Soil and farm management effects on yield and nutrient concentrations of food crops in East Africa
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Science of the Total Environment
Abstract
Crops that grow on soils with higher fertility often have higher yields and higher tissue nutrient concentrations.
Whether this is the case for all crops, and which soil and management factors, or combinations mostly affect
yields and food nutrient concentrations however, is poorly understood. Here, the main aim was to evaluate effects
of soil and management factors on crop yields and food nutrient concentrations in (i) grain, fruit and
tuber crops, and (ii) between high and low soil fertility areas.
Total elemental concentrations of Mg, P, S, K, Ca, Fe, Zn, Mn and Cu were measured using a portable X-Ray Fluorescence
Spectrometer (pXRF) in maize grain (Zea mays; Teso South, Kenya: n = 31; Kapchorwa, Uganda n =
30), cassava tuber (Manihot esculenta; Teso South: n = 27), and matooke fruit (Musa acuminata; Kapchorwa,
n=54). Soil properties measuredwere eCEC, total N and C, pH, texture, and total elemental content. