Effects Of Soil Penetration Resistance On Maize Root And Water Relations Of In A Red Soil

Drought is a very complicated synthesis process, it will cause the change of a series of physical, chemical and biological properties of soil. In the process of drought,the penetration resistance of red soil will increase sharply, crop root elongation is blocked, even stop, The ability to absorb water and nutrients will reduced, which will have effects on the physiology characteristics of root system,such as water potential of crop root, root activity and root cells form, however very few studies about effects of penetration resistance on crops. Also not clear for the effect of drought stress. The objectives of this thesis were to study the effects of red soil penetration resistance on maize root system under different drought degree, and then analyze the effects of soil penetration resistance on the relationships of moisture between crops and soil. From the results, some scientific basis were provided for discussing the formation mechanism of seasonal drought.The field experiment was carried out in the red soil experimental station of huazhong agricultural university from June to September in2013. The plot regulated the soil penetration resistance by four tillage measures, which included deep tillage-D, conventional tillage-C, no tillage-N, and compaction-P. and set up six drought degree(4、8、12、16、20、24days without irrigation) in each tillage. Measuring the soil penetration resistance of different levels with SC900Soil Compaction Meter, at the same time, testing soil water content, root morphology, root tip cell size, root water potential, leaf water potential and root activity.1) Root length of maize will shorten with the increase of the penetration resistance, Under the same drought degree, comparison of Root length of maize in the4tillage, the arrangement is D>C> N>P; root diameter will coarsen along with the increase of the the soil penetration resistance, under the same drought degree, comparison of Root diameter in the4tillage, the arrangement is P>N>C>D; the penetration resistance have effects on the cell of root, especially on the cell of root tip, the greater the red soil penetration resistance,the bigger cell layer thickness, the smaller the single cell thickness. Results showed that the red soil penetration resistance affected the corn root morphology significantly.2) Under the same drought degree, comparison of root water potential in the4 tillage is P<N<C<D; root water potential of maize will reduce With the increase of penetration resistance, and the relationship between root water potential-soil water content is more closely; Similar to root water potential, leaf water potential of maize is decreased with the increase of red soil penetration resistance. The results showed that it is not conducive to improve the water relations between maize and and soil under drought conditions along with red soil penetration resistance increased.3)Root system activity of maize increasing firstly and then decrease with the increase of the red soil penetration resistance decreases, along with the change of soil penetration resistance, root system activity of maize will appear a peak in the process. Root activity in the C and N should be greater than the root activity of D and P, shows that in addition to the soil penetration resistance, root activity was also significantly affected by tillage, it is essential to pay attention to the problem.The relationship between the root morphology、root activity and water potential of root and leaf of Maize and red soil penetration resistance is similar under the different drought degree; greater the red soil penetration resistance is, more significantly the influence is, which will promote the water relations between maize and soil, As to the red soil in this study, deep tillage reduced its penetration resistance significantly, however no tillage or compaction resulted in the high penetration resistances, so it effect the Maize growth directly and was not helpful to ease the seasonal drought.