Journal of the Indian Society of Soil Science

Field studies were conducted on a silty clay loam soil during 1990–91 and 1991–92 to study the effect of different soil water conservation (SWC) practices such as presowing irrigation and conventional tillage (digging up to 0.15 m) (A), tillage (conventional tillage) after harvest of rice (B), conventional tillage with Lantana camara incorporation (C), minimum tillage with mulch of Lantana camara (D) and conventional tillage with mulch of Lantana camara (E) under normal (120 kg N ha⁻¹) and lower levels (0 and 60 kg N ha⁻¹) of nitrogen application on root growth, leaf area index (LAI), water use and yield of rainfed wheat in rice-wheat rotation. Root growth (root mass density, root volume and root length density) determined at different growth stages and at harvest, increased with the application of N and was higher in mulched treatments, during both the years of study. The maximun root growth and water uptake were obtained at reeommended N level (120 kg N ha⁻¹) and in mulched treatments. The leaf area index (LAI) recorded at maximum tillering and flowering stages, increased significantly with increase in N levels. The D and E (mulched) treatments, maintained higher values of LAI and significant effect was observed at both the stages during the years 1990–91 and 1991–92. The dry matter production recorded at different growth stages, viz., crown root initiation (CRI), maximum tillering (MT), flowering (FS) and at crop harvest (AH) (grain as weUas graw yield) significantly increased with N application during both the years of crop study. The soil water conservation (SWC) practices, viz. D and E (mulched treatment) showed hither dry matter yield at different growth stages and at harvest. The effect was significant at crown root initiation stage and at harvest during both the years of study and at flowering stage during the second year of study.