| In recent years,the global warming,the deterioration of the ecological environment,the frequent occurrence of natural disasters,and the shortage of water resources have posed a serious threat to the high yield and stable production of the corn industry.Among them,the occurrence of drought will have a series of effects on crops,and the contradiction between water demand and water shortage is increasingly sharp,which requires the improvement of water resources utilization efficiency.Therefore,the development of efficient and water-saving agricultural irrigation has become the internal demand of agricultural sustainable development.It is of great significance for the comprehensive construction of water-saving agriculture to study the physiological water consumption law of the critical period of water requirement during the whole growth period of maize,and to make appropriate irrigation in time to improve the water use efficiency.Based on the research project of the relationship between the physiological water requirements of typical crops and soil moisture in the hilly region of central Sichuan Province,Zhongyu 3 spring maize was selected as the research object,and the canopy was arranged in Jianyang Yucheng test station of Sichuan agricultural scientific research institute.The water gradient control test was carried out during the Milky milk ripening period.The physiological and ecological indexes,such as transpiration rate,net photosynthetic rate,stomatal conductance and water use efficiency,were measured by LC-pro + photosynthetic apparatus.Soil moisture content and soil water suction were measured by HH2 type soil hygrometer and DIK-3521.By means of single factor analysis of variance(one-way ANOVA)and correlation analysis,the physiological and ecological indexes and Soil Moisture Indexes of spring maize were quantitatively studied by using SPSS and EXCEL software.The conclusions are as follows:(1)During drought stress,the daily photosynthetic rate,stomatal conductance and transpiration rate of Spring Maize during jointing and tassel stage were similar.The dynamic peak value of T3(21%),T4(18%)and T5(15%)day was earlier than that of T1(27%)T2(24%),and appeared at about 9:00 in the morning.The mean water use efficiency(WUE)was T3(21%)>T5(27%)>T4(18%)>T2(24%)>T1(27%).It shows that a certain degree of drought stress is beneficial to the improvement of water use efficiency.The variance analysis showed that: jointing and tassel stage had a drought stress on spring maize.With the increase of drought stress,net photosynthetic rate,transpiration rate and stomatal conductance of spring maize showed a decreasing rule.(2)Water control flowering silking stage,when soil moisture was reduced to T3(21%),net photosynthetic rate,stomatal conductance and transpiration rate showed a significant peak in advance.When the water gradient decreased to T3(21%),the physiological and ecological indexes changed significantly,and the decline rate increased rapidly.With the further deepening of drought stress,the physiological and ecological indexes showed a standstill,such as stomatal closure and transpiration rate decreased,while the net photosynthetic rate fell to a negative,weak and water use efficiency of photosynthesis,dry matter accumulation of leaves will have irreversible harm.After drought,T4(18%)T5(15%)has a compensation effect,and all physiological and ecological indexes have been greatly improved.(3)During filling milky stage,spring maize was controlled by moisture.The peak of net photosynthetic rate,stomatal conductance and transpiration rate of spring maize appeared at noon after T1(27%)and T2(24%),and remained at a high level throughout the day.The drought stress of spring maize was carried out during the milking-milk ripening period,and the physiological and ecological indexes were not consistent with the drought stress of different degrees.The maximum value of net photosynthetic rate,stomatal conductance and water use efficiency appeared at T1(27%)water level,but the maximum value of transpiration rate appeared in T2(24%).(4)To study the effect of drought on different physiological stages of spring maize physiological and ecological index of moisture gradient in T1(27%),the water use efficiency of WUE showed the jointing heading flowering silking stage > filling milk stage,the transpiration rate(E),net photosynthetic rate,stomatal conductance value for filling milk stage anthesis silking >jointing heading.When the water gradient was controlled at T2(24%),the jointing and heading stage of spring maize was significantly different.When the water drops to T3(21%)and the gradient,eco physiological indexes at the flowering silking stage showed significant difference. |
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