ABSTRACT
I. INTRODUCTION For centuries, cultivation has been used to prepare the soil for crop establishment. The main purpose has been to control weeds, but cultivation also removes crop residue, reduces compaction, and prepares a "seedbed." Tillage is usually referred to as physical manipulation of soil properties for the express purpose of crop production (SSSA, 1987). Tillage management aims at achieving optimal range of edaphic factors for the two plant processes-seed germination and seedling emergence, and growth and proliferation of root systems of crops. Conventional tillage (CT) is known to enhance soil erosion, deplete soil organic carbon, and deteriorate soil structure. The intensive rice (Oryza sativa L.)-wheat (Triticum aestivum L.) cropping system of the Indo-Gangetic Plains (IGP) has thrown new challenges for devising tillage systems where the crops following in quick succession have divergent adaptive requirements. Tillage under intensive cropping systems has the additional challenge to ensure high water-, nutrient-, and energy-use efficiencies.
