Comparing tools for determining crop nutrient requirements

Soil fertility depletion, spatially variable nutrient limitations, and increasing climate variability are major constraints to crop productivity and resource conservation in Sub‑Saharan Africa (SSA). Sustainable nutrient management strategies that simultaneously improve crop yields, enhance soil health, and reduce nutrient losses are urgently needed to strengthen agricultural resilience. This study presents an integrated modelling framework for quantifying gaps in nitrogen (N), phosphorus (P), and potassium (K) fertilization under water‑limited conditions. The aim is to support site‑specific nutrient recommendations that improve fertilizer use efficiency while contributing to soil and water conservation.The framework combines three complementary models. INITIATOR simulates soil nutrient stocks and flows, providing a spatially explicit assessment of nutrient availability and potential depletion risks. WOFOST estimates water‑limited maize yield potential, capturing the influence of rainfall variability and soil moisture dynamics on attainable production. QUEFTS then models nutrient uptake and yield responses, enabling calculation of nutrient requirements that match crop demand without excess application. Together, these components enable a holistic evaluation of nutrient management in soil–crop–water systems on different management levels.The approach was applied to Uganda, a country characterized by strong agro‑ecological diversity, high interannual rainfall variability, and widespread soil degradation. Using 1 km resolution SoilGrids data and climate records from 2001–2024, spatially explicit water‑limited yield potentials were simulated for maize across the country. Fertilizer requirements were calculated based on median attainable yields for the period . Results reveal substantial geographic variation in nutrient availability, nutrient use efficiency, and fertilizer needs. In many areas, low soil nutrient stocks combined with high potential yield estimates lead to large fertilization gaps, while in other regions the gap is smaller due to relatively higher soil fertility or lower potential yields due to moisture constraints.These findings demonstrate that uniform fertilizer recommendations are unlikely to be effective under the diverse soil and climatic conditions of SSA. The proposed modelling framework provides a robust decision‑support tool for developing precision nutrient management strategies that align nutrient inputs with both crop demand and water availability. Such targeted approaches can help reduce nutrient losses to the environment, maintain soil fertility, and support sustainable intensification efforts across smallholder farming systems. This work highlights the potential of integrated soil–crop–climate modelling to guide context‑appropriate nutrient management solutions that enhance productivity while promoting soil and water conservation.

The effect of long-term use of nitrogen, phosphorus and potash fertilizers and their combinations (N, P, K, NP, NK, PK and NPK) on chang in sod-podzolic heavy loamy soil (Albic Retisol (Abruptic, Aric Loamic)) was studied the content of gross potassium and its easily exchangeable, exchangeable and non-exchangeable compounds. The research was carried out in a meter layer of soil under the conditions of a long-term stationary experiment laid down in the Perm Region in 1978. In the experiment, ammonium nitrate or urea, double or simple superphosphate and potassium chloride were used. The dose of fertilizers was 90 kg/ha in the primary plant food. Long-term application of potassium chloride in pure form and in combination with superphosphate and nitrogen fertilizers (K90, (PK)90, (NK)90, (NPK)90) provided an increase in the gross content of potassium in the arable soil layer by 1.1–1.2 times and its various compounds by 1.1–2.8 times (relative to the control variant). A narrowing of the ratio of non-exchangeable forms of potassium to exchange forms is noted here. Changes in the meter layer of soil depended on the combination of fertilizers, the studied form of potassium compounds in the soil. The introduction of only nitrogen and phosphorus fertilizers (N90, P90, (NP)90) without compensation for potassium removal during five rotations of the eight-field field crop rotation led to a decrease in the reserves of exchangeable and non-exchangeable potassium compounds in the 0–40 cm layer by 15–20%. The minimum level of potassium exchange compounds in sod-podzolic heavy loamy soil in a layer of 0–20 cm was 108–112 mg/kg.

