Overuse Of Fertilizers Research Articles

NITROGEN USE EFFICIENCY (NUE) AND RICE PRODUCTIVITY AS AFFECTED BY DIFFERENT LEVELS OF NITROGEN APPLICATION IN HILL CONDITIONS OF NEPAL

In Nepal, rice is the major staple food crop and is ranked first as a cultivated crop. Nitrogen is one of the most important factors limiting its yield. There has been an overuse of nitrogen fertilizer in rice fields resulting in low N use efficiency and high loss of nitrogen. A field experiment was carried out on acidic sandy loam soil of the Directorate of Agricultural Research, Gandaki, Lumle, from June to November 2016 and 2017 to evaluate the performance of cold-tolerant rice (Lumle-2) and nutrient use efficiency as affected by various levels of nitrogen application. The experiment was laid out in a randomized complete block design with five different level of nitrogen as treatments (0, 50, 100, 130, 150 Kg N ha-1) and replicated four times. Phosphorus, potassium and FYM were applied at the recommended dose. A significantly marked increment in grain yield was noticed in both years as the nitrogen level increases up to 130 Kg N ha-1. However, when the nitrogen dose exceeded 130 Kg N ha-1 have decreasing effect in grain yield, straw yield and NUE. The productivity (4.35 t ha-1) and NUE of cold tolerant rice (Lumle-2) can be improved significantly by applying an optimum level of N fertilizer up to 130 Kg N ha-1.

Environmental challenges of the Northern Indian plains and their implications

The Northern Indian Plains are facing severe environmental challenges that threaten the health and well-being of millions of people in the region. Deforestation, soil degradation, water pollution and scarcity, and poor air quality are some of the major environmental issues that require urgent attention. Deforestation in the region has resulted in the loss of biodiversity, soil erosion, and reduced water availability. Soil degradation is another major issue in the region, resulting from unsustainable agricultural practices, overuse of chemical fertilizers, and erosion caused by deforestation. It has also reduced soil fertility, resulting in lower crop yields and reduced agricultural productivity. Using chemical fertilizers and pesticides has also led to water pollution, affecting the health of people and animals who rely on these water sources. Water scarcity and pollution are major challenges in the region, with many people having limited access to clean and safe drinking water. The pollution of water sources due to industrial and agricultural activities has further compounded the problem, leading to waterborne diseases and various health issues. Finally, air pollution is a major environmental challenge in the Northern Indian Plains, with high levels of particulate matter and other pollutants affecting people's health in the region. Burning crops, vehicular emissions, and industrial activities contribute to poor air quality, leading to respiratory illnesses, cardiovascular disease, and other health issues. This study aims to provide a comprehensive overview of the mentioned environmental challenges in the Northern India Plains by utilizing contemporary literature and evidence-based research to establish its findings.

Preliminary N2O Emissions of Major Vegetable Cropping Systems in Peri-urban Hanoi, Vietnam

Crop management practices in intensive vegetable production can influence nitrous oxide (N2O) emissions from soils. This study quantified seasonal N2O emissions and N2O emission intensities, and investigated the factors driving emissions in different vegetable management practices. Emissions from four typical vegetable crops (two choy sums, a mustard, and a cabbage) were intensively measured over the 2016 autumn season on farms in Van Noi and Dang Xa communes in the Hanoi peri-urban area. Different N2O emissions were observed in the four leafy vegetable crops. The average daily emissions varied from 12.15 g to 40.08 g N2O-N ha-1 and the autumn season N2O emissions varied from 1.13 kg to 8.45 kg N2O-N ha-1 across the four crops. The greatest daily and season emissions were from cabbage, and the lowest were from mustard. Emission intensities varied among the types of vegetables and was the lowest at the mustard farm (37 kg CO2-e t-1), indicating that the crop management practices increased the mustard yield but retained a low N2O emission rate. Practices responsible for high N2O emissions were overuse of nitrogen fertilisers and furrow irrigation. An improvement in the farmers’ adoption of best practices in fertiliser application and irrigation could reduce N2O emissions without affecting crop productivity.

