Effect of Application Method on Availability of Elemental Sulfur in Cropping Sequences

Authors:
Publisher website
Google Scholar
Abstract
There have been indications that many rice‐growing areas in developing countries are becoming deficient in S. This greenhouse study was conducted to compare the effectiveness of elemental S (ES) mixed with soil (incorporated) or deep‐placed in a band to that of incorporated gypsum on crop growth in sequences of rice‐rice ( Oryza sativa L.) or rice‐maize‐maize ( Zea mays L.). The soil used was an S‐deficient Josephine sandy loam (Typic Hapoxerults). Rates of S applied were 0, 14, 28, 42, 56 or 112 mg S kg −1 . Incorporated elemental S and gypsum were equally effective in increasing grain and straw yields of the first rice crop, whereas deep‐placed ES was less effective. Deep‐placed ES became more effective than incorporated ES and gypsum for the subsequent crop of rice in terms of increasing plant dry‐matter yield. Two statistically distinct relationships were obtained between S uptake by the second rice crop and P‐extractable SO 4 ‐S in the soil prior to that crop: one for incorporated ES and gypsum treatments, and the other for deep‐placed ES treatments. A weak S response was observed for the first maize crop after rice, regardless of sources and methods of S application. However, a strong S response was obtained with the second maize crop (the third crop in the sequence). At lower initial rates of applied S, the residual effect of deep‐placed ES was greater than that of incorporated ES and gypsum. A single relationship for all the S treatments was obtained between total S uptake by the second maize crop and P‐extractable SO 4 ‐S in the soil after the first maize crop.