Ecophysiological Mechanism Of Interaction Between Hemarthria Compressa And Its Mixture Species

Whip grass (Hemarthria compressa) is popular perennial forage and often used in grassland agricultural system in south china. Whip grass 'Guangyi' mixed separately with white clover (Triflium repen) Ladinno, alfalfa(Medicago sativa) 'Shengshi' and red clover(T. repens)'Duoli' by 25% seeding proportion gradient in the field of Sichuan Agricultural University, Ya'an city, Sichuan Province from 2006 to 2007. The objective of the study was to find the optimal mixture system through the evaluation the stability dynamic community, canopy characteristics ,yield and quality of forages in different mixture system, the results showed that:The first, through synthetic analysis to stability of community, yield and quality of forage, 4 optimal mixture treatments was found.'75%Whip grass+25%white clover' , average yield was 36102.3kg/hm², the average contend of crude protein (CP) was 15.89%, and acidic detergent fiber (ADF) was 17.80%, neutral detergent fiber (NDF) was 35.8%.'50%Whip grass+50%alfalfa' , average yield was 43704.37kg/hm², the average contend of CP was 15.8%, and the average contend of ADF was 17.80%, NDF was 35.8%.'75%Whip grass +25% alfalfa', average yield was 40482.36kg/hm², the average contend of CP was 13.24%, and ADF was 23.61%, NDF was 47.0%.The second, the interspecific relation between whip grass and its mixture grasses, and succession trend of the mixture grassland were observed'75%Whip grass+25%white clover', the competitive rate (CR) of white clover in this group decreased slowly, white clover and whipgrass could coexist for a long time, it could be the optimal mixed group.Both whip grass and alfalfa had strong competitive ability, the stability of the mixed grassland depended on the mixed ratio between them. The CP of whip grass and alfalfa in the treatment of '50%alfalfa+50%Whip grass' approached 1:1, that means the could coexist for a long time.Whip grass mixed with red clover, the competitive ability of red clover was poor, the competitive ability in treatment of '25%red clover+75%whipgrass' decreas e slowly, but vanished after the July 2007. It need input seeds to keep the mixed s ystem.The third, according to the yield, canopy characteristics and ray radiation in the optimal treatments, 4 canopy parameter modes for high yield was found.'75%Whip grass+25%white clover' was Y=1886.7X^0.6931 (coefficient correlation R²=0.6107, X-LAI, Y-yield)The mathematic simulate equation founded by LAI and yield in the treatment of '50%alfalfa+50%Whip grass' was Y=831.72X^1.3013 (coefficient correlation R²=0.7941, X-LAI, Y-yield)'25%alfalfa+75%Whip grass' was Y=842.89x^1.2349 ( coefficient correlation R²=0.7615, X-LAI, Y-yield)...