Source Identification, Ecological Risk and Spatial Analysis of Heavy Metals Contamination in Agricultural Soils of Tanjaro Area, Kurdistan Region, Iraq

The current work accomplished a comprehensive evaluation of heavy metals pollution in soil of agricultural areas from Tanjaro sub-district, Sulaimaniyah province, Kurdistan Region, NE Iraq. Ninety soil samples were collected from thirty different locations. Concentrations of 16 heavy metals were measured by inductively coupled plasma optical emission spectrometry ICP-OES. The pollution index (PI), potential ecological risk index (Er), enrichment factor (EF), and ecological risk index (RI) were used to assess the pollution in soil samples. High levels of Li and Ni, and moderate Ba, Cd, Hg, and Pb according to the results of concentration analysis, pollution index (PI), and potential ecological risk (ERI). High levels of Cd and Hg according to the results of Er. Agglomerative hierarchical clustering (AHC) and principal component analysis (PCA) suggested that heavy metals were generated from different natural and anthropogenic sources like natural weathering, fertilizer application, and transportation. Origins of Hg, Cd, Ni, and Pb are probably from activities like overuse of pesticides and fertilizers, whereas Pb could be exhausted from vehicle exhausts as well. Furthermore, spatial distributions revealed nonpoint source pollution for the studied heavy metals. The obtained results help in the remediation techniques of contaminated soils such as dilution with decontaminated soil or extraction or separation of heavy metals.

Chemical Fertilizer Imports and the Environment: Evidence-based Approach for a Green Economy Accounting for the Tradeoff

The direct and indirect impact of high-input use agriculture- popularised by the Green Revolution- on the environment is the major thrust of this perspective. The paper discusses an integrated approach to minimise the negative impacts, accounting for the proposed ban of synthetic fertilizers and the tradeoff between the environment and productivity resulting from such a ban. Noteworthy stylised facts of the discussion are threefold. First, the Green Revolution reduced the growth of extensive expansion of agricultural lands via intensification, which subdued the pressure on forest cover. Additionally, productivity increase releases marginal lands for vital ecological services such as pollinator habitats. Second, synthetic fertilizer resulted in higher productivity in the agriculture sector, increasing the GDP and facilitating structural transformation. Given that a quarter of the workforce is in the agriculture sector, gradual movement of the labor force to the industrial sector is vital, while the agriculture sector workforce become self-reliant in facing environmental and climatic events. Thus, continuous investment in agricultural productivity growth should be a priority to create fiscal space for the investments in meaningful green initiatives and reduce the vulnerability of the rural poor. Third, evidence-based solutions such as site-specific fertilizer recommendations, soil testing, and discouraging overuse of nitrogenous fertilizer through tariffs should be practised to mitigate the adverse environmental impact of synthetic fertilizer, especially nitrogen fertilizer. Complete removal of the subsidy may generate overreaching welfare and environmental ramifications, although it is widely suggested.

Effectiveness of green microalgae as biostimulants and biofertilizer through foliar spray and soil drench method for tomato cultivation

The over-use of synthetic chemical fertilizer has an adverse effect on humans. To overcome this issue, there is a need for organic farming. The present study is intended for identifying the possibilities of microalgal (Chlorella vulgaris) application on tomato (Solanum lycopersicum L.) cultivation as a suitable biofertilizer as well as biostimulant. The application of Chlorella vulgaris by foliar spray method, soil drench method with and without cowdung and control (untreated). Soil is suitable for tomato cultivation according to the soil analysis. Laboratory cultured Chlorella vulgaris enriched with carbohydrate (40.75±0.55), protein (29.56±0.72), lipids (30.20±0.25), total chlorophyll (0.531±0.42), carotenoids (0.261±0.35) and also other elements such as carbon (26.03±0.21), nitrogen (4.18±0.48), sodium (5.63±0.54) and potassium (6.94±0.17). Mixed treatment of cowdung with C. vulgaris shows enhanced growth than other groups. The higher concentration (100%) of foliar spray, C. vulgaris by soil drench and C. vulgaris + cowdung, elicits fruit length of about 8.8 ± 0.36, 10.5 ± 0.61 and 11.7 ± 0.35 cm, fruit diameter of about 13.3 ± 0.73, 14.2 ± 0.24 and 16.7 ± 0.31 cm, number of seeds/fruit of about 89±0.45, 118±0.98 and 153±0.96 g and seed weight/fruit of about 4.5 ± 0.14, 5.2 ± 0.19 and 6.5 ± 0.28 g respectively. The quality of the tomato was attributed to the increased total soluble solid of about 5.78±0.39, 6.27±0.92 and 7.09±0.75 g/100 g, total soluble sugar of about 4.30±0.76, 5.37±0.57 and 7.40±0.90 g/100 g, l-Ascorbic acid of about 14.6 ± 0.86, 17.9 ± 0.93 and 19.23±0.69 g/100 g, total protein of about 4.88±0.36, 5.82±0.88 and 6.37±0.23 g/100 g and moisture of about 94.1 ± 0.81, 95.5 ± 055 and 96.5 ± 0.42 g/100 g in foliar spray, C. vulgaris by soil drench and C. vulgaris + cowdung methods of applications respectively. There is a significant increase in mineral content such as phosphorus, potassium, calcium and magnesium in treated fruits as compared to control. Similarly shelf life (days) of foliar spray (5.0 ± 0.19), soil drench (6.0 ± 0.55), mixed treatment (7.0 ± 0.16) was increased than control(4 ± 0.65). Among three treatments, C. vulgaris + cowdung showed better results than other treatment. Soil drench method of application shows better outcomes than foliar spray application. Microalgae Chlorella vulgaris can be applied as biofertilizer/biostimulants in tomato cultivation by replacing conventional chemical fertilizer.

