Optimizing nitrogen fertilizer use for more grain and less pollution

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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Carbon footprint of crop production in China: an analysis of National Statistics data

The Journal of Agricultural Science ◽

10.1017/s0021859614000665 ◽

2014 ◽

Vol 153 (3) ◽

pp. 422-431 ◽

Cited By ~ 48

Author(s):

K. CHENG ◽

M. YAN ◽

D. NAYAK ◽

G. X. PAN ◽

P. SMITH ◽

...

Keyword(s):

Carbon Footprint ◽

Crop Production ◽

Management Practices ◽

Fertilizer Application ◽

N Fertilization ◽

Paddy Rice ◽

N Fertilizer ◽

Carbon Equivalent ◽

Ghg Mitigation ◽

Application Rates

SUMMARYAssessing carbon footprint (CF) of crop production in a whole crop life-cycle could provide insights into the contribution of crop production to climate change and help to identify possible greenhouse gas (GHG) mitigation options. In the current study, data for the major crops of China were collected from the national statistical archive on cultivation area, yield, application rates of fertilizer, pesticide, diesel, plastic film, irrigated water, etc. The CF of direct and indirect carbon emissions associated with or caused by these agricultural inputs was quantified with published emission factors. In general, paddy rice, wheat, maize and soybean of China had mean CFs of 2472, 794, 781 and 222 kg carbon equivalent (CE)/ha, and 0·37, 0·14, 0·12 and 0·10 kg CE/kg product, respectively. For dry crops (i.e. those grown without flooding the fields: wheat, maize and soybean), 0·78 of the total CFs was contributed by nitrogen (N) fertilizer use, including both direct soil nitrous oxide (N2O) emission and indirect emissions from N fertilizer manufacture. Meanwhile, direct methane (CH4) emissions contributed 0·69 on average to the total CFs of flooded paddy rice. Moreover, the difference in N fertilizer application rates explained 0·86–0·93 of the provincial variations of dry crop CFs while that in CH4 emissions could explain 0·85 of the provincial variation of paddy rice CFs. When a 30% reduction in N fertilization was considered, a potential reduction in GHGs of 60 megatonne (Mt) carbon dioxide equivalent from production of these crops was projected. The current work highlights opportunities to gain GHG emission reduction in production of crops associated with good management practices in China.

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Carrot Yield, Quality, and Storability in Relation to Preplant and Residual Nitrogen on Mineral and Organic Soils

HortTechnology ◽

10.21273/horttech.16.2.0286 ◽

2006 ◽

Vol 16 (2) ◽

pp. 286-293 ◽

Cited By ~ 9

Author(s):

Sean M. Westerveld ◽

Mary Ruth McDonald ◽

Alan W. McKeown

Keyword(s):

Mineral Soil ◽

Organic Soil ◽

Application Rate ◽

Yield Response ◽

Organic Soils ◽

Residual Soil ◽

N Application ◽

Application Rates ◽

Yield Quality ◽

N Management

The Nutrient Management Act (NMA) established in the province of Ontario in 2002 has prompted a re-evaluation of nitrogen (N) management practices. However, N management research in Ontario is currently outdated. The experiment in this 3-year study was designed to establish the yield response of carrot (Daucus carota) to N fertilization on mineral and organic soils and identify the relative yield effects of preplant and residual soil N. In 2002, N was applied at 0%, 50%, 100%, 150%, and 200% of recommended N application rates in Ontario as ammonium nitrate (organic soil: 60 kg·ha-1 preplant; mineral soil: 110 kg·ha-1 split 66% preplant/33% sidedress). Experimental units were split in half in 2003 and 2004, and N was applied to one half in 2003 and both halves in 2004 to identify the effects of residual N from the previous season on yield. Crop stand, yield, and quality were assessed at harvest, and storability was assessed by placing carrots into cold storage for 6 months. Nitrogen application rate had no effect on the yield, quality, or storability of carrots grown on organic soil. On mineral soil there were no effects of applied N in the first year of the 3-year study. In the second and third year on mineral soil, yield increased in response to increasing N, up to 200% and 91% of the recommended application rate, respectively, based on the regression equations. Yield declined above 91% of the recommended application rate in the third year due to a decrease in stand at higher N application rates. There were no effects of N on carrot quality or storability on mineral soil. On mineral soil, residual N from the 2002 season had more effect on yield at harvest in 2003 than N applied in 2003. This major effect of residual soil N on yield provides an explanation for the lack of yield response to preplant N application in previous studies conducted in temperate regions. These results indicate that there is no single N recommendation that is appropriate for all years on mineral soil. Assessing the availability of N from the soil at different depths at seeding is recommended to determine the need for N application.

