D.K. Kundu

Integrated Fertilizer Prescription Equations for Recommendations of Fertilizers in Jute–Rice–Garden Pea Sequence on Alluvial Soil of Eastern India

Field experiment was conducted on alluvial soils (Typic Eutrochrept) of eastern India by adopting inductive cum targeted yield model to assess the fertility status, fertilizer requirements, and formulation with and without integrated plant nutrient supply fertilizer (IPNS) prescription equation for jute fiber, rice grain, and garden pea on soil-test and yield target bases. By using yields, initial soil-test values, uptake of nutrients, and fertilizer doses applied, the basic data [viz., nutrient requirement (NR) and contributions of nutrients from soil (Cs), fertilizers (Cf), and farmyard manure (Cfym)] were computed and used to develop fertilizer prescription equations for jute fiber, rice grain, and garden pea with and without IPNS under a jute–rice–garden pea sequence. The greatest nutrient requirement was observed in jute [2.88:0.97:5.07 kg nitrogen (N)/phosphorus (P)/potassium (K)] followed by rice (2.34:0.47:3.48 kg N/P/K) and garden pea (0.52:0.11:0.39 kg N/P/K) for the production of 100 kg yields of jute fiber/rice grain/green pod, respectively. It was found that soil has contributed the greatest percentage of N (20.6%) and K (47.29%) toward the total N and K uptake by rice followed in jute whereas the greatest percentage contribution of P (21.1%) occurred in jute. However, the greatest contribution of N, P, and K from the fertilizer was observed in jute, followed by rice and garden pea. Nitrogen contribution from fertilizer was 12.5 and 42.9% greater in jute than rice and garden pea, respectively. The greatest fiber and green pod yield in jute were recorded in the high-fertility gradient (strip III), whereas maximum rice grain yield was observed in the low-fertility gradient (strip I), which clearly indicated that high-fertility status favored the production of jute and garden pea but low-fertility status is suitable for rice production. By following ready table, a farmer can save N, phosphorus pentoxide (P2O5), and dipotassium oxide (K2O) in amounts of 3.21, 9.93, and 10.94; 6.35, 7.00, and 9.15; and 34.0, 26.0, and 34.4% more as compared to without IPNS respectively in jute, rice, and garden pea. Application of farmyard manure (FYM) in different fertility gradients improved the organic carbon (C) and available N, P, and K with increasing fertility.

Identification of Minimum Data Set Under Balanced Fertilization for Sustainable Rice Production and Maintaining Soil Quality in Alluvial Soils of Eastern India

ABSTRACT The scarcity of non-renewable fertilizers resources and the consequences of climate change can dramatically influence the food security of future generation. Introduction of high yielding varieties, intensive cropping sequence and increasing demand of food grains day-by-day, application of recommended dose of fertilizers could not fulfill our targets due to outdated fertilizers recommendations are yet in practice. It not only alters soil quality, nutrient balance, microbial and enzymatic ecology but also affected productivity and sustainability of rice in Gangetic alluvial soils of India. The effect of fertilizers application based on “fertilizing the soil versus fertilizing the crop” which insure real balance between the applied and available soil nutrient is urgently needed. Hence, the present study was conducted during three consecutive crop seasons (2010, 2011, and 2012) to assess the effect of imbalance and balance fertilization based on initial soil test values and targeted yields, and to determine the effect of farmyard manure (FYM) when superimposed with balanced fertilizers on identification of minimum data set for the development soil quality, nutrient acquisition, and grain yield of rice. The six fertilizer treatments were laid out in a randomized block design with three replications. The treatments were: T1-control (no fertilization), T2-farmyard manure @ 5 t ha−1, T3-farmers practice (60:30:30 kg N:P2O5:K2O ha−1), T4-precise application of mineral fertilizers based on initial soil test values (77:24:46 kg N:P2O5:K2O ha−1) for targeted grain yield of 4.0 t ha−1, T5-precise application of mineral fertilizers based on initial soil test values (74:23:43 kg N:P2O5:K2O ha−1) plus FYM (5 t ha−1) for targeted grain yield of 4.0 t ha−1 and T6-precise application of mineral fertilizers based on initial soil test values (135:34:65 kg N:P2O5:K2O ha−1) for targeted rice grain yield of 5.0 t ha−1. Result revealed that the targeted rice grain yield of 4.0 and 5.0 t ha−1 was achieved in T4 and T6 treatments with 1.59% (4.06 t ha−1) and –3.40% (4.83 t ha−1) deviations, respectively. T4, T5, and T6 significantly increased crop growth, nutrient uptake, available P (Pa) and K (Ka) and augmented rice grain yield by 10.6, 20.2 and 31.6%, respectively, over T3. Microbial biomass carbon, soil respiration and enzymatic activity were enhanced significantly in T5 as compared to T6. Highest soil quality index was found in T5 (0.95) followed by T6 (0.90) and, lowest was in T1 (0.63). The contribution of minimum data set (MDS) toward the SQI was in the descending order of ALP (30.6%) > SOC (21.5%) > Ka (11.3%) > PSM (9.68%) > Na (8.51%). Overall, rice yield and soil quality was improved by using balance fertilization based on fertilizing the crop Vs fertilizing the soil in alluvial soils of India.