Optimal Fertilizer Application Research Articles

MULTIVARIATE PROBIT MODELING OF CLIMATE-SMART ADAPTATION CHOICES AMONG FARMERS IN SUB-SAHARAN AFRICA: GHANAIAN STUDY OF COCOA FARMERS

Climate change and variability pose significant challenges to cocoa production in many sub-Saharan African countries, and Ghana is no exception. Therefore, knowledge of how farmers react to climate change and its variability effects is crucial in developing policies and programs to guide the design and implementation of effective climate-smart adaptation strategies at the farm level in Africa. This study aims to examine climate-smart adaptation choices cocoa farmers make as coping strategies for climate change and variability in Ghana using a multivariate probit modeling approach. Following a multistage sampling procedure, primary data was collected from 720 cocoa farmers across the major cocoa-growing regions in Ghana. The study found major adaptation choices for cocoa farmers to include improved and resistant varieties, optimal fertilizer application, optimal pesticide application, adjusting planting/harvesting dates, shade tree management, crop diversification, non-crop diversification, and off-farm economic diversification. We further observed that farmers’ adaptation choices were significantly influenced by climate change and adaptation-related variables such as rainfall variability index, temperature variability index, climate change impact perception index, and CSA awareness as well as agroclimatic zone effects. Concerning the influence of farmer and farm-specific variables, the study identifies that sex, age, education, farm size, quality of extension services delivery, access to credit, and membership in farmer groups were significant predictors of farmers’ CSA decision choices. This study offers beneficial insights for policymakers and stakeholders on how to promote climate-smart adaptation methods among cocoa farmers in Ghana.

Fertilizer application parameters for drip-irrigated peanut based on the fertilizer effect function established from a "3414" field trial.

Scientific fertilization is an important technical means of achieving high and stable peanut yields. Using soil testing and formula fertilization, the "3414" optimal regression design was used and included 14 nitrogen (N), phosphorus (P), and potassium (K) fertilization treatments. Ternary quadratic functions of the fertilizer effect were established according to three-season field experiments and the regression analysis of fertilizer-yield function was performed to explore the optimal fertilizer application mode and ratio for peanuts under mulched drip irrigation (MDI), and a suitable fertilizer application system was established. The ternary quadratic equation relating peanut yield (y) and the fertilizer application rates of N (N), P (P2O5), and K (K2O) was obtained after fitting, i.e., y = 2912.528 + 21.432N + 16.324P + 6.181K - 0.051N2 - 0.109P2 - 0.061K2 + 0.017NP + 0.023NK + 0.086PK, and significance analysis and typicality assessment were performed. The model R 2 was 0.9709, both values are extremely significant (p < 0.01), which indicates that the obtained ternary quadratic fertilizer effect function is typical and could be used for statistical purposes and fertilization recommendations. Three quadratic fertilizer effect functions were obtained. Among them, the equation for K is extremely significant, and the equations of N and P are significant. According to the assumption that the marginal yield is zero and the marginal profit is zero, the fertilizer application rate with the maximum yield, the fertilizer application rate with the best economic benefits, and the corresponding yields were obtained. The optimal fertilizer application rate predicted by the ternary quadratic fertilizer effect function was relatively high, so the three quadratic fertilizer effect functions were used for prediction. Under the test conditions, the recommended fertilizer application rates for peanuts under MDI are 256.6 kg N per ha, 164.2 kg P2O5 per ha, and 213.2 kg K2O per ha, the recommended fertilization ratio is 1:0.64:0.83, and the recommended ratio under formula fertilization is 23:15:19. The study has developed a data-based decision support system for Xinjiang drip-irrigated peanut, which assists farmers and agricultural managers in making more scientific and precise fertilization decisions based on the specific growth requirements of the crops and soil conditions. This evidence-based methodology enhances the precision of agricultural management, which is conducive to increasing crop yields while reducing resource wastage and environmental impact. However, multipoint and multiyear experiments are still needed to ensure that the findings are adaptable to the diverse soil conditions and fluctuating climate patterns that may be encountered in practice.

