Soil pore and hydraulic conductivity relationship under different tillage practices in a maize-wheat cropping system

Abstract

The soil pore system is an important hydraulic property to understand the hydro- physical behavior of soil. The present study aimed to assess the impact of long-term tillage practices (CT - conventional tillage, MT - minimum tillage, and ZT - zero tillage) on flow weighted mean pore radius (r ), the number of pores (n ), and soil 0 0 pore-hydraulic conductivity relationship in different sampling dates in a maizewheat cropping system. Steady state infiltration rates were measured using a hood infiltro-meter at 0, -1 and -3 cm pressure heads and standard procedures were applied to estimate hydraulic conductivity [K(h)], r and n . Results showed , the 0 o highest r value during the wheat-growing period whereas, the lowest was observed 0 during the maize growing period in all pressure heads and tillage practices. This indicates better connectivity of pores during the wheat-growing period. Results also revealed that r was in the order ZT > MT > CT. ZT resulted in a lesser n , 0 0 whereas no distinct differences were observed between CT and MT. Conservation tillage practices (ZT and MT) had a greater r value for the corresponding hydraulic 0 conductivity than the CT practice. This indicates to a higher contribution of interaggregate flow in conservation tillage practices. The results of the spearmen's analysis represented the distinct influence of the different tillage practices on the correlation between the hydraulic conductivity with other soil parameters such as bulk density, aggregate mean weight diameter, and soil organic carbon.