Effect of sulphur on growth, productivity and economics of aerobic rice (Oryza sativa)

A field experiment on rice (Oryza sativa L.)–wheat [Triticum aestivum (L.) emend. Fiori & Paol.] cropping system was conducted during the rainy season (kharif) of 2010 and 2011 with 5 treatments in rice (viz. control and 30 and 60 kg S/ha each through gypsum and phosphogypsum) and 3 treatments in wheat (viz. 0, 15 and 30 kg S/ha through elemental sulphur) at New Delhi. Irrespective of the sources, sulphur application had a positive and significant influence on growth parameters, sulphur uptake, sulphur-use efficiency, yield attributes and grain yield of aerobic rice. The sulphur uptake by grain and straw of rice increased with sulphur applied through gypsum or phosphogypsum. The highest agronomic efficiency, crop-recovery efficiency and physiological efficiency was observed with S applied @ 30 kg S/ha through gypsum. Averaged across 2 years, application of sulphur through gypsum @ 30 kg S/ha, gypsum @ 60 kg S/ha, phosphogypsum @ 30 kg S/ha and phosphogypsum @ 60 kg S/ha increased the grain yield of rice by 9.5, 11.2, 8.7 and 10.7% respectively, over the control (no sulphur). However, significant response to sulphur was observed only up to 30 kg S/ha applied through either of the sources. Sulphur application @ 60 kg S/ha gave the highest net returns but statistically not superior to 30 kg S/ha. The highest benefit: cost ratio was recorded with application of sulphur @ 30 kg/ha through gypsum.