A steady-state N balance approach for sustainable smallholder farming

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.

scholarly journals Identifying Sustainable Nitrogen Management Practices for Tea Plantations

Nitrogen ◽  
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.

scholarly journals Farm nitrogen balances in six European agricultural landscapes – a method for farming system assessment, emission hotspot identification, and mitigation measure evaluation

2012 ◽  
Vol 9 (7) ◽  
pp. 8859-8904 ◽  
Author(s):  
T. Dalgaard ◽  
J. F. Bienkowski ◽  
A. Bleeker ◽  
J. L. Drouet ◽  
P. Durand ◽  
...  
Keyword(s):  
Large Scale ◽  
Farming System ◽  
Agricultural Landscapes ◽  
N Losses ◽  
Livestock Farms ◽  
N Management ◽  
Short Time ◽  
Measure Evaluation ◽  
On Farm

Abstract. Six agricultural landscapes in Poland (PL), the Netherlands (NL), France (FR), Italy (IT), Scotland (UK) and Denmark (DK) were studied, and a common method was developed for undertaking farm inventories and the derivation of farm nitrogen (N) balances and N surplus from the in total 222 farms and 11 440 ha of farmland. In all landscapes, a large variation in the farm N surplus was found, and thereby a large potential for reductions. The highest average N surpluses were found in the most livestock-intensive landscapes of IT, FR, and NL; on average 202 ± 28, 179 ± 63 and 178 ± 20 kg N ha−1yr−1, respectively. However, all landscapes showed hotspots, especially from livestock farms, including a special UK case with landless large-scale poultry farming. So, whereas the average N surplus from the land-based UK farms dominated by extensive sheep grazing was only 31 ± 10 kg N ha−1yr−1, the landscape average was similar to those of PL and DK (122 ± 20 and 146 ± 55 kg N ha−1yr−1, respectively) when landless poultry were included. However, the challenge remains how to account for indirect N surpluses and emissions from such farms with a large export of manure out of the landscape. We conclude that farm N balances are a useful indicator for N losses and the potential for improving N management. Significant correlations to N surplus were found, both with ammonia air concentrations and nitrate levels in soils and groundwater, measured during the landscape data collection campaign from 2007–2009. This indicates that farm N surpluses may be used as an independent dataset for validation of measured and modelled N emissions in agricultural landscapes. However, no significant correlation was found to N measured in surface waters, probably because of the short time horizon of the study. A case study of the development in N surplus from the landscape in DK from 1998–2008 showed a 22 % reduction, related to statistically significant effects (p < 0.01) of measures targeted at reducing N emissions from livestock farms. Based on the large differences between the average and the most modern and N-efficient farms, it was concluded that N-surplus reductions of 25–50 % as compared to the present level were realistic in all landscapes. The implemented N-surplus method was thus effective at comparing and synthesizing results on farm N emissions and the potentials of mitigation options, and is recommended for use in combination with other methods for the assessment of landscape N emissions and farm N efficiency, including more detailed N sink and N source hotspot mapping, measurements and modelling.

scholarly journals Multicompartment Ecosystem Mass Balances as a Tool for Understanding and Managing the Biogeochemical Cycles of Human Ecosystems

2001 ◽  
Vol 1 ◽  
pp. 802-808 ◽  
Author(s):  
Lawrence A. Baker ◽  
Diane Hope ◽  
Ying Xu ◽  
Jennifer Edmonds
Keyword(s):  
Management Practices ◽  
Management Strategies ◽  
The United States ◽  
N Balance ◽  
N Leaching ◽  
Treatment Technology ◽  
Ecosystem Level ◽  
Human Ecosystems ◽  
N Management ◽  
Central Arizona

Nitrogen remains a ubiquitous pollutant in surface and groundwater throughout the United States, despite 30 years of pollution control efforts. A detailed multicompartment N balance for the Central Arizona-Phoenix ecosystem is used to illustrate how an ecosystem-level approach can be used to develop improved N management strategies. The N balance is used to demonstrate how nitrate in pumped groundwater used for crop irrigation could be used to reduce inputs of commercial fertilizer and decrease N leaching to aquifers. Effectively managing N pollution also will require an understanding of the complex factors that control the N balance, including targeted regulations, individual human behavior, land-use conversion, and other ecosystem management practices that affect the N balance. These sometimes countervailing factors are illustrated with several scenarios of wastewater treatment technology and population growth in the Phoenix area. Management of N eventually must be coupled to management of other elements, notably carbon, phosphorus, and salts. We postulate that an ecosystem framework for pollution management will result in strategies that are more effective, fairer, and less expensive than current approaches.