Nutrient use efficiency concept is used to increase the overall performance of rainfed rice by providing economically optimum nutrition to the crops and at same time minimizing nutrient losses from the crop yield. A field experiment was undertaken during wet seasons of 2017 and 2018 to evaluate the response of soil applied Potassium and Nitrogen splitting in rice (Sahbhagi Dhan) under rainfed lowland conditions. The experimental was laid out on a sandy loam soil of Bihar Agricultural College farm, Sabour to derive inputs for rationalizing the use of Potassium (K) and Nitrogen (N) fertilizers by splitting and real time management respectively for making them more suitable for rainfed conditions. Nutrient and water management are important for diversifying and intensifying the rainfed rice based cropping systems. The experiment involved three K splitting schemes viz., K0 (No K application), K40 (K applied as basal @ 40 kg K2O per ha) and K20+20 (K application as basal, and at panicle initiation stage each @ 20 kg K2O per ha) in main plots, and five N splitting schemes in sub plots viz.,N0 (No N application), N50+50 (N application as basal and at active tillering, each @ 50 kg per ha) NSPAD (N application as basal each application @ 33.33 kg ha-1 and top dressing as guided by SPAD meter with critical SPAD value of 38, NGS (N application as basal @ 33.3 kg per ha and top dressing as guided by Green Seeker optical sensor) and N33+33+33 (N application as basal, at active tillering and at panicle initiation, each @ 33.3 kg per ha.). The results revealed that the overall AEN, PFPN, REN and partial nutrient balance (PNB) of across all levels of K & N splitting for rainfed rice was comparatively lower than that of control plot which reflects that the nutrient splitting strategy of the effect of application of potassium and nitrogenous fertilizers was more than the direct effects in rainfed rice. Overall, the results indicated that the K & N splitting the use of real time fertilizers splitting in rainfed rice optimizing nitrogen use efficiency, as well as increased rainfed rice production and uptake thereby led to increased nutrient use efficiency of applied nutrients and crops.

The physical and chemical properties of clinoptilolite zeolite can be used to enhance soil nutrient availability for optimum crop use. Amending nitrogen, phosphorus, and potassium fertilizers with clinoptilolite zeolite could create a pool of negative charges to retain and release nutrients timely for crop use. Thus, we used clinoptilolite zeolite to enhance Typic Paleudults sorption (adsorption and desorption) of nitrogen, phosphorus, potassium, and this soil’s pH buffering capacity. The treatments evaluated were: (i) 250 g soil alone, (ii) 20 g clinoptilolite zeolite alone, (iii) 250 g soil + 20 g clinoptilolite zeolite, (iv) 250 g soil + 40 g clinoptilolite zeolite, and (v) 250 g soil + 60 g clinoptilolite zeolite. Clinoptilolite zeolite increased soil nitrogen and potassium adsorption, nitrogen desorption, and soil pH. Moreover, ability of the soil to resist drastic change in pH (pH buffering capacity) was improved. Additionally, phosphorus adsorption and desorption of phosphorus and potassium were reduced. Higher potassium adsorption with lower potassium desorption suggests that the clinoptilolite zeolite sorbs potassium effectively. The clinoptilolite zeolite nitrogen, phosphorus, and potassium contributed to the reduction in the adsorption these nutrients. The clinoptilolite zeolite improved nitrogen, phosphorus, and potassium availability and soil buffering capacity to prevent these nutrients from being fixed or lost through for example, leaching. Therefore, clinoptilolite zeolite application could contribute to improved use of nitrogen, phosphorus, and potassium fertilizers to prevent soil, air, and water pollution. Additionally, our intervention could improve nitrogen, phosphorus, and potassium use efficiency.

Environmental and resource use analysis of plant factories with energy technology options: A case study in Japan

A field experiment was conducted during 2014 at Universiti Putra Malaysia, Serdang, Malaysia, to evaluate the effect of incorporation of crop residues with supplemental inorganic fertilizers on yield and quality of maize crop. Treatments included an unfertilized control, incorporation of maize residue, soybean residue and a mixture of maize and soybean residue with and without phosphorus and potassium fertilizer and the use of a complete inorganic nitrogen, phosphorus and potassium fertilizer. Results showed that soybean and maize + soybean residue applied without inorganic fertilizers or with inorganic fertilizer (phosphorus and potassium) increased maize yield and enhanced grain quality of maize. However, incorporation of maize residue without supplemental inorganic fertilizer was ineffective in increasing grain cob yield (11,237 kg/ha) and grain quality ( 11.1% protein content, 10.9 o brix sugar content and 4.77% oil content) of the maize crop above that of control (10,323 kg/ha green cob yield, 8.30 % protein content, 9.00 o brix sugar content and 4.77% oil content). The application of soybean residue with supplemental phosphorus and potassium fertilizer gave maize yield (37,290 kg/ha) similar to that of the complete inorganic fertilizer treatment (36,500 kg/ha). Therefore, inorganic nitrogen fertilizer can be replaced with soybean residues without any reduction in maize yield and grain quality.

