Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Doctorat → Pays-Bas → The phosphorus and nitrogen nutrition of bambara groundnut (Vigna subterranea (L.) Verdc.) in Botswana soils : an exploratory study

Wageningen Universiteit Pays Bas (1999)

The phosphorus and nitrogen nutrition of bambara groundnut (Vigna subterranea (L.) Verdc.) in Botswana soils : an exploratory study

Ramolemana, G.M. 

Titre : The phosphorus and nitrogen nutrition of bambara groundnut (Vigna subterranea (L.) Verdc.) in Botswana soils : an exploratory study

Auteur : Ramolemana, G.M. 

Université de soutenance : Wageningen Universiteit

Grade : PhD thesis 1999

Résumé partiel
Bambara groundnut ( Vigna subterranea (L.) Verdec.) is a legume crop grown especially by small farmers mainly in semi-arid parts of Africa both in mixed cultivation and pure stands. It is considered as a hardy crop because of its drought tolerance, resistance to pests and diseases and ability to yield on chemically poor soils. The crop produces edible seeds which can be eaten unripe or stored as dried pulse for later consumption. In Botswana it is grown under semi-arid conditions by small farmers as a minor crop. Attempts have been made to increase the bambara groundnut yield through application of nutrients and improvement of the nitrogen-fixing capacity. This research has not been undertaken systematically and especially the responses to P and N fertilizers did not show a clear pattern. Given the low available P levels and the limited N supply in Botswana soils, a research programme was undertaken to investigate the P and N nutrition of bambara groundnut. The main objectives of the study were :(i) to investigate the effects of applied P and N on growth and development of bambara groundnut in Botswana soils, and (ii) to investigate the P and N uptake, shoot concentrations at different growth and development stages of bambara groundnut and (iii) how uptake, internal concentration and growth are related. The experimental programme consisted of five pot experiments and a large field experiment with P and irrigation as treatments in which bambara groundnut was grown on a representative low P soil. In addition a sand culture experiment was conducted to establish the critical P concentration in bambara groundnut shoots. The critical P levels were subsequently used to determine the P status of bambara groundnut plants in farmers’ fields. In Chapter 2 the question was whether bambara groundnut will respond to P fertilization in a P-poor soil in the absence and presence of added Rhizobium inoculum, whether bambara groundnut selections are different with respect to P nutrition, and whether soil moisture level under field conditions limits P uptake. In a preliminary pot experiment, which was terminated at flowering (51 days after sowing ; DAS), the response of bambara groundnut shoot dry matter (DM) to P fertilization (fertilizer ground and thoroughly mixed with the soil) was positive and linear. There was no effect of P fertilization on nodulation both in the absence and presence of added inoculum. Leaf blade P and N concentrations were not affected by P fertilization. The two selections showed basically the same response to P fertilization. The indigenous rhizobia seemed to be sufficiently effective in nodulating bambara groundnut. In the field, P fertilization (fertilizer broadcast after ploughing and worked into the soil with a digging fork) had no effect on bambara groundnut plants, while irrigation increased all plant growth parameters except root DM. Total seed yield was 2.8 t and 4.2 t ha -1for rainfed and irrigated treatments, respectively. Leaf blade P and N concentrations were not affected neither by P fertilization nor by soil moisture content.

Mots clés : vigna subterranea / phosphorus / nitrogen / plant nutrition / fertilization / botswana

Présentation : Wageningen Dissertation

Wageningen Dissertation Abstracts

Page publiée le 10 juin 2008, mise à jour le 16 avril 2020