Increasing sustainability for rice production systems

Rice (Oryza sativa L.) is the staple food for millions of people in Asia and the world; however, it is also the largest consumer of freshwater resources worldwide. More than 75% of the world's rice is grown under flooded conditions. However, the long-term sustainability of this flooded system is threatened by the rapid changes in climatic events causing erratic rainfall and abiotic stresses, looming water and energy crisis, low nitrogen use efficiency, increasing micronutrient deficienties, increasing labor costs and reduced labor availability, increased methane emissions, yield stagnation, and the negative effects of rice crops on post-rice crops. The narrow genetic background in rice has also slowed the pace of breeding rice cultivars tolerant to abiotic and biotic stresses which has resulted in yield stagnation. While direct-seeded rice has become popular in developed countries, saving water and labor resources and reducing methane emissions, developing countries in Asia struggle to disseminate direct seeding technologies due to the lack of government support and policy. Weed management in direct seeded rice is still a major bottle neck in wide scale adoption of this rice system in developing world. Mechanical transplanting of rice is gaining momentum in Asia, reducing labor requirements, ensuring timely transplantation, and saving water during initial growth. Nonetheless, government support and strong policy are needed to boost its uptake by providing subsidies to purchase mechanical transplanters and training farmers to use this technology. With deteriorating soil health due to continuous cultivation of rice with cereals in rotation, overuse of synthetic fertilizers, and increased co-occurrence of abiotic and biotic stresses in rice, there is a need to adopt integrated crop management techniques, and to identify genes of interest and quantitative trait loci (QTL) for their introgression into desired plants. These interventions will improve the improve biotic and abiotic stress tolerance in rice. There is also a need for extensive campaign and policy support from the government to force farmers to harvest their rice crops using specific rice harvesters that can save the yield losses that occur when using wheat combine harvesters—a common practice in many developing countries.

Robust clustering for assessing the spatiotemporal variability of groundwater quantity and quality

The long-term spatiotemporal assessment of groundwater resources through robust clustering techniques can be used to promote remediation measures for groundwater depletion and contamination. To fully understand the variability of groundwater quantity and quality due to anthropogenic activities and climate changes, a new ensemble clustering framework based on the Combining Multiple Clusters via Similarity Graph (COMUSA) method was developed. This new approach was applied and evaluated in the context of groundwater well systems on the Ghorveh-Dehgolan Plain (GDP), which is located in western Iran, for groundwater level (GWL) and 13 physicochemical parameters during four periods (the average of data from 1988–1990, 1997–1999, 2006–2008, and 2015–2017). The classification was confirmed by using the cluster validity index of the silhouette coefficient (SC), which indicated that the cluster ensemble method could improve the performance of individual clustering methods for groundwater quantity and quality by up to 12% and 20%, respectively. Piper plots, US Salinity Laboratory Staff (USSL) diagrams, and the pollution index of groundwater (PIG) were assessed for all clusters of physicochemical variables to analyse groundwater suitability for drinking and irrigation purposes. The results of the cluster ensemble showed that a critical pattern of groundwater depletion occurred in the western half of the GDP, while the eastern part was recognized as the most polluted zone on the plain. It could be concluded that the decline in GWL was not the only reason for the increase in groundwater quality variables, but other factors, such as noticeable cropland expansion and the overuse of chemical fertilizers and pesticides, were also influential factors related to these patterns. Taken together, the results of this study contribute to better recognizing the spatiotemporal changes in groundwater quantity and quality under the intense pressure of anthropogenic activities.