On-farm udder health monitoring

2011 ◽  
Vol 39 (02) ◽  
pp. 95-100
Author(s):  
J. C. van Veersen ◽  
O. Sampimon ◽  
R. G. Olde Riekerink ◽  
T. J. G. Lam
Keyword(s):  
Management Practices ◽  
Health Management ◽  
Action Plan ◽  
Real Life ◽  
Health Data ◽  
Control Points ◽  
Udder Health ◽  
Critical Control Points ◽  
On Farm ◽  
Clinical Problems

SummaryIn this article an on-farm monitoring approach on udder health is presented. Monitoring of udder health consists of regular collection and analysis of data and of the regular evaluation of management practices. The ultimate goal is to manage critical control points in udder health management, such as hygiene, body condition, teat ends and treatments, in such a way that results (udder health parameters) are always optimal. Mastitis, however, is a multifactorial disease, and in real life it is not possible to fully prevent all mastitis problems. Therefore udder health data are also monitored with the goal to pick up deviations before they lead to (clinical) problems. By quantifying udder health data and management, a farm is approached as a business, with much attention for efficiency, thought over processes, clear agreements and goals, and including evaluation of processes and results. The whole approach starts with setting SMART (Specific, Measurable, Acceptable, Realistic, Time-bound) goals, followed by an action plan to realize these goals.

Concepts and Practices for Improving Nitrogen Management for Vegetables

1992 ◽  
Vol 2 (1) ◽  
pp. 121-125 ◽  
Author(s):  
George J. Hochmuth
Keyword(s):  
Water Management ◽  
Management Practices ◽  
Management Strategies ◽  
N Fertilization ◽  
Nitrogen Management ◽  
Land Grant ◽  
Land Grant Universities ◽  
Production Practices ◽  
Negative Impacts ◽  
N Management

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.

scholarly journals Precision Agriculture for Resource Use Efficiency in Smallholder Farming Systems in Sub-Saharan Africa: A Systematic Review

2021 ◽  
Vol 13 (3) ◽  
pp. 1158
Author(s):  
Cecilia M. Onyango ◽  
Justine M. Nyaga ◽  
Johanna Wetterlind ◽  
Mats Söderström ◽  
Kristin Piikki
Keyword(s):  
Resource Use ◽  
Precision Agriculture ◽  
Large Scale ◽  
English Language ◽  
Management Practices ◽  
Smallholder Farmers ◽  
Management Strategies ◽  
Sub Saharan Africa ◽  
Smallholder Farming ◽  
Sub Saharan

Opportunities exist for adoption of precision agriculture technologies in all parts of the world. The form of precision agriculture may vary from region to region depending on technologies available, knowledge levels and mindsets. The current review examined research articles in the English language on precision agriculture practices for increased productivity among smallholder farmers in Sub-Saharan Africa. A total of 7715 articles were retrieved and after screening 128 were reviewed. The results indicate that a number of precision agriculture technologies have been tested under SSA conditions and show promising results. The most promising precision agriculture technologies identified were the use of soil and plant sensors for nutrient and water management, as well as use of satellite imagery, GIS and crop-soil simulation models for site-specific management. These technologies have been shown to be crucial in attainment of appropriate management strategies in terms of efficiency and effectiveness of resource use in SSA. These technologies are important in supporting sustainable agricultural development. Most of these technologies are, however, at the experimental stage, with only South Africa having applied them mainly in large-scale commercial farms. It is concluded that increased precision in input and management practices among SSA smallholder farmers can significantly improve productivity even without extra use of inputs.

scholarly journals Estimating Soil Water Susceptibility to Salinization in the Mekong River Delta Using a Modified DRASTIC Model

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1636
Author(s):  
Thanh N. Le ◽  
Duy X. Tran ◽  
Thuong V. Tran ◽  
Sangay Gyeltshen ◽  
Tan V. Lam ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Water ◽  
Management Practices ◽  
Global Climate ◽  
Anthropogenic Activities ◽  
Rapid Development ◽  
Anthropogenic Factors ◽  
Drastic Model ◽  
River Catchment ◽  
Modified Drastic

