Effect Of Soil Droughts And Penetration Resistance Onwater Relations Of Maize In Clayey Red Soil

Seasonal drought is one of the important obstacles of agricultural production in red soil area. For clayey red, as the water content decreased, soil penetration resistance has increased rapidly; affecting the crop root growth and distribution, change the ability to absorb water and nutrients, thus affecting crop water relations. Therefore, crop drought stress on clayey red soil is often accompanied by penetration resistance stress. There are many literatures about the influence of soil water and penetration resistance respectively on plant growth and development, but the literatures are few on the course of soil penetration resistance on crop in the process of drought, the interaction between the two is not yet clear. In this paper, we study on the different treatments of drought, analyzed the effect of the soil resistance on the soil-crop water relations. From the results, discussing the formation mechanism of seasonal drought, some scientific bases were provided for prevention and cure the seasonal drought in red soil area.Field experiment in red soil experimental station of Huazhong Agricultural University in Xianning Hubei, two season’s corn plot test is carried out from June to October of 204-2015. The field experiment plot set up four different tillage treatments that deep tillage, conventional tillage, no-tillage and compaction. Each tillage measures set up well-watered, slight drought and severe drought conditions of three different water treatments from corn 8 leaf stage, field plot soil is the red soil which is derived from the same quaternary red clay, planting corn varieties is Zhangdan 958. In 12 leaf stage, 16 leaf stage and VT stage measuring soil water content and root and leaf water potential of corn in field. Repeat this three times each region, the main results are showed as follows:1) The soil water content and penetration resistance distribution in soil profile has a certain regularity has a certain regularity, soil moisture content increased with the increase of soil depth increased significantly, but the soil penetration resistance increased with the increase of soil depth, first after the decrease trend. Soil penetration resistance to peak at 20 cm, the compaction resistance under severe drought treatment reached 2.797 MPa. In well-wanted, the differences of soil water content and resistance between different tillage treatment is little, along with the increase of drought degree, the difference increased. The penetration resistance increases with the decreasing of water content, both significant nonlinear negative correlation relationships. When soil water content increased to a certain degree, the soil penetration resistance reaches a critical point and leveled off, wet red soil also has the high penetration resistance, and it has to do with its own characteristics of red soil.2) Under different tillage treatments, the root and leaf water potential and net photosynthetic rate have obvious difference, in order to D>C>N>P. With the increased levels of drought, cultivation treatments are differences. The influence of drought and tillage on crop root and leaf water potential reached extremely significant, their interaction reached significantly, In well-watered, the coefficient of soil penetration resistance is greater than the water content, with the increase of drought degree, soil water content is reduced, penetration resistance increase, both common affects crop water relations, by analysis of variance, the influence of drought of maize root leaf water potential is greater at this time.3)Red soil drought and penetration resistance affect the growth and distribution of root system. Red soil drought and penetration resistance affect the growth and distribution of root system, under the slight drought, corn root system of vertical and horizontal distribution range increased. But in the severe drought, the root of the vertical and horizontal distribution is significantly reduced. In the range of soil depth 20 to 40 cm, deep tillage compared with conventional tillage, no-tillage and compaction respectively higher-0.23%、15.13% and1.60 times. In the range of 10-15 cm, deep tillage compared with conventional tillage, no-tillage and compaction respectively higher 30.40%、44.13% and 53.45%. Tillage could control the root level and vertical distribution.4) The effect of drought and tillage on crop yield reached extremely significant, their interaction reached significantly, can effectively control the relationship between drought and crop yield. The crop yield and soil water content had significantly positive correlation, but crop yield and soil penetration resistance had significantly negative correlation. The orders were D>C>N>P, with the increase of drought degree, tillage treatment differences increased. In well-watered, the coefficient of soil penetration resistance is greater than the water content, means their interaction reached significantly, the influence of penetration resistance on crop yield is greater than the water content. With the increase of drought degree, soil water content is reduced, water penetration resistance has increased dramatically, by analysis of variance, drought and resistance combined impact maize yield, the influence of drought on corn yield more at this time.Clay red soil penetration resistance is in dynamic change, the water and resistance interaction of red soil in drought was complex.In mild and moderate droughts,soil penetration resistance affected crop greater than water stress.As the drought aggravated, soil resistance increased sharply, then it made the crop water relation worse, soil water stress affected crop greater than penetration resistance stress. Cultivation measures can significantly change the soil water and penetration resistance. No-till measures on crop water relations have significant side effects. Deep tillage can obviously decrease soil penetration resistance, regulating the corn crop water effect is remarkable.