Edaphic and climatic factors and the nutrient dynamics in Uapaca kirkiana dominated miombo woodland agroforestry ecosystems

Abstract

Soil and foliar analysis were used to investigate influence of edaphic and climatic factors on the soil–plant nutrient dynamics in Uapaca kirkiana dominated woodland ecosystem in Zimbabwe. Examination of the relationship between soil factors and foliar nutrient concentrations as analysed by multiple regression analysis showed that between 60 and 97% of the variations in foliar nutrient concentrations during the wet period, with the exception of nitrogen, could be explained by soil factors: soil nutrient content, texture and pH. In the dry winter period, influence of these soil factors on foliar nutrient content was in the range between 48 and 97%. Factors that had significant influence (P < 0.05) were particularly exhibited during the wet period and these were those influencing foliar P, Fe, Mn and Zn. Multiple regression analysis between climatic factors and foliar nutrients showed temperature had a statistically significant negative relationship with Fe whilst precipitation had a highly significant positive relationship with Fe during the dry winter period. Correlation between foliar Fe and rainfall was negatively statistically significant during the rainy period (P < 0.05) and became positively statistically highly significant during the dry period (P < 0.01). There was also a highly statistically significant negative relationship between the total annual rainfall and foliar nitrogen during the dry winter period. Findings of the study highlight importance of both soil and climatic factors on soil–plant nutrient dynamics in the miombo ecosystem, and should therefore be taken into consideration when establishing U. kirkiana in an agroforestry system.