Sulfur use efficiency of radish as affected by sulfur source and rate in typic ustifluvent soil

摘要

Radish is one of the most popular root crops in the tropical and temperate regions. Sulfur deficiency is common in coarse textured soil due to leaching loss. Root yield of radish is reported to increase with sulfur application. Field experiments was conducted in two seasons to study the effect of sulfur (S) rate and source on radish ( Raphanus sativus L.) nutrition, an experiment was conducted in a Padugai sandy clay loam (Typic Ustifluvents) deficient in available sulfur. The treatments consisted of four levels of S viz., 0, 25, 50 and 100 kg ha^-1 applied through four sources viz., ammonium sulfate, super phosphate, gypsum and potassium sulfate Data were recorded on radish root yield, S uptake, available S, S uptake efficiency (SUPE), S utilization efficiency (SUTE), S use efficiency (SUE), fertilizer S uptake efficiency (FSUPE), fertilizer S utilization efficiency (FSUTE) and fertilizer S use efficiency (FSUE). The results revealed that addition of graded rate of S significantly increased root yield, S uptake and available S over the control. Application of S at 100 kg ha^-1 gave highest root yield of 33.5 t ha^-1 (season- I) and 36.8 t ha^-1 (season-II) and also sulfur uptake and available sulfur. Among the S sources, gypsum was better than the other sources. Increased S-application increased SUPE and SUE. The SUTE was highest in control plants and decreased with S level. On the other hand FSUPE and FSUE were highest at a rate of 50 kg S ha^-1 and FSUTE was highest at 25 kg S ha^-1. Among S sources, gypsum had higher S use efficiency and its components compared to the other S sources.