Prospects of using saline water for irrigation in groundnut (Arachis hypogaea)-pearlmillet (Pennisetum glaucum) cropping system in saline black soils of Saurashtra

Abstract

A field experiment was conducted at Directorate of Groundnut Research, Junagadh (Gujarat) during crop years 2007–2008 and 2008–2009, to evaluate the performance of groundnut (Arachis hypogaea L.)-pearlmillet Pennisetum glaucum (L) cropping system in calcareous saline black clay soil (Vertisol) using water varying in salinity levels. The experiment was conducted on a fixed site. The experiment was laid out in a split plot design with three replication where four salinity levels of irrigation water [0.5 (control), 2.0, 4.0 and 6.0 dS/m] were allotted to main plots and eight genotypes of groundnut (‘DRG 12’, ‘GG 4’, ‘ICGS 37’, ‘TAG 24’, ‘TG 26’, ‘GG 20’, ‘ICGS 76’ and ‘ICGV 86325’) were in sub plots. After the harvest of groundnut, pearlmillet was raised to find out the performance of succeeding crop under different residual and direct salinity levels. Results indicated that water and soil salinity up to 4.0 and 1.6 dS/m, respectively can be safely used for realizing optimum groundnut pod yield. Among the tested genotypes, ‘ICGS 76’ and ‘GG 20’ were found to be more tolerant to salinity than other genotypes. The other genotypes performed well at germination stage but did not perform well at the later stages of crop growth. Pearlmillet can tolerate the water and soil salinity up to 4.0 and 4.4 dS/m, respectively in calcareous black clay soils. With an increase in the salinity of the irrigation water, the soil salinity in the root zone increased both in groundnut and pearlmillet crops but the buildup in salinity was more in pearlmillet than in kharif groundnut plots mainly owing to availability of sufficient rain water to leach down the salt below the root zone in case of groundnut.ble