Increasing yields while reducing soil nutrient accumulation by straw strip mulching in the dryland wheat (Triticum aestivum L.) cropping system of Northwest China

Surface mulching is an effective strategy to increase yields in rainfed agroecosystems. The plastic film residue and overuse of chemical fertilizer cause a serious non-point source pollution and high production input cost. With mulching, farmers typically attempt to maintain the balance of soil nutrients and reduce fertilizer use while ensuring high yields. Straw strip mulching (SM) is a new mulching technique, but the effects on nutrient uptake have not been studied yet. Therefore, 19 field comparative experiments were conducted in four growth seasons of winter wheat with three mulching treatments: (1) straw strip mulch (SM), a partial ground mulching using whole corn stalks that alternate with planting strips without mulch; (2) full-field plastic film mulching (PM); and (3) no mulching with wheat sown in rows, as a control (CK). Compared with CK, on average over all experiments, SM increased grain yield by 11.5%, biomass by 19.0%, the total aboveground uptakes of nitrogen (N), phosphorus (P) and potassium (K) by 16.1%, 18.4% and 22.9%. There were no significant differences between SM and CK in N and P requirements, the N, P and K concentrations in grain. The increased total aboveground uptake of each nutrient was closely associated with higher biomass, grain yield and straw yield (r = 0.66 −0.84, P < 0.01). Relative to CK, SM significantly decreased the total accumulation of residual NO3-N in the top 100 cm at maturity stage by 32.3% (22.7 kg ha-1) in typical fertilization (N, 120 kg ha-1; P2O5, 90 kg ha-1) and by 33.8% (45.8 kg ha-1) in high fertilization (N, 150 kg ha-1; P2O5, 120 kg ha-1), and the leaching of NO3-N into the deep soil below 40 cm. When only grain nutrients exported from the field after harvest in typical fertilization, N balance in SM, PM and CK accounted for 43.8%, 38.5% and 48.6% of N input, while P balance for 74.8%, 74.0% and 78.4% of P input, respectively, indicating possible saving potentials in fertilizer costs for all treatment, but the saving potential of P is much greater than that of N. Relative to PM, SM had similar the total aboveground nutrients uptake, similar to or slightly less grain yields, and higher economic benefit. SM is suitable for popularizing in a semiarid rainfed agroecosystem.

Mobilization of organic nitrogen and phosphorus and reduction of synthetic fertilizer usage by Ceriporia lacerata HG2011 in pepper cultivation

Overuse of synthetic fertilizers leads to soil deterioration, environmental pollution, and poor crop quality. To seek microbes that are effective in mobilizing nutrients accumulated in soils is of utmost significance to reduce fertilizer use and increase fertilizer efficiencies. Thus, the mobilization of organic nitrogen (N) and phosphorus (P) by a wood-rot fungus Ceriporia lacerata HG2011 and pepper performances in response to this fungus were investigated in the laboratory and field. The results showed that C. lacerata HG2011 grew well and produced extracellular protease and phosphatase to convert peptone into free amino acid and NH4+-N, and lecithin into soluble inorganic P in liquid culture. Similarly, NH4+-N, water soluble P and Olsen P were increased by the release of protease and phosphatase as the fungus grew on and in the sterile soil. Compared with only synthetic fertilizer treatment, pepper nutrient uptake (including N, P, and K), nutrient agronomic efficiency, and fruit yield and quality were improved by the application of synthetic fertilizers plus C. lacerata HG2011 and remained unchanged in the treatment of reduced synthetic fertilizers plus C. lacerata HG2011. The field soil that received this fungus showed the higher activities of protease and phosphatase, which lead to higher N and P availability than that without C. lacerata HG2011.Taken together, C. lacerata HG2011 mobilized organic nitrogen and phosphorus, increased pepper yield and quality, and reduced synthetic fertilizer use without yield and quality sacrifices, showing a promising new use in modern sustainable agriculture beyond medical, industrial, and environmental purposes.

