Effect of continuous application of ammonium sulfate and urea on irrigated rice
1989
Buntan, A. | Corpuz, I.T. (Maros Research Inst. for Food Crops, Ujung Pandang (Indonesia). Agronomy Dept.)
The effect of continuous application of ammonium sulfate on rice yield and on some physicochemical properties of wetland soil was studied. The clayey soil had pH 6.2 (slighly acidic); 0.12% total N (low); 150 ppm available P (fairly high); 19.8, 7.9, 0.8 meq Ca, Mg, K/100 g soil (high); and 8 ppm SO4-S content (low). N was deficient and S was below the critical 9 ppm level. The experiment was established in 1984 wet season (WS) after a simple trial to identify the problem of plant yellowing despite the application of urea. The rice crop was observed to respond to the application of ammonium sulfate. Twelve treatments were arranged in a randomized complete block design with four replications. P as TSP and K as KCl were applied (60 kg each) in treatments 2 to 12. Grain yield was higher when S was applied, at any level. The significant increase in yield was due to N. Application of P and K without S or N did not have any significant effect on yield.
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