Fertilizer Management Research Articles

Biochar and Humic Substances Roles for Nitrogen Transformation in Agriculture

Sustainable soil fertility management is crucial for global food security and addressing environmental challenges from modern agriculture. Soil health, alongside water availability, is essential for crop productivity, and soil degradation threatens food security by lowering yields and intensifying climate change. Nitrogen (N) cycling is central to soil fertility, supporting plant growth through nutrient replenishment and microbial activity. However, N is often lost through leaching, volatilization, and denitrification, reducing nitrogen use efficiency (NUE) and contributing to water pollution and greenhouse gas (GHG) emissions. Optimizing nitrogen retention in soils is vital for improving productivity and minimizing environmental harm. Biochar (BC) and humic substances (HSs) have emerged as effective strategies for improving N management. BC enhances soil fertility by increasing soil pH, cation exchange capacity, and water retention, while reducing nutrient leaching and promoting carbon sequestration. HSs, including humic acids (HA), fulvic acids (FA) and humin (HU), improve nutrient cycling by stimulating microbial activity and enhancing nutrient transport. Together, BC and HSs provide synergistic benefits for soil health, particularly in challenging environments like saline or nutrient-depleted soils. This review highlights the roles of BC and HSs in enhancing soil fertility, promoting N mineralization, and improving crop productivity. It emphasizes their potential for sustainable agricultural practices, climate change mitigation, and long-term soil health. Keywords: Biochar, Climate changes, Humic substances, Remediation, Soil fertility.

Nutrient Distribution in the Soil Profile Under Different Tillage Practices During a Long-Term Field Trial

Conservation tillage practices are increasingly used in agricultural systems. However, these practices require a complex approach regarding soil nutrition. Adequate nutrient content in soils is important for crop production, as reduced and no-tillage practices change the distribution of nutrient contents (P, K, Mg, and Ca) in the soil profile, necessitating new approaches for agronomists in crop nutrition. Little is known about the time changes in nutrient distribution in the soil profile under conservation tillage practices. Long-term field experiments with conventional (CT—plowing to 20–22 cm), reduced (RT—chiseling to 8–10 cm), and no-tillage (NT) practices were established in Prague–Ruzyně (Czech Republic) in 1995. This four-year crop rotation consisted of winter wheat changing with oilseed rape or pea. The soil nutrient contents have been determined since 2009 using the Mehlich 3 method and through extraction in 0.5 M ammonium acetate. The obtained results showed that P, K, and, to a lesser extent, Mg contents increased in the soil surface layer (0–10 cm) under the reduced and no-tillage practices, whereas Ca and pH values showed an opposite trend. We found an unbalanced ratio of nutrients in the upper soil layer in RT and NT caused by a high concentration of the monovalent cation K+ and the leaching of the divalent cations Ca2+ and Mg2+ into the deeper soil layers. In conventional practices, the ion contents are equalized throughout the topsoil due to the soil inverting during plowing. The determination of nutrient contents in deeper soil layers revealed that, over time, calcium, magnesium, and potassium were transported to deeper parts of the soil profile under RT and especially NT. Low nutrient ratios were found in the surface layer under RT and NT, negatively affecting the quality of the soil surface layer, including its structure. Fertilizer management and nutrient ratios in soils under RT and NT should be considered to maintain and possibly improve sustainable agricultural practices in fields with reduced or no-tillage practices. Furthermore, nutrient contents and their mutual ratios should be evaluated in more soil layers under these systems, enabling the detection of eventual problems in the upper layer that must be addressed by changing fertilization.

Impact of irrigation, fertilizer, and pesticide management practices on groundwater and soil health in the rice-wheat cropping system-a comparison of conventional, resource conservation technologies and conservation agriculture.

