Interaction effect of sulphur and zinc in groundnut (Arachis hypogaea) and their availability in Tonk district of Rajasthan

Abstract

A field experiment was conducted during rainy (kharif) season 2001 and 2002 at research farm of Banasthali (Rajasthan), to evaluate the interaction effect of four levels each of sulphur (0, 20, 40 and 60 kglha) and zinc (0, 2.5, 5.0 and 7.5 kglha) on groundnut (Arachis hypogaea L.). From the groundnut-growing fields of Tonk district, 125 surface (0-1 5 cm) soil samples were collected randomly for estimating availabe of S and Zn. Total S and Zn contents in the soil varied from 142.0 to 232.0 kglha and 4.0 to 26.0 mglkg with mean values of 170.2 kglha and 21.3 mglkg respectively. The availability of 0.15 per cent CaC0,-extractable S and DTPA-extractable Zn was 6.1- 17.8 kglha and 0.31 -0.81 mglkg respectively. Out of the soils studied, 59 per cent were found deficient in S and 31 per cent in Zn. Application of 40 kg Slha and 5 kg Znlha significantly increased the pod yield of groundnut. The positive and significant interaction between S and Zn resulted in highest pod yield of groundnut (2,251 kg/ ha) at 40 kg S and 5 kg Znlha. Maximum benefit: cost ratio was recorded with the application of 40 kg S and 2.5 kg Znlha. The use effeciency of S and Zn decreased with increase in the level of S and Zn, and maximum use ef- ficiency was recorded at lower levels of S and Zn application.