Bayesian calibration and uncertainty analysis of an agroecosystem model under different N management practices

Efficient N management practices usually involve many potential strategies, but always involve choosing the correct amount of N and the coupling of N management to efficient water management. Nitrogen management strategies are integral parts of improved production practices recommended by land-grant universities such as the Institute of Food and Agricultural Sciences, Univ. of Florida. This paper, which draws heavily on research and experience in Florida, outlines the concepts and technologies for managing vegetable N fertilization to minimize negative impacts on the environment.

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A steady-state N balance approach for sustainable smallholder farming

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2106576118 ◽

2021 ◽

Vol 118 (39) ◽

pp. e2106576118

Author(s):

Yulong Yin ◽

Rongfang Zhao ◽

Yi Yang ◽

Qingfeng Meng ◽

Hao Ying ◽

...

Keyword(s):

Steady State ◽

Management Practices ◽

Global Climate ◽

N Balance ◽

Smallholder Farming ◽

N Losses ◽

Application Range ◽

High Yields ◽

N Management ◽

On Farm

Hundreds of millions of smallholders in emerging countries substantially overuse nitrogen (N) fertilizers, driving local environmental pollution and global climate change. Despite local demonstration-scale successes, widespread mobilization of smallholders to adopt precise N management practices remains a challenge, largely due to associated high costs and complicated sampling and calculations. Here, we propose a long-term steady-state N balance (SSNB) approach without these complications that is suitable for sustainable smallholder farming. The hypothesis underpinning the concept of SSNB is that an intensively cultivated soil–crop system with excessive N inputs and high N losses can be transformed into a steady-state system with minimal losses while maintaining high yields. Based on SSNB, we estimate the optimized N application range across 3,824 crop counties for the three staple crops in China. We evaluated SSNB first in ca. 18,000 researcher-managed on-farm trials followed by testing in on-farm trials with 13,760 smallholders who applied SSNB-optimized N rates under the guidance of local extension staff. Results showed that SSNB could significantly reduce N fertilizer use by 21 to 28% while maintaining or increasing yields by 6 to 7%, compared to current smallholder practices. The SSNB approach could become an effective tool contributing to the global N sustainability of smallholder agriculture.

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Conceptual Framework of Connectivity for a National Agroecosystem Model Based on Transport Processes and Management Practices

JAWRA Journal of the American Water Resources Association ◽

10.1111/1752-1688.12890 ◽

2020 ◽

Author(s):

Jeffrey G. Arnold ◽

Michael J. White ◽

Peter M. Allen ◽

Philip W. Gassman ◽

Katrin Bieger

Keyword(s):

Conceptual Framework ◽

Management Practices ◽

Transport Processes ◽

Model Based ◽

Agroecosystem Model

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Limitations of Improved Nitrogen Management to Reduce Nitrate Leaching and Increase Use Efficiency

The Scientific World JOURNAL ◽

10.1100/tsw.2001.457 ◽

2001 ◽

Vol 1 ◽

pp. 10-16 ◽

Cited By ~ 13

Author(s):

James L. Baker

Keyword(s):

Water Quality ◽

Nitrate Leaching ◽

Management Practices ◽

Nitrate Nitrogen ◽

Nitrogen Management ◽

N Leaching ◽

N Loss ◽

Use Efficiency ◽

Rate Method ◽

N Management

The primary mode of nitrogen (N) loss from tile-drained row-cropped land is generally nitrate-nitrogen (NO3-N) leaching. Although cropping, tillage, and N management practices can be altered to reduce the amount of leaching, there are limits as to how much can be done. Data are given to illustrate the potential reductions for individual practices such as rate, method, and timing of N applications. However, most effects are multiplicative and not additive; thus it is probably not realistic to hope to get overall reductions greater than 25 to 30% with in-field practices alone. If this level of reduction is insufficient to meet water quality goals, additional off-site landscape modifications may be necessary.

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Identifying Sustainable Nitrogen Management Practices for Tea Plantations

Nitrogen ◽

10.3390/nitrogen3010003 ◽

2022 ◽

Vol 3 (1) ◽

pp. 43-57

Author(s):

Rhys Rebello ◽

Paul J. Burgess ◽

Nicholas T. Girkin

Keyword(s):

Management Practices ◽

Synergistic Effects ◽

Soil Health ◽

N Leaching ◽

N2o Emissions ◽

Nitrification Inhibitors ◽

Financial Barriers ◽

Trade Offs ◽

High Yields ◽

N Management

Tea (Camellia sinensis L.) is the most widely consumed beverage in the world. It is mostly grown in the tropics with a heavy dependence on mineral nitrogen (N) fertilisers to maintain high yields while minimising the areas under cultivation. However, N is often applied in excess of crop requirements, resulting in substantial adverse environmental impacts. We conducted a systematic literature review, synthesising the findings from 48 studies to assess the impacts of excessive N application on soil health, and identify sustainable, alternative forms of N management. High N applications lead to soil acidification, N leaching to surface and groundwater, and the emission of greenhouse gases including nitrous oxide (N2O). We identified a range of alternative N management practices, the use of organic fertilisers, a mixture of organic and inorganic fertilisers, controlled release fertilisers, nitrification inhibitors and soil amendments including biochar. While many practices result in reduced N loading or mitigate some adverse impacts, major trade-offs include lower yields, and in some instances increased N2O emissions. Practices are also frequently trialled in isolation, meaning there may be a missed opportunity from assessing synergistic effects. Moreover, adoption rates of alternatives are low due to a lack of knowledge amongst farmers, and/or financial barriers. The use of site-specific management practices which incorporate local factors (for example climate, tea variety, irrigation requirements, site slope, and fertiliser type) are therefore recommended to improve sustainable N management practices in the long term.