Agricultural intensification in the Northwestern Indo-Gangetic Plain (NWIGP), a critical food bowl supporting millions of people, is leading to groundwater depletion and soil health degradation. This is primarily driven by conventional cultivation practices in the rice-wheat (RW) cropping system, which dominates over 85% of the IGP. Therefore, this study presents a systematic literature review of input management in the RW system, analyzes district-wise trends, outlines the current status, identifies problems, and proposes sustainable management options to achieve development goals. Our district-wise analysis estimates potential water savings from 20 to 60% by transitioning from flood to drip, sprinkler, laser land leveling, or conservation agriculture (CA). Alongside integrating water-saving technologies with CA, crop switching and recharge infrastructure enhancements are needed for groundwater sustainability. Furthermore, non-adherence with recommended fertilizer and pesticide practices, coupled with residue burning, adversely affects soil health and water quality. CA practices have demonstrated substantial benefits, including increased soil permeability (up to 51%), improved organic carbon content (up to 38%), higher nitrifying bacteria populations (up to 73%), enhanced dehydrogenase activities (up to 70%), and increased arbuscular mycorrhizal fungi populations (up to 56%). The detection of multiple fertilizers and pesticides in groundwater underscores the need for legislative measures and the promotion of sustainable farming practices similar to European Union strategies. Lastly, emphasis should be placed on fostering shifts in farmers' perceptions toward optimizing input utilization. The policy implications of this study extend beyond the NWIGP region to the entire country, stressing the critical importance of proactive measures to increase environmental sustainability.

Effects of Integrated Nutrient Management on Growth, Nodulation, and Yield of Soybean [Glycine max (L.) Merr. var. Puja

Inefficient fertilizer management is a major reason for the low soybean productivity in Nepal. This study conducted at an altitude of 811 meters in Baitadi, Nepal, examined the effects of integrated nutrient management on soybean growth, nodulation, and yield. Employing an RCBD experimental layout with 3 replications, the study evaluated 9 treatments, namely: Control, Rhizobium+100% PK, Rhizobium+50% RDF, Rhizobium+75% RDF, Vermicompost+50% RDF, Vermicompost+75% RDF, FYM+50% RDF, FYM+75% RDF, RDF (NPK @ 10:40:30 kg/ha). The results revealed that ‘Rhizobium+100% PK’ produced maximum plant height (140.8 cm), dry weight growth rate (2.89 gram/plant/day), nodule count (11.33), and nodule mass (0.55 gram). ‘Rhizobium+75% RDF’ produced the highest number of trifoliate leaves (62.78) and leaf area index (15.30). Furthermore, ‘Vermicompost+50% RDF’ resulted in a maximum fresh weight growth rate (7.86 gram/plant/day), ‘RDF’ resulted in the highest root diameter (12.89 mm), and ‘FYM+75% NPK’ produced highest 1000-grain weight (145.9 g). The treatments ‘VC+75 % RDF’ and ‘Rhizobium+50 % RDF’ stood out with a remarkable grain yield of 3.659 tons/ha and 3.642 tons/ha respectively. These two treatments were statistically indistinguishable regarding grain yield. The application of ‘VC+75 % RDF’ or ‘Rhizobium+50 % RDF’ can prove to be an effective way to enhance the productivity of soybean. However, the performance of soybean can vary depending on the variety, intercultural operations, environmental conditions, and residual nutrient status of the soil. Therefore, we recommend further research to solidify these findings.

Response of Onion (Allium cepa L.) Bulb to the Combined Effect of Vermicompost and Mineral Fertilizer under Irrigated Soil Condition in Raya Azobo and Kilte-Awulaelo Districts South and Eastern Tigray, Ethiopia

