Effects Of Drip Irrigation Amount On The Photosynthetic Physiology,Yield And Quality Of Silage Maize

At present,the shortage of water resources is becoming more serious in the development of silage maize in Inner Mongolia.This study with the purpose of clarifying the optimal drip irrigation amount for the growth of silage maize in the semi-arid regions and providing the theoretical support for the silage maize cultivation techniques of lower water consumption and higher efficiency,researching the effects of five drip irrigation amount(W1:486.54 m³·hm^-2;W2:807.81 m³·hm^-2;W3:1129.07 m³·hm^-2;W4:1450.34 m³·hm^-2;W5:1771.60 m³·hm^-2)on water consumption,growth,photosynthetic physiology characteristics,yield,water use efficiency and nutrition quality of silage maize in two-year experiments.Xianyu 335and Zhongxingqingsi No.1 was used as the experimental material in this experiment.The main results are described here in.?1?Drip irrigation led to increase soil water content in the 0-60 cm soil layer after jointing stage.The evapotranspiration of whole growth stage increased as a peak curve with increasing of irrigation level and the W4 treatment significantly increased the evapotranspiration.?2?The plant height and dry weight increased with increasing irrigation level at the trumpeting stage.The W3 treatment and the W4 treatment significantly increased plant height and dry matter during the filling stage and the silage harvesting stage.Therefore,the appropriate increase in the amount of drip irrigation is conducive to promote the growth of plants.?3?Increasing drip irrigation level led to increase leaf net photosynthesis rate?Pn?,transpiration rate?Tr?,stomatal conductance?Gs?and intercellular CO₂concentration?Ci?in the two years at the silking stage.The increase amplitude of Pn,Tr,Gs and Ci decreased with increasing drip irrigation level.There was no significant difference of Pn,Tr,Gs and Ci between the W3 treatment and the W4 treatment.?4?The fresh yield,dry matter yield,water use efficiency of fresh yield?WUE_f?and water use efficiency of dry matter yield?WUE_d?were increased firstly and then decreased while increasing drip irrigation level.The W3 treatment increased the fresh yield and dry matter yield as well as WUE_f and WUE_d.Increasing drip irrigation level significantly reduced the irrigation water use efficiency of fresh yield?IWUE_f?and irrigation water use efficiency of dry matter yield?IWUE_d?,the decrease amplitude of IWUE_f and IWUE_d were decreased.?5?Increasing drip irrigation amounts reduced the nutritional quality of silage maize.The content of neutral detergent fiber,acid detergent fiber,starch and crude ash increased with increasing drip irrigation level,whereas the crude protein content,ether extract content and relative feed value decreased.In summary,in the semi-arid regions,the W3 treatment(1129.07 m³·hm^-2)can promote the growth of silage maize,increase the photosynthetic performance of leaves,and finally increase the yield and water utilization efficiency of silage maize with better nutritional quality.