Optimisation de la fertilisation phosphatée et effet d’un tricompost sur le rendement de la pomme de terre (solanum tuberosm) sur sol acide au Burundi

Abstract

Potato (Solanum tuberosum L.) is one of the most important food crops in Burundi due to its high nutritional value, short production cycle, and significant contribution to food security and household income. Nevertheless, potato yields achieved by smallholder farmers remain far below the crop’s production potential because of declining soil fertility, inadequate nutrient management, climatic variability, and increasing pressure from pests and diseases. In this context, the present study aimed o evaluate the effect of different levels of phosphate fertilization, combined with the application of a tricompost, on the growth and yield of potato (Solanum tuberosum L.) grown on acidic soil in Burundi, in order to identify the optimal combination to sustainably improve the productivity of this crop. The experiment was conducted at the Karusi Regional Research Station using a randomized complete block design with eight treatments and three replications. The treatments consisted of different combinations of cattle manure, COEJEBU compost, mineral NPK fertilizers, and dolomite. Agronomic parameters assessed included plant height, number of stems per plant, total number of tubers, number of marketable large tubers, and tuber yield. The results showed that integrated fertilization significantly improved potato growth and productivity compared with the control treatments. The highest performances were obtained with cattle manure combined with NPK 60-90-60 plus dolomite (T3) and cattle manure combined with NPK 60-75-60 plus dolomite (T4), which produced yields of 6,291.04 kg ha⁻¹ and 6,202.43 kg ha⁻¹, respectively. These treatments also recorded the highest values for plant height, stem number, and production of large tubers. The treatment consisting of COEJEBU compost combined with NPK 60-90-60 and dolomite (T8) achieved an intermediate yield of 5,526.88 kg ha⁻¹, highlighting the potential of locally produced compost as a sustainable alternative for improving soil fertility and crop productivity. The findings demonstrate that integrated nutrient management enhances nutrient availability, stimulates vegetative growth, and significantly increases potato yield. However, the yields obtained remained considerably lower than the varietal potential estimated at approximately 30 t ha⁻¹, indicating the influence of additional limiting factors such as rainfall deficits, pest and disease incidence, inadequate water management, and seed quality constraints. Overall, integrated fertilization represents an effective and sustainable strategy for improving potato production in former Karusi Province and offers promising opportunities for strengthening food security and farmers’ livelihoods in Burundi.