Hydrodynamic behavior of a near-saturated sandy-loam soil shortly after incorporating compost or zeolite

Abstract

Little is known about short-term effects of compost and zeolite addition on hydrodynamic properties of nearsaturated coarse-textured soils. These effects were tested for a sandy-loam soil by a Mini-Disk Infiltrometer at three pressure heads (-6, 􀀀 3 and 􀀀 1 cm) and a wide range of amendment percentages, pa. Soil hydraulic conductivity was determined on two dates separated by nearly one month whereas soil sorptivity was determined at the end of the sampling period. Overall, the effect of the compost varied from null to appreciable since increasing pa from 0 % to 40 % did not affect the considered parameter or induced a decrease by up to eight times. Instead, the zeolite was largely ineffective since the tested parameters did not vary with pa. At the end of the experiment, the soil amended with zeolite was up to 70–90 % more sorptive and conductive than that amended with the compost. Perhaps the particles of compost represented a physical obstacle to water flow and probably also induced some soil water repellency. Instead, the particles of zeolite were wettable, and they did not appreciably alter the pore size distribution. Adding compost can determine a decrease in the ability of a near-saturated soil to draw and conduct water but this ability does not change with zeolite. Other investigations are required to confirm these results, test the suggested explanation and finally draw general conclusions. The applied methodology in this investigation is easy, cheap and suitable for prolonged monitoring without causing an appreciable alteration of the sampled soil.