Crop Field Level Estimation of Nitrogen Input from Fertilizer Use in Jeju Island, South Korea: Management Methods to Prevent Groundwater NO3-N Contamination

The application of synthetic nitrogen (N) fertilizers has boosted crop yields globally. However, it has also imposed on environmental pollution problems. An estimation of actual fertilizer N inputs at the crop field level is needed to establish effective N management plans to control groundwater NO3-N contamination. Here, a survey to collect the types of cultivated crop and fertilizer application rate was conducted during 2016–2018, covering 44,253 small crop fields (7730 ha) in the western part (Hanrim and Hankyung regions) of Jeju Island, South Korea. Foreign vegetables, citrus fruits, and bulb vegetables are the major crop types grown in the total cultivated areas of 2165.6 ha, 1718.7 ha, and 944.9 ha, respectively. For several crops (green garlic, potato, and chives), the over-use of N fertilizers is observed, the amount of which is 1.73–4.95 times greater than the standard fertilizer application rate. The highest level of fertilizer N input is observed for bulb vegetables in both the regions (Hanrim: 500.5 kg/ha, Hankyung: 487.1 kg/ha), with nearly 80% of the N fertilizer input turned into surplus N loading. A comparison between a spatial interpolation map of the fertilizer N input and that of the groundwater NO3-N concentration implies that the excessive use of synthetic fertilizer results in the degradation of groundwater quality by NO3-N. N management plans for the study area are suggested based on the N fertilizer input at the crop field level. This study highlights that sustainable N management plans should be arranged at the crop field level, considering the spatial heterogeneity of N fertilizer use.

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Nitrogen Leaching and Nitrogen Balance under Differing Nitrogen Fertilization for Sugarcane Cultivation on a Subtropical Island

Water ◽

10.3390/w13050740 ◽

2021 ◽

Vol 13 (5) ◽

pp. 740

Author(s):

Ken Okamoto ◽

Shinkichi Goto ◽

Toshihiko Anzai ◽

Shotaro Ando

Keyword(s):

N Uptake ◽

Fertilizer Application ◽

Application Rate ◽

N Fertilizer ◽

N Leaching ◽

N Recovery ◽

N Application ◽

Fertilizer Application Rate ◽

Sugarcane Yield ◽

Cropping Seasons

Fertilizer application during sugarcane cultivation is a main source of nitrogen (N) loads to groundwater on small islands in southwestern Japan. The aim of this study was to quantify the effect of reducing the N fertilizer application rate on sugarcane yield, N leaching, and N balance. We conducted a sugarcane cultivation experiment with drainage lysimeters and different N application rates in three cropping seasons (three years). N loads were reduced by reducing the first N application rate in all cropping seasons. The sugarcane yields of the treatment to which the first N application was halved (T2 = 195 kg ha−1 N) were slightly lower than those of the conventional application (T1 = 230 kg ha−1 N) in the first and third seasons (T1 = 91 or 93 tons ha−1, T2 = 89 or 87 tons ha−1). N uptake in T1 and T2 was almost the same in seasons 1 (186–188 kg ha−1) and 3 (147–151 kg ha−1). Based on the responses of sugarcane yield and N uptake to fertilizer reduction in two of the three years, T2 is considered to represent a feasible fertilization practice for farmers. The reduction of the first N fertilizer application reduced the underground amounts of N loads (0–19 kg ha−1). However, application of 0 N in the first fertilization would lead to a substantial reduction in yield in all seasons. Reducing the amount of N in the first application (i.e., replacing T1 with T2) improved N recovery by 9.7–11.9% and reduced N leaching by 13 kg ha−1. These results suggest that halving the amount of N used in the first application can improve N fertilizer use efficiency and reduce N loss to groundwater.

