Limiting nutrients for bean production on contrasting soil types of Lake Victoria Crescent of Uganda

Common bean (Phaseolus vulgaris L.) is one of the most important grain legumes in East Africa, but its yield has remained below the genetic potential. Declining soil fertility is among the primary constraints to bean production in most East African bean producing regions. Often existing recommendations are generic and inept to guide farm level decision making on nutrient replenishment. A greenhouse nutrient omission study was conducted to determine the limiting nutrients in three soils of Masaka District, commonly cropped to beans: \u201cLiddugavu\u201d a Phaeozem, \u201cLimyufumyufu\u201d a Cambisol and \u201cLuyinjayinga\u201d an Umbrisol soil. Nine treatments; (i) complete nutrient treatment, (ii) N omitted, (iii) P omitted, (iv) K omitted, (v) Mg omitted, (vi) S omitted, (vii) Ca omitted, (viii) Micronutrients omitted and (ix) control without nutrients. Each treatment was randomly assigned to the three soils and replicated three times using a completely randomised design. Nitrogen, phosphorus and potassium were limiting nutrients for bean production in Umbrisol (Luyinjayinja) while in Cambisol (\u2018Limyufumyufu), common bean production was most limited by soil acidity. The performance varied with soil types, with beans grown on the Phaeozem registering greater leaf number and growth, confirming both scientist\u2019s and local farmer\u2019s knowledge that this soil has greater potential than the other two soils.Le haricot commun (Phaseolus vulgaris L.) est un des l\ue9gumes \ue0 grains les plus importants en Afrique de l\u2019Est, mais son rendement reste toujours en dessous de son potentiel g\ue9n\ue9tique. La baisse de la fertilit\ue9 du sol est parmi les contraintes primaires \ue0 la production du haricot dans la plupart des r\ue9gions productrices de l\u2019Afrique de l\u2019Est. Le plus souvent, les recommandations sont g\ue9n\ue9riques et inad\ue9quates pour guider la prise de d\ue9cision au niveau champ sur le r\ue9approvisionnement en nutriment. Une \ue9tude sous serre sur l\u2019omission de nutriment a \ue9t\ue9 conduite pour d\ue9terminer les nutriments limitants dans les trois sols du district de Masaka, commun\ue9ment utilis\ue9s pour produire du haricot\ua0: \u201cLiddugavu\u201d un sol du Phaeozem, \u201cLimyufumyufu\u201d un sol du Cambisol et \u201cLuyinjayinga\u201d un sol du Umbrisol. Neuf traitements, (i) traitement complet de nutriments, (ii) N omis, (iii) P omis, (iv) K omis, (v) Mg omis, (iv) S omis, (vii) Ca omis, (viii) micronutriments omis et (ix) control sans nutriments. Chacun des traitements a \ue9t\ue9 al\ue9atoirement distribu\ue9 aux trois types de sols et r\ue9pliqu\ue9 trois fois dans un dispositif compl\ue8tement al\ue9atoire. Azote, phosphore, et potassium ont \ue9t\ue9 les nutriments limitants pour la production du haricot dans Umbrisol (Luyinjayinja) tandis que dans Cambisol (\u2018Limyufumyufu), la production du haricoct commun a \ue9t\ue9 limit\ue9e par l\u2019acidit\ue9 du sol. Les performances varient en fonction des types de sols, avec le haricot produit sur le Phaeozem comptant plus de feuilles et de croissance, confirmant \ue0 la fois les connaissances des scientifiques et des populations locales qui stipulent que le sol a un potentiel plus \ue9lev\ue9 que les deux autres sols

Fertiliser use: one of the keys to attaining and sustaining higher crop yields

No Abstrac

Non-point Source Pollution into Lake Victoria from Bukora, Uganda Sub-catchment

Non-point source pollution from agricultural land is a major contributor of N, P and sediments resulting into eutrophication and siltation of water bodies. The extent of this pollution is accelerated by poor land management practices that lead to extensive soil erosion. PoUutant concentrations and loads from two micro-catchments of Bukora sub-catchment. a predominantly agro-pastoral area of Rakai district. were studied over a three-year period. The two microcatchments are drained by two rivers. which eventually discharge into Lake Victoria. Three hydrological stations were constructed onto the two rivers and water sampling and river discharge measurement routine is carried out. During the study period, highest rain fall amounts were recorded in April, while peak river discharge (Oow rate) occurred during July, signifying a 3-months ground recharge period. Concentrations and loads of Total N (TN) and Total P (TP) were related to Total Suspended Solids (TSS) indicating the contribution of N and P-rich sediments toN and P loading. Seasonal trends in TSS, TP and TN concentrations and loads were closely related to river discharge. Mean annual concentrations for TN ranged from 3.2 to 10.4 mg L-1 with loads of 40 to 70 ton yr-1. Annual means for TP ranged from 0.2 to 0.4 rng L-1 wilh loads of 4 to 51 ton y-1, while TSS ranged from 12 to 94 mg L-1 with loads of 2 to 40 ton yr-1. Concentrations and loads ofTSS, TN and TP were reduced across a wetland, especially during periods of low flow. High sediment, N and P pollutant concentrations and loads are likely a result of extensive soil erosion in the area_ Results call for promotion or better land management practices so as to reduce non-point pollution of rivers and consequently. lake Victoria.Keywords: Eutrophication, Water quality. Watershed management. Wetlands

An integrated approach to sustainable utilisation of land resources for a better environment

No Abstract

Limiting nutrients for bean production on contrasting soil types of Lake Victoria Crescent of Uganda

Common bean (Phaseolus vulgaris L.) is one of the most important grain legumes in East Africa, but its yield has remained below the genetic potential. Declining soil fertility is among the primary constraints to bean production in most East African bean producing regions. Often existing recommendations are generic and inept to guide farm level decision making on nutrient replenishment. A greenhouse nutrient omission study was conducted to determine the limiting nutrients in three soils of Masaka District, commonly cropped to beans: “Liddugavu” a Phaeozem, “Limyufumyufu” a Cambisol and “Luyinjayinga” an Umbrisol soil. Nine treatments; (i) complete nutrient treatment, (ii) N omitted, (iii) P omitted, (iv) K omitted, (v) Mg omitted, (vi) S omitted, (vii) Ca omitted, (viii) Micronutrients omitted and (ix) control without nutrients. Each treatment was randomly assigned to the three soils and replicated three times using a completely randomised design. Nitrogen, phosphorus and potassium were limiting nutrients for bean production in Umbrisol (Luyinjayinja) while in Cambisol (‘Limyufumyufu), common bean production was most limited by soil acidity. The performance varied with soil types, with beans grown on the Phaeozem registering greater leaf number and growth, confirming both scientist’s and local farmer’s knowledge that this soil has greater potential than the other two soils.This article is published as Kyomuhendo, P., M.M. Tenywa, O. Semalulu, A. Lenssen, R. Yost, S. Kyebegola, L. Goettsch, R. Mazur. 2018. Limiting nutrients for bean production on three contrasting soils. African Crop Science Journal. 26:543-554. doi: 10.4314/acsj.v26i4.8.</p