Growth and yield of maize in response to reduced fertilizer application and its impacts on population dynamics and community biodiversity of insects and soil microbes

In the North China Plain, farmers are using excessive amounts of fertilizer for the production of high-yield crop yield, which indirectly causes pollution in agricultural production. To investigate an optimal rate of fertilizer application for summer maize, the fertilizer reduction experiments with 600 kg/ha NPK (N: P2O5: K2O = 28: 8: 10) as normal fertilizer application (NFA), (i.e., 100F), were conducted successively during 2020 and 2021 to study the effects of reduced fertilizer rates, including 90% (540 kg/ha; i.e., 90F), 80% (480 kg/ha; i.e., 80F), 62.5% (375 kg/ha; i.e., 62.5F) and 50% (300 kg/ha; i.e., 50F) of NFA, on the plant growth of maize, the dynamics of key population abundances and community diversity of insects, and the composition and diversity of microbial community and finally to find out the N-metabolic enzymes’ activity in soil. Our findings revealed that the fertilizer reduction rates by 10% - 20% compared to the current 100% NFA, and it has not significantly affected the plant growth of maize, not only plant growth indexes but also foliar contents of nutrients, secondary metabolites, and N-metabolic enzymes’ activity. Further, there was no significant alteration of the key population dynamics of the Asian corn borer (Ostrinia furnacalis) and the community diversity of insects on maize plants. It is interesting to note that the level of N-metabolic enzymes’ activity and microbial community diversity in soil were also not affected. While the fertilizer reduction rate by 50% unequivocally reduced field corn yield compared to 100% NFA, significantly decreased the yield by 17.10%. The optimal fertilizer application was calculated as 547 kg/ha (i.e., 91.17% NFA) based on the simulation analysis of maize yields among the five fertilizer application treatments, and the fertilizer application reduced down to 486 kg/ha (i.e., 81.00% NFA) with a significant reduction of maize yield. These results indicated that reduced the fertilizer application by 8.83% - 19.00% is safe and feasible to mitigate pollution and promote sustainable production of maize crops in the region.

Agricultural Decision Support System

Abstract: In India, agriculture stands as the backbone of the economy, yet farmers encounter persistent challenges rooted in conventional farming methods that result in suboptimal yields and environmental degradation. To address these issues, a transformative shift towards precision agriculture is imperative. Our Agricultural Decision Support System (ADSS) represents a pioneering initiative harnessing advanced machine learning algorithms to confront these challenges head-on. By scrutinizing soil characteristics alongside critical weather parameters encompassing temperature, humidity, pH levels, and precipitation, our system furnishes tailored recommendations for crop selection and optimal fertilizer application. Through the implementation of our innovative solution, farmers stand poised to diversify their crop cultivation, augment yields, and pave the way for sustainable agricultural practices. The integration of our system offers farmers the opportunity to explore new crop varieties, potentially leading to heightened profitability and the mitigation of soil pollution concerns.

Optimizing nitrogen and phosphorus application to improve soil organic carbon and alfalfa hay yield in alfalfa fields.

Soil organic carbon (SOC) is the principal factor contributing to enhanced soil fertility and also functions as the major carbon sink within terrestrial ecosystems. Applying fertilizer is a crucial agricultural practice that enhances SOC and promotes crop yields. Nevertheless, the response of SOC, active organic carbon fraction and hay yield to nitrogen and phosphorus application is still unclear. The objective of this study was to investigate the impact of nitrogen-phosphorus interactions on SOC, active organic carbon fractions and hay yield in alfalfa fields. A two-factor randomized group design was employed in this study, with two nitrogen levels of 0 kg·ha-1 (N0) and 120 kg·ha-1 (N1) and four phosphorus levels of 0 kg·ha-1 (P0), 50 kg·ha-1 (P1), 100 kg·ha-1 (P2) and 150 kg·ha-1 (P3). The results showed that the nitrogen and phosphorus treatments increased SOC, easily oxidized organic carbon (EOC), dissolved organic carbon (DOC), particulate organic carbon (POC), microbial biomass carbon (MBC) and hay yield in alfalfa fields, and increased with the duration of fertilizer application, reaching a maximum under N1P2 or N1P3 treatments. The increases in SOC, EOC, DOC, POC, MBC content and hay yield in the 0-60 cm soil layer of the alfalfa field were 9.11%-21.85%, 1.07%-25.01%, 6.94%-22.03%, 10.36%-44.15%, 26.46%-62.61% and 5.51%-23.25% for the nitrogen and phosphorus treatments, respectively. The vertical distribution of SOC, EOC, DOC and POC contents under all nitrogen and phosphorus treatments was highest in the 0-20 cm soil layer and tended to decrease with increasing depth of the soil layer. The MBC content was highest in the 10-30 cm soil layer. DOC/SOC, MBC/SOC (excluding N0P1 treatment) and POC/SOC were all higher in the 0-40 cm soil layer of the alfalfa field compared to the N0P0 treatment, indicating that the nitrogen and phosphorus treatments effectively improved soil fertility, while EOC/SOC and DOC/SOC were both lower in the 40-60 cm soil layer than in the N0P0 treatment, indicating that the nitrogen and phosphorus treatments improved soil carbon sequestration potential. The soil layer between 0-30 cm exhibited the highest sensitivity index for MBC, whereas the soil layer between 30-60 cm had the highest sensitivity index for POC. This suggests that the indication for changes in SOC due to nitrogen and phosphorus treatment shifted from MBC to POC as the soil depth increased. Meanwhile, except the 20-30 cm layer of soil in the N0P1 treatment and the 20-50 cm layer in the N1P0 treatment, all fertilizers enhanced the soil Carbon management index (CMI) to varying degrees. Structural equation modeling shows that nitrogen and phosphorus indirectly affect SOC content by changing the content of the active organic carbon fraction, and that SOC is primarily impacted by POC and MBC. The comprehensive assessment indicated that the N1P2 treatment was the optimal fertilizer application pattern. In summary, the nitrogen and phosphorus treatments improved soil fertility in the 0-40 cm soil layer and soil carbon sequestration potential in the 40-60 cm soil layer of alfalfa fields. In agroecosystems, a recommended application rate of 120 kg·ha-1 for nitrogen and 100 kg·ha-1 for phosphorus is the most effective in increasing SOC content, soil carbon pool potential and alfalfa hay yield.

A global meta-analysis on surface and drip fertigation for annual crops under different fertilization levels

So far, many studies have examined the effects of surface (FF) and drip (DF) fertigation compared to surface (FC) and drip (DC) irrigation along with fertilization at different levels of fertilizer on crop yield indices, nutrient use efficiency (NUE), and irrigation water productivity (WP); however, each of them have been conducted under different conditions. Because of the scattered results and the lack of a general conclusion from the published results, conducting a meta-analysis as a structured method for arriving at an overall conclusion regarding the effects of different fertigation methods on different indices is essential. This study was conducted to examine the effects of surface and drip fertigation methods and different fertilizer application levels on crop yield, NUE, and WP. To this end, eight global databases of publications (e.g., Scopus and Web of Science) were reviewed. A total of 5494 studies were extracted, of which 32 studies met the entry criteria for the meta-analysis. To assess the effects of fertigation, each study was used to extract the effect sizes for each index. A total of 119 effect sizes were obtained for crop yield, 85 for NUE, and 84 for WP. The meta-analysis results showed that surface and drip fertigation methods increased the average yield by 20%. NUE and WP on an average increased by 26% and 51%, respectively. Based on the reported results, the optimal fertilizer application level is 75% of the recommended dose, which can reduce fertilizer use by 25% without significantly reducing the yield. In general, fertigation can be recommended as an effective operation for improving the proposed indices examined in both surface and drip fertigation methods.

Influence of Organic Fertilizer Sources and Application Rates on Onion Production in Georgia, USA

A range of organic fertilizers are available for vegetable crops; however, there is a lack of information regarding the performance and rates of organic fertilizers commonly used in the production of Vidalia onion (Allium cepa). Two commercial organic fertilizers, a mixed source organic fertilizer [MIX (10N–0.9P–6.6K)] and a pelleted poultry litter [PPL (5N–1.8P–2.5K)], were evaluated in two soil types at application rates of 0, 100, 150, 200, 250, and 300 lb/acre nitrogen (N) to determine their impact in the production of Vidalia onions in Georgia, USA, with the objective of determining an optimal fertilizer source and application rate. Field trials were conducted in the 2019–20 and 2020–21 growing seasons in Watkinsville, GA, USA (Cecil series sandy clay loam soil) and Tifton, GA, USA (Tifton series loamy sand soil) on certified organic land. There were significant interactions among location, year, and fertilizer application rate for total marketable yield. In Watkinsville, total marketable yields of onions at different N rates ranged between 1320 and 4565 lb/acre in 2019–20, and between 9951 and 28,749 lb/acre in 2020–21. In Tifton, total marketable yields ranged from 3776 to 9264 lb/acre and 7094 to 14,066 lb/acre in the 2019–20 and 2020–21 seasons, respectively. Aboveground onion N accumulation at harvest was affected by an interaction among location, study year, and fertilizer rate. The largest plant N accumulation was in Watkinsville in 2020–21, ranging from 26 to 50.8 lb/acre N in the 0- and 300-lb/acre N treatments, respectively. In 2020, there were no differences in soil inorganic N at harvest between plots receiving the MIX (9 lb/acre N) or PPL (9.8 lb/acre N) in either location. In 2021, soil inorganic N was greater in plots receiving the MIX fertilizer (14.8 lb/acre N) compared with the PPL fertilizer (11.2 lb/acre N). Yields increased linearly with additional fertilizer; therefore, an optimal application rate for organic fertilizers was not determined.