Saltwater intrusion risk assessment is a foundational step for preventing and controlling salinization in coastal regions. The Vietnamese Mekong Delta (VMD) is highly affected by drought and salinization threats, especially severe under the impacts of global climate change and the rapid development of an upstream hydropower dam system. This study aimed to apply a modified DRASTIC model, which combines the generic DRASTIC model with hydrological and anthropogenic factors (i.e., river catchment and land use), to examine seawater intrusion vulnerability in the soil-water-bearing layer in the Ben Tre province, located in the VMD. One hundred and fifty hand-auger samples for total dissolved solids (TDS) measurements, one of the reflected salinity parameters, were used to validate the results obtained with both the DRASTIC and modified DRASTIC models. The spatial analysis tools in the ArcGIS software (i.e., Kriging and data classification tools) were used to interpolate, classify, and map the input factors and salinization susceptibility in the study area. The results show that the vulnerability index values obtained from the DRASTIC and modified DRASTIC models were 36–128 and 55–163, respectively. The vulnerable indices increased from inland districts to coastal areas. The Ba Tri and Binh Dai districts were recorded as having very high vulnerability to salinization, while the Chau Thanh and Cho Lach districts were at a low vulnerability level. From the comparative analysis of the two models, it is obvious that the modified DRASTIC model with the inclusion of a river or canal network and agricultural practices factors enables better performance than the generic DRASTIC model. This enhancement is explained by the significant impact of anthropogenic activities on the salinization of soil water content. This study’s results can be used as scientific implications for planners and decision-makers in river catchment and land-use management practices.

Aeroacoustic Analysis of a UAV Propeller Operable at Various Altitudes

2021 ◽  
Author(s):  
Ji-Hun Song ◽  
Seungsoo Jang ◽  
Youn-Jea Kim
Keyword(s):  
Steady State ◽  
Turbulence Model ◽  
Technological Development ◽  
Basic Research ◽  
Noise Pollution ◽  
Maximum Error ◽  
Unmanned Aircraft ◽  
Time Step ◽  
Application Range ◽  
Noise Characteristics

Abstract With technological development and the wide application range of unmanned aerial vehicles (UAVs), the regulation of UAV altitude limits in many countries is further alleviated, and the problem of UAV noise pollution has emerged with the recent advent of urban air mobility (UAM) and personal air vehicle (PAV) markets. In this study, one typical propeller, the T-motor 15 × 5 propeller, was analyzed by use of the commercial CFD software, ANSYS FLUENT V19.3. The effects of gravity and convection were analyzed to determine the noise characteristics at altitude using the FW-H equation. A high-altitude drone, which operates at heights from 0 to 10 km with 1,000 to 5,000 revolutions per minute, was analyzed using the steady-state k-ω SST turbulence model. And using the steady-state data to initialize values, an unsteady analysis was performed with the LES turbulence model. The time step was divided based on the 1-degree rotational time, and the velocity residual on each axis was calculated until a value of 10−7 or less was achieved and there was no fluctuation of thrust, at which point it was considered converged. The CFD results were validated with the experimental results for thrust and their results show that the maximum error was 8.64%. The overall sound pressure level was calculated, and noise characteristics in the audible frequency range according to receiver points were also compared. Through this study, thrust and noise data according to altitude were provided. The aerodynamic and aeroacoustic characteristics at high-altitudes, which are generally difficult to measure by experiment, are also presented. Therefore, the appropriate operating altitudes and rotational speeds will be presented through the aeroacoustics analysis corresponding to operational altitude, and the basic research data can then be applied to upcoming unmanned aircraft system (UAS) market.

Linking on-farm dairy management practices to storm-flow fecal coliform loading for California coastal watersheds

2005 ◽  
Vol 107 (1-3) ◽  
pp. 407-425 ◽  
Author(s):  
D. J. Lewis ◽  
E. R. Atwill ◽  
M. S. Lennox ◽  
L. Hou ◽  
B. Karle ◽  
...  
Keyword(s):  
Fecal Coliform ◽  
Management Practices ◽  
Dairy Management ◽  
Coastal Watersheds ◽  
Storm Flow ◽  
On Farm

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

Nitrogen ◽  
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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