Changing patterns of urban-rural nutrient flows in China: driving forces and options

Yu, Chunyan; Xiao, Yuchen; Ni, Shaoqiang

doi:10.1016/j.scib.2016.12.006

Cited by 15 publications

(10 citation statements)

References 9 publications

(14 reference statements)

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“…Significant amounts of nutrients are embedded in agricultural products that are transported from rural and peri-urban areas to urban areas (Lin et al 2014;Zhu et al 2017). This transfer contributes to nutrient accumulation in urban areas (Yu et al 2017;Zhu et al 2017) and to nutrient depletion in rural areas, especially when animal manure and human wastes from urban and peri-urban areas are not recycled back to rural areas (Goulding et al 2008;Jones et al 2013). The accumulation of manure and human waste in urban and peri-urban areas contributes to a range of unwanted human health and environmental effects (Herrero et al 2018).…”

Section: Introductionmentioning

confidence: 99%

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Manure recycling from urban livestock farms for closing the urban–rural nutrient loops

Tadesse

Oenema

Beek

et al. 2020

Nutr Cycl Agroecosyst

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Rapid urbanization in developing countries is attracting urban livestock farming, which is associated with feed nutrient imports and manure nutrient accumulations. Here, we report on manure nutrients (N, P and K) production on urban livestock farms in Addis Ababa and Jimma in Ethiopia, and estimate manure recovery on these farms and its recycling in urban, peri-urban and rural crop farms. Estimates were based on data from farm surveys, statistics, literature and model calculations. Urban livestock farms had on average 13 tropical livestock units and positive N, P and K balances. Urban crop farms had negative N and K balances, and did not use manure from urban livestock farms. We estimated that 0.5–2.6 Gg N, 0.2–0.8 Gg P and 0.9–3.7 Gg K can be collected in manure from the 5,200 urban livestock farms in Addis Ababa year−1, and can be recycled in crop land. Two manure allocation strategies were explored: balanced P fertilization and balanced N fertilization. The former allowed greater precision in matching nutrient supply to demand, and was associated with greater manure transport and distribution, up to rural areas. Manure recycling has several benefits: synthetic fertilizer savings (75–300 million Ethiopian Birr year−1 for Addis Ababa), soil fertility replenishment, and reductions in water pollution. However, there are various cultural, educational and institutional barriers for manure recycling. We argue that more quantitative data and scenario analyses are needed for deliberative decision making and for exploring more sustainable development pathways of urban livestock farms, re-connected to crop farms via manure recycling.

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Section: Introductionmentioning

confidence: 99%

“…Moreover, governmental policies and regulations for manure collection and recycling are lacking (Komakech 2014;Tadesse et al 2018) or incipient (Herrero et al 2018) in developing countries. This leads to accumulation of nutrients in urban and peri-urban areas, and to pollution and eutrophication of rivers and lakes (Yu et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Manure recycling from urban livestock farms for closing the urban–rural nutrient loops

Tadesse

Oenema

Beek

et al. 2020

Nutr Cycl Agroecosyst

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“…Use of inorganic N fertilizers requires much less labour than careful manure management. Yu et al (2017) reported that farmers became more willing to use inorganic fertilizers than the labour-intensive crop residues and manures, the latter often requires composting before application. Clearly, the cost of labour for manure management is one of the barriers for N recycling.…”

Section: Effects Of N Allocationmentioning

confidence: 99%

Nitrogen allocation and recycling in peri-urban mixed crop–livestock farms in Ethiopia

Tadesse

Oenema

Beek³

et al. 2018

Nutr Cycl Agroecosyst

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Mixed crop-livestock (MC-LS) farms are assumed to be more environmental friendly than specialized livestock systems, due to their better options for internal nutrient recycling. However, there are large differences among MC-LS farms in nutrient allocation and recycling. Here, we posit that the relative allocation of nitrogen to crop and livestock compartments, expressed as crop-livestock ratio (CLS), determines the performance of MC-LS farms. Among 300 urban and peri-urban farms studied in 2014, 42 MC-LS farms (Addis Ababa: 20; Jimma: 22) were re-interviewed in 2016, using MonQIt (monitoring tool) questionnaire. The performances of these farms were evaluated using partial nitrogen balance (PNB), N use efficiency (NUE), N recycling index and net farm income (NFI). CLS was negatively related to N input, PNB and NFI. Livestock oriented MC-LS farms had 4-5 times higher N input and 7 times higher PNB than crop oriented MC-LS farms, because they had 2-4 times higher NFI and purchased more external N input. This indicated that N allocation has significant environmental and economic implications. Sensitivity analyses suggested that NUE at farm system level can be improved by 20-25% and N recycling (NR) by 10-20% over the current condition. In conclusion, MC-LS farms are diverse, and much of the diversity can be captured by the CLS indicator. NUE and NR of peri-urban MC-LS farms in Ethiopia can be significantly improved through NUE enhancing measures: targeted exchange of crop residues and manure between crop and livestock activities within and between farms and improving animal NUE through breeding and precision feeding. Keywords Crop-livestock ratio (CLS) Á Smallholder Á NUE Á Food security Á Circular economy

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“…The study of the urban planning practices in ancient China can provide insights on how to plan with nature and enhance the cultural perspective of urban planning work. In another paper, Yu et al showed that nutrient recycling practiced in Chinese cities for thousands of years helped to maintain food production in China without environmental pollution [8]. The cessation of this practice in the past three decades has contributed to concentration of nutrients in urban environments and increased use of synthetic fertilizers in agricultural production.…”

Section: Implementation Of China's New Urbanization Strategy Requiresmentioning

confidence: 99%

Implementation of China’s new urbanization strategy requires new thinking

Yang

Gong

2017

Science Bulletin

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Changing patterns of urban-rural nutrient flows in China: driving forces and options

Cited by 15 publications

References 9 publications

Manure recycling from urban livestock farms for closing the urban–rural nutrient loops

Manure recycling from urban livestock farms for closing the urban–rural nutrient loops

Nitrogen allocation and recycling in peri-urban mixed crop–livestock farms in Ethiopia

Implementation of China’s new urbanization strategy requires new thinking

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