Balancing quality and productivity of Apocynum venetum with N and P fertilizer management under drip irrigation in arid conditions of Northwest China

Although Apocynum venetum L. is a valuable native species in China for economic and industrial purposes, less studies have been conducted to determine the optimum fertilizer application rate for cultivating it. The leaves of A. venetum are used as traditional Chinese herbs and the fiber is referred to as “king of wild fiber’’ because of its anti-microbial and anti-UV features. It grows in poor soils but currently populations of wild A. venetum in China are decreasing rapidly. Developing cultivation techniques for endangered A. venetum to achieve sustainable long-term use of this plant resource has become urgent and important. The role of nutrient supply in increasing yield and quality is currently unknown. To maximize the productivity and economic value of A. venetum, a 3-yr nutrient trial was conducted under drip irrigation to evaluate optimal fertilizer application for producing high yield (dry leaves) and better quality. The effects of N/P combination (N0-0 kg/ha, N1-17.4 kg/ha, N2-34.8 kg/ha, and N3-52.2 kg/ha; P0-0 kg/ha, P1-28.6 kg/ha, P2-57.2 kg/ha, and P3-85.8 kg/ha) on plant growth, yield, as well as the quality of drip-fertilized A. venetum, in northwest China were also investigated. Principal component analysis (PCA) and membership function analysis were implemented to develop a comprehensive evaluation model of nutrient interactions to determine the best N/P fertilizer application scheme for simultaneous yield and quality improvement of A. venetum. Overall, fertilization promoted the growth of A. venetum. With increasing fertilizer application, the growth, leaf yield, and quality of A. venetum tended to increase and then decrease. The maximum leaf yield was achieved under T6 (N2P2) treatment that was increased by 213.1 %, 184.3 %, and 88.3 % compared with controls from 2018 to 2020, respectively. Under T6 as well, the best total flavonoid, rutin, and isoquercitrin contents were observed, which were increased by 52.17 %, 68.39 %, and 128.07 % on average for three years. Correlation analysis showed that agronomic traits (plant height, stem diameter, secondary branch, and reproductive branch number) were positively correlated with both yield (aboveground biomass, yield) and quality (rutin, isoquercitrin, and total flavonoids content). According to the comprehensive evaluation model, the optimum N/P fertilizer pairing combination was N2P2, which resulted in the best quality and highest yield of A. venetum. The current research determined the fertilizer application to cultivate A. venetum and elucidated the effects on productivity and quality. This study provides a foundation for developing cultivation practices of A. venetum and promoting its application.

Формализация параметров модуля фертигации в системах капельного орошения

Purpose: to formalize the parameters on which the choice of optimal fertilizer application rates depends with fuzzy sets for constructing a fuzzy model and a control system for the fertigation module. Materials and methods. The use of Soft Computing methods is required by the need to represent the input variables values in the form of fuzzy sets, with further structural and parametric identification of a fuzzy model for controlling the concentration of nutrients in the solution. This will enable to compile fuzzy knowledge bases in the form of “IF – THEN” rules and, using fuzzy logic methods, to determine the well-defined values of output variables: the necessary application rates of nitrogen, phosphorus and potassium with irrigation water. Results. As input variables, the parameters on which the choice of optimal fertilizer rates depends are determined. At the output of the model, three variables determining the norms of nitrogen, phosphorus and potassium of the nutrient solution are used. For each of the selected input and output variables, the measurement ranges and the linguistic term values are selected and membership functions are constructed. Conclusions. The conducted formalization of input and output values will make it possible to build the structure of the fertigation module control model, to form fuzzy rule bases and to implement fuzzy logical inference according to the Mamdani algorithm. This will allow defuzzification of the output variables using the center of gravity method in order to obtain a clear numerical value at the output. It is also possible to carry out parametric identification of the obtained model from the training sample by adjusting the membership functions parameters of the. Thanks to the use of IoT technologies, it will be possible to carry out external control and, if necessary, manual control of the fertigation system.