Background: In Ethiopia, onion (Allium Cepa L.) is a major vegetable crop. However, due to erratic cultivation, rising mineral fertilizer prices and inadequate soil fertility management, its productivity is declining. Integrated nutrient management is a cost-effective approach to fertilizing soil. If used properly, the combination of vermicomposting with mineral fertilizers is one of the most promising options. Nonetheless, in the study areas, the appropriate application rate of vermicompost and NPSZn fertilizer on onion production has not been well examined. Methods: A field experiment was conducted in the irrigated soil conditions of Kilte-Awulaelo and Raya Azobo districts. The study used a randomized complete block design with three replications and twelve experimental treatments (4.5, 3 and 1.5 t ha-1 vermicompost rates combined with NPSZn 75, 50 and 25 kg ha-1). Full recommended 6 t ha-1 vermicompost, 100 kg ha-1 NPSZn fertilizer and absolute control were used. The collected agronomic data were subjected to ANOVA using SAS statistical software (SAS 9.0) and mean separation was done using LSD. Result: Most of the measured onion growth and yield parameters were significantly affected by the joint application of vermicompost and NPSZn. It varies among districts. Maximum bulb yields of 51.2 t ha-1 in Kilte-Awulaelo and 42.5 t ha-1 in Raya Azobo district were obtained from the application of 4.5 t ha-1 vermicompost with 50 kg ha-1 NPSZn and 4.5 t ha-1 vermicompost with 75 kg ha-1 NPSZn respectively. The combined application of vermicompost with NPSZn fertilizer enhanced onion growth and yield.

Enhancing Indigenous Cropping Systems under Climate Change: A Case Study of Maize (Zea mays L.) and Groundnut (Arachis hypogea) in Northern Ghana

Due to the continuous cropping of maize and groundnuts on the same land in northern Ghana for livelihood, production yields have declined significantly below potential levels. The purpose of this study was to evaluate the ecological limitations affecting maize and groundnut productivity in northern Ghana and also to analyze the socioeconomic constraints impacting the livelihoods of smallholder farmers. Five cropping systems (viz. sole continuous maize (SCM), sole continuous groundnut (SCG), maize-groundnut intercrop (MGI), groundnut/maize rotation (GMR) and maize/groundnut rotation (MGR)), each with or without fertilizer were established under RCBD at Nyankpala during the 2021 and 2022 cropping seasons. For the fertilized rotation treatments, the maize crop received 60-N, 40-P2O5, and 40-K2O, kg/ha, while the groundnut crop received 20-N, 40-P2O5, and 40-K2O, kg/ha using NPK 11, 22, 21, kg/ha with trace elements S, Zn and B. The cropping systems were characterised on grain yields, yield related parameters, resource use and economic returns on investments. The results showed that intercrop and rotation treatments gave better yields. Their land equivalent ratios (LER) were 1.2 and 1.09 respectively, in the two seasons. Maize grain yield under the rotation increased from 2.5 to 3.8 t/ha while groundnut pod yield increased from 0.6 to 0.9 t/ha. The system with highest economic returns was recorded for the rotation systems either with or without fertilizer application. To improve livelihoods and productivity, smallholder farmers in northern Ghana should adopt intercrop and rotation systems, incorporate fertilizer application, and consider soil fertility management practices. Policy support and extension services can facilitate the adoption of these sustainable agricultural practices.

Fertilizer management approaches influence nutrient leaching from residential landscapes.

Residential lawn management often includes fertilizer application to encourage healthy plant growth and support the aesthetic preferences of homeowners and communities. These inputs may negatively impact the environment by increasing nutrient export to aquatic ecosystems via surface runoff or leaching through soil into groundwater. Fertilizer management and nutrient export are of particular concern in karst areas like North-Central Florida, where the underlying karst geology leads to rapid, direct connections between surface and groundwater ecosystems. We quantified nitrogen (N) and phosphorus (P) leaching from residential landscapes in North-Central Florida. We investigated nutrient leaching from landscapes spanning a real estate gradient and across different fertility treatments (no N fertilizer, synthetic mineral fertilizer, biosolids-based organic mineral fertilizer, compost topdressing, natural areas). We measured leachate from these landscapes weekly for 1 year. All residential landscapes, including control yards that received no N fertilizer, leached >10x more nitrate than natural areas, and landscapes treated with synthetic fertilizer exhibited an >80x increase in nitrate leaching. Fertilizer treatments also appeared to alter the N leaching composition, with a greater proportion of total dissolved N leaching coming from nitrate in fertilized treatments (synthetic and organic) compared to natural, control, or compost-treated landscapes. These results show that landscape management and human actions are important drivers of nutrient leaching in residential landscapes. While all residential lawns leached more N than natural areas, less leaching was associated with certain management approaches. When implemented at larger scales, these approaches may reduce the likelihood of negative impacts of residential landscapes on regional water quality.

