Quantitative Evaluation Of Fertility Of Tropical Soils Research Articles

Estimating Nutrient Uptake Requirements for Melon Based on the QUEFTS Model

Imbalanced and excessive fertilizer application has resulted in low yields and reduced nutrient use efficiency for melon production in China. Estimating nutrient requirements is crucial for effectively developing site-specific fertilizer recommendations for increasing yield and profit while reducing negative environmental impacts. Relationships between the yield and nutrient uptake requirements of above-ground dry matter were assessed using 1127 on-farm observations (2000–2020) from melon production regions of China. The quantitative evaluation of fertility of tropical soils (QUEFTS) model was used to estimate nutrient requirements. It predicted a linear increase in yield at balanced nutrient uptake levels until the yield reached approximately 60–80% of the potential yield. In order to produce 1000 kg of fruit, 2.9, 0.4 and 3.2 kg/ha of N, P and K (7.2:1.0:7.8), respectively, were required for above-ground parts, while the corresponding nutrient internal efficiencies were 345.3, 2612.6 and 310.0 kg per kg N, P and K, respectively, whereas 1.4, 0.2 and 1.9 kg of N, P and K were required to replace nutrients removed after harvest. The corresponding fruit absorption rates were 47.0%, 59.5% and 58.2%, respectively. Field validation experiments confirmed the consistency between observed and simulated uptake rates, indicating that this model could estimate nutrient requirements. These findings will help develop fertilizer recommendations for improving melon yield and nutrient use efficiency.

Quantitative estimating nutrient uptake requirements for sugarcane based on QUEFTS model in China

Estimating balanced nutrient requirements of sugarcane (Saccharum L. spp.) in China is crucial to develop the optimum fertilization strategies to increase yields and fertilizer use efficiency. In this study, the datasets involving the main sugarcane growing ecological regions were collected from field experiments from 1995 to 2019. Quantitative evaluation of fertility of tropical soils (QUEFTS) model was preliminarily established to investigate the relationship between sugarcane yield and nutrient uptake accumulation and estimate the nutrient requirements for sugarcane at a target yield. QUEFTS model predicted a linear increase in cane yield before the yield reached approximately 60%–70% of the potential yield. Results showed that the total plants had acquired 1.70 kg N, 0.21 kg P, and 2.52 kg K to produce 1000 kg of cane, and the corresponding internal efficiencies (IEs) for N, P, and K were 587.34, 4739.47, and 396.12 kg/kg. Moreover, the simulated balanced nutrients removal from the cane were 1.02 kg N, 0.15 kg P, and 1.63 kg K per 1000 kg of cane, accounting for approximately 60.00%, 71.12% and 64.58% of the total plants, respectively. Field validation experiments suggested that the QUEFTS model could be used to simulate nutrient requirements to help make fertilizer recommendations for sugarcane. QUEFTS model was considered to be an effective alternative for estimating the optimal balance nutrient requirements for sugarcane crops and potentially be helpful when making future decisions regarding fertilizer recommendations for sugarcane in China.

Establishment and validation of site specific fertilizer recommendation for increased barley (Hordeum spp.) yield, northern Ethiopia