Effect of Chemical Fertilizer Application on Maize Production in China over the Past 15 Years: A Meta-Analysis

Although there are many new types of environmentally friendly fertilizers that can improve maize yield, chemical fertilizers are the most widespread type of fertilizer used in the agricultural sector of China due to their low cost and ease of application. However, the misuse of chemical fertilizers could lead to environmental problems, such as the massive emission of greenhouse gases (GHG). Therefore, it is important to determine how fertilizer-use efficiency (FUE) could be improved to stabilize or increase maize yield while reducing GHG emissions. In this study, we collected 6618 date records which include three datasets (for N, P, and K) from five maize-growing regions in China from 2005 to 2018, and performed a meta-analysis on the effects of N, K, and P fertilization levels on maize yield, partial factor productivity (PFP), agronomic efficiency (AE), and the carbon footprint of maize production. Additionally, scenario analyses were performed to estimate optimal fertilizer application rates for stabilizing or increasing maize yield while reducing GHG emissions. It was shown that FUE and maize yield responses to fertilization level varied in different regions. Compared to the past, the maize production of China has improved significantly in terms of FUE and its carbon footprint in recent years. Because of improvements in maize cultivars and cultivation technologies, it is possible to decrease N, P, and K application rates and reduce per unit area carbon footprint of maize, without compromising yield. In the future, N fertilization should be reduced by 10% from current levels, and the application of P and K fertilizers should be increased or decreased depending on the conditions of each maize-growing region. Thus, it should be possible to stabilize or even increase yields and reduce GHG emissions of maize production, thereby achieving green and efficient development.

Improving Yield and Water Productivity of Rainfed Summer Maize in Smallholder Farming: A Case Study in Hebei Province, China

Because of the strong competition for a limited resource of water and demand for food production, understanding yield and water productivity (WP) potentials and exploitable gaps in the current production of intensively rainfed maize (Zea mays L.) is essential on the regional scale in China. In this study, we conducted 411 site–year on-farm trials to assess the actual yield and WP of rainfed summer maize and its yield and WP potentials in Hebei Province, China. Each on-farm trial contained detailed information of three different treatments: no fertilizer application (CK), current farmers’ practices (FP, depending on local farmer field fertilization management), and optimum fertilizer application (OPT, depending on soil testing and balanced fertilization). Results revealed that the yield and WP of rainfed summer maize in Hebei Province were 7635 kg ha−1 and 20.7 kg ha−1 mm−1, respectively, and the yield and WP potentials were 12,148 kg ha−1 and 32.0 kg ha−1 mm−1, respectively. Thus, the farmers attained 62.8% of the yield potential and 64.7% of the WP potential. A wide variation was observed in terms of the yield and WP across various types of farming. Compared with high-yield and high-WP (HYHW) farming, in low-yield and low-WP (LYLW) farming, the yield decreased by 24.9% and WP decreased by 44.4%. Nitrogen fertilizer application rate and rain were the most significant factors for yield and WP gaps among farmers, respectively. Other factors, such as solar radiation (tSola), soil available phosphorus content (AP), potassium fertilizer application rate, and grass-referenced evapotranspiration from planting to maturity (ET0), contributed the most to the variations in the yield and WP. Scenario analysis indicated that the optimization of fertilization levels from current to optimal for each farming could increase the yield and WP by 9.7% and 14.8%, respectively; closing gaps between the farming groups and achievement of the standard of HYHW farming by all farmers could increase the yield and WP by 14.8% and 35.5%, respectively; and achieving the yield and WP potentials could increase the yield and WP by 59.1% and 54.8%, respectively. These findings provided farming-based evidence that optimal nutrient management, advanced and climate-adapted agronomy practices, and higher soil fertility are essential for future maize production.

Optimal Fertilizer Application Reduced Nitrogen Leaching and Maintained High Yield in Wheat-Maize Cropping System in North China.