Agronomic Management of Faba Bean (Vicia faba L.): A Review

The faba bean (Vicia faba L.) is a winter crop that can be cultivated as a versatile crop. It’s yield and quality being strongly influenced by environmental and agronomic factors, nutritional content, medicinal properties, and ability to fix nitrogen biologically. Therefore, to maximize advantages of faba bean cultivation, choosing the appropriate varieties, planting times, techniques, plant density, depth of sowing, and ensuring proper crop nutrients and irrigation is essential. For successful faba bean production in subtropical climates, it's important to assess the performance of different varieties under these specific conditions. Planting dates and soil temperature are crucial for germination, growth, and yield. At the same time, the crop's performance is also influenced by sowing methods, plant density, sowing depth, and water and fertilizer management. Integrating faba beans into cropping systems is expected to offer various ecological benefits. This paper reviews the existing literature on the agronomic practices of faba beans.

Differential Study on Estimation Models for Indica Rice Leaf SPAD Value and Nitrogen Concentration Based on Hyperspectral Monitoring

Soil and plant analyzer development (SPAD) value and leaf nitrogen concentration (LNC) based on dry weight are important indicators affecting rice yield and quality. However, there are few reports on the use of machine learning algorithms based on hyperspectral monitoring to synchronously predict SPAD value and LNC of indica rice. Meixiangzhan No. 2, a high-quality indica rice, was grown at different nitrogen rates. A hyperspectral device with an integrated handheld leaf clip-on leaf spectrometer and an internal quartz-halogen light source was conducted to monitor the spectral reflectance of leaves at different growth stages. Linear regression (LR), random forest (RF), support vector regression (SVR), and gradient boosting regression tree (GBRT) were employed to construct models. Results indicated that the sensitive bands for SPAD value and LNC were displayed to be at 350–730 nm and 486–727 nm, respectively. Normalized difference spectral indices NDSI (R497, R654) and NDSI (R729, R730) had the strongest correlation with leaf SPAD value (R = 0.97) and LNC (R = −0.90). Models constructed via RF and GBRT were markedly superior to those built via LR and SVR. For prediction of leaf SPAD value and LNC, the model constructed with the RF algorithm based on whole growth periods of spectral reflectance performed the best, with R2 values of 0.99 and 0.98 and NRMSE values of 2.99% and 4.61%. The R2 values of 0.98 and 0.83 and the NRMSE values of 4.88% and 12.16% for the validation of leaf SPAD value and LNC were obtained, respectively. Results indicate that there are significant spectral differences associated with SPAD value and LNC. The model built with RF had the highest accuracy and stability. Findings can provide a scientific basis for non-destructive real-time monitoring of leaf color and precise fertilization management of indica rice.

Exploring Potential of Organo-mineral Fertilizers in Augmenting Crop Yield and Quality – A Review

