Soil structural improvements with the addition of Lantana camara biomass in rice‐wheat cropping

Abstract

Abstract. A long‐term field experiment was initiated in June 1988 in a silty clay loam soil to investigate the potential of Lantana camara, an obnoxious weed, for improving structural properties and productivity of soil in rice‐wheat cropping. Lantana was incorporated into the soil 10–15 days before puddling at 10, 20 and 30 t/ha (fresh weight).At the end of the sixth cropping season, Lantana additions increased the organic carbon (OC) of the 0–15 cm soil layer by 11–24%, and of water‐stable aggregates (WSA, 0.50–8.0 mm diameter) by 10–21%; OC of WSA <0.50 mm diameter remained unaffected. About 17–25% of the applied OC was retained in the soil. The OC increase resulted in a decrease in bulk density of the plough layer (0–15 cm) by 7%, a decrease in aggregates of 2–8 mm diameter and of clods by 4% and 6%, respectively. There was an increase in water‐stable aggregates and aggregate porosity, and a decrease in clod‐breaking strength from 420 to 216 kPa. Soil cracking at the surface changed from wide, deep cracks in hexagonal pattern to a close‐spaced network of fine cracks. Lantana additions increased <5mm wide cracks at the expense of 10–20 mm wide cracks; 5–10 mm wide cracks remained unchanged. Total volume of cracks decreased by 36% and surface area of cracks by 55% compared with the control plots.