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Yield and Quality of Carrot Cultivars with Eight Nitrogen Rates and Best Management Practices

HortScience ◽

10.21273/hortsci15983-21 ◽

2021 ◽

pp. 1-7

Author(s):

Robert Conway Hochmuth ◽

Marina Burani-Arouca ◽

Charles Edward Barrett

Keyword(s):

Best Management Practices ◽

Management Practices ◽

Sandy Soils ◽

Application Rate ◽

Fresh Market ◽

Marketable Yield ◽

N Application ◽

Winter Climate ◽

Best Management ◽

Application Rates

Carrot (Daucus carota) production has increased in North Florida and South Georgia since 2015. Deep sandy soils, moderate winter climate, availability of irrigation water, and proximity to eastern markets are favorable for carrot production in the region. Nitrogen (N) is required for successful carrot production, and the current recommended N application rate in Florida is 196 kg·ha−1. The objective of this study was to verify the recommended N rate for the sandy soils of North Florida using current industry standard cultivars and practices. Carrot cultivars for the whole carrot fresh market, Choctaw and Maverick, and cultivars for the cut-and-peel market, Triton and Uppercut 25, were direct seeded on 102-cm-wide pressed bed tops on 29 Oct. 2016 and 2 Nov. 2017 in Live Oak, FL. Eight N application rates (56, 112, 168, 224, 280, 336, 392, and 448 kg·ha−1) were tested, and all N applications were placed on the bed top. N rates were split and timed to increase N use efficiency. Regression analyses were used to determine the optimal N rate for carrots in North Florida. A quadratic plateau regression for both seasons combined indicated 206 kg·ha−1 N was the optimal rate for carrots, with marketable yield of 71.3 Mg·ha−1, regardless of cultivar. All four cultivars attained acceptable yield including Uppercut 25, which exhibited significant foliage damage following freezing temperatures. This study resulted in updated information on best management practices for carrot production in Florida, especially nutrient stewardship.

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Historical nitrogen fertilizer use in agricultural ecosystems of the contiguous United States during 1850–2015: application rate, timing, and fertilizer types

Earth System Science Data ◽

10.5194/essd-10-969-2018 ◽

2018 ◽

Vol 10 (2) ◽

pp. 969-984 ◽

Cited By ~ 47

Author(s):

Peiyu Cao ◽

Chaoqun Lu ◽

Zhen Yu

Keyword(s):

Environmental Problems ◽

N Fertilizer ◽

N Loss ◽

Fertilizer Use ◽

N Fertilizers ◽

Nitrate N ◽

The Us ◽

N Management ◽

N Fertilizer Use ◽

N Use

Abstract. A tremendous amount of anthropogenic nitrogen (N) fertilizer has been applied to agricultural lands to promote crop production in the US since the 1850s. However, inappropriate N management practices have caused numerous ecological and environmental problems which are difficult to quantify due to the paucity of spatially explicit time-series fertilizer use maps. Understanding and assessing N fertilizer management history could provide important implications for enhancing N use efficiency and reducing N loss. In this study, we therefore developed long-term gridded maps to depict crop-specific N fertilizer use rates, application timing, and the fractions of ammonium N (NH4+-N) and nitrate N (NO3−-N) used across the contiguous US at a resolution of 5 km  ×  5 km during the period from 1850 to 2015. We found that N use rates in the US increased from 0.22 g N m−2 yr−1 in 1940 to 9.04 g N m−2 yr−1 in 2015. Geospatial analysis revealed that hotspots for N fertilizer use have shifted from the southeastern and eastern US to the Midwest, the Great Plains, and the Northwest over the past century. Specifically, corn in the Corn Belt region received the most intensive N input in spring, followed by the application of a large amount of N in fall, implying a high N loss risk in this region. Moreover, spatial-temporal fraction of NH4+-N and NO3−-N varied largely among regions. Generally, farmers have increasingly favored ammonia N fertilizers over nitrate N fertilizers since the 1940s. The N fertilizer use data developed in this study could serve as an essential input for modeling communities to fully assess N addition impacts, and improve N management to alleviate environmental problems. Datasets used in this study are available at https://doi.org/10.1594/PANGAEA.883585.

