Study On Macropore Flow In Soil Of Unsufficient Irrigation Rice Field

The rice is one of the main food crops of our country. The stability anddevelopments of the production scale of the rice are very important ingrain-production. The water that the rice needs is more than others. With thedevelopment of the saving irrigation and the pinch of water resource more andmore, it is very important to research the upland rice cultivation andunsufficient irrigation.However, due to the unsufficient irrigation which caused by cracks, muchwater lost in irrigation; on the other hand, the chemicals which remains in soilwill be taken speedily to ground water through cracks by preferential flow andthereby make it polluted.Aiming at the problem that lie on the maeropore flow, the researchprogress fix quantify study on the macropore flow, with technique of theanalyzing image and numerical picture system, though the soil the tiny viewstructure. The moving model of the macropore flow with the theories of fractaldimension was studied in the research. Main work and creative points are asfollowing:(1) Built up the analytical technique of numerical picture system from thesoil sample handling, the picture obtaining and analyzing. The result showedthat the analytical technique of numerical picture system didn't need the highcost and could describe the number, size and distribution of soil macropore. Atthe same time, set up the analysis index of macropore structure(the number ofmacropore N, the macroporosityΦ, the area A, the perimeter P, the becominground ratio C, the average aperture R_P, the hole complications D, themacropore area variation of the picture 5mm space between V_j, the macroporeoverlapping degree O_P). Analyzed the various rule and difference of differentquality soil macropore structure in the soil vertical section. The resultexpressed that we could quantificationally evaluate the difference of the different quality soil macropore structure from the macropore result analysisindex.(2) Water penetrating experiment showed that water in the original shapesoil with macropores would cause macropore flow. And with the increase ofwater supplement runoff, the penetrating time in the original shape soil woulddecrease. The experiment proved that water transport would increase with theincrease of water supplement under the condition that other conditions aresame. Experiments also show that the quality of soil will influence thepenetrating water. Water penetrating in sandy loam is quicker than the speedof that in clay, under the condition that other conditions are same.(3) Because of the holding of soil humidity and moving of humidity anddissolve lying on the geometry shape of soil to a large extent. So when decidedthe fractal dimension only consider the size of soil is not complete obviously.With technique of the analyzing image and numerical picture system, theresearch gained the number, size and shape dates of the big hole. The fractaldimension D_v was computed though adopting area method. As the result, D_v is1.8567 and 1.7044. The result show: fractal dimension was different when thecharacters of soil change. As a whole, the soil quality is thinner (content moreglue); the fractal dimension number is bigger.This paper researched the soil macropore flow of unsufficient irrigationrice field, enriched the macropore research theory and it had the scientificguiding meanings to the adequate irrigation and the reduction of agricultureaerial pollution.