Water retention and infiltration affected by conventional and conservational tillage on a maize plot; rainfall simulator and infiltrometer comparison study
Abstract
Tillage practices have a profound influence on the propensity for overland flow formation. The hydrological behavior of nine experimental plots was investigated by means of saturated hydraulic conductivity (Ks) and water retention analysis provided by single-ring infiltrometer (INF) and rainfall simulator (RS) infiltration measurements.
The applied management practices encompassed no-tillage, reduced tillage and several forms of conventional tillage methods. Specifically, the influence of wide and narrow sowing rows and the use of cover crops were examined.
Finally, the applicability of INF and RS for overland flow formation evaluation on cropped plots was compared. The reduced tillage practices resulted in the Ks and water retention increase, implying a lower propensity for overland flow formation.
The Ks in the reduced tillage plots were higher by 30-50% compared to conventionally tilled and by 20% compared to no-tilled plots, respectively. The differences in water retention were less straightforward as the reduced tilled plots exhibited higher retention than conventionally tilled plots (by >20%) but lower values compared to no-tilled plots in June (by 15%).
The utilization of narrow sowing rows generally resulted in higher Ks and enhanced water retention compared to wide rows. The use of cover crops in the conventionally tilled plots led to a 40% increase in Ks and a 90% increase in water retention.
Hence, the use of reduced tillage, narrow sowing rows or cover crops in the conventionally tilled plots were found desirable for the mitigation of soil erosion, flash flood occurrence and sufficient groundwater recharge. Eight times higher variance of Ks using a single-ring infiltrometer compared to RS indicated the incomparability of these two methods.
Therefore, the RS should be considered as a benchmark for evaluating the propensity to overland flow formation on cropped plots.