Improving Nitrogen Use Efficiency—A Key for Sustainable Rice Production Systems

Fertilizer use and genetic improvement of cereal crops contributed to increased yields and greater food security in the last six decades. For rice, however, fertilizer use has outpaced improvement in yield. Excess application of nutrients beyond crop needs, especially nitrogen (N), is associated with losses to the environment. Environmental pollution can be mitigated by addressing fertilizer overuse, improving N use efficiency, while maintaining or improving rice productivity and farmers' income. A promising approach is the site-specific nutrient management (SSNM), developed in the 1990s to optimize supply to meet demand of nutrients, initially for rice, but now extended to other crops. The SSNM approach has been further refined with the development of digital decision support tools such as Rice Crop Manager, Nutrient Expert, and RiceAdvice. This enables more farmers to benefit from SSNM recommendations. In this mini-review, we show how SSNM can foster sustainability in rice production systems through improved rice yields, profit, and N use efficiency while reducing N losses. Farmer adoption of SSNM, however, remains low. National policies and incentives, financial investments, and strengthened extension systems are needed to enhance scaling of SSNM-based decision support tools.

Growth and Yield Response of Chilli (Capsicum annum L) for the Combined Organic and Inorganic Fertilizer Application

It is well known that the overuse of inorganic fertilizers has catastrophic impacts on forms of life and the environment. In chemical fertilizers, Nitrogen is one of the main elements that has a high leaching potency which leads to pollute both surface and groundwater resources. This study was carried out to identify the best organic and inorganic fertilizer combination that gives the highest yield in MI-Green. The treatments are 3 kg/pot cow dung (control 1), (T1), 2 kg/pot cow dung (control 2) (T2), 2 kg/pot cow dung + foliar urea spray (T3), 2 kg/pot cow dung + urea soil application (T4), 3 kg/pot cow dung+ foliar spray (T5) and 3 kg/pot cow dung + Urea soil application (T6). Results disclosed a significant effect (p&lt;0.05) on growth and yield in T5. Hence, it can be concluded that 3kg/pot cow dung+ foliar spray combination can be used to improve the growth and yield of MI-Green chilli.

Public contestation over agricultural pollution: a discourse network analysis on narrative strategies in the policy process

The overuse of fertilizers in agriculture and their entry into freshwater has many negative impacts on biodiversity and poses problems for drinking water resources in Germany. In response to exceeding levels of nitrate concentrations in groundwater in parts of the country, an intense public dispute evolved and a significant policy change in fertilizer regulation occurred in 2020. Based on the German case of agricultural water pollution, this study demonstrates in an innovative way how discourse network analysis is a fruitful method for the integrated study of actor coalitions and their use of narrative strategies in public debate. Theoretically, the study draws on the narrative policy framework (NPF) to explain how actor coalitions use narrative strategies to attempt to influence policymaking on water pollution by agricultural activities. The empirical analysis builds on newspaper articles and press releases disseminated between 2010 and 2020. The results demonstrate how two opposing actor coalitions with congruent policy beliefs formed in the struggle over fertilizer regulation. These not only diverged in their policy beliefs but also differed in their use of narrative strategies to try to expand or contain the policy issue. More precisely, the coalitions adapted their narratives over time in response to changes in the likelihood to win or lose. Furthermore, the results suggest the coalition in favor of stricter fertilizer regulation was more sophisticated in its effort to mobilize specific target groups. Overall, the article provides a valuable contribution to the literature on the NPF by combining research on coalition formation and policy narratives.

Decoupling pollution-agricultural growth and predicting climate change impacts on decoupling index using Bayesian network in different climatic regions.