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Long-Term Response of Groundwater Nitrate Concentrations to Management Regulations in Nebraska's Central Platte Valley

The Scientific World JOURNAL ◽

10.1100/tsw.2010.25 ◽

2010 ◽

Vol 10 ◽

pp. 286-297 ◽

Cited By ~ 25

Author(s):

Mary E. Exner ◽

Hugo Perea-Estrada ◽

Roy F. Spalding

Keyword(s):

Crop Production ◽

Management Practices ◽

Sprinkler Irrigation ◽

Fertilizer Application ◽

Application Rates ◽

Nitrate Concentrations ◽

Management Area ◽

Platte River Valley ◽

N Management ◽

The Impact

The impact of 16 years (1988–2003) of management practices on high groundwater nitrate concentrations in Nebraska's central Platte River valley was assessed in a 58,812-ha (145,215-ac) groundwater quality management area intensively cropped to irrigated corn (Zea maysL.). Crop production and groundwater nitrate data were obtained from ~23,800 producer reports. The terrace, comprising ~56% of the study area, is much more intensively cropped to irrigated corn than the bottomland. From 1987 to 2003, average groundwater nitrate concentrations in the primary aquifer beneath the bottomland remained static at ~8 mg N/l. During the same period, average groundwater nitrate concentrations in the primary aquifer beneath the terrace decreased from 26.4 to 22.0 mg N/l at a slow, but significant (p< 0.0001), rate of 0.26 mg N/l/year. Approximately 20% of the decrease in nitrate concentrations can be attributed to increases in the amount of N removed from fields as a consequence of small annual increases in yield. During the study, producers converted ~15% of the ~28,300 furrow-irrigated terrace hectares (~69,800 ac) to sprinkler irrigation. The conversion is associated with about an additional 50% of the decline in the nitrate concentration, and demonstrates the importance of both improved water and N management. Average N fertilizer application rates on the terrace were essentially unchanged during the study. The data indicate that groundwater nitrate concentrations have responded to improved management practices instituted by the Central Platte Natural Resources District.

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Assessment of Reactive Nitrogen Flows in Bangladesh’s Agriculture Sector

Sustainability ◽

10.3390/su14010272 ◽

2021 ◽

Vol 14 (1) ◽

pp. 272

Author(s):

Md. Mizanur Rahman ◽

Jatish Chandra Biswas ◽

Mark A. Sutton ◽

Julia Drewer ◽

Tapan Kumar Adhya

Keyword(s):

Food Production ◽

Holistic Approach ◽

N Fertilizer ◽

N Application ◽

Agriculture Sector ◽

Application Rates ◽

The Status ◽

Reactive N ◽

N Management ◽

Nitrogen Flows

To assess the status of and trends in agricultural nitrogen (N) flows and their wider consequences for Bangladesh, in this study, we analyzed data from national and international bodies. The increased rates of N fertilizer applied for increased food production leaves behind a huge amount of unutilized reactive N (Nr). N fertilizer use is the largest in the crop sector, an important sector, where current annual consumption is 1190 Gg. The present combined annual Nr production from crop, fishery, and livestock sectors is ~600 Gg, while emissions of nitrous oxide (N2O), a potent greenhouse gas, are ~200 Gg. Poor N management results in Nr leaking into the environment, which has increased approximately 16-fold since 1961. One potential consequence is the disruption of ecosystem functioning. The balanced tradeoff between food production and reducing Nr input needs to be achieved. One solution to reducing Nr may be a holistic approach that optimizes N application rates and incorporates waste of one subsector as an input to another applying the principle of the circular economy.

