Cropping poorly-drained lowland soils: Alternatives to rice monoculture, their challenges and management strategies
2020
Goulart, Rafael Ziani | Reichert, José Miguel | Rodrigues, Miriam Fernanda
Lowland areas consist mostly of hydromorphic, poorly-drained soils, constituting an important agricultural frontier in Brazil and around the world. Flood-irrigated rice cultivation has become a monoculture in lowland soils, degrading soil structure and causing weed resistance, partially overcome by crop rotation and soil tillage. Rotation with dryland crops, such as soybean and corn, is an alternative that contributes to improving soil conditions and increase farmers’ profit. For rice cultivation, the occurrence of a compacted layer with reduced porosity and hydraulic conductivity is beneficial since compaction reduces water loss by drainage during the flood-irrigated crop cycle. However, for dryland crops, this compacted layer prevents water infiltration, reduces soil volume explored by roots, and maintains flooding conditions for longer time. Chisel tillage disrupts the compacted layer, while the construction of ridges raises the root system out of the saturated layer, creating a favorable microenvironment for root growth. This review paper presents advances in cropping and soil tillage practices in poor drainage soils, offering different combinations to reduce costs and increase the efficiency of the production system. Profitable farming is possible by growing flood-tolerant crops with proper management practices, making lowland soils as an alternative to increasing food diversity and supply.
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