Applying the principles of healthy products through agriculture practices has become an important issue due to significant environmental impacts of agrochemicals application. The agrochemicals have been recognized as an essential component of modern agriculture, but they are also an important source of environmental pollution that threatens the human's health and are main sources of carbon emissions. Pesticides and fertilizers application are important in the process of Iran's food production. In Iran, intensifying the agricultural production has led to overuse of chemical fertilizers and pesticides. This work is the first effort to quantify and compare the decoupling index pollution from agricultural sector using Tapio decoupling indicator and predict climate change impacts on this index by using Bayesian network across the whole country of Iran. For this purpose, required annual data of predictor variables for the period of 2008 to 2018 was used to calculate the decoupling index. For projecting climate change impacts on this index by using Bayesian network, monthly mean values of climatic variables were used. While Iranian farmers are criticized for pesticide overuse, these study findings showed that during the period of 2008-2018, decoupling index for pesticides (agricultural pollution by using pesticide) and decoupling index for fertilizer (agricultural pollution by using fertilizer) in the selected provinces fluctuate between RD-SD, SD-SD, SD-SD, and RD-SD. Therefore, the decoupling states show that in most study years, there is a strong decoupling of agricultural growth in selected provinces. This means that in the selected provinces, pollutant emissions of chemical fertilizer and pesticides use for agricultural productions have decreased and it has been well controlled. Therefore, by expansion of agricultural sector, the situation of agricultural pollution in these provinces in most years has not been intensified. Control of agricultural pollution in these provinces has shown a positive and significant impact on public health. In selected provinces, the cleaner agricultural products and application of organic fertilizers have been increased. This study results also showed that the climate change will accelerate increment of pests population and thus pesticides application in different climatic regions.

Does agricultural cooperative membership help reduce the overuse of chemical fertilizers and pesticides? Evidence from rural China.

The overuse of chemical fertilizers and pesticides (CFPs) has negatively impacted the environment and human health. It is an urgent issue that should be addressed. In this study, we investigate whether agricultural cooperatives can serve as an institutional arrangement that helps reduce the consumption of CFPs, using the data of 2012 family farms from the Ministry of Agriculture and Rural Affairs of China. Various approaches, including instrumental variable-based two-stage residual inclusion approach (2SRI), endogenous switching probit (ESP) model, and endogenous switching regression (ESR) model, are utilized to help address the endogeneity issues of the cooperative membership variable. The results show that agricultural cooperative membership significantly increases the probability of reducing fertilizers and pesticides of the family farms and improves net return per yuan CFPs. The further analysis shows that agricultural cooperative production services reduced the usage of fertilizers and pesticides, while cooperatives marketing services only significantly lowered the use of pesticides. Our findings highlight the importance of promoting the development of agricultural cooperatives to support green agricultural production in China.

Los límites de la productividad del cultivo de papa en Ecuador entre 2017 y 2018

The homogenization of agricultural cultivation practices in the world for the purpose of increasing productivity brings with it multiple consequences, among which are: soil erosion, practices and varieties. Potato was one of the first crops on which technologies related to the Green Revolution were applied, which brought increases in yields, however, its effect wore off over time, and in many cases causes decreasing yields, as is the case of potato in Ecuador. In this sense, the present study aims to evaluate the performance of inputs (fertilizers, phytosanitary control, seeds) immersed in potato production and the characteristics (irrigation availability, location, labor) of the Agricultural Production Units through the estimation of a multiple regression model with information from the Continuous Agricultural Surface and Production Survey of 2017 and 2018. The results show that the overuse of chemical fertilizers and phytosanitary control causes decreasing crop yields; likewise, the need for public irrigation systems to increase productivity is highlighted. At the same time, the results confirm the loss of productivity between 2017 and 2018 by about 25%, and the existence of territorial gaps in production, in which the province of Carchi has higher yields. Additional Keywords: Green Revolution, diminishing returns, multiple regression.

Water environmental pressure assessment in agricultural systems in Central Asia based on an Integrated Excess Nitrogen Load Model

Agricultural runoff is the main source of water pollution in Central Asia. Excessive nitrogen (N) inputs from overuse of chemical fertilizers are threatening regional water resources. However, the scarcity of quantitative data and simplified empirical models limit the reliability of grey water footprint (GWF), particularly in undeveloped regions. In this study, we developed an Integrated Excess Nitrogen Load Model (IENLM) to calculate excess N load and evaluate its potential water environmental pressure in Central Asia. The model optimized the biological N fixation and atmospheric N deposition modules by involving more environmental variables and human activities. Results showed that N fertilizer application contributed over 60% to total N input and was mainly responsible for 42.9% increase of total GWF from 101.5 to 145.0 billion m3 during 1992 - 2018. Water pollution level (WPL) increased from 0.55 in 1992 to 2.41 in 2018 and the pollution assimilation capacity of water systems has been fully consumed just by N load from agriculture since 2005. GWF intensity and grey water pollution – efficiency types in all Central Asian countries have improved in recent years except for Turkmenistan. N fertilizer application and agricultural economy development were the main driving factors induced N pollution. Results were validated by riverine nitrate concentrations and the estimates from prior studies. In future, combining the N fertilizer reduction with other farm management practices were projected to effectively improve the WPL. The modeling framework is favorable for N pollution research in data-scarce regions and provides a scientific basis for decision-making for agriculture and water resource managements.

