Study On Water Production Function And Optimal Irrigation Schedule Of Lucerne

In recent years,because of the economic development and the population increase,the problem of lacking water resourses is becoming more and more serious and agricultural irrigation water is lack.On this backgroup,how to optimally allocate the limited irrigation water at the different growth stage of the crop and how to irrigate the crop to get maximal benefit and become a hot research in the agricultural irrigation field.Base on above,this paper studied the deficient irrigation of Lucerne in Helingeer in Hohhot.Under the different duty,study forage crop sensitive response to water stress; sensitive level in different growing stage.According to the analysis,we chose the water production function of Lucerne suitable for the local and we gain suitable irrigation program and optimal management decision.It had significance to making full use of limited water resourses , adjusting the soil moisture regime and increasing yield.Meanwhile,it offered the technical support for forage crop production of dairy industry and the sustained development of environment in Huhhot.The main conclusions indicated that:(1) Under deficient irrigation of Lucerne, plant height and LAI of water shortage in any stage is smaller than sufficient irrigation;plant height and LAI of water shortage in branch—squaring is smaller than water shortage in flowering mature period;under water shortage in same stage,plant height and LAI of light drought is bigger than heavy drought.(2) Through water requirement of Lucerne research,we drew the conclusion that water requirement regulation of Lucerne different growth stage: it is less at earlier and later stage than at metaphase.The water need intensity of day at turning green period is 2.41 mm/d,it is smaller; it reached peak value at flowering stage,is 7.87 mm/d.Following that is mature period,mainly growth is reproductive growth,the water need intensity decrease.(3) Based on data of deficient irrigation in field,this paper analysised relationship between production and water consumption by using five crop water production function representative in International and selected adaptive crop water production function of Lucerne in local areas.Through analyzing and comparison,Jensen model was better to express of the quantitative relation between yield and water.It revealed distribution of sensitive index:λ2>λ3>λ4>λ1>λ5.That was branch period,squaring period, flowering stage,turning green period,mature period.(4) This paper maked optimization irrigation procedure of Lucerne based on Jensen crop water production function model,using the principle of dynamic programming.When the irrigation water was less,in order to great great yield ,water need of water deficit sensitive response stage must be satisfied.Under limited irrigation water,water requirements of branch—squaring period must be satisfied,because in this period,the yield of Lucerne increase greatly along with the increasing of water supply.