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Nutrient management in smallholder peri-urban farming systems

a case study in southern Vietnam

Hedlund, Anna (2003). Nutrient management in smallholder peri-urban farming systems. Uppsala : Sveriges lantbruksuniv. ; 33
ISBN 91-576-6601-6
[Licentiate thesis]

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Abstract

Fertiliser use in agriculture increased rapidly during the green revolution and global fertiliser use increased by about 310% from the mid-1960s to the end of the 1980s. Nutrient management in Vietnam was not part of this development until after the start of the reform policy ‘doi moi’, which entailed the introduction of new crops and new fertilisers, increased the consumption of mineral fertilisers, and led to higher yields, but also possibly to higher losses of nutrients to the environment. This development is most pronounced in the peri-urban areas and the densely populated river deltas (the Red River delta and the Mekong River delta). The objective of this thesis was to investigate the existing nutrient management in a peri-urban village northwest of Ho Chi Minh City in southern Vietnam and to elucidate the farmers’ underlying rationale. Nutrient management was assessed by nutrient balances and flows on 9 representative farms containing one or more of the following production units: pigs, crops, and fish. The data were gathered through interviews and chemical analysis of inputs and outputs. Participatory methods were used to gather information on the farmers’ concepts about soil fertility and fertilisers and their access to information. The results from the nutrient balances showed that the farming systems investigated were high nutrient input systems and that there was generally poor nutrient use efficiency both at farm and field level. On the livestock farms nutrient input ranged from 209 to 2113 kg N, 76-771 kg P and 84-1167 kg K ha-1 year -1. On the stockless farms the figures were generally somewhat lower, i.e. 38-928 kg N, 25-656 kg P, and 32-486 kg K ha-1 year -1. Except in one rice field, the nitrogen balances at field level were positive in all cases, with surpluses of between 31 to 1736 kg N ha -1 and year. The P balances were positive in all fields with surpluses of between 20 to 1292 kg P ha-1 and year, while the K balances were somewhat lower with surpluses of 9 to 913 kg K ha-1 and year, and negative in one rice field and one orchard. The positive farm balances on livestock farms could to some degree be explained by the high livestock density and poor use of the excreta from livestock production. The positive balances at field/crop level could be explained by the farmers’ concept of fertilisers which included a wide range of amendments added to promote good conditions for plant growth. The farmers’ concept of fertilisers did not comprise the nutrient flow, which may indicate that the farmers did not know that their nutrient management created nutrient surpluses. Instead they perceived that they fertilised too little, due to low investment capacity resulting from the unstable market. However the economic inputs were only 5-10% of the income from crop harvest, although they were slightly higher for high-income crops (e.g. jasmine and vegetables) and newly established orchards. The positive nutrient balances may pose an environmental hazard and suggested measures to improve nutrient management were to make the nutrient flow transparent to the farmers by providing information on the nutrient content of different fertilisers as well as the nutrient requirement of the crop. For livestock farms it is also important to make better use of liquid excreta and to spread solid manure on larger areas than today.

Authors/Creators:Hedlund, Anna
Title:Nutrient management in smallholder peri-urban farming systems
Subtitle:a case study in southern Vietnam
Year of publishing :December 2003
Volume:33
Number of Pages:35
Papers/manuscripts:
NumberReferences
ALLI. Hedlund, A., Witter, E., and Bui Xuan An. 2003. Assessment of N, P and K management by nutrient balances and flows on peri-urban smallholder farms in Southern Vietnam. European Journal of Agronomy, 20(1-2): 71-87. II. Hedlund, A., Witter, E., Hoang Fagerström, M.H., and Bui Xuan An. Nutrient management and farmers’ concept of soil fertility and fertilisers - a case study in southern Vietnam. Manuscript.
Place of Publication:Uppsala
ISBN for printed version:91-576-6601-6
ISSN:1100-4525
Language:English
Publication Type:Licentiate thesis
Full Text Status:Public
Agris subject categories.:P Natural resources > P35 Soil fertility
Subjects:Not in use, please see Agris categories
Agrovoc terms:farmers, fertilizers, soil fertility, phosphorus, soil sorption, suburban agriculture, nutrients, viet nam
Keywords:farmers’ concept, fertiliser, nutrient management, nutrient budgets, nutrient balances, nutrient use efficiency, phosphorus sorption-desorption isotherms, peri-urban, PRA/RRA methods, soil fertility, Vietnam
URN:NBN:urn:nbn:se:slu:epsilon-263
Permanent URL:
http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-263
ID Code:416
Department:(NL, NJ) > Dept. of Soil Sciences
Deposited By: Anna Hedlund
Deposited On:03 Dec 2003 00:00
Metadata Last Modified:02 Dec 2014 10:04

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