Effects Of Clipping On Alfalfa And Its Field Characteristics With Growth Years

The studies carried out in the plain of West-Liao River in Inner Mongolia with material of alfalfa (Medicago sativa L. cv. Algonquin) during 2003 to 2005, in order to set up the system of alfalfa in irrigated field and discuss the influence of its growth years on the physical and chemical properties of soil. The result showed:The fresh yield of five clipping times, the hay yield of three clipping times and the crude protein yield of four clipping times was the highest one respectively in the four cutting ways. And the more clipping times, the higher nutritive qualities. The dry weight of root was the highest under the three clipping times while the lowest under the five clipping times. The contents of nitrogen and carbohydrate in roots and stubbles of four-clipping-time was the lowest in the five clipping models. The over-wintering rate of five clipping times was 13.7%, 12.6% and 8.3% lower than that of two, three and four clipping times respectively. The effect of clipping times on plant height, branches, and hay yield of alfalfa were decreased with the clipping stubbles increased; The complementary relationship that the plant height, branches, and hay yield for different clipping times among the stubbles in a year had been discovered. The nutritive quality, dry weight of root, volume of root, over-wintering rate and sustaining production of 10cm stubble height possess more advantage than those of 5cm stubble height. The production advantage of 5cm stubble height merely manifest the first two years, which tends to decrease with the increase of its clipping years.There was significantly negative correlation with r=-0.8462 between the days after over-winter and crude protein(%), while significantly positive correlation with r=0.9249 and r=0.8857 between the days after over-winter and crude fiber(%),rate of stalk to leaf(SLR).The liner regression equations could be respectively expressed as: y=25.428-0.1583x; y=6.1818+0.3328x; y=0.3847+0.0262x. The influence of clipping dates in fall on forage yield of alfalfa next year was mainly at the first clipping, which tends to decrease with...