Study On Irrigation Schedule And Transpiration Of Walnut Tree Under Drip Irrigation

This paper through field experiment,studied transpiration of walnut tree which is 10 years, and irrigation schedule under drip irrigation in the arid region.The experiment was conducted in the farm of grain and oil in Wensu county, Akesu region. The experiment was designed vertical trial by 3 factors and 3 levels in order to confirmed irrigation schedule under drip irrigation. Three factors were 3 different growth stages(including blooming stage,fruit accelerated growth stage and crust stage ).Three levels were different lower limit of irrigation(including 70%,60%,50% of field holding capacity of soil water).There were 9 treatments and three repetitions. This study used Dynaga systems to continuous observations on transpiration. The experiment started from first April to the finally day of August, 153days.The research fruits were as follows:(1)Daily variations of transpiration velocity was similar with solar radiation and air temperature in growth stages. Transpiration velocity of the time of highest value occurred around 12:00～13:00, which was earlier 1-2 hours for solar radiation and air temperature. The variations trend of transpiration velocity was in opposition to relative humidity, which was reduce with the increase of relative humidity.(3)During the growth stages, transpiration velocity was significantly related to wind velocity(V),air temperature(Ta),relative humidity(RH),solar radiation(Rn).The regression equation was: Tr=1374.6-8.19Ta+0.31Rn-36.99V-7RH (n=4560,r2=0.75)(4)The relationship of ET0 and Tr was osculation, the trend of variety was similar. Wave crest and trough was synchro. The variety of data was consistent. Tr was significantly related to ET0. The regression equation was: Tr=0.5568ET0+1.059.The equation showed linearity. The relative coefficient was 0.762.(5)Under the drip irrigation, different growth stages have different index for lowest soil water content. Both in blooming stage and fruit accelerated growth stage, the index for lowest soil water was soil moisture content 60% which was fitting for growing, and crust stage was 50% of soil moisture content. The per of irrigation amount of walnut tree was 680m3/hm2, the times of irrigation were 12 and the total irrigation amount was 8160m3/hm2 during the growth stages. Gained a best resultant was treatment 5 by analyzed vertical experiment. Daily water requirement in April was 3.73mm/d, in May was 4.6mm/d,in June was 5.9mm/d,in July was 5.87mm/d,and in August was 3.7mm/d.The total of irrigation amount was 728.25mm.Each month for the modulus of water consumption were 15.27%,19.58%,24.3%,24.98% and 15.7% respectively. There was different effect on index for physiology,yield and fruit quality in different growth stages because of lowest soil water content.