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CIFOR-ICRAF s’attaque aux défis et aux opportunités locales tout en apportant des solutions aux problèmes mondiaux concernant les forêts, les paysages, les populations et la planète.

Nous fournissons des preuves et des solutions concrètes pour transformer l’utilisation des terres et la production alimentaire : conserver et restaurer les écosystèmes, répondre aux crises mondiales du climat, de la malnutrition, de la biodiversité et de la désertification. En bref, nous améliorons la vie des populations.

CIFOR–ICRAF publishes over 750 publications every year on agroforestry, forests and climate change, landscape restoration, rights, forest policy and much more – in multiple languages.

CIFOR–ICRAF addresses local challenges and opportunities while providing solutions to global problems for forests, landscapes, people and the planet.

We deliver actionable evidence and solutions to transform how land is used and how food is produced: conserving and restoring ecosystems, responding to the global climate, malnutrition, biodiversity and desertification crises. In short, improving people’s lives.

Appropriate farm management practices for alleviating N and P deficiencies in low-nutrient soils of the tropics

Exporter la citation

Tropical upland regions have both the world's highest population growth rates and a preponderance of soils less suitable for agriculture. Nitrogen deficiency is almost universal, while acid infertility and the related problem of P deficiency affect more than 40% of tropical soils. Nutrient depletion, as opposed to inherent infertility, affects large areas due to continuous cropping with few inputs. Nitrogen management requires a continual supply of N that can be achieved through fertilization, green manuring, legume rotations or leguminous tree-shrub fallows. Rotations and fallows usually require foregoing one or more staple crop harvests, which is not feasible for smallholder farmers in land-limited areas. In such areas there are few options for farmers except mineral N fertilizers. Phosphorus availability can be built up in soils, but to achieve this, external inputs of inorganic P are essential. Use of P-efficient crops, or mobilisation of soil organic P by various means, are temporary solutions since they involve only offtake with no addition. Phosphorus additions may be either as soluble processed fertilizers or indigenous phosphate rocks (PRs). Most tropical PR deposits are unreactive and require processing before use. Some lower-cost options include partial acidulation, blending with soluble P sources or microbial solubilization. The relevance of microbial solubilization in particular requires testing at larger scale. There are no magic solutions to soil nutrient deficiencies or toxicities; to maintain productivity mineral fertilizers are necessary. They should be used in judicious amounts and coupled with improved organic matter management.

DOI:
https://doi.org/10.1023/A:1020685728547
Dimensions Nombre de citations:

    Année de publication

    2002

    Auteurs

    Smithson P C; Giller, K.E.

    Langue

    English

    Mots clés

    farm management, smallholders, fallow

    Géographique

    Kenya, Zimbabwe

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