Inorganic fertilizers are essential for improving crop yield and quality through enhanced crop efficiency. However, their continuous use often causes nutrient imbalances, leading to poor yield and quality. Organic manures, while effective in improving soil fertility and crop productivity, face challenges such as limited availability, variable quality, transportation issues, heavy metal contamination and slow nutrient release. The exclusive dependence of either organic or inorganic fertilizers has not adequately fulfilled the increasing demands for enhanced agricultural output and quality. To address these challenges, organo-mineral fertilizers (OMFs) have emerged as an innovative solution. OMFs are derived from the combination of mineral and organic nutrient sources, integrating the benefits of both. This low input technology supplies nutrients in balanced quantities that are readily and steadily available throughout the growing season. OMFs improve soil physical properties, enhance fertility and support sustainable crop production. They also promote plant resistance to biotic and abiotic stress, offering a holistic approach to agricultural challenges. The development of OMFs aligns with the recycling of urban, industrial and agricultural residues, reducing dependency on raw materials for chemical fertilizers and contributing to environmental sustainability. Advances in OMF preparation, using various mineral and organic matrices, have demonstrated their ability to address nutrient deficiencies, particularly in tropical soils, where poor fertility often limits productivity. OMFs enhance soil physico-chemical and biological properties, addressing soil degradation while improving crop yield and quality. They ensure an optimal supply of nutrients, support long-term soil health and align with modern fertilizer management strategies aimed at sustainable agricultural productivity. In conclusion, OMFs are a promising solution for boosting crop quality and yield while maintaining soil fertility. By incorporating the advantages of organic and inorganic inputs, they provide a balanced, sustainable, and efficient strategy to address growing demands for food production.

Comparative Study of Water and Fertilizer Regimes on Water Potential, Phenolic Substances, and Photosynthetic Characteristics of Pistacia weinmannifolia

Effective water and fertilizer management is crucial for the forestry production of Pistacia weinmannifolia. This experiment employed an orthogonal design to measure the water potential, anthocyanins, chlorophyll, and photosynthetic parameters of Pistacia weinmannifolia under different water and fertilizer regimes. The effects of different water and fertilizer regimes on the water potential, phenolic compounds, and photosynthetic characteristics of Pistacia weinmannifolia were analyzed. A comprehensive analysis method was used to evaluate and establish the best water and fertilizer regimes system. The results showed that the water and fertilizer regimes increased the water potential, anthocyanins, chlorophyll content, flavonoids, and photosynthesis (p < 0.05). During the mid-growth stage and late mid-stage growth of Pistacia weinmannifolia, the fertilizers with the most significant effects on water potential, chlorophyll, and anthocyanins were nitrogen (N) and phosphorus (P). The supply of a certain amount of N and P had positive effect on water potential, chlorophyll, and anthocyanins. Increasing N content was more effective in improving carboxylation efficiency than increasing P content. The effect of N content on photosynthetic efficiency was greater than that of P content Analyses using the TOPSIS model demonstrate that Pistacia weinmannifolia exhibits superior comprehensive efficiency in water potential, chlorophyll, flavonoid, and anthocyanin content. When applying 0.54 g·plant−1 of pure P and 0.67 g·plant−1 of pure N, with the relative soil moisture content maintained at 85%, the optimal comprehensive benefit for photosynthetic indicators is achieved with 0.34 g·plant−1 of pure P and 0.77 g·plant−1 of pure N, while maintaining the relative soil moisture content at 46.66%. These findings indicate that the water–fertilizer coupling treatment group exhibited improved growth status and photosynthesis. Therefore, the cultivation of Pistacia weinmannifolia should prioritize maintaining a balanced water–fertilizer ratio to optimize resource utilization.

Integrated Soil Fertility Management by Application of bulk and Nano-sawdusts for Enhancing Biomass Yield and Nutrients Content of Maize Plant Grown on Different Soil Types

Integrated Soil Fertility Management by Application of bulk and Nano-sawdusts for Enhancing Biomass Yield and Nutrients Content of Maize Plant Grown on Different Soil Types

Processing Horse and Cow Manure Waste in the Production of Fertilizer and Biogas at Flores Bajawa Agricultural College