Sustainable food production and feeding a growing population are among the main challenges in the world nowadays. Studies suggest that improving nitrogen use efficiency (NUE) is among the key strategies for sustainable crop production. However, yield response to chemical nitrogen fertilizer use (N use) and the NUE was not fully investigated both in China and Africa. The purpose of this article was, therefore, to investigate the findings of different nitrogen fertilization rate experiments and thereby identify a potential approach that could be used to improve wheat yield and NUE in Africa and China. In addition, we aimed to evaluate the effects of soil characteristics, such as pH and soil organic matter (SOM) on wheat yield responses to N uses. A meta-analysis was conducted to systematically assess the results of previous studies published in peer-reviewed journal articles. We identified and used 65 studies conducted in different African countries and 154 in different provinces of China. The articles were obtained from Tylor, Google Scholar, and Web of Science databases. The result indicated that the mean yield response to chemical nitrogen fertilizers use (N use) in Africa was far lower than that in China, implying the presence of higher wheat yield gaps in Africa than in China. In addition, the wheat yield responses to N uses showed different patterns in both regions. That is, while it was increasing with N application in Africa, it increased and reached a peak at 200 kg ha−1 in China, indicating the existence of nitrogen accumulation in the provinces of China. The findings also showed significant influences of soil organic matter (SOM), pH, and precipitations on wheat yield responses to N uses. The higher yield gap in Africa can be improved by increasing nitrogen use to the optimum nitrogen fertilizer rate level, which can also increase nitrogen use efficiency and yield response. In Africa, the high yield response to N use was accompanied by N depletion, while in China it was with a high N surplus in the soil. The effects of pH, SOM, and precipitation were generally more pronounced in Africa than in China.

The world’s population is assumed to increase from 7 billion now to 8.3 billion in 2025. The world will need 70–100% more food by 2050 (Godfray et al., 2010). Therefore, the production of cereals, especially wheat, rice, and maize, which accounts for half of human calorie intake, has to be increased. Currently, plant growth is enhanced by the input of chemicals which act as plant growth regulators (using a hormonal mechanism) and as nutrients. Of the nutrients added to the soil, nitrogen and phosphorus are the major ones. They are, together with potassium, applied as chemical fertilizers to improve grain yield. According to Roberts (2009), the present global annual use of chemical nitrogen, phosphorus, and potash fertilizer is 130, 40, and 35 million tonnes, respectively. The high input of chemicals raises a number of concerns such as water contamination leading to

Effects of long-term organic and inorganic fertilization on greenhouse gas emissions and soil nutrient stoichiometry in a rice–rice–fallow cropping system

Although nitrogen fertilizer use has boosted crop yields, excessive application diminishes crop nitrogen use efficiency (NUE) and causes environmental problems. Therefore, increasing crop NUE is urgently needed for agricultural sustainability. Through a genome-wide association study, we identified a locus, NCR1 (Nitrate Concentration Regulator 1), that correlates with nitrate concentrations in maize root xylem. NCR1 encodes a MYB transcription factor that positively regulates the transcription of nitrate transporter NRT2.3 expressed predominantly in root xylem parenchyma cells. The NCR1-NRT2.3 transcription module responds to external nitrogen and controls nitrate translocation from roots to shoots. The superior NCR1-In allele with a 123-bp promoter deletion has decreased in frequency as nitrogen fertilizer use in China has increased. Overexpression of NCR1 or NRT2.3, or introgression of NCR1-In, increases grain yield and nitrogen content in the shoot and seed. This study uncovers a crucial genetic module for improving grain yield and NUE in maize.

Aims This paper assessed the effect that the vertical stratification of nutrients in conservation cropping systems of Australia has on phosphorus (P) and nitrogen (N) fertiliser use efficiency.

