Efficient cropping systems and their energetics for sustainable irrigated tropical ecosystems

Abstract

An experiment was conducted at Bheemarayanagudi, Karnataka, during 201011, 201112 and 201213 to find out efficient cropping systems and to know energetics of different cropping systems. Ten cropping systems, viz. sole Bt cotton ( Gossypium spp.), Bt cottongreengram [Vigna radiate (L.) Wilczek], Bt cottongreen-manure crop sun hemp (Crotalaria juncea (L.), Bt cottonsesame (Sesamum indicum L.), maize (Zea mays L.)chickpea (Cicer arietinum L.), sunflower (Helianthus annuus L.)wheat [Triticum aestivum (L.) Emend. Fiori & Paol.], sun- flowerchickpea, chilli (Capsicum annuum L.) + onion (Allium cepa L.) (1:2 row proportion), transplanted Bt cot- ton and ricerice (Oryza sativa L.) as check were evaluated under irrigated condition to find out efficient cropping systems. The transplanted Bt cotton gave the maximum cotton-equivalent yield (2.73 t/ha ) and was significantly superior to that of ricerice (2.29 t/ha), while Bt cottongreengram (2.53 t/ha), Bt cottonsesame (2.61 t/ha), maizechickpea (2.47 t/ha) and chilli + onion (2.41 t/ha ) were at par with transplanted Bt cotton as well as rice rice. All cropping systems gave significantly higher net returns over ricerice cropping system ( 44,730/ha) ex- cept sunflowerwheat or chickpea; highest being with transplanted cotton ( 79,507/ha). All the systems were sig- nificantly superior to ricerice (0.96) in benefit: cost ratio and maizechickpea recorded the highest benefit: cost ratio (3.31). Energetics revealed different trend, wherein protein yields were higher with maizechickpea (0.73 t/ ha), while carbohydrate yield (6.32 t/ha) was higher with rice-rice. Among all the systems, the highest land-utiliza- tion index was observed with Bt cottonsesame cropping system (76.7%).