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Dynamics of the Fertilizer Value Chain in Mozambique

Sustainability ◽

10.3390/su12114691 ◽

2020 ◽

Vol 12 (11) ◽

pp. 4691

Author(s):

Helder Zavale ◽

Greenwell Matchaya ◽

Delfim Vilissa ◽

Charles Nhemachena ◽

Sibusiso Nhlengethwa ◽

...

Keyword(s):

Value Chain ◽

Agricultural Productivity ◽

Fertilizer Application ◽

Application Rate ◽

Demand And Supply ◽

Fertilizer Use ◽

Fertilizer Value ◽

Crop Uptake ◽

Fertilizer Application Rate ◽

Side Constraints

Mozambique is characterized by low agricultural productivity, which is associated with low use of yield-enhancing agricultural inputs. Fertilizer application rate averaged 5.7 kg ha−1 in Mozambique during the period 2006 to 2015, considerably low by regional targets, yet constraints that affect fertilizer use have not been thoroughly investigated. This study examined the constraints on fertilizer value chains in Mozambique to contribute to fertilizer supply chain strengthening. We used a combination of multivariate analysis and descriptive methods. Our findings indicate that fertilizer use has both demand and supply constraints. Key demand-side constraints include liquidity challenges, limited awareness about the benefits of using fertilizer, and low market participation, while the main supply-side constraints include high transaction costs, limited access to finance, and lack of soil testing results and corresponding fertilizer recommendations by soil type and crop uptake. These results suggest that scaling up the input subsidy program through vouchers (either paper-based vouchers or e-vouchers) with demonstration plots and effective targeting could drive up smallholders’ demand for fertilizer and fertilizer supply by strengthening a sustainable network of wholesalers and retailers. This would likely boost agricultural productivity.

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Optimizing nitrogen fertilizer use for more grain and less pollution

10.21203/rs.3.rs-361734/v1 ◽

2021 ◽

Author(s):

Keyu Ren ◽

Minggang Xu ◽

Rong Li ◽

Lei Zheng ◽

Shaogui Liu ◽

...

Keyword(s):

Crop Production ◽

Management Practices ◽

Application Rate ◽

N Fertilizer ◽

N Application ◽

Fertilizer Use ◽

Application Rates ◽

Operational Practices ◽

N Management ◽

N Fertilizer Use

Abstract Optimal nitrogen (N) management is critical for efficient crop production and agricultural pollution control. However, it is difficult to implement advanced management practices on smallholder farms due to a lack of knowledge and technology. Here, using 35,502 on-farm fertilization experiments, we demonstrated that smallholders in China could produce more grain with less N fertilizer use through optimizing N application rate. The yields of wheat, maize and rice were shown to increase between 10% and 19% while N application rates were reduced by 15–19%. These changes resulted in an increase in N use efficiency (NUE) by 32–46% and a reduction in N surplus by 40% without actually changing farmers’ operational practices. By reducing N application rates in line with official recommendations would not only save fertilizer cost while increasing crop yield, but at the same time reduce environmental N pollution in China. However, making progress towards further optimizing N fertilizer use to produce more grain with less pollution would require managements to improve farmers’ practices which was estimated to cost about 11.8 billion US dollars to implement.

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Effects of nitrogen fertilizer application rate and time to first harvest on leaf area index; leaf nitrate content and yield of irrigated leaf rape (Brassica napus L. var. Giant)

International Journal of Horticultural Science ◽

10.31421/ijhs/27/2021/9441 ◽

2021 ◽

Vol 27 ◽

Author(s):

J. Masaka ◽

M. Chandiposha ◽

B. T. Makaure ◽

B. Mazina

Keyword(s):