Agricultural nitrogen (N) non-point source pollution in the North China Plain is a major factor that affects water quality and human health. The characteristics of N leaching under different N application conditions should be further quantified accurately in winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) rotation farmland in North China, and a basis for reducing the risk and evaluation of N leaching in this area. A three-year field experiment was conducted using an in situ leakage pond method at a typical farmland in Henan in 2017–2020. Crop yield, soil nitrate N residues, and N utilization were also studied during the study period. Five N fertilizer rates were established with 0 (CK), 285 (LN), 465 (MN), 510 (MNO), and 645 (HN) kg N ha−1 for one rotation cycle. MNO was applied with chemical and organic fertilizers. The concentration of nitrate N in the soil leaching solution of CK, LN, MN, MNO, and HN was 0.81-, 1.49-, 3.65-, 5.55-, and 7.57-fold that of the World Health Organization’s standard for underground drinking water. The exponential relationship between the N application rate and leaching was obtained when the annual N input exceeded 300 kg ha−1, and the N leaching rate increased greatly. The leaching rate of nitrate N in the total N was 50.6–82.4% under different treatments of N application. The combination of chemical and organic fertilizers treatment (MNO) reduced the amount of N that was leached in dry years. The nitrate leaching amount of summer maize accounts for 83.0%, 49.4%, and 72.0% of the total nitrate leaching amount of the whole rotation cycles in 2017–2020. LN and MN were recommended as the optimized N application here (285–465 kg N ha−1) with the two-season rotation grain yield of 17.2 ton ha−1 (16.5–17.9 ton ha−1) and nitrate N leaching of 21.6 kg ha−1 (12.6–30.5 kg ha−1).

Optimum fertilizer application rate to ensure yield and decrease greenhouse gas emissions in rain-fed agriculture system of the Loess Plateau

Application of nitrogen (N) can increase the supply of N in soil and, in turn, can lead to higher yield—but also to large increase in emissions of greenhouse gases (GHGs) if applied in excess. To determine the optimum dose of N for maize planting system, we analysed the relationship between yield and emissions of GHGs at seven levels of N, namely 50, 100, 150, 200, 250, 300, and 350 kg ha−1, using the DNDC (denitrification decomposition) model and maize grown with and without mulching. The model simulated the following variables: maize production; emissions of carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4); global warming potential (GWP); and GHG intensity (GHGI). We used data from 1980 to 2013 for a rain-fed region of the Loess Plateau in north-western China and validated the DNDC model against data from field experiments. The model performed well in simulating yield and GHG emissions (Adj.R2 > 0.61). Under mulching, the average yield of maize was 3.6–12.2 t ha−1 and the partial factor productivity was 73.1–35.0 kg kg−1; and both of these were significantly higher 78%–236% than those in the crop without mulching. The emissions of CO2, N2O, and the GWP increased with the increase in the dose of N whereas CH4 emissions remained unaffected by the dose. Mulching increased yields significantly in the north-western region, and the GWP and GHGI were higher mainly in the central and north-western regions. The optimum dose of N for maize grown with mulching ranged between 150 kg ha−1 and 200 kg ha−1 and offers the best balance between higher yield and lower emissions. The optimum dose may promote the development of mulched maize and provide a reference standard for dryland agriculture in zones with similar climates elsewhere in the world.

Fuzzy logic based prediction of micronutrients demand for harumanis mango growth cycles

Harumanis is a famous green eating mango cultivar that has been commercially cultivated in Malaysia’s state of Perlis. A variety of nutrients are found in soil, all of which are necessary for plant growth. Micronutrients such as Nitrogen (N), Phosphorus (P), and Potassium (K) are essential for Harumanis mango (Mangifera Indica) to growth. The importance of soil fertility in achieving high plant productivity and quality cannot be overstated. It should be used in a moderate amount and in a balanced manner. Predicting appropriate nutrients and the right timing to satisfy the tree’s demands is critical. The aim of this study is to create for Harumanis mango a fuzzy logic-based system to analyse the results of soil tests for nitrogen (N), phosphorus (P), and potassium (K) in the Harumanis mango orchard. The interpreted data are used to estimate N-P-K nutrient levels and indicate the optimal fertilizer solution and application timing for each Harumanis growth stages. The system utilizes Fuzzy Logic Control (FLC) to predict the nutrients demand for Harumanis mango growth. Results shows the system able to calculate and predict values of required N-P-K fertilizer for optimal growth. Thus, assist farmers in predicting the proper amount of N-P-K to apply to Harumanis mango soil.

Application of K and Zn Influences the Mineral Accumulation More in Hybrid Than Inbred Maize Cultivars.

