Land and Water are the two most important natural resources in the development of Agriculture. The success of the agriculture mainly depends on proper and scientific utilisation of these resources. Crop productivity can be best optimised on watershed basis when these resources interact in a synergetic manner. In this paper, we discuss the food production activity in Karnataka. Particularly, from the point of view of water usage. The impact of large irrigation projects is also discussed. The preliminary analysis shows that water and fertilizer play an important role in agricultural production. But addition of irrigation has not resulted in any increase in overall food grains production. This means that we need to look at microlevel practices. Trend and regression analysis also show that effects due to these factors are marginal.