Fertilizer Application ◽

Application Rate ◽

N Fertilizer ◽

Nitrate Content ◽

Agricultural Practice ◽

Brassica Napus L ◽

Area Index ◽

Fertilizer Application Rate ◽

Increasing Demand ◽

Leaf Nitrate

In Zimbabwe, smallholder cultivation of leaf rape is of considerable importance due to the increasing demand for the leaf vegetable from the rapidly increasing urban populations. A two-season field trial was conducted in the Agricultural Practice Experimental Plots of the Midlands State University in central Zimbabwe. The objective of the study was to establish selected biometric responses of leaf rape to N fertilizer rates and time to first harvesting. Increasing the rate of N fertilizer application considerably improves the yield of fresh rape leaf; LAI and concentration of leaf nitrate. Delaying rape leaf harvest after N fertilizer side dressing can be used as a strategy to boost rape leaf yield for vegetable markets with high single delivery demand. When harvesting is deliberately delayed after N fertilizer application rape LAI are significantly increased. Delaying the first leaf harvests by 7; 14 and 21 days after N fertilizer side dressing amendments increases the content of nitrate in fresh rape leaves. Fresh rape yield can be more accurately predicted by values of rape LAI. Nitrate concentrations in fresh rape leaf is a poor predictor of rape yield under field conditions.

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Estimation for N Fertilizer Application Rate and Rice (Oriza sativa L.) Biomass by Ground-based Remote Sensors

Korean Journal of Soil Science and Fertilizer ◽

10.7745/kjssf.2012.45.5.749 ◽

2012 ◽

Vol 45 (5) ◽

pp. 749-759

Author(s):

Jae-Sig Shim ◽

Joeng-Hwan Lee ◽

Su-Jung Shin ◽

Soon-Dal Hong

Keyword(s):

Fertilizer Application ◽

Application Rate ◽

N Fertilizer ◽

Remote Sensors ◽

Fertilizer Application Rate ◽

Oriza Sativa

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Use of a Nitrogen Budget to Predict Nitrogen Losses in Processing Butternut Squash with Different Nitrogen Fertilization Strategies

HortScience ◽

10.21273/hortsci.45.11.1734 ◽

2010 ◽

Vol 45 (11) ◽

pp. 1734-1740 ◽

Cited By ~ 1

Author(s):

Laura L. Van Eerd

Keyword(s):

Ammonium Nitrate ◽

Crop Yields ◽

Field Studies ◽

Fertilizer Application ◽

Application Rate ◽

N Fertilizer ◽

Environmental Concerns ◽

N Loss ◽

N Losses ◽

Fertilizer Application Rate

With rising input costs and environmental concerns, growers are seeking methods to minimize nitrogen (N) inputs and off-field N losses while maintaining crop yields. Field studies on processing butternut squash (Cucurbita moschata Duchesne ex Poir.) were conducted in 2004–2007 at 11 locations in Ontario, Canada, to determine the optimal N rate and estimate potential N losses. Preplant broadcast ammonium nitrate was applied at five rates between 0 and 220 kg N/ha. In contrasting years (i.e., cool/wet versus warm/dry versus average), 64% of sites were nonresponsive to N fertilizer as indicated by no differences in marketable squash yield. In responsive sites, the most economical rate of N (MERN) was between 105 and 129 kg N/ha of N fertilizer, indicating that the Ontario-recommended rate of 110 kg N/ha seems appropriate for responsive sites. At 110 kg N/ha, no yield advantage resulted from using a controlled-release N (CRN) or split-applying ammonium nitrate at preplant and vine elongation at 65 + 45 kg N/ha, respectively, compared with the same amount applied preplant. Apparent N losses (N inputs – N outputs) at harvest were 83 and 29 kg N/ha greater at a fertilizer application rate of 220 kg N/ha than at 0 and 110 kg N/ha, respectively. At 110 kg N/ha, crop removal balance and apparent N loss calculations suggest relatively low risk of N loss from the field during the growing season and after harvest, respectively. However, environmental and economical risks would be minimized if nonresponsive sites could be identified before N fertilizer application.