Establishing model based balanced nutrient requirements for barley (Hordeum spp.) in the northern Ethiopia can solve the fertilizer recommendation problems and enhance crop yield. The Quantitative Evaluation of Fertility of Tropical Soils (QUEFTS) model was used to estimate balanced nitrogen (N), phosphorus (P) and potassium (K) requirements for barley production in Alaje, northern Ethiopia. The objectives were to (i) quantify soil N, P and K supply and recommend fertilizers using QUEFTS model; (ii) investigate response of QUEFTS fertilizer application on yield and nutrient uptake and (iii) validate QUEFTS model performance. The experiment had four treatments: (T1) model based fertilization; (T2) blended fertilization; (T3) farmers’ fertilization practices and (T4) control/no fertilizer. Soil information of the experimental plots were analyzed and used as model input to estimate soil nutrient supplies and recommend fertilizer. Yield and agronomic data were recorded and nutrient uptake and use efficiencies were analyzed. Model performance and accuracy were also checked using root mean square error, coefficient of determination, index of agreement and percent bias. The result revealed that the N, P and K soil supply ratio in the field experimental plots were 9:1:6. The higher grain yield of 4747 kg ha−1 was recorded in the QUEFTS based fertilization plots. Validation results indicated that there is a good correlation between the QUEFTS predicted and observed grain yields implying that the QUEFTS model can be a base for development of simple and cost-effective decision support tools for nutrient management and fertilizer recommendations. Thus, the model performance and prediction accuracy is promising and can help farmers to adjust fertilizer application rates based on crop requirements.

Quantitative Estimation of the Nutrient Uptake Requirements of Peanut

Understanding the characteristics of the balanced nutrient requirements for peanut to achieve target yields is paramount when formulating fertilizer management strategies to increase yields and avoid fertilizer loss. Nutritional requirement estimation models can provide effective alternatives for the estimation of the optimum crop balanced nutrient requirements under varied agricultural conditions which are less time consuming and expensive. In the present study, the quantitative estimation of the optimum crop balanced nutrient requirements of peanut in China were obtained using quantitative evaluation of fertility of tropical soils (QUEFTS) model. The database covered the main agro-ecological region for peanut crops in China between 1993 and 2018. The predicted results of the QUEFTS model indicated that nutrient uptake requirements increased linearly with increasing pod yields until the yields had reached approximately 60% to 70% of the potential pod yields. It was found that with the increasing pod yields during the nutrient linear absorption stage, the plants had required 38.4 kg N, 4.3 kg P, and 14.0 kg K in total to produce 1000 kg of pods, and the corresponding internal efficiencies were 26.0 kg N/kg, 235.0 kg P/kg, and 71.6 kg K/kg, respectively. In addition, the balance rates of the removal nutrient in the pods were determined to be 29.4 kg N, 2.9 kg P, and 4.9 kg K per 1000 kg of pod yield, or approximately 76.5%, 67.4%, and 34.7% of N, P, and K in the total plants, respectively. This study’s field validation experiments verified the applicability and accuracy of the QUEFTS model. Therefore, it was considered to be an effective alternative for the estimation of the optimal balance N, P, and K uptake requirements for peanut crops. These findings will potentially be helpful when making future decisions regarding fertilizer recommendations for peanut crops in China.

Validation of quefts model for site specific nutrient management in white YAM (Dioscorea rotundata POIR.)

Yam (Dioscorea spp.) is an important tropical tuber crop contributing to food and nutritional security of economically backward and ethnic people of many countries in Africa, South America and Asia. Yam yield in the major growing environments of India has been stagnating despite the development of high yielding varieties and increasing use of chemical fertilizers. On-station experiments were conducted to evaluate the performance of site-specific nutrient management (SSNM). Field and crop specific NPK rates were calculated using quantitative evaluation of fertility of tropical soils (QUEFTS) model. The yield advantage of SSNM over current recommendation was 8.16 t ha−1 (mean of 3 yrs). The increase in agronomic efficiency and recovery efficiency of N in SSNM over current recommendation was 24.1 kg kg−1 and 0.09 kg kg−1, respectively. Similar increases were observed for P and K. The results showed the potential of SSNM in increasing yield and nutrient use efficiency of white yam.

