Impacts of soil structure on crop growth
K. Rajkai 1
K.R. Végh 1
G. Várallyay 1
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Research Institute for Soil Science and Agricultural Chemistry of HAS, 15 Herman O. str, Budapest, 1022-Hungary
Acceptance date: 1997-02-14
Int. Agrophys. 1997, 11(1-2): 97–109
Intensive agricultural utilisation of soils may change the structural status and through it the credibility and fertility of soils. Since soil structure has not been quantified explicitly, studying structure-related soil phenomena is still actual. The goal of the present study was to apply field measurements on structure related soil hydrophysical properties and to study their mutual effect on crop growth. Near hydraulic water conductivity, bulk density, water retention characteristics of soils were measured in a wheat and a maize field as well as the soil water content dynamics during the vegetation period. Simulation models (SOIL and SOILN) were applied for studying different effects of soil structural status on winter wheat and maize crop's developments and on yields. Simulation results showed that water limitation in fields having normal and high bulk density topsoil developed gradually. In the low bulk density field case, water limitation on crop growth is noticeable almost from the beginning of crop growth. Though the combined effects of soil water stress and rooting due to soil structure resulted in marked differences in simulated yields, the effect of the saturated water conductivity and bulk density on the crop yield alone proved to be non significant. However, when a consequence was introduced regarding the plant root distribution, which differs in different soil physical conditions, a strong effect on the crop's growth was detected. This finding demonstrates the complex nature of the phenomenon called structural status of soil, and it definitely requires further research.