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Site-specific nutrient management (SSNM) for a rice (Oryza sativa L.)-growing domain is typically developed by first using the nutrient omission plot technique (NOPT) to determine yield responses with added nitrogen (N), with added phosphorus (P), and with added potassium (K) and then conducting an evaluation experiment to verify an SSNM practice developed from the NOPT results. We hypothesized that an effective SSNM practice could be more rapidly developed through concurrent NOPT experiments and evaluation of a preliminary best-bet SSNM practice derived from experiences in other rice-growing domains. Our study domain was rainfed lowland rice in an Indonesian tidal swampland without past NOPT experiments and without a verified SSNM practice. Concurrent NOPT and evaluation experiments were conducted in the wet season (WS) and dry season across 20–25 farmers' fields either directly or not directly influenced by tides. Rice yields and gross return above fertilizer cost for a preliminary SSNM practice were higher than for farmers' fertilizer practice in both seasons and for two fertilizer practices based on soil tests in WS. The inherent ability of SSNM to adjust fertilizer rates for an attainable target yield and time fertilizer applications to match crop demand contributed to the superiority of SSNM. In NOPT experiments, relative yields without added N, without added P, and without added K respectively averaged 0.70, 0.89, and 0.88 across seasons and tidal locations. These relative yields enabled preliminary SSNM fertilizer rates to be further adjusted for the rice-growing domain. Rice growers in domains without a verified SSNM practice can benefit, before NOPT experiments are completed, by using generic SSNM guidelines for timing fertilizer applications and adjusting fertilizer rates for a target yield. After completion of NOPT experiments, the fertilizer rates can be further adjusted based on measured yield responses with added N, P, or K. [ABSTRACT FROM AUTHOR]

Nepal is a major rice producer of South Asia, feeding more than 20 million people of the country and abroad. However, productivity and profitability of rice are low in Nepal compared to other regional countries. Large yield gaps exist between attainable and farmers' yields and nutrient management is identified as one of the major reasons. Nutrient Expert® (NE), a decision-support tool based on site-specific nutrient management (SSNM) principles has been validated and applied in many countries of Asia and Africa as new recommendation protocol for nutrient management in selected crops, including rice. Present study used NE® Rice as nutrient management protocol in farmers' fields across Terai and mid-hills regions of Nepal during 2014–2018. The study revealed that NE-based fertilizer recommendations resulted in increase in yield over 2.0 t.ha−1 (p ≤ 0.05) and double the profits compared to existing blanket fertilizer recommendation, and farmers' fertilizer practice. Due to large variations in slope, altitude, soil, and management, performance of NE® varied across locations. Its performance was better in Terai due to flat lands and less variations in soil types, compared to sloping lands and varied soils of mid-hills. NE tool provided adequate guidance to apply the required rate of fertilizer that matched the crop requirement and soil nutrient supply of each farmer fields. The novelty of the study is introduction of a dynamic fertilizer recommendation approach that can supplement the existing static blanket recommendation system. We conclude that Nutrient Expert® - Rice can be considered as an effective tool for nutrient recommendation for rice in Nepal. [ABSTRACT FROM AUTHOR]

Irrigated rice (Oryza sativa L.) and wheat (Triticum aestivum L.) yield increases in Punjab, India, have slowed in recent years. Future yield increases may occur in smaller increments through fine-tuning of crop management mainly by accounting for the large spatial and temporal variation in soil characteristics. On-farm experiments were conducted from 2002-03 to 2004-05 at 56 sites in six key irrigated rice-wheat domains of Punjab to evaluate an approach for site-specific nutrient management (SSNM). Site-specific N–P–K applications were calculated by accounting for the indigenous nutrient supply, yield targets, and nutrient demand as a function of the interactions between N, P, and K. The performance of SSNM was tested for two rice and two wheat crops. Compared with the current farmers’ fertilizer practice (FFP), average grain yields increased from 5.1 to 6.0 and 4.2 to 4.8 Mg/ha for rice and wheat crops, respectively, while plant N, P, and K accumulations increased by 12 to 20%. Improved timing and/or splitting of fertilizer N increased N recovery efficiency from 0.20 and 0.17 kg/kg in FFP plots to 0.30 and 0.27 kg/kg in SSNM plots in rice and wheat crops, respectively. The agronomic N use efficiency was 63 to 83% greater with SSNM than with FFP. The gross return above fertilizer cost (GRF) was 13-14% greater with SSNM than with FFP. Future SSNM research must build on the present approach to develop a more practical way for achieving similar benefits across large areas without site-specific modeling and with minimum crop monitoring.

Field experiments were conducted at the Annamalai University Experimental Farm, Annamalai nagar, Tamil Nadu to study the effect of Site Specific Nutrient Management for Transplanted Rice Cv. ADT 36 and ADT 43. There are fifteen treatments viz., T1 - 150: 15: 50 kg NPK ha-1, T2 - 150: 30: 50 kg NPK ha-1, T3 - 150: 45: 50 kg NPK ha-1, T4 - 150: 60: 50 kg NPK ha-1, T5 - 150: 15: 75 kg NPK ha-1, T6 - 150: 30: 75 kg NPK ha-1, T7 - 150:45:75 kg NPK ha-1, T8 - 150: 60: 75 kg NPK ha-1, T9 - 150: 15:100 kg NPK ha-1, T10 - 150:30:100 kg NPK ha-1, T11 - 150:45:100 kg NPK ha-1, T12 - 150:60:100 kg NPK ha-1, T13 - LCC:15:80 kg NPK ha-1, T14 - 150:50:50 kg NPK ha-1, T15 - control. The treatments were replicated thrice adopting randomized block design. The study revealed that in both the seasons, growth and yield components viz., plant height, number of tillers hill-1, leaf area index and dry matter production were increased by the application of T8 - 150: 60: 75 kg NPK ha-1. Application of treatment, T8 - 150: 60: 75 kg NPK ha-1 recorded the highest grain yield of 5280 and 5390 kg ha-1 with ADT 36 and ADT 43 respectively. The treatment T8, was followed by the treatment, T12 - 150:60:100 kg NPK ha-1. [ABSTRACT FROM AUTHOR]