Balanced nutrient requirements for maize in the Northern Nigerian Savanna: Parameterization and validation of QUEFTS model

Establishing balanced nutrient requirements for maize (Zea mays L.) in the Northern Nigerian Savanna is paramount to develop site-specific fertilizer recommendations to increase maize yield, profits of farmers and avoid negative environmental impacts of fertilizer use. The model QUEFTS (QUantitative Evaluation of Fertility of Tropical Soils) was used to estimate balanced nitrogen (N), phosphorus (P) and potassium (K) requirements for maize production in the Northern Nigerian Savanna. Data from on-farm nutrient omission trials conducted in 2015 and 2016 rainy seasons in two agro-ecological zones in the Northern Nigerian Savanna (i.e. Northern Guinea Savanna “NGS” and Sudan Savanna “SS”) were used to parameterize and validate the QUEFTS model. The relations between indigenous soil N, P, and K supply and soil properties were not well described with the QUEFTS default equations and consequently new and better fitting equations were derived. The parameters of maximum accumulation (a) and dilution (d) in kg grain per kg nutrient for the QUEFTS model obtained were respectively 35 and 79 for N, 200 and 527 for P and 25 and 117 for K in the NGS zone; 32 and 79 for N, 164 and 528 for P and 24 and 136 for K in the SS zone; and 35 and 79 for N, 199 and 528 for P and 24 and 124 for K when the data of the two zones were combined. There was a close agreement between observed and parameterized QUEFTS predicted yields in each of the agro-ecological zone (R2 = 0.69 for the NGS and 0.75 for the SS). Although with a slight reduction in the prediction power, a good fit between the observed and model predicted grain yield was also detected when the data for the two agro-ecological zones were combined (R2 = 0.67). Therefore, across the two agro-ecological zones, the model predicted a linear relationship between grain yield and above-ground nutrient uptake until yield reached about 50 to 60% of the yield potential. When the yield target reached 60% of the potential yield (i.e. 6.0 t ha−1), the model showed above-ground balanced nutrient uptake of 20.7, 3.4 and 27.1 kg N, P, and K, respectively, per one tonne of maize grain. These results suggest an average NPK ratio in the plant dry matter of about 6.1:1:7.9. We concluded that the QUEFTS model can be widely used for balanced nutrient requirement estimations and development of site-specific fertilizer recommendations for maize intensification in the Northern Nigerian Savanna.

Quantitative determination of NPK uptake requirements of taro (Colocasia esculenta (L.) Schott)

Taro yield in many parts of the world is stagnant mainly due to conventional blanket recommendation of fertilizers, lower nutrient use efficiency and imbalance in the use of nutrients. The Quantitative Evaluation of Fertility of Tropical Soils (QUEFTS) model was used for determining the region specific balanced NPK uptake requirements and recommendations for a target yield of taro. The constants for minimum and maximum accumulation (kg cormel kg−1 nutrient) of N (33 and 177), P (212 and 606) and K (25 and 127) were derived as standard model parameters. The results showed that taro requires N, P and K accumulation of 12.97, 2.75 and 17.47 kg t−1 of cormel yield, suggesting an average NPK ratio in the plant dry matter of about 4.7:1:6.4. The NPK fertilizer requirements for different potential yield situations were also calculated. The results need to be validated in major taro growing regions.

Site-specific nutrient requirements of NPK for potato (Solanum tuberosum L.) in Western Indo-gangetic plains of India based on QUEFTS

Potato productivity in India is static due to unbalanced use of nutrients and intensive cropping system. Nutrient use efficiency and yield can be increased by application of nutrients based on quantitative approaches. We calibrated the quantitative evaluation of fertility of tropical soils (QUEFTS) model for the estimation of NPK requirements for different targeted yields of potato. Published data sets were used to calibrate the model. The results of the study showed that to produce one ton of potato tubers, 18, 4, and 24 kg N, P, and K, respectively, would be needed with internal efficiencies of 55, 285, and 42 kg tuber dry yield/kg N, P, and K removed. The observed yields of potato with different amount of nutrients were in agreement with the values predicted by the model. Therefore, the QUEFTS model based NPK fertilizer recommendations can be adopted for site-specific nutrient management of potato.