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Synthesis of Climate, Soil Factors, and Nitrogen Management Practices Affecting the Responses of Wheat Productivity and Nitrogen Use Efficiency to Nitrogen Fertilizer in China

Sustainability ◽

10.3390/su10103533 ◽

2018 ◽

Vol 10 (10) ◽

pp. 3533 ◽

Cited By ~ 1

Author(s):

Yunqi Wang ◽

Jiapeng Yang ◽

Rui Zhang ◽

Zhikuan Jia

Keyword(s):

Nitrogen Use Efficiency ◽

Management Practices ◽

Wheat Yield ◽

Soil Factors ◽

Nitrogen Use ◽

N Application ◽

Average Annual Temperature ◽

Coated Urea ◽

Use Efficiency ◽

N Management

The reported effects of nitrogen (N) fertilizer on wheat yield and nitrogen use efficiency (NUE) vary greatly, due to differences in climate, soil factors, and N management practices in different regions of China. We collected literature published during 1950–2017 that reported the yield and NUE for wheat in China, under N application and control treatments, and analyzed the data therein. A significant increase in yield was observed with N application, and varied with climate, soil factors, and N management practices in different regions. A larger increase in yield was observed under an average annual temperature of 13–15 °C, an average annual precipitation of >800 mm, respectively. Greater yield-increasing effects were observed in soil with a coarse soil texture, lower soil total N, available N, and a soil pH of ≤7 and >8, respectively. In Northwest China, the yield increase was greater under multiple coated urea applications after anthesis, while the higher NUE was observed under single coated urea application before anthesis. In North China, the yield and NUE were greater under multiple coated urea applications before anthesis. In South China, the yield and NUE were greater under multiple N applications. Consequently, to improve wheat yield and NUE, site-specific N management practices should be adopted.

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Effect of Rhizobium Inoculation and Tillage Practices on Fodder Cowpea (Vigna unguiculata)

Legume Research - An International Journal ◽

10.18805/lr-4373 ◽

2020 ◽

Author(s):

Mallikarjun . ◽

Hardev Ram ◽

Rakesh Kumar ◽

Magan Singh ◽

R. K. Meena ◽

...

Keyword(s):

Management Practices ◽

Conventional Tillage ◽

Available N ◽

Tillage Practices ◽

Split Plot ◽

Green Fodder ◽

Fodder Yield ◽

Growth Attributes ◽

N Management ◽

Plot Design

Background: Agriculture and its allied sectors is an important sector in employment, income and food security. The increasing demands for food grains and cash crops, the area under fodder crops has been static since last 3-4 decades (8.4 mha) resulted into a net deficit in dry and green fodder is around 10 and 35%, respectively making livestock rearing more challenging. Conventional agriculture has largelybeen characterized by conventional tillage which caused soil degradation and negative impacts on soil physical and biological activity. To mitigate these negative effects, resource conservation technologies (RCTs) was tested and adopted to save substantial quantity of irrigation water, reducing the cost of cultivation, timely sowing, improve input use efficiency and left indirect effect on mitigating the adverse effect of climate changes. Biological N2 fixation (BNF) can make plants self-sustaining for N nutrition and avoiding the need for mineral N fertilization. The current study aimed enhancing fodder production by adoption of modern tillage practices and efficient N management. Methods: In this field-laboratory investigation during 2017-18, experiment was laid out in the split plot design consisting of three tillage practices zero tillage (ZT), conventional tillage (CT) and raised bed (RB) and six N management viz., N0, N75, N75+Rhizo, N100, N100+Rhizo and N125%. The soil of the experimental field was clay loam in texture having pH 7.30, EC; 0.35 dS/m, medium in organic carbon (0.63%), low in nitrogen (188.48 kg/ha), medium in phosphorus (23.56 kg/ha) and potassium (271.12 kg/ha). The recommended dose of fertilizer and other cultural practices was applied as per treatments with standard process. The crop was harvested at 60 days after sowing and weighed for green fodder yield. The observations growth, yields and quality parameters was recorded as per the standard method. Statistical analysis was done using analysis of variance in split plot design. Result: ZT practices significantly improved growth attributes, fodder yield and available nitrogen. Higher fodder yield of cowpea was recorded with ZT as compared to CT and it was statistically similar in RB. The nitrogen management practices had significant effect on root length and root nodules, plant growth attributes, fodder yield and available N, P and K. The significant fodder yield was increase with successive increase of N application up to 75% N + rhizobium, over 0 and 75% N alone. The present work shows that adoption of ZT and inoculation of rhizobia had significantly improved soil health and stabilized fodder yield of cowpea besides decrease fertilizer nitrogen requirement in the irrigated agro-ecosystem of T-IGP.

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