Study On Water Consumption And Water Production Function Of Orange Tree

Pingyuan County, located at Meizhou City of Guangdong Province, which is famous for its largest production base of oranges and named as the Township of Guangdong orange. The area belongs to subtropical monsoon climate zone with sufficient sunshine and rainfall, making it more suitable for planting orange. Although the annual precipitation amount is ample, but uneven distribution of rainfall, which indicates that it mainly rains concentrating from May to August, plus the huge amount of evaporation and transpiration, there appears seasonal droughts often, seriously affecting and restricting the high and stable yield of local orange. In order to understand the rules of consumption water of orange and work out the reasonable irrigation system, this paper conducted a study on regulated deficit irrigation experimental of orange from March 2015 to November 2015 in Dragon Fruit Industry Park, Pingyuan County at Meizhou City of Guangdong Province. It set 4 different levels of water deficit including comparison(75%~70%FC), light drought(70%~55%FC), drought(55%~45%FC) and heavy drought(45%~35%FC) in the flowering and fruiting period, fruit expanding period, fruit coloring period and fruit mature period with a total of 13 treatments. Each treatment was repeated three times. This paper explores growth, quality, yield, water consumption, water production function and irrigation schedule of orange under different water deficit treatments and concludes that:(1)Research of orange fruit shape index, size, quality and yield under different water deficit treatment conditions shows that orange fruit shape index had no significant difference, mostly at around 1.1, with an oblong, which indicates that the water deficit treatment growth caused no damage. The largest fruit size appeared in the expansion period of moderate water deficit of fruit trees, with 366.14 cm3, comparing with the control group, it increased by 41.4%. As for the study on quality, fruit enlargement period of mild water deficit treatment and fruit coloring period of moderate water deficit treatment can both improve the fruit sugar content and vitamin C content, and the vitamin C content of the fruit of the treatment of mild water deficit in fruit expanding stage was increased by 21.5%, the sugar content increased by 14.5% compared with the control group. Fruit vitamin C content of moderate water deficit treatment during fruit coloring period increased 15.1%, sugar content increased by 12.2% compared with the control group. At the same time, the yield of fruit trees in the period of light drought treatment was increased by 9.2% compared with the control group.(2)Bycalculating four stagesof soil containing water monitoring and water consumption of orange trees, the result indicates that during the period of fruit expansion, the amount of water consumption was the most, the daily water consumption was the least, and the total water consumption of the fruit trees in the normal treatment was much more than that in the other treatments. In addition, the total water content was 659.8mm, the water use efficiency was 8.26kg/m3, the total water consumption was 575.0mm, the water use efficiency was highest in the fruit expanding period, and the water use efficiency was 10.35kg/m3.(3)According to the test data in 2015, this paper conducted the whole growth period of water production function model and the phase water production function Jensen model of regression analysis, the average error was 4.93% comparing Jensen model to calculate the output and the actual output, the average error of the linear model and nonlinear model were 5.82% and 7.93%. Relatively speaking, using Jensen model to calculate orange yield was more accurate.(4)Through the orange tree suitable soil moisture upper and lower water consumption and water consumption analysis, the result indicates that blossom and fruit set period, fruit expanding stage, fruit coloring period and mature period four stages irrigation quota were 15.54 mm, 23.31 mm, 15.54 mm, 15.54mm; Irrigation period were 12, 8, 11, 37; Irrigation times were 4 times, 10 times, 3 times and 2 times. Coupling analysis on the selection of the annual rainfall data of four typical years of natural rainfall amount and water requirement respectively were: wet years 0.9, flat water years 0.8, drought years 0.7, dry years 0.7. This shows that in four growth stages of orange, precipitation in the aggregate could satisfy the orange tree water requirements. But in the month, in addition to the level of 0.7 in October, the coupling degree of the other typical year is 0. Besides, coupling degree was lower in November. So these two months need timely irrigation.