK. The unstable coefficient of Stability Water Aggregate (SWA) shows that SF1～SF4 are significantly lower than that of CK. SF4 is increase obviously than the fractal dimension D of CK. The mechanical aggregate of SF4 includes R0.25, SF1 and SF2 are obviously greater than CK in the 20-40 centimeters soil layer. SF2 is obviously greater than the Mean Weight Diameter (MWD) of CK. SF2 is obviously greater than the Geometric Mean Diameter (GMD) of CK. Percent of Aggregate Damage rate (PAD)of CK shows that SF1～SF4 are obviously lower than that of CK. SF1-SF4 are obviously greater than the unstable coefficient of Stability Water Aggregate(SWA) of CK. SF2 is reduce obviously than the Fractal dimension D of CK.2.The result of the effects of deep tillage and straw returning on soil porosity shows that SF1～SF4 have greater significant increase than CK before spring sowing, and increased by 13.44%,16.83%,23.38% and 23.11%;SF1～SF4 have great significant increase when compare with CK at filling stage, increased by 16.94%,16.96%,16.94% and 22.54%; SF1-SF4 have greater significant increase than CK in harvest time, increased by 18.65%,20.08%,22.57% and 25.54%.3.The result which the deep tillage and straw returning tests on soil water capacity shows that the high yield field is lower than CK, the average soil infiltration rate is faster than CK, cumulative infiltration is more than the ordinary production field. Between high yield field, with the increase of the commune straw counters-field years time, the soil water capacity gradually reduced, the average soil infiltration rate gradually accelerated, the cumulative infiltration of soil increase gradually.4. Due to years of the commune maize straw manure returning decomposition rate is different. In order to further system research soil infiltration curve and soil water characteristic ratio, to set indoor monocyclic infiltration method and pressure membrane apparatus, simulate the field experiment. Studied under the condition of the same density, applying different proportion biological carbon (0%,1%,3%,5%,8%,10%) in different soil (sand loam, clay loam) effect on the properties of the soil hydraulic conductivity. Illustrate the deep tillage and straw returning change the soil structure and effect on soils’ water. The results show that the bulk density under the condition of unchanged, adding different proportions of biological carbon different effects on soil and loam. Biological carbon is added in the sand, with the increase of the content of biological carbon soil infiltration rate, cumulative infiltration volume decreases, and can effectively improve the ability of soil moisture. For loam, when biological carbon added from 1% to 1%, water-holding capacity, infiltration rate and cumulative infiltration amount increases, when the adding amount of 10%, instead of the 8% when processing a decrease.5.In order to further system research annual variation soil structure difference. Taking the indoor simulation in the field of seasonal freezing and thawing process experiment. Set to freeze frequency 0,2,4,6 times indoor simulated freezing experiment. The results showed that alternative freezing and thawing can significantly increase the soil pore number super, it significantly reduced Feret-d average pore diameter and soil area in the low production. Alternative freezing and thawing significantly reduce the pore number of aggregates>5mm for high yield field, alternative freezing and thawing significantly reduced the middle-and-low-yield porosity of the aggregate number of 0.5 to 1 mm,1 to 2 mm and the 2 to 5mm.Alternative freezing and thawing significant increase the low production aggregate average pore size of 2 to 5 mm.6. The result which the deep tillage and straw returning tests on corn root system shows that soil root dry weight, root length and root surface area of SF1-SF4 significantly greater than CK in 0-60 cm soil layer. The aboveground dry matter accumulation of SF2-SF4 significantly greater than CK. The SPAD of SF1-SF4 significantly greater than CK. The maximum photochemical efficiency effectively of SF4 significantly greater than CK. Yield components,the spike numbers of SF3 and SF4 significantly more than CK,the 1000-grain weight of SF1-SF4 significantly more than CK,the yield of SF3 and SF4 significantly more than CK, the biomass of SF2-SF4 significantly more than CK.