Study Of Subsurface Drip Irrigation Schedule On Alfalfa Seed Production

The application of subsurface drip irrigation (SDI) in the agricultural products such as cotton, corn, fruit trees is being matured gradually. It was begin to use in the alfalfa of grass production, but the report of application in the alfalfa seed production was little. This article will introduce the SDI to the production of alfalfa seed, and explore the rule of water and salt movement in the alfalfa seed production field. Thus we can find the effect factors of SDI to the growth and seed production in alfalfa, and establish a viable system of SDI for the standardization and scale production of alfalfa seeds provide theoretical support.The underground drip irrigation belt was laid on every row and the single irrigation water was from 150m3/hm2 to 900m3/hm2,6 different treatments were installed in the alfalfa experimental site where there was a 60 cm space between two rows. The results of alfalfa seed production in SDI system 12h after the irrigation is:space distribution of soil moisture is spheroidicity moist figure for the center with drops, and the extended distance in the horizontal direction is bigger than in the vertical direction. The size of the moist figure is positive correlated with irrigation water. The irrigation water is larger, the greater of moist figure under ground. The formation of salinity movement shape is out of shape in the low irrigation water (W1,W2,W3) and salinity are make the wetting area in the shape of an ellipsoid at the high irrigation water(W4,W5,W6). With the irrigation water increased, the root weight shows significant increase trendy. The curve of seed yield of alfalfa present an appearance of parabolic shape, and when total irrigation amount reached 3600 m3/hm2, and the single irrigation reached 600 m3/hm2, the highest yield of 832.51kg/hm2 can be obtained. Different irrigation treatments have remarkable difference in inflorescence per plant (F=0.875, P<0.01), There are significant difference for flower per inflorescence (F=1.835, P<0.05),and seed number per pod (F=1.58, P<0.05) and grain weight per plant (F=2.836, P<0.05). And no significant difference for valid number of branch and pod number per inflorescence. Water consumption and demand in the different treatments were increased with the amount of irrigation. The water use efficiency was reduced with the amount of irrigation increase.Test results of alfalfa seed production in irrigation institution is:the irrigated quantum of water was 71.7 mm in budding to flowering period(5.29～6.10),92.6 mm in peak blooming stage(6.10～6.20),113.7mm in end flowering period (6.20～6.30),120.1 mm in pod bearing period (6.30～7.10),116.2 mm in pod-mature period (7.10～7.20),118.2 mm in mature period (7.20～8.6)。...