Macropore effects in conventional tillage and no-tillage soils

ABSTRACT: In an earlier study, it was shown that short-term ( 2 h) steady-state ring infiltration rates were not reduced in NT plots compared to CT, in spite of a shallow hardpan in NT; this was arributed to macropores that penetrated the hardpan. A 1-cm rain immediately after chemical application reduced leachate concentrations of Cl by about half in both the NT and CT treatments. With the 1-cm initial rain, chloride had an apportunity to diffuse into stagnant regions of the matrix and as a result was excluded from flow in macropores and interaggregate space. Macropores will probably cause the greatest leaching losses when a chemical is applied to the surface of NT and a large rain occurs soon after application.