Application of QUEFTS Model for Site-Specific Nutrient Management of NPK in Sweet Potato (Ipomoea batatas L. Lam)

ABSTRACTSweet potato productivity in India is either stagnated or lowering down over the past many years. The main reasons for low yield are conventional blanket recommendation of fertilizers, lower nutrient-use efficiency and imbalance in the use of fertilizers. Recommendation of major nutrients, nitrogen, phosphorus, and potassium (NPK), based on quantitative approaches will augment sweet potato production per unit area by increasing the nutrient-use efficiency. The present study calibrated the Quantitative Evaluation of Fertility of Tropical Soils (QUEFTS) model for the estimation of NPK requirements and fertilizers recommendations for different target yields of sweet potato. The QUEFTS basically works on the principle of NPK nutrient interactions and climate-adjusted yield potential of a region. Published data sets from several field experiments related to NPK carried out till date were collected to reflect the environment variability. The results of the present study showed that to produce one ton tuber, 16:6:18 kg N, P, and K, respectively, would be needed with the internal efficiencies of 61:167:57 kg tubers kg−1 NPK removed. The maximum accumulation and dilution (kg tuber kg−1 nutrient removed) of N (40, 80), P (96, 272), and K (30, 85) were also derived as standard parameters in QUEFTS for optimum fertilizer recommendation in tropical and subtropical regions of India. The observed yields of sweet potato with different amounts of nutrients were in agreement with the values predicted by the model. Therefore, it is utmost important to have the results of the study validated in major growing environments of India for fertilizer recommendation in sweet potato.

Site‐Specific Nutrient Management for Cassava in Southern India

Cassava (Manihot esculenta Crantz.) yield in the major growing environments of India has been stagnating despite the development of high yielding varieties and increasing use of chemical fertilizers. On farm experiments were conducted to evaluate the performance of site‐specific nutrient management (SSNM). Field and crop specific NPK rates were calculated using quantitative evaluation of fertility of tropical soils (QUEFTS) model. The average 2‐yr yield advantage of SSNM over farmer fertilizer practice (FFP) was 7 Mg ha−1. The N agronomic efficiency increase of SSNM over FFP was 32 kg kg−1, the N recovery efficiency of SSNM was 0.14 kg kg−1 greater than that of FFP and the N physiological efficiency of SSNM was 54 kg kg−1 greater than that of FFP, whereas the partial factor productivity of SSNM was 148 kg less than that of FFP. Use of SSNM led to a reduction of fertilizer costs by an average of US$10 ha−1 crop−1 and an increase in gross return above fertilizer costs by $254 ha−1 crop−1 compared with FFP. Zone NPK recommendation maps and customized fertilizer blends were also developed. The results showed the potential of SSNM in significantly increasing yield and nutrient use efficiency of cassava. Future research is needed to validate the customized fertilizer blends and fine tune zone NPK recommendation maps which will help reduce the need for field specific modeling and intensive crop monitoring.

Modeling the Response of Cassava to Fertilizers: A Site-Specific Nutrient Management Approach for Greater Tuberous Root Yield

Conventional fertilizer-management strategy results in decreased fertilizer-use efficiency and unbalanced nitrogen (N)–phosphorus (P)–potassium (K) applications. The quantitative evaluation of fertility of tropical soils (QUEFTS) model was used for determining region-specific balanced NPK uptake requirements and recommendations for a target yield of cassava. Minimum and maximum internal efficiencies of N, P, and K were estimated as 35 and 80 for N, 250 and 750 for P, and 32 and 102 for K (kg tuberous root per kg nutrient removed). Linear increases in tuberous root yield with N, P, and K uptakes of 17.6, 2.2, and 15.6 kg N, P, and K per 1000 kg tuberous root yield were observed. Relationships between soil supply and soil chemical properties and between fertilizer nutrient recovery efficiencies with their rates of application were developed for major cassava-production regions. Good agreement between measured and predicted yields was observed while calibrating the model, which shows that the model can be used for making site-specific NPK recommendations for cassava in major cassava production regions of India.