Productivity Enhancement of Cucumber (Cucumis sativus L.) through Optimized Use of Poultry Manure and Mineral Fertilizers under Greenhouse Cultivation

Cucumber, a widely cultivated vegetable, is mostly grown under greenhouse conditions. In recent years, the overuse of inorganic fertilizers for higher yield attainment adversely has affected human health and the environment. Therefore, a greenhouse experiment was designed to evaluate the effects of different nutrient sources (poultry manure (PM) and mineral fertilizer (MF)) on productivity-enhancing parameters of cucumber via univariate and multivariate analyses. Amounts of PM and MF (NPK15:15:15) were added to coco-peat per cubic meter by weight/volume (w/v) ratios as follows: T1 (control), 60 kg PM; T2, 30 kg PM + 3 kg MF; T3, 30 kg PM + 5 kg MF, and T4, 30 kg PM + 7 kg MF. The univariate analysis performed on the collected data illustrated the significant enhancement in growth and productivity for the integrated use of PM and MF. Multivariate analyses (correlation, clustering, and Principal Component Analysis) validated the results of univariate analysis by differentiating treatments into two groups. The three treatments obtained a distinguished group from T1 (Control) and did not show significant differences among each other, with a maximum yield increase by T2 (74.6%). According to these results, T2 could improve cucumber productivity under greenhouse conditions. It can be taken as recommendations for better quality and yield enhancement in future improvement programs and cucumber-related farming communities.

Estimation of nitrogen content in cucumber plant (Cucumis sativus L.) leaves using hyperspectral imaging data with neural network and partial least squares regressions

In recent years, farmers have often mistakenly resorted to overuse of chemical fertilizers to increase crop yield. However, excessive consumption of fertilizers might lead to severe food poisoning. If nutritional deficiencies are detected early, it can help farmers to design better fertigation practices before the problem becomes unsolvable. The aim of this study is to predict the amount of nitrogen (N) content (mg ​l−1) in cucumber (Cucumis sativus L., var. Super Arshiya-F1) plant leaves using hyperspectral imaging (HSI) techniques and three different regression methods: a hybrid artificial neural networks-particle swarm optimization (ANN-PSO); partial least squares regression (PLSR); and unidimensional deep learning convolutional neural networks (CNN). Cucumber plant seeds were planted in 20 different pots. After growing the plants, pots were categorized and three levels of nitrogen overdose were applied to each category: 30%, 60% and 90% excesses, called N30%, N60%, N90%, respectively. HSI images of plant leaves were captured before and after the application of nitrogen excess. A prediction regression model was developed for each individual category. Results showed that mean regression coefficients (R) for ANN-PSO were inside 0.937–0.965, PLSR 0.975–0.997, and CNN 0.965–0.985 ranges, test set. We conclude that regression models have a remarkable ability to accurately predict the amount of nitrogen content in cucumber plants from hyperspectral leaf images in a non-destructive way, being PLSR slightly ahead of CNN and ANN-PSO methods.

Rule-of-Thumb Instructions to Improve Fertilizer Management: Experimental Evidence from Bangladesh

Heavy government subsidies have led to inefficient application and overuse of fertilizer in Bangladesh. This results in above-optimal costs to farmers as well as to the environment and the public. In a randomized controlled trial, we provide farmers with a simple tool (a leaf color chart) and basic, rule-of-thumb instructions to guide the timing and quantity of urea (nitrogen) application. Treatment farmers reduce urea use by 8% without compromising yield, suggesting significant scope for improving urea management. The results are mainly driven by farmers delaying urea application as returns to urea are low early on in the season and urea applied is likely to be wasted. Cost-effectiveness estimates suggest that each dollar spent on this intervention produces a return of US$2.8 due to reduction of urea use over three seasons, as well as significant environmental benefits. We also find suggestive evidence that optimizing the timing of urea application affects farmers’ yields, plausibly as the intervention allows farmers to reallocate urea application to times when returns to urea are highest.