Horses and cows have long been domesticated animals in Indonesia, one of which is at the Flores Bajawa Agricultural College. Horse and cow manure, which are solid waste products generated from metabolism, can generally pollute the environment, so they need to be processed. Therefore, it is necessary to conduct research on the utilization of horse and cow manure waste in the production of manure fertilizer and biogas. Manure is usually made from liquid or solid livestock waste mixed with food scraps, which will later function as humus. Biogas is a gas produced from organic waste such as animal and human manure stored in an airtight environment. The purpose of this research is to understand the utilization and processing of horse and cow manure waste into fertilizer and biogas. The methods used in this research are observation and experimentation. Fertilizer is made from a mixture of horse and cow manure. Meanwhile, biogas from horse and cow manure is produced with three treatments and various fermentation periods of 7, 14, and 21 days. One way to process horse and cow manure waste is to convert it into organic fertilizer and biogas. The fertilizer and biogas that have been produced are used to enrich agriculture and also as a source of fuel. The longer the fermentation time of the fertilizer and biogas, the better the nutrient content of the fertilizer and the greater the volume of gas produced in the biogas production process.

Response of soil carbon and nitrogen stocks to irrigation - A global meta-analysis

Irrigation has profound influences on carbon (C) and nitrogen (N) stocks in agricultural soil. However, the global-scale irrigation effects on C and N pools in farmland soils, as well as the C: N ratio (C/N), remain unclear. This study integrates existing studies on C and N in irrigated farmland worldwide and investigates the responses of soil C and N concentrations, stocks, and the C/N to irrigation by meta-analysis. The results suggest that irrigation has a significantly positive impact on soil organic carbon (SOC) and total nitrogen (TN) stocks overall, with the stocks increase by 10.9 % and 7.4 %, respectively, and a 3.1 % increase in the C/N, but has no significant impact in soil microbial biomass carbon (MBC). The positive feedback of SOC (6.0 %) and TN (6.6 %) stocks in topsoil is more pronounced in response to irrigation than that in subsoil. The impact of irrigation on SOC stocks is greater in semi-arid regions and under flood irrigation. Furthermore, SOC stocks increase more in sandy and loamy soils compared to clay soil, while TN exhibits larger increases in clay soil. The results also indicate that the response of C/N to irrigation is more pronounced under the condition of deep soil, sandy soil, and semi-arid regions. The influence of irrigation on SOC stocks and the C/N increases with the duration of irrigation, while the impact on TN stocks tends to weaken. Our study deepens the understanding of the mechanisms behind irrigation's effects on soil C and N stocks and therefore provides theoretical insights for the management of soil fertility in irrigated agriculture.

Low Impact of Nitrogen Fertilization on Grafted Tomatoes under High-tunnel Production

High-tunnel systems can improve and prolong production under challenging climate, but research on nitrogen management and grafting is still needed. This study analyzes the effects of rootstock and two N fertilization levels in northern Nevada under high-tunnel commercial production. We report on tomato yield, growth, leaf nutrient profile, and spectral indices [i.e., soil plant analysis development (SPAD) and normalized difference vegetation index (NDVI)] correlation with leaf nitrogen. Although rootstock influenced yield and leaf nutrient profile depending on location, no clear effect from the nitrogen fertilization was observed in growth and yield. Moreover, the low accuracy of SPAD and NDVI indices in predicting leaf nitrogen status undermined the capacity to provide enough support for a sustainable nitrogen fertilization management.

Evaluating the trade-offs between nutrient and cadmium levels in soils in northeastern China: Accounting for variations in soil factors

