Structure and impact of cattle manure trade in crop–livestock systems of Vietnam

Abstract

Cattle manure value chains play important biological and economic roles in smallholder crop–livestock systems in developing countries, but relative to other livestock products our understanding of the nature and impact of manure sales is limited. In regions with an active manure trade, farmers face a choice between manure use on-farm and sales, which affects nutrient flows and participant incomes. We analyzed the manure value chain operating in south-central Vietnam as an example of the function and role of manure trade in crop–livestock systems. Lowland cattle farmers sell manure through a network of chain participants, including small-scale collectors, lowland and highland traders, to pepper, coffee, dragon fruit and rubber farms in the central highlands and southeast coast. We collected and summarized quantitative data (e.g., manure-related labor, manure transactions, and fertilizer and manure use) gathered in semi-structured interviews with value-chain participants [lowland cattle owners (n = 101), traders (n = 27) and end users (n = 72)]. Lowland cattle owners were selected by stratified random sampling, and subsequent participants were identified in preceding interviews. One key finding concerns the seasonality of the manure value chain: most manure flowed between February and August (lowland dry season and period of peak highland demand) from lowland communes to highland coffee and pepper farms for use as organic soil amendments. Fewer sales occurred, at a lower price, to southeast coastal dragon fruit farms and rubber companies. Value addition to manure occurred via drying, bagging, collection, transport and composting. The presence of local traders facilitated market sales for smallholder cattle owners, and prices through the value chain generally reflected costs for value addition. The geographic distribution of cattle relative to agricultural land influenced the flow of manure, with net outflows from regions with higher animal density to regions with lower density and higher value crop production. Manure trade was an important source of supplementary income for farmers and a primary livelihood activity for traders. Value chain participant net incomes ranged from near US$100 yr−1 for lowland farmers to over US$13,000 yr−1 for traders, and returns to labor were just over US$0.50 h−1 for lowland farmers and US$2 h−1 for traders. The quantitative information generated during our descriptive assessment provides an important first step toward manure value chain improvement, indicates survey methods that can be applied in other areas, and identifies next steps necessary to evaluate chain evolution and resilience.

Urea and composted cattle manure affect forage yield and nutritive value in sandy soils of south‐central Vietnam

“…Assuming no N losses, composted manure could be applied at or near farmer‐desired rates for a backyard 0.1‐ha plot (up to 263 kg N ha −1 year −1 ) but this would not leave any compost for application to other crops. In reality, a composted manure shortfall would arise, because most farmers do apply compost to rice, cassava and peanut production lands and may also sell or trade manure (McRoberts et al., ). Two farmers reported compost purchases from neighbouring farms at 300,000 Vietnam đồng (VND) per ox cart load ($14.29 USD per ~0.5 m 3 or 500 kg dry manure) .…”

Scenarios of Sustainable Fishing in the Zapatosa Marsh (Colombia) Simulated with a System Dynamics Model

“…The modelling process demands the identification and definition of problems, the overall system conceptualization and the qualitative modelling, which often impact our initial system understanding. ST and SD can support designing better policies working on the systems structure both enhancing insights elicitation and increasing the stimulus to performing accurate policy discussion and evaluation [12]. Through the CLD, an explicit understanding of the problem can be generated, identifying the relationships between the components of the structure, especially the biotic and socioeconomic aspects.…”

From Top–Down Regulation to Bottom–Up Solutions: Reconfiguring Governance of Agricultural Nutrient Loading to Waters

“…Historically, all farms operated in this category. Even today, many developing countries suffer from nutrient deficiency [64].…”

“…The facility will cause point-source pollution in the form wastewater, air, and noise emissions [64]. From a legal perspective, the wastewater emissions pose the biggest challenge.…”

“…The facility will produce a maximum of 12,000 m 3 wastewater per year. Even after treatment, the wastewater will contain ammonium nitrogen (maximum 20 mg/L) and nitrogen (maximum 20 mg/L) [64].…”