Research On The Maize Rhizosphere Regulation Mechanism Under The Condition Of Mulching And Construction Of Root Water Uptake Model

Water is the lifeline of agriculture. And it is the source of human life as well as the wholenational economy. The conflicts between agricultural water resources supply and demand isincreasingly obvious in China, It is imperative to develop modern agricultural high efficiencywater saving technology. In order to develop water saving agriculture and precision agriculture,immediate understanding spatial dynamic variation of soil moisture in the field is theprerequisite. Water uptake by plant roots is the main approach of plant water consumption,accurate control characteristics of the root system of crop and soil water dynamic rule is thenecessary data for the study of SPAC system soil water transmission properties. The results ofthis research have far reaching significance for determining water saving cultivation model inroot area.Combined with the Heilongjiang Province of graduate innovation research project“Research on the Maize Rhizosphere Regulation Mechanism under the Condition of Mulchingand Construction of Root Water Uptake Model”（YJSCX2012-022HLJ）and the youth sciencefund project of national science foundation of china “Study of the Mechanism of DifferentMulching Tillage Measures on Soil Regulation and Moisture Conservation and the ForecastSystem of Soil Moisture in the Black Soil Area in the Songnen plain”(51109037).Throughmaking the experimental study in the Northeast Agricultural University of HeilongjiangProvince from2011.3to2012.11. Methods the field investigation and the combined methods inboth field trial and numerical simulation were carried out for the research of corn plant growth、space distribution characteristics of corn roots and maize rhizosphere regulation mechanismunder different treatments. Establishment of root water uptake model of two-dimensional withroot weight density、root length density and root surface area density.The results of this researchprovide strong support for SPAC system soil water transmission properties under the conditionof mulching.The main research contents and results are as follows:(1) Research of corn plant growth and Production conditions. Maize growth and yieldimpact factor studies under the two different conditions of the laminating Cover straw have shown that: the corn leaf area index, plant height and stem diameter growth consistent basicallythe same growing, presented a single peak curve at the whole growth stage. Straw coverage caneffectively collects rainfall, decrease evaporation and realize high and stable grain production inthe earlier growing stage.Stubble-mulch had high efficiency of rainfall harvesting and increasingentropy. There are also significant differences under straw mulch modes. Maize yield was shownthat the shallow-tillage mulch treatment was the best,and higher than the conventional tillage1.84%~9.32%, increasing16.14%.There was no significant advantage under the completecoverage of no-till.(2) Research of space distribution characteristics of corn roots. Effective corn roots aremainly distributed in40cm below the surface and radial20cm within the range. The indicatorsof root has an exponential decreased trend with the increase in horizontal distance and verticaldepth under different treatments.Stubble-mulch measures conducive to the promotion of drylandpenetration of corn roots.Root weight and root surface area are the best in shallow loose crushedstalk compacted,and easy to extend deep roots. Exponential function on root indicators wereobtained by fitting two-dimensional root density distribution function.This function can betterreflect the two-dimensional of the maize root spatial distribution of dynamic changes.(3) Establishment and validation of corn root water uptake rate model. Establishment ofroot water uptake model of two-dimensional with root weight density、root length density androot surface area density. Using the ADI method to solve the numerical model of soil watermovement, simulated and measured values relative errors are less than10%,it can reach thesimulation accuracy. Root surface area density correction model to calculate the effect is moreideal.