Couple Effect Of Fertilizer And Water On The Growth、Yield And Quality Of Alfalfa Under Subsurface Drip Irrigation

Alfalfa, as the most important green feed, will play an more important role in animal husbandry and dairy industry development. Subsurface drip irrigation (SDI), as a new water-saving irrigation technique, has been more widely promoted and used. Studying the couple effects of fertilizer and water on the growth、yield and quality on alfalfa will provide scientific basis for alfalfa production on the plains of Beijing, which is of great significance to development of alfalfa industry, animal husbandry and dairy industry. Experimental trials were carried out to study water-fertilizer coupling of Alfalfa under subsurface drip irrigation. In the water-potassium experiment two factors completely randomized block design was applied, and Alfalfa was grown under four potassium application levels and W2(2days)、W3(3days)、W4(4days) three irrigation levels making twelve combination treatments. And in the water-phosphorus, alfalfa was grown under three phosphorus application levels (0、9、18g/m2)and W22.5(22.5mm/7days)、W30(30mm/7days)、W37.5(37.5mm/7days)、W45(45mm/7days) four irrigation quantity. At the stage of initial flowering, the plant height, leaf-stem radio, yield, crude protein content, acid detergent fiber, acid etergent fiber and neutral detergent fiber content of each treatment were measured. The results showed as follows:1. The study is conducted within the water and fertilizer gradient range. Water and potassium supply had significant effect on the plant height、leaf-stem ratio、fresh forage yield、crude protein content、acid detergent fiber and neutral detergent fiber content of Alfalfa (P<0.05). The plant height、leaf-stem ratio、fresh forage yield、crude protein content decreased with the irrigation frequency, and the sequence is W2treating> W3treating> W4treating in the irrigation condition, while the acid detergent fiber and neutral detergent fiber content were gradually improved. In addition, the plant height、leaf-stem ratio fresh forage yield、crude protein content were significantly enhanced by the application of potassium (P<0.05),while the acid detergent fiber and neutral detergent fiber content were significantly decreased.The plant height fresh forage yield were increased first, then reduced with increasing application of potassium, while the leaf-stem ratio and crude protein content were gradually improved; the neutral detergent fiber and acid detergent fiber content were reduced in the whole with increasing application of potassium.2. The results of water-phosphorus experiment showed that water and phosphorus supply had significant effect on the plant height、leaf-stem ratio、fresh forage yield、rude protein content、 acid detergent fiber and neutral detergent fiber content of Alfalfa (P<0.05).In the appropriate range, the leaf-stem ratio、forage yield and crude protein content were increased with the irrigation quantity, and the sequence is W45treating> W37.5treating> W30treating> W22.5treating in the irrigation condition, while the irrigation quantity has negative effects on the acid detergent fiber and neutral detergent fiber content. Under the different level of phosphorus, the plant height、leaf-stem ratio、fresh forage yield、 rude protein content were significantly improved with increasing application of phosphorus (P<0.05),while the acid detergent fiber and neutral detergent fiber content were decreased with increasing application of potassium.