Maize (Zea mays L.) is an important crop used for feeding humans and cattle globally. Deficiency of potassium (K) and zinc (Zn) adversely impacts the maize crop productivity and quality. However, the application of these nutrients shows variant responses in different maize cultivars. To understand this perspective, the current study aimed at investigating K and Zn’s optimal concentration in different hybrid and inbred maize cultivars. The treatments were based on three zinc levels (0, 6, and 12 mg Zn kg−1) and K levels (0, 30, and 60 mg kg−1), and their respective combinations. The experiment results showed that combined fertilization approaches of Zn and K (Zn12K60) improved the plant biometric, and physiological attributes of maize crop. The results revealed a significant increase in plant height (45%), fresh weight (70%), and dry weight (45%). Similarly, physiological attributes significantly improved the relative water content (76.4%), membrane stability index (77.9%), chlorophyll contents (170%), and photosynthetic rate (130%) in both inbred and hybrid genotypes. Furthermore, Zn and K (Zn12K60) increased transpiration rate (E), stomatal conductance (Ci), and internal CO2. In conclusion, maize hybrids (Neelam and DK-6142) were observed best compared with inbred (Afghoi and P-1543) cultivars with the combined application of Zn and K (Zn12K60). Thus, these inbred varieties should be preferred for fodder requirement with optimum fertilizer (Zn12K60) application in Zn deficient soils.

Evaluation of Quality Protein Maize Variety under Integrated Uses of Different Fertilizer Sources in Jimma, South Western Ethiopia

Studies on the combined use of organic and inorganic fertilizers for maize are lacking at Jimma conditions. Therefore, a field experiment was conducted to determine the effect of integrated uses of organic with inorganic fertilizers sources on productivity of quality protein maize (QPM) variety BHQPY545 at Kersa, Omonada woreda and Jimma on station, Southwestern Ethiopia during 2016 and 2017 main cropping seasons and one year validation at Omonada woreda. The experiment involved factorial combinations of inorganic and organic fertilizer with negative control, 150 kg ha -1 NPSZnB+140 kg ha -1 urea top dressed, recommended NP 2 O 5 (92/69 kg ha -1 ), 100% compost, 25% compost + 75% recommended NP, 50% compost + 50% recommended NP, 75% compost + 25% recommended NP and 100% compost + 100% recommended NP fertilizer which was laid out in randomized complete block design (RCBD). The compost was added based on N equivalency of recommended fertilizer rate. Data on yield and yield components of maize were subjected to ANOVA using SAS version 9.3. The over location and year highest grain yield (8443 kg ha -1 ) and above ground biomass (21.52 t ha -1 ) was obtained from 100% compost + 100% recommended NP fertilizer. Partial budget analysis revealed 100% compost + 100% recommended NP fertilizer realized the maximum net return (39,718 ETB) with marginal rate of return (94%). From farmers decision point and current on farm input availability and technical feasibility and economic analysis, 92/69 kg ha -1 N/P 2 0 5 fertilizer application taken as optimal fertilizer application and recommended for production of BHQPY545 in Jimma area and other similar humid agro-ecologies of southwestern Ethiopia. Keywords : Grain yield, inorganic fertilizer, organic fertilizer, recommended fertilizer rate, soil health. DOI: 10.7176/ALST/88-01 Publication date: July 31 st 2021

Fertilizer recommendation for foxtail millet based on yield response and nutrient accumulation

Foxtail millet (Setaria italica (L.) Beauv.) is an economically and nutritionally important crop grown primarily in Asian countries. However, optimal NPK fertilizer application rates and ratios have not been established for foxtail millet cultivation. In this study, a two years field experiment was conducted in typical warm-temperate sub-humid continental monsoon climate of brown soil, aimed to establish a rational nitrogen:phosphorus: potassium (N:P:K) ratio to improve foxtail millet production. Four N (0, 112.5, 225.0, and 337.5 kg ha−1), four P (0, 45.0, 90.0, and 135.0 kg ha−1), and four K (0, 75.0, 150.0, and 225.0 kg ha−1) fertilization rates were employed in fourteen different treatments. Crop yield, agronomic characteristics, and nutrient enrichment were evaluated. Crop yield was significantly influenced by the N:P:K ratio. The highest crop yield (3927.0 kg ha−1) was achieved with 112.5 kg ha−1 N, 90.0 kg ha−1 P, and 150.0 kg ha−1 K treatment. It was 68.8% higher than the control. The optimal N, P, and K application rates were 130.4–173.5, 83.5–103.8, and 133.4–153.2 kg ha−1, respectively. Crop yield was positively correlated with plant height, leaf length and width, kernel P and K, and chlorophyll. Rational fertilization improves foxtail millet yield and may be applied for the improvement of crop productivity and the mitigation of agricultural pollution.

