Study On Water Consumption Regulation And Irrigation Scheduling Of Pepper Under Drip Irrigation Mulched In Shule River Basin

In recent years,the demand of water resources has increased dramatically with economic and social development in Shule River Basin,which has resulting in ecological water demand dropped and underground water level declined,the deterioration of the ecological has directly influenced to the ecological safety of Hexi corridor,even the whole northwest region.Especially the development scale expanded of regional agriculture and the rapid growth of agricultural water,as so to the water conflict the increasingly prominent between agricultural irrigation and ecological.An important approach to solve the ecological issues of Shule River Basin is return water to ecology through some measures,such as the water-saving and efficient agricultural development;strengthen agricultural water-saving technology research and implementation of agricultural water-saving measures,etc.,to ensure strategic security of Hexi ecological barrier.In 2014,the experiment of drip irrigation mulched would be carried out by take American Red Pigment peppers as study material in Shule River experimental station,Tsinghua University sand water science and water conservancy and Hydropower Engineering Key Laboratory,Yumen Town,Jiuquan City,Gansu Province,the results will provide academic evidence for reasonable irrigation and efficient cultivation of pepper in Shule River Basin.The main contents include: analysis the influence of different irrigation amount on the growth index,nutritional quality,yield and water use efficiency of pepper and water consumption regulation,then set up the function of water production,finally optimizing irrigation scheduling.The following preliminary conclusions are obtained:(1)The plant high and leaf area coefficient of pepper would be increased with the increase of irrigation amount,and the growth regulation appeared “s” shaped curve.The dry matter weight of aerial parts of pepper showed a rising trend from slow,fast to slow state,stem proportion reached peak since fruit bearing periods,and fruit dry weight for whole plant dry weight ratio increases gradually from fruit stage to expanding stage.(2)The amount of irrigation is very important to the nutritional quality of pepper by analysis of pepper quality.Compared with deficient irrigation(CK),drip irrigation mulched could effectively coordinate the relationship among soluble sugar,soluble protein,soluble solids and vitamin C,and its quality is better than that of CK.(3)The crop yield was not increased with the increase of irrigation amount by analysis of pepper yield and water use efficiency,and the water use efficiency decreased with the increase of irrigation amount during the period of the whole growth.Comprehensive consideration of the above mentioned two factors,medium amount of irrigation quota was more favorable to the increase of pepper yield,namely,drip irrigation mulched is more conductive to water-saving and increase production.(4)Pepper under drip irrigation mulched is mainly absorbed the soil moisture of 0-40 cm,generally the change of soil moisture content for different treatment is basically consistent during the growth period in different soil layer,and the amplitude variation would decrease with the increase of soil depth,meanwhile,the more irrigation water in different treatment,the more the soil moisture content in the same soil layer.(5)The amount of water consumption is have something to do with irrigation amount for the each treatment of irrigation quota in the whole growth period of pepper,and both were increased with the increase of irrigation water,and showed significantly positively correlated relationship.Compared with the conventional pipe irrigation CK under mulched film irrigation,the drip irrigation under film can effectively reduce the water consumption of pepper during the whole growing period.The water consumption of pepper was showed changed trends from low to high and then decreased,which was in accordance with the growth regulation of pepper.The water consumption regulation showed as following from large to small in the whole growth period: flowering stage,seedling stage,fruit enlargement stage,mature stage.The water consumption regulation of pepper can be showed from strong to weak: fruit stage > mature stage > enlargement stage > anthesis stage > seedling stage,of which water consumption intensity is maximum due to shorter growth time of fruit setting stage;although the amount of water consumption is larger,the strength of water consumption is low due to longer flowering period.The amount of pepper water consumption in three periods,such as flowering,fruit bearing and enlargement stage account for 60% of the whole growth period,and is the three stages of key water requirements and play a critical role in pepper yield.(6)Through analysis of the test data,the amount of water consumption,the actual yield and irrigation quota would be obtained for each treatment in the whole growth period,and function model is set up by take irrigation quota and the amount of water consumption as the independent variable.The suitable irrigation quota of 418 mm is given by solving the model under drip irrigation mulched.Based on the climate and other natural conditions as well as the acceptance degree of farmers,the irrigated times of pepper is recommend as nine times,and the irrigation quota is 418 mm under drip irrigation mulched in Shule river basin.The irrigation times were one,three,two,two and one times in seedling,flowering and fruiting bearing,expanding and mature period,respectively.