Status and Response of Sulphur in Alluvial Soils for Higher Yield of Potato

Abstract

The current study was carried out to assess the status of forms of sulphur (S) in soils of Etawah district, Uttar Pradesh. Separate set of field experiment was carried out during rabi season of 2007–08 and 2008–09 at Etawah to study the effect of sources and levels of S on potato. The total S content in soils of Etawah district ranged from 75 to 190 mg kg−1 with a mean value of 130.9 mg kg−1. The mean values of organic-S, SO4-S and non-sulphate-S were 43.8, 12.1 and 74.2 mg kg−1, respectively. All the forms of S gave significantly positive correlation with organic carbon (OC) indicating S as the integral part of soil organic matter (SOM). Approximately 62% soils under study were deficient in available S. The results of field experiment revealed that the potato (Solanum tuberosum L.) crop responded significantly to applied S through various sources. Tuber yield of potato and starch content in tubers increased significantly with increasing levels of S up to 40 kg ha−1. Sulphur uptake also followed the similar trend of tuber yield. Among the sources of S tested, ammonium sulphate was best with respect to yield, starch content and uptake of S by potato tubers. Next in order were gypsum, elemental S and pyrite. The net return (Rs.135340 ha−1) and B/C ratio (1.91: 1) were higher when ammonium sulphate was used as a source of S. Potato crop grown with 60 kg S ha−1 gave maximum net return (Rs.147305 ha−1) and B/C ratio (2.08: 1). Ammonium sulphate recorded significantly higher S use efficiency and S uptake efficiency over other sources of S. Sulphur use efficiency and S uptake efficiency decreased with 60 kg S ha−1 over lower levels of S application.