Optimal P fertilization using low-grade phosphate rock-derived fertilizer for rice cultivation under different ground-water conditions in the Central Plateau of Burkina Faso

ABSTRACT Previous studies have reported two major methods of increasing PR solubility; calcination and partial acidulation. In addition, soil water condition would influence the solubility of P fertilizers. However, the effects of local P fertilizers, namely calcined PR (CPR) and partially acidulated PR (PAPR) on rice yield under different soil water conditions have not been explored comprehensively. The aims of the present study were to evaluate the effects of local P fertilizers produced from PR in Burkina Faso under different soil water conditions and to propose local fertilizers with optimal application rates for different soil water conditions. The field experiments were conducted at four farmers’ fields with different ground-water levels (GWL). CPR, PAPR, and superphosphate were applied at rates of 0, 7.6, 15.3, and 30.5 kg P ha−1, respectively. Superphosphate mostly consists of water-soluble P fraction (WP), PAPR of WP and alkaline ammonium citrate-soluble P fraction (SP), and CPR of SP and 2% citric acid-soluble P fraction (CP). The solubility is in the order of WP > SP > CP. The GWL was monitored during the growing season, and yield components were observed. Results of multiple regression analysis showed that WP influenced grain yield under all soil water conditions, whereas SP only influenced grain yied at mean GWL > −24.7 cm. Therefore, PAPR with high WP has an advantage over CPR in the field with GWL > −18.7 cm, and both CPR and PAPR are effective in fields with GWL > −6.5 cm. The optimal application rate was 14.4 kg P ha−1 as WP in the field with low GWL (mean −29.2 cm), 15.2–15.9 kg P ha−1 as WP + SP in the field with middle GWL (mean −24.7 to −18.7 cm), and 11.1 kg P ha−1 as WP + SP in the field with high GWL (mean −6.5 cm). According to the results, the optimal fertilizer types and application rates differ according to the soil water conditions.

A Review on Responses of Potato to Macro and Micro Fertilizers Application

Potato was considered as food security crop in Ethiopia because of its high yielding potential, high nutritional quality, short growing period and wider adaptability. In area coverage, it is second widely grown crop next to ‘Enset’ (Ensete ventricosum L.). Its production is affected by many factors. Among these factors, optimum fertilizer application is the main factor degrading the productivity of the crop. Achieving optimum fertilizer application depends on the climate, soil, variety and availability of the water. This review was aimed to access all available fertilizer trials to point out the types of fertilizers soil is deficient in relation to potato crop response and needed additional application during production cycles for boosting yield. Almost all soil of arable lands of Ethiopia was deficient in nitrogen (N), phosphorus (P), and sulfur(S). In addition, a larger part of arable land was deficient in N, P, S, and boron (B). Some lands’ soils require addition of either of potassium or Zinc other time both. Potato is requiring both macro and micro elements for high yield and better quality product. It is concluded that, most reviewed sources indicate that there was less recommendation concerning micro and macro elements for potato in the country in relation to the variable ecology of the country owned. DOI: 10.7176/ALST/87-05 Publication date: April 30 th 2021

Effects of different fertilization rates on growth, yield, quality and partial factor productivity of tomato under non-pressure gravity irrigation.

To select the optimum fertilizer application under specific irrigation levels and to provide a reliable fertigation system for tomato plants, an experiment was conducted by using a microporous membrane for water-fertilizer integration under non-pressure gravity. A compound fertilizer (N:P2O5:K2O, 18:7:20) was adopted for topdressing at four levels, 1290 kg/ha, 1140 kg/ha, 990 kg/ha, and 840 kg/ha, and the locally recommended level of 1875 kg/ha was used as the control to explore the effects of different fertilizer application rates on growth, nutrient distribution, quality, yield, and partial factor of productivity (PFP) in tomato. The new regime of microporous membrane water-fertilizer integration under non-pressure gravity irrigation reduced the fertilizer application rate while promoting plant growth in the early and intermediate stages. Except for the 990 kg/ha fertilizer treatment, yields per plant and per plot for each fertilizer application rate were higher than or equal to those of the control. The new regime could effectively improve PFP and reduce soil nutrient enrichment. Fertilizer at 840 kg/ha showed the optimum results by increasing PFP by 75.72% as compared to control. In conclusion, the fertilizer rate at 840 kg/ha has not only maintained the productivity of soil but also tomato growth and quality of fruit which makes the non-pressure gravity irrigation a potential and cost-effective way for fertilizer application.