Modelling the quantitative evaluation of soil nutrient supply, nutrient use efficiency, and fertilizer requirements of wheat in India

Wheat yields in many parts of India are stagnant. The main reason forthis is conventional blanket fertilizer recommendation, lower fertilizer useefficiency, and imbalanced use of fertilizers. Estimation of fertilizerrequirements based on quantitative approaches can assist in improving wheatyields and increasing nutrient use efficiency. We used the QUEFTS (QUantitativeEvaluation of Fertility of Tropical Soils) model for estimation of nitrogen(N),phosphorus (P), and potassium (K) requirements and fertilizer recommendationsfor a target yield of wheat. The model considers the interactions of N, P, andK, and climate adjusted potential yield of the region. Published data fromseveral field experiments dealing with N, P, and K conducted during the years1970 to 1998 across wheat-growing environments of India, covering a wide rangeof soil and climatic conditions, were used to reflect the environmentalvariability. The relationships between indigenous N, P, and K supply and soilorganic carbon, Olsen P, and ammonium acetate-extractable K, respectively, wereestablished. The required N, P, and K accumulation in the plant for 1 tonnegrain yield was 23.1, 3.5, and 28.5 kg, respectively, suggestinganaverage NPK ratio in the plant dry matter of about 6.6:1:8.1. The constants forminimum and maximum accumulation (kg grain kg−1) of N (27 and60), P (162 and 390), and K (20 and 59) were derived as the standard modelparameters in QUEFTS for fertilizer recommendation for irrigated wheat in thetropical and subtropical regions of India. Relationships of apparent recoveryefficiencies of fertilizer N, P, and K with levels of their application werealso determined. The observed yields of wheat with different amounts of thesenutrients were in good agreement with the values predicted by the model,indicating that the model can be used for fertilizer recommendations.

The oil palm (Elaeis guineensis Jacq.)

Cassava is an important tropical root crop with versatile uses in food, feed, green energy and industrial sectors. It is grown mostly for food in Sub-Saharan Africa, food and other uses in Latin America and feed and other uses in Asia. The current global level of productivity of about 12 t/ha is only 12% of its potential productivity. Major reasons for the wide yield gap are lack of scientific nutrient management and unbalanced crop nutrition. In this review, we update the gap in cassava productivity, soil requirements, nutrient requirements and evolution of fertilizer recommendations and its impact on bridging the yield gap. Research work on mineral nutrition of cassava, especially in Asia and Latin America is aplenty. Among the major nutrients, cassava removes large quantity of potassium along with the harvested produce compared to the other nutrients. The range of critical levels of P and K reported for cassava was lower than the corresponding values reported for most of the crops, which shows its adaptability to grow and yield under poor soil fertility conditions. Studies on nutrient requirements of cassava showed that the N:P:K uptake ratio in total plant dry matter was 6.2:1:6.6. The total N, P and K uptake requirements for producing one ton of fresh cassava tuber ranged from 2.9 to 6.9 kg for N, 0.68 to 1.3 kg for P and 3.9 to 7.9 kg for K. Large variations in blanket NPK recommendations could be observed among different countries. An attempt to compare inorganic nutrient management with organic nutrition on growth, yield, quality and soil properties is also made. Presently, more knowledge-intensive and computer simulation model-based site-specific nutrient management (SSNM) using models such as quantitative evaluation of fertility of tropical soils (QUEFTS) has proved to be a better alternative in reducing the yield gap of cassava in India and some West African countries. More basic knowledge need to be emanated from further research for developing field level nutrient recommendations under changing climate, especially drought. Development of a cassava SSNM network (CSN), analysis and interpretation of already existing data of different national and international research institutes and generation of required additional field data will help to further improve the SSNM technology and its wider application for precision nutrient management, combating wide spread nutrient disorders and enabling better yields among cassava growing countries across the globe.