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Management of nitrogen and nitrification inhibitors for corn and wheat production on claypan soils

10.32469/10355/62047 ◽

2017 ◽

Author(s):

◽

Habibullah

Keyword(s):

Growth Stage ◽

Production Systems ◽

Block Design ◽

Growing Season ◽

N Fertilizer ◽

Nitrification Inhibitors ◽

N Losses ◽

Fertilizer Use ◽

Application Rates ◽

N Fertilizer Use

Use of nitrification inhibitors (NI) in agricultural production systems is considered a risk management strategy for both agricultural and environmental considerations. It can be utilized when risk of reduced nitrogen (N) fertilizer use efficiency or yield, and risk of pollution from mineral N is high. Field research was conducted on corn (Zea mays L.) from 2012 to 2015 in Northeast Missouri. Treatments consisted of two application timings of urea ammonium nitrate (UAN) fertilizer solution [pre-emergence (PRE) and V3 growth stage], two application rates (143 and 168 kg N ha-1 ), with and without a NI (nitrapyrin), and a non-treated control which were arranged in randomized complete block design. UAN applied at a rate of 143 kg ha-1 with nitrapyrin at the V3 growth resulted in the highest yield (8.6 Mg ha-1 ). Similarly, pre-emergence application of UAN 168 kg ha-1 with nitrapyrin resulted in greater yields (7.7 Mg ha-1 ). UAN application rates and timings affected soil NO3-N and NH4-N concentration more than nitrapyrin presence or absence during the growing season. A side-dress application of a lower rate of UAN with nitrapyrin at V3 corn growth stage may be useful when risk of N losses during the growing season due to unfavorable precipitation events and other environmental variables is high. A pre-emergence application of UAN with nitrapyrin was useful and it may eliminate the need for split-application of N fertilizer later in the season. Workload on growers soon before planting or during growing season, excessive wet field conditions in early spring, reduced N fertilizer use efficiencies due to uncertain climatic conditions during growing season, and environmental concerns of pollution from - 30 - N escaping from agriculture production systems may give an incentive to growers and policy makers to increase the use of nitrapyrin in the future.

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Historical Nitrogen Fertilizer Use in Agricultural Ecosystem of the Continental United States during 1850–2015: Application rate, Timing, and Fertilizer Types

10.5194/essd-2017-132 ◽

2017 ◽

Cited By ~ 1

Author(s):

Peiyu Cao ◽

Chaoqun Lu ◽

Zhen Yu

Keyword(s):

United States ◽

The United States ◽

Environmental Problems ◽

N Fertilizer ◽

Past Century ◽

N Loss ◽

Fertilizer Use ◽

N Management ◽

N Fertilizer Use ◽

N Use

Abstract. Tremendous amount of anthropogenic nitrogen (N) fertilizer has been applied to agricultural lands to promote the crop production in the United States since the 1850s. However, inappropriate N management practices caused numerous ecological and environmental problems which are difficult to quantify due to paucity of historically spatially explicit fertilizer use maps. Understanding and assessing N fertilizer management history could provide essential implications for enhancing N use efficiency (NUE) and reducing N loss. In this study, we therefore developed long-term gridded maps depicting crop-specific N fertilizer use rate, timing, and fraction of ammonium N (NH4+-N) and nitrate N (NO3−-N) across the contiguous U.S at a resolution of 5 km × 5 km during 1850–2015. We found that N use rates of the U.S. increased from 0.28 g N m−2 yr−1 in 1940 to 9.54 g N m−2 yr−1 in 2015. Geospatial analysis revealed that the hotspots of N fertilizer use have shifted from the southeastern and eastern U.S. to the Midwest and the Great Plains during the past century. Specifically, corn of the Corn Belt region received the most intensive N input in spring, followed by large N application amount in fall, implying a high N loss risk in this region. Moreover, spatial-temporal fraction of NH4+-N and NO3−-N varied largely among regions. Generally, farmers have increasingly favored NH4+-N form fertilizers over NO3−-N fertilizers since the 1940s. The N fertilizer use data developed in this study could serve as an essential input for modeling communities to fully assess the N addition impacts, and improve N management to alleviate environmental problems. Datasets available at https://doi.pangaea.de/10.1594/PANGAEA.883585.

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

Water ◽

10.3390/w13192715 ◽

2021 ◽

Vol 13 (19) ◽

pp. 2715

Author(s):

Eun-Hee Koh ◽

Beom-Seok Hyun ◽

Eunhee Lee ◽

Min-Chul Kim ◽

Bong-Rae Kang ◽

...

Keyword(s):

Fertilizer Application ◽

Application Rate ◽

N Fertilizer ◽

Fertilizer N ◽

Fertilizer Use ◽

Field Level ◽

Fertilizer Application Rate ◽

Crop Field ◽

Management Plans ◽

N Management

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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