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The QUEFTS (QUantitative Evaluation of the Fertility of Tropical Soils) model is a valuable tool for developing location-specific management of macronutrients such as N, P, and K to attain higher yields. A review analysis is conducted to understand the applicability of the QUEFTS model in developing site-specific nutrient management (SSNM) for different crops. A total of 33 published articles are available for the QUEFTS model for different crops across the world. The SSNM is available for rice, wheat, maize, potato, tropical tuber crops (cassava, sweet potato, elephant foot yam, taro, and yam), peanut, watermelon, soybean, radish, tea, sweet potato, elephant foot yam, yam, and taro in different countries using the QUEFTS model, and it is discussed in this review. The maximum values of accumulation and dilution of N, P, and K; the balanced nutrient requirements to produce 1000 kg of crop yield; and their internal efficiencies are discussed in this review paper. The review shows that the QUEFTS model parameters derived for rice, wheat, and maize can be directly adapted to different environmental conditions. The data available for potato demand further refinement of the model for its general application irrespective of the agro-climatic conditions. The two sets of data available for cassava are similar and can use the same model parameters for further studies for nutrient management. Single set of data for other crops shows the necessity for more studies to increase their production. The modeled values for different crops presented in this review can further assist the decision-makers in scheduling fertilizer applications for the respective crops, reducing fertilizer and economic losses, and maintaining soil quality. Thus, QUEFTS can be widely used as a simple model to recommend nutrient management practices. However, the QUEFTS model considers only the mean meteorological parameters irrespective of their daily variations. It also considers the soil as a homogeneous medium, which influences the crop yield estimation, which needs to be addressed among agricultural researchers. Therefore, further modifications are also needed for QUEFTS to incorporate different agro-climatic and management conditions and different interactive processes, including other micronutrients, irrigation practices, and sub-soil properties as this model assumes that nutrients are the only limiting factors in crop yield. This review also demands the necessity to focus on the nutrient management of other food crops to ensure food security. [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]

An experiment was conducted to study the effect of nutrient management and varieties of maize on productivity and economics and their residual effect on succeeding gobhi sarson crop. Four nutrient management treatments (viz. site-specific nutrient management, SSNM; recommended fertilizer dose, RFD; 50% RFD and farmer's practice) were applied to five varieties of maize (viz. PAC 740, PMZ-4, PSCL 4640, HQPM 1, and BISCO 855) during the kharif seasons of 2012 and 2013 at Palampur. The residual effects of fertilizers were studied in succeeding gobhi sarson. The SSNM-based nutrient application in maize significantly increased crop dry matter, cobs/ha, grain yield, nitrogen, phosphorus and potassium (NPK) uptake, succeeding gobhi sarson seed yield, maize grain equivalent yield, net return, profitability, and B:C. The SSNM-based nutrient application in maize resulted in 4.2–4.6% and 32.6–46.2% higher system productivity and Indian Net Rupee (INR) 4,507–4,926 and INR 28,837–30,078 higher net returns of over recommended fertilizer application and farmer practice, respectively. SSNM had lowest productivity cost of INR 3.1/kg grain. Apparent NPK productivity (62.4 kg grain/kg NPK applied) was highest under 50% RFD. BISCO 855 was earliest in silking with bolder grain. PMZ-4 and PSCL 4640 gave significantly higher dry matter, cob number, grain and stover yield, apparent NPK and physiological productivity, maize equivalent yield, net return and B:C, and lower productivity cost. Gobhi sarson seed yield was not significantly affected by preceding maize varieties. For higher system productivity and income from the maize-gobhi sarson, SSNM with PMZ 4 or PSCL 4640 varieties of maize must be adopted. [ABSTRACT FROM AUTHOR]

This study was conducted in order to determine the status of different pools of inorganic phosphorus in surface and sub-surface soils, changed over 3 years of intensive cropping with Rice-Maize-Green gram (residual) under site-specific nutrient management and work out the correlation among different pools of P. Postharvest soil properties indicated that soil pH was increasing gradually due to lime addition as one input, in spite of the removal of basic cations. There was small but a positive build up of organic carbon, available N and P. There was a drastic reduction in available K status in postharvest soil with available S were found. Phosphorus was fractionated broadly in two groups (a) Inorganic-P and (b) Organic-P. The inorganic P fractions constituted 71.9–86.0% of total P, whereas organic-P constituted 14.0–28.1% in surface soil and 75.9–81% and 18.1–24.1% in subsoil, respectively. The sequence of different pools in order of Fe-P > RS-P > Al-P > Ca-P > occluded-P > saloid-P (surface soil 0–15 cm) and RS-P > Fe-P > Ca-P > Occluded-P > Al-P > saloid-P (Subsurface soil 15–30 cm). Bray's extracted-P is positively correlated with Fe (r = 0.71*) and Al-P (r = 0.67*) indicating the major contribution of both fractions toward available P pool in surface soil, whereas, Al-P majorly contribute in sub-surface soil. Among the inorganic fractions of Phosphorus, Fe-P (r = 0.72*) are showing positive and significant relationship with total uptake of P, in surface soil and Al-P (0.70*) in sub-surface soil. Thus, understanding the use of both inorganic and organic fertilizer under intensive cropping for 3 years must be planned carefully because the interaction of different forms of P, in acidic soil and various other factors influencing P availability to plants. [ABSTRACT FROM AUTHOR]

Crop modelling can provide us with a vast amount of real-time information about fertilizer dose to achieve the target yield, crop conditions, etc. Nutrient-use efficiency in wheat is low because of conventional blanket and imbalanced fertilizer use. Estimation of fertilizer requirements based on quantitative approaches can assist in improving yields and nutrient-use efficiency. Field experiments were conducted in 20 sites in eastern India to assess the soil supply, requirement and internal efficiency of nitrogen (N), phosphorous (P), potassium (K) and zinc (Zn) in wheat. The data were used to calibrate the QUEFTS (QUantitative Evaluation of the Fertility of Tropical Soils) model for site-specific, balanced fertilizer recommendations. The parameters of maximum accumulation (a) and maximum dilution (d) in wheat were calculated for N (35 and 100 kg), P (129 and 738 kg), K (17 and 56 kg), and Zn (21502 and 140244 mg). Grain yield of wheat showed good correlation with N (R² = 0.937**), P (R² = 0.901**) and K uptake (R² = 0.801**). The NPK ratio to produce 1 ton grain yield of wheat was derived to be 4.9:1.0:8.9. The relationships between chemical properties and nutrient supplying capacity of soils were also established. The model was validated using the data of four other experiments. Observed yields with different amounts of N, P, K and Zn were in good agreement with the predicted values suggesting that the validated QUEFTS model can be used for site-specific nutrient management in wheat. [ABSTRACT FROM AUTHOR]