Abstract: The present study was designed to exploring the effect of forage diversity on productivity,forage chemical composition,and soil nitrogen profile by well-grown forage species in Karst region of southwestern China.The diversity effect,including selection and complementary effect,was employed to explore the underlying mechanism.Forage species included four legumes ［White Clover (Trifolium repens L. ), Red Clover (Trifolium retenseL. ), Alfalfa (Medicago sativa L. ) and Common Aeschynomene Herb ( Aeschyomene americana var. americana) ］,two no-legumes ［Green Bristlegrass Herb (Setaria anceps Stapf ex Massey) and Broadleaf Paspalum (Paspalum atratum cv. Reyan 11.) ］. Experimental treatments included monocultures of six species and mixtures of 2,3,4,and 6 species,in a standard randomized block design. Productivity,forage chemical compositions,soil nitrogen content,selection and complementary effects were determined. Result showed that forage species diversity enhanced forage production and yield of CP except biculture. Forage species diversity showed a great impact on the nutritional value of forages,which was exhibit as decreased CP concentration and increased NDF and ADF concentration in the mixture of forage. In addition,forage species diversity also greatly affected the soil-plant N cycling,which was exhibit as increased crude protein production,soil total N and available N. Analysis of relative yield and diversity effect indicated that selection and complementary effect affected the diversity-ecosystem function,and selection effect was the main cause in our study. Selection effect facilitated some forage to grow in arid environment,and thus impact on the productivity and chemical composition of forage and soil nitrogen profile.

Key words: Forage species diversity, Selection effect, Complementary effect, Chemical composition, Nitrogen, Karst region

CLC Number: 

• S14