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Extent and Variation of Nitrogen Losses from Non-legume Field Crops of Conterminous United States

Nitrogen ◽

10.3390/nitrogen1010005 ◽

2020 ◽

Vol 1 (1) ◽

pp. 34-51

Author(s):

Amitava Chatterjee

Keyword(s):

United States ◽

Management Strategies ◽

Application Rate ◽

Fertilizer N ◽

N Loss ◽

N Losses ◽

Field Crops ◽

N Application Rate ◽

Spatio Temporal ◽

N Management

Nitrogen (N) losses from field crops have raised environmental concerns. This manuscript accompanies a database of N loss studies from non-legume field crops conducted across the conterminous United States. Cumulative N losses through nitrous oxide-denitrification (CN2O), ammonia volatilization (CNH3), and nitrate leaching (CNO3−) during the growing season and associated crop, soil, and water management information were gathered to determine the extent and controls of these losses. This database consisted of 404, 26, and 358 observations of CN2O, CNH3, and CNO3− losses, respectively, from sixty-two peer-reviewed manuscripts. Corn (Zea mays) dominated the N loss studies. Losses ranged between −0.04 to 16.9, 2.50 to 50.9, and 0 to 257 kg N ha−1 for CN2O, CNH3 and CNO3−, respectively. Most CN2O and CNO3− observations were reported from Colorado (n = 100) and Iowa (n = 176), respectively. The highest values of CN2O, and CNO3− were reported from Illinois and Minnesota states, and corn and potato (Solanum tuberosum), respectively. The application of anhydrous NH3 had the highest value of CN2O loss, and ammonium nitrate had the highest CNO3− loss. Among the different placement methods, the injection of fertilizer-N had the highest CN2O loss, whereas the banding of fertilizer-N had the highest CNO3− loss. The maximum CNO3− loss was higher for chisel than no-tillage practice. Both CN2O and CNO3− were positively correlated with fertilizer N application rate and the amount of water input (irrigation and rainfall). Fertilizer-N management strategies to control N loss should consider the spatio-temporal variability of interactions among climate, crop-and soil types.

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Excessive Application of Fertilizer, Agricultural Non-Point Source Pollution, and Farmers’ Policy Choice

Sustainability ◽

10.3390/su11041165 ◽

2019 ◽

Vol 11 (4) ◽

pp. 1165 ◽

Cited By ~ 5

Author(s):

Haixia Wu ◽

Yan Ge

Keyword(s):

Point Source ◽

Organic Fertilizer ◽

Fertilizer Application ◽

Application Rate ◽

Chemical Fertilizer ◽

Shaanxi Province ◽

Annual Growth Rate ◽

Point Source Pollution ◽

Fertilizer Application Rate ◽

Non Point Source Pollution

This paper takes 516 households who planted wheat in Heyang County, Shaanxi Province in 2018, as samples to construct three policy environments: Technological guidance for planting, subsidies for organic fertilizer application, and agricultural tailwater discharge standards. The experimental choice method was used to empirically analyze policy preferences during the process of fertilizer reduction. The results indicate that households show different preferences for the three policy settings: The fertilizer application rate is reduced by 6.98% if providing full technological guidance for farmers throughout the wheat planting process and is reduced by 5.18% under the background of providing appropriate organic fertilizer subsidies. The agricultural tailwater discharge standards have the least impact on the reducing level of chemical fertilizer application, with decreasing amounts of only 1.85% and 0.77% under the second-level and the first-level agricultural tailwater discharge standards, respectively. These results indicate that households in Heyang County, Shaanxi Province, demonstrate a low willingness to accept the agricultural tailwater discharge standards in order to cut down on the amount of chemical fertilizer application and the agricultural non-point source pollution. Therefore, compared with a compounded annual growth rate (CAGR) of 1% of fertilizer usage nationwide according to the Chinese Ministry of Agriculture, given the current planting environment and policies design, providing comprehensive technological guidance as well as price subsidies for the organic fertilizer can significantly and robustly reduce the excessive application of fertilizer in Heyang County, Shaanxi Province, under the best scenario, thereby further alleviating agricultural non-point source pollution.

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