Phosphorus limitation in rice systems of southeast Asian acid uplands

George Thomas, Roder Walter, Trébuil Guy, Van Keer Koen. 1996. Phosphorus limitation in rice systems of southeast Asian acid uplands. In : Symposium on plant-soil interactions at low pH = [Congrès sur les interactions plantes-sols à faible pH]. Anon. s.l. : s.n., 1-10. International Symposium on Plant-Soil Interactions at Low pH. 4, Belo Horizonte, Brésil, 17 Mars 1996/24 Mars 1996.

Autre titre : Limitation du phosphore dans les systèmes de riz pluviaux sur sols acides en Asie du sud-est

Résumé : Severe acidity and high P-fixation are characteristics of many rice upland soils in Southeast Asia. Rice yields are reported often to be limited by P deficiency, yet the extent of P limitation in these rice uplands are not known. Experiments were conducted in several farmers' fields in Laos, the Philippines and Thailand with treatments of no fertilizer (fermer practice) and near-non-limiting applications of P or N, P and K. Rice grain yield, total dry matter and P uptake with no applied nutrients averaged 1.1 t ha-1 4.0 t ha-1 and 4.4 kg ha-l, respectively. Near-non-limiting application of P alone increased grain yield, total dry matter and P uptake by 20, 24 and 57%, respectively. The P uptake response by as much as twice or more in magnitude than grain yield or total dry matter responses indicate that the grain and dry matter were at sub-optimal P contents under farmers' traditional production conditions. The responses were more pronounced when N and K were also applied; dry matter increased by an additional 1.4 t ha-1 with P+NK. The total dry matter increase with P+NK was 57%, but only 17% of this increased dry matter was partitioned to grain thus reducing the benefit from P+NK application. The data indicate that low soil P supply is limiting rice production even at the subsistance lever. Further, the low partitioning of dry matter to grain in these traditional upland varieties appears to be a serious limitation to increasing grain yield.

Mots-clés Agrovoc : riz pluvial, sol acide, fertilisation, phosphore, azote, rendement des cultures, teneur en matière sèche

Mots-clés géographiques Agrovoc : République démocratique populaire lao, Thaïlande, Philippines

Classification Agris : F04 - Fertilisation

Auteurs et affiliations

• George Thomas
• Roder Walter
• Trébuil Guy, CIRAD-CA-RIZ (FRA) ORCID: 0000-0002-1370-4731
• Van Keer Koen

Source : Cirad - Agritrop (https://agritrop.cirad.fr/389856/)

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