System of Rice Intensification (SRI) was evaluated for the variety Hardinath-1 under nutrient omission treatment (-N, -P, -K, -Zn, -B and +All) through field experiment conducted in randomized complete block design (RCBD) with six treatments and four replications during spring season of 2018 at agriculture field of Sailaja Acharya Memorial Polytechnic, Siswani Jahada, Morang. The highest grain (4.62 t/ha) and straw yields (7.75 t/ha) were obtained from the fully fertilized plot (i. e.+All treatments) which might be due to application of all of the major nutrients in sufficient amount (i. e. 150 : 45 : 45 : 20 : 5 N : P : K : Zn : B kg/ha) along with following SRI principles. Omitting the major nutrients showed significantly lesser growth and yield parameters of rice. The P omitted treatment showed significantly higher sterility percentage (23.74) as P had major role on grain filling and development. The nutrients omission treatment also produced significant effect on plant uptake of N, P, K, Zn and B. Significantly higher uptake of N (76.73 kg/ha), P (38.28 kg/ha), K (52.41 kg/ha), Zn (0.086 kg/ha) and B (0.022 kg/ha) was obtained from fully fertilized plot. Based on plant uptake of nutrient on omission plot, native N, P, K, Zn and B supplying capacity of the soil at research plot was found to be 23.51, 25.94, 37.59, 0.075 and 0.019 kg/ha, respectively. The recovery efficiency of applied N, P, K, Zn and B was found to be 35.48, 5.7, 32.93, 0.06 and 0.06%, respectively. Owing to native nutrient supplying capacity of the soil at the research site, N, P, K, Zn and B required to obtain the target yield of 5 t/ha was found 139.5 kg N/ha, 45.22 kg P/ha, 50.8 kg K/ha, 12.1 kg Zn/ha and 2.6 kg B/ha, respectively. [ABSTRACT FROM AUTHOR]

On farm trials were conducted for two year to evaluate the effect of soil test based site specific nutrient management (SSNM) vis-a-vis other farmers practice on rice (Oryza sativa L.) and wheat (Triticum aestivum L.) productivity in villages of Ghaziabad (Uttar Pradesh) and Faridabad (Haryana). Results revealed that the SSNM led to significant increase in grain yield of rice and wheat crops in both the years as compared to the state recommended NPK fertilizer treatment and farmers practices. On an average, SSNM increased the grain yield of rice crop by 19.9% and 14.9% at Partapur and Badarpur said, respectively, over farmers practice. The corresponding increases in grain yield of wheat at Kumbhawas and Badarpur said were 13.9% and 15.4 %. The maximum net profits of Rupees 9 401/ha and Rupees 12 100/ha were obtained from rice under SSNM at Badarpur Said and Partapur, respectively. In wheat crop, the highest net profits of Rupees 6 346/ ha at Badarpur said and Rupees 4 346/ha at Kumbhawas were recorded under SSNM. The lowest yield and net profits from both the crops were obtained with farmers practices. The physicochemical properties (pH, EC and organic carbon) do not get deteriorated due to various nutrient management practices. Available major (NPK), secondary (S) and micronutrients (Zn and B) exhibited significant differences due to treatment variations. SSNM proved significantly superior in respect of buildup of these nutrients in soil.

Fertilizer K and P requirements for rice ( Oryza sativa L.) can be determined with site-specific nutrient management (SSNM) using estimated target yield, nutrient balances, and yield gains from added nutrient. We used the QUEFTS (QUantitative Evaluation of the Fertility of Tropical Soils) model with >8000 plot-level observations to estimate the relationship between grain yield and nutrient accumulation in above-ground dry matter of irrigated rice with harvest index ≥ 0.4. Predicted reciprocal internal efficiencies (RIEs) at 60–70% of yield potential corresponded to plant accumulation of 14.6 kg N, 2.7 kg P, and 15.9 kg K per tonne of grain yield. These RIEs enable determination of plant requirements for K and P and net output of K and P in harvested grain and removed crop residues at a target yield. Yield gains for nutrient applied to irrigated rice averaged 12% for K and 9% for P for 525 to 531 observations. For fields without certain yield gain, fertilizer K and P requirements can be determined by a partial maintenance approach (i.e., fertilizer input < output in nutrient balance), which considers nutrient supply mediated through soil processes and balances trade-offs between financial loss with full maintenance rates and risk of excessive nutrient depletion without nutrient application. When yield gains to an added nutrient are certain, partial maintenance plus yield gain can be used to determine fertilizer requirements. The SSNM-based approach and algorithms enable rapid development of field-specific K and P management. [ABSTRACT FROM AUTHOR]