00281nam a2200109Ia 450000500170000000800410001708200120005810000150007024500340008526000440011930000080016320260224040945.0260224s9999||||xx |||||||||||||| ||und||  a630 KUM  aKumar, A.  0aPerspectives in agroecosystem  aNew Delhi: Daya Publishers House,c2003  a413