Fertilizer Nitrogen, Phosphorus and Sulphur Prescription for Aromatic Hybrid Rice (Oryza sativa L.) using Targeted Yield Approach

Abstract

Soil test crop response correlation studies involving integrated plant nutrition system (STCR-IPNS) were carried out on aromatic hybrid rice on an Inceptisol using Ramamoorthy’s inductive cum ‘targeted yield model’. Four levels of fertilizer nitrogen (N), phosphorus (P) and sulphur (S) and three levels of farmyard manures were randomized in three fertility strips each having 24 plots. A marked fertility gradient among strips with respect to N, P and S was developed by addition of increasing levels of fertilizers and farmyard manure. During 2010, coefficient of variation for KMnO4-N, Olsen’s-P and 0.15 % CaCl2 extractable-S ranged 10.10–12.32, 20.71–22.63 and 13.45–15.82 %, respectively, whereas corresponding ranges of coefficient of variation during 2011 were 11.83–12.76, 21.47–24.32 and 19.29–22.85 %, respectively. Presence of variation in soil test values was very well reflected by variability (coefficient of variation ≥20.41 %) exhibited by grain yield and uptake of N, P and S. Soil and plant analysis data was further utilized to compute basic parameters like nutrient requirement(NR) and percentage contributions of nutrients from soil, fertilizer and farmyard manure to total nutrient uptake. Basic parameters of N, P and S were observed as NR: 1.91, 0.32 and 0.18 kg per quintal of grain; contribution of nutrient from soil: 23.6, 32.4 and 24.9 %; contribution of nutrients from fertilizer: 36.3, 36.2 and 27.4 % and contribution of nutrients from farmyard manure: 24.1, 9.72 and 9.19 %, respectively. Using basic data, fertilizer prescription equations were developed for aromatic hybrid rice and ready reckoners of fertilizer doses for the range of soil test values and desired target yields were thus generated. Adoption of STCR-IPNS approach to recommend fertilizer nutrients resulted in saving of costly fertilizer inputs. On an average, addition of 10 t ha−1 could save 6 kg of N and P and 3 kg of S when applied along with fertilizer NPS.