Beyond Intensification.

Agricultural land use covers 38% of the Earth’s terrestrial area, consumes 71% of the global water withdrawal, and emits 30-35% of the annual global greenhouse gas emissions. Agricultural activities impact numerous environmental processes ,even beyond the planetary boundaries, including climate change and variability, soil and water quality and renewability, and biogeochemical cycling (of C, N, P, H₂O etc.) and biodiversity. Intensification of agroecosystems since the 1960s has increased the irrigated land area by a factor of 2, fertilizer use by a factor of 5, and N use by a factor of 8. Yet, 1 in 7 people are food- insecure ,1 in 3 are malnourished, and 24% of the land is prone to degradation. This trend must be reversed through  adoption of sustainable intensification and climate-resilient agro-ecosystems by  improving production in under-performing agroecosystems ; increasing production per unit land area, time and inputs of water, fertilizers, agrochemicals and energy; and enhancing ecosystem functions and services. The strategy is to close the yield gap and improve the use efficiency of  limited and non-renewable resources. With the increase in world population from 7.2 in 2013 to 9.6 in 2050 and ~11 billion  in 2100 ,and conversion of  agricultural land to non-agricultural uses, per capita arable land area and renewable water supply will decrease substantially. Rather than looking for a silver bullet or a panacea, it is important to  identify and pursue multiple paths, and avoid being myopic and locked into a specific strategy of soil management. Thus, a range of innovative systems must be developed to enhance agricultural production such as conservation agriculture, precision farming ,agro-silvo-pastoral systems, organic amendments and disease suppressive soils  etc. Some emerging technologies  such as sky farming, and soil-less agriculture (aeroponics, hydroponics, aquaponics) may also have specific niches. With discovery of water on Mars and Moon and interests in  inter-planetary exploration, space agriculture may become a  relevant  research focus with regards to  the effects of hypogravity on soil processes and plant growth.  Thus, soil scientists and agronomists must look beyond intensification of terrestrial ecosystems to expand the knowledge base and explore the  less- travelled paths.