Spatiotemporal patterns of livestock manure nutrient production in the conterminous United States from 1930 to 2012

After-cooking darkening (ACD) is a common undesirable trait of potato tubers, caused by the oxidation of the chlorogenic acid-iron compound after cooking, which includes boiling, frying and dehydration. The degree of the darkening is known to be cultivar-dependent and to vary with climatic conditions. However, there is limited information on the effect of different management practices and long-term storage on ACD. In this study, we used three independent experiments to investigate the effects of soil type, different management practices and storage on the susceptibility of ACD. Experiment 1 compared two soil types, two planting dates, and two rates of nitrogen (N), phosphorus (P) and potassium (K) fertilization in two years for ‘Russet Burbank’ potato. Experiment 2 compared seven rates of N fertilization in two years for Russet Burbank and ‘Shepody’ potato. Experiment 3 compared five rates of K fertilization in two years on Russet Burbank potato. In general, the degree of darkening was reduced when climatic conditions and management practices resulted in conditions favorable for crop growth. The degree of ACD generally increased under drier climatic conditions, in soil that was more susceptible to drought, and with delayed planting; however, these effects were not measured in all cases. Similarly, the degree of ACD increased under N deficient conditions. However, N fertilization did not reduce darkening in all trials, and the benefit of N fertilization was not apparent as storage duration was increased. There was a small benefit to K fertilization in Experiment 3; however, K fertilization had no effect on ACD in Experiment 1. There was no effect of P fertilization on ACD. Although significant, the magnitude of the effects of soil type and management practices on ACD was small in comparison to the effects of cultivar and storage duration on ACD.

The study evaluates water-nutrient management effects on drip-irrigated capsicum yield. Pooled data from plant height, number of branches, fruit weight, and yield were analyzed across various irrigation (I1 @ 80%, I2 @ 90%, I3 @ 100% of IWR) and nitrogen fertilization (N1 @ 80%, N2 @ 90%, N3 @ 100% of RDN) levels. Results indicated significant individual effects of water and nitrogen levels on growth and yield parameters, with optimal outcomes observed at I2 (irrigation at 90% of Irrigation Water Requirement) and N2 (fertigation at 90% of the Recommended Dose of Nitrogen). The highest plant height and number of branches/plant were achieved under I2N2, while the lowest were under I1N1. Yield-contributing parameters, including average fruit weight and number of fruits per plant, were also highest at I2N. Irrigation water productivity (IWP) and fertilizer nitrogen use efficiency (NUEf) were significantly improved at moderate irrigation and nitrogen levels, with I2N2 showing the best results. Quality assessments revealed that moderate irrigation and nitrogen levels enhanced fruit quality attributes such as fruit length, flesh thickness, and total phenolic content, while excessive irrigation and nitrogen reduced these qualities. Water scarcity is a critical issue in Punjab, and optimizing irrigation and nitrogen management can significantly improve yield and quality. The study suggests that moderate deficit irrigation (90% IWR) combined with optimal nitrogen application (90% RDN) is ideal for maximizing capsicum growth and yield in water-scarce regions. These findings offer practical recommendations for farm managers and policymakers to enhance capsicum cultivation efficiency and conserve freshwater resources.

All countries, including Korea, are currently experiencing the effect of rapid climate change. As a result, the cultivation area of many crops including wheat is changing, or productivity is falling sharply. If enough nitrogen is present in the soil, the increase in atmospheric carbon dioxide due to the greenhouse effect can lead to increased photosynthesis of plants, resulting in increased productivity. By contrast, a low proportion of nitrogen in soil does not increase production, often leading to the use of nitrogen fertilizers to increase crop productivity: this causes serious environmental pollution due to the leakage of nitrogen fertilizers used by crops. Increasing the understanding of the molecular level of the plant nitrogen use efficiency mechanism may contribute to increased productivity of crops and reduced of environmental pollution by nitrogen. In Korea, cultivars have developed 35 kinds of wheat, such as ‘keumgang’ and ‘Chokyeong’, which can be used for specific purposes such as baking or noodles. In this study we investigate ‘keumgang’ and ‘Chokyeong’ in order to elucidate the mechanism of nitrogen use ability of wheat and contribute to the reduction of environmental pollution by providing guidelines for the proper use of nitrogenous fertilizer.