Chapter 13 - Land and Water Management Strategies for the Improvement of Crop Production

Abstract

In the majority of world agroecosystems water relations in the soil–plant continuum are not optimal during the vegetation period. Hence, agricultural crops are usually exposed to one or both (at various times of a growing season) of the water imbalances such as water scarcity (deficit) and/or waterlogging/inundation. Both water stresses endanger food production, often contributing to various additional constraints (soil salinity/alkalinity, organic matter depletion). Managing the optimal water relations in the root zone in the agroecosystems is becoming increasingly challenging due to global climate change and variability, deterioration of environmental resources, as well as insufficient investments in the management of the land and water resources in croplands. Under waterlogging conditions crop production can be efficiently improved by implementing an adequate drainage system(s), currently in existence on ~200Mha worldwide (mostly on hydromorphic and/or halomorphic soils). Given the complexity of waterlogging and the related constraints (e.g., shallow groundwater table, nonuniform soil stratigraphy, poor soil permeability), one of the most promising remedial strategies was shown to be a combined drainage system (open drainage channels and tile drainage, e.g., central and south-eastern European agroecosystems) with additional periodic land measures (mole draining, deep ripping). Modern sustainable agricultural strategies for water-deficient conditions, either in irrigated or rain-fed agriculture, are directed at managing the natural potential of agroecosystems, with the aim to improve the efficiency of water resource usage. Irrigation and conservation agricultural practices are currently implemented worldwide on around ~300Mha and ~120Mha, respectively. Even though irrigation is one of the most effective strategies against water deficit, it is unlikely it will be implemented on increasing acreage in the future because of strong competition for good-quality water, but there are opportunities for improved efficiency of water usage (e.g., transition from traditional to more efficient modern irrigation systems).