Agricultural soils have relied on the application of fertilizers to enhance soil fertility and yields in response to increasing food demands. However, the potentially hazardous trace elements that accumulate in soils have been largely overlooked. In this study, we set out to determine the soil factor indicators in croplands using Exploratory Factor Analysis to illuminate the trade-off between surplus soil nutrients and cadmium (Cd) accumulation as a result of fertilizer application. The research in northeastern China highlights the fact that studies tend to ignore the accumulation and distribution of hazardous heavy metals in production fields in favor of an over-emphasis on soil fertility indicators; an ultimately unsustainable approach. The model showed that soil nutrient could be identified based on three soil factors: soil organic matter, soil available nutrients, and soil nutrient buffer structures. Fertilization enhanced the level of available nutrients and significantly increased both soil organic matter and available phosphorus by 0.71 % and 11 mg kg−1, respectively. However, the long-term application of phosphorus (P) leads to a P-surplus and leaves soils more susceptible to Cd accumulation. The 90th percentile estimate of soil Cd concentration was 1.4 times higher than the P-optimal level. Scenario analyses of long-term fertilizer management indicated that, over a 50-year simulation period, the impact of Cd accumulation in soils in traditional agriculture was insignificant. However, prolonged application of excess P-fertilizer would lead to a continuous increase in the concentration of accumulated Cd from 0.17 mg kg−1 to 0.40 mg kg−1. Trade-off and scenario analyses guide agricultural fertilization practices to preserve soil quality while sustaining productivity.

Enhancing precision nitrogen management for cotton cultivation in arid environments using remote sensing techniques

Context or problemRemote sensing, particularly through unmanned aerial vehicles (UAVs), has emerged as a pivotal tool in precision agriculture, especially for nitrogen (N) management. Traditional methods, while effective in quantifying crop N status using the Nitrogen Nutrition Index (NNI), fall short in providing quantitative fertilization strategies. MethodsThis study bridges this gap by developing a comprehensive method that leverages multispectral remote sensing data from UAVs to refine N fertilizer management in cotton cultivation within arid environments. By integrating both field observations and UAV-derived multispectral data, we established robust models capable of estimating both leaf and overall cotton nitrogen contents (CNC-leaf and CNC-all), as well as NNI, throughout the growing season. This facilitated real-time calculation of required N fertilizer doses in cotton fields. ResultsWe uniquely applied covariance diagnosis and full subset screening techniques, underscoring the efficacy of vegetation index categories (VIs) in enhancing prediction accuracy. The Random Forest (RF) model exhibited superior performance in predicting plant nitrogen content, particularly in CNC-leaf prediction (Calibration: R²=0.92, RMSE=7.7 g m⁻², MAE=5.5 g m⁻²; Validation: R²=0.60, RMSE=16.5 g m⁻², MAE=12.2 g m⁻²) as opposed to CNC-all prediction (Calibration: R²=0.78, RMSE=117.0 g m⁻², MAE=154.3 g m⁻²; Validation: R²=0.34, RMSE=138.4 g m⁻², MAE=190.4 g m⁻²). The RF model also demonstrated optimal performance in NNI prediction (Calibration: R²=0.93, RMSE=0.05, MAE=0.04; Validation: R²=0.73, RMSE=0.12, MAE=0.10), surpassing the predictions for CNC. ConclusionsUtilizing CNC and NNI estimates derived from the optimized RF model, this study succeeded in generating a comprehensive map detailing the N fertilizer requirement across cotton Fertilization zones were established for different treatments, revealing that biochar application levels primarily determine nitrogen fertilizer needs. As biochar application increases, nitrogen fertilizer demand decreases. Moreover, nitrogen application rates typically increase when irrigation levels reach either 120 % ETc or 60 % ETc. Implications or significanceThis innovative approach not only empowers farmers with intuitive and accurate tools for real-time cotton N management but also fosters enhanced agricultural practices by integrating advanced remote sensing technologies with sophisticated data analysis methods. The findings of this study have significant implications for sustainable and efficient agricultural practices, particularly in arid regions, setting a new precedent in precision nitrogen management.

The River Ythan Navigation, Aberdeenshire

The River Ythan in Aberdeenshire is the only natural inland waterway in northern Scotland. It was navigable for about 10km from Newburgh, the port for Ellon since 1276, to the Meadow of Waterton, the landing place for Ellon. The peak of fluvial traffic was in the late 18th to early 20th centuries during the agricultural improvements for the import of manure fertiliser, bones, guano and coal, and the export of grain. Cargos were brought by coasters for 2.5km upriver to Newburgh where they were transhipped into lighters, which were sailed, poled or towed by a tug upriver to Meadow of Waterton. This article describes the harbour works, now largely demolished, by means of site inspections made from 1984 to 1986 and describes the history of this little-known example of fluvial transport, and the history of Newburgh as a coastal port. The Newburgh Quay at Culterty was built in 1842 by Mr Robert Black, a local shipowner, and is well preserved although the original buildings have been replaced by modern houses. The nearby Inches Pier was built by The Aberdeen Lime Company sometime between 1842 and 1866 on a small tidal islet. There was a long wooden pier to the low tide mark in the river channel, and a short causeway to the shore on the north side of the Foveran Burn. The pier was abandoned in c 1923 after the company’s coaster sank, and there are scant remains now. Docks were built at Meadow of Waterton probably in 1842 by Mitchell & Rae, agricultural and coal merchants, fertiliser manufacturers and shipowners (1840–1977). They consisted of two docks perpendicular to the river with warehouses. The East Dock was 30–49m long and 9m wide, and the West Dock was 61m long and 9m wide. The docks fell into disuse in 1924 and were infilled in the 1970s and 1980s, with no trace now. The upper navigation was closed in 1924, replaced by motor transport, while Newburgh continued to be used as a coastal port until 1968.

The Use of Pig Manure Fertilizer on the Growth, Production, Protein Content, and TDN of Pakchong Grass

Manure is a fertilizer that comes from a mixture of livestock waste, urine, and leftover livestock feed. Pig manure can be used as fertilizer because it contains Nitrogen, phosphorus and potassium. Solid pig manure contains quite high Nitrogen nutrients of 0.95%, Phosphorus 0.35%, and Potassium 0.40%, so that pig manure is effective as an organic fertilizer that will be beneficial for plant growth. This study aims to see the effect of the use of pig manure fertilizer on the growth, production, nutritional quality and TDN of Pakchong Grass. A Randomized Block Design (RAK) was used with five treatments, namely without the use of pig manure fertilizer (P0), Grass Plants fertilized with 5 tons/ha of pig manure fertilizer (P1), Grass Plants fertilized with 10 tons/ha of pig manure fertilizer (P2), Grass Plants fertilized with 15 tons/ha of pig manure fertilizer (P3), and Grass Plants fertilized with 20 tons/ha of pig manure fertilizer (P4). The results of this study indicate that providing pig manure fertilizer of up to 20 tons/ha can increase the growth, production, quality and TDN of Pakchong Grass.

Effects of Integrated Decomposed Cattle Manure and Inorganic Fertilizer on Yield and Yield Components of Food Barley (<i>Hordeum vulgare</i> L.) in West Region of Ethiopia

Food Barley (Hordeum vulgare L.) is important major cereal crop which cultivated widely over the word. It is very important and categorized as food security crop in highlands of Ethiopian. This research was carried out in west region of Ethiopia Arjo, Gedo and Shambo in 2021 and 2022 cropping season with the objective of determine optimum integrated inorganic fertilizer and cattle manure for food barley production. The experiment was arranged with five level of NPS (0,25%, 50%, 75%, and 100%) of recommended combined with four level of decomposed cattle manure 0, 3tone/hectare, 6tone/ha and 9tone/a using RCBD in factorial arrangement and replicated three times. Analysis of variance showed grain yield, 1000sw, biological yield and plant height significantly affected by integrated fertilizer. Highest grain yield 2665kg/ha was harvested from the plot received 100% and 3tone/ha. Harvest index, seed per spike, spike length and number of tillers per spike were not affected by the treatment. The partial budget analysis revealed two treatments integrated 100% in organic fertilizer and 3tone/ha cattle manure and 9tone/ha cattle manure and 50% inorganic fertilizer which their MRR 605 and 1482 respectively were economically feasible. Therefore, the farmers and investors are advised to use these selected treatments for food barley production and soil fertility improvement.