There appears to be no alternative but to increase agricultural productivity (i.e. crop yield per unit area) and the associated total and individual factor productivities (i.e. biological output per unit of total production input, and output per unit of individual factors of production such as energy, nutrients, water, labor, land and capital) to meet the global food, feed, fiber and bio-energy demand and to alleviate hunger and poverty. However, until now, agricultural intensification from intensive tillage-based production systems generally has had a negative effect on the quality of many of the essential natural resources such as soil, water, terrain, biodiversity and the associated ecosystem services provided by nature. This degradation of the land resource base has caused crop yields and factor productivities to decline and has forced farmers, scientists and development stakeholders to search for an alternative paradigm that is ecologically sustainable

as well as profitable. Another challenge for agriculture is its environmental footprint and climate change. Agriculture is responsible for about 30% of the total greenhouse gas emissions of CO2, N2O and CH4 while being directly affected by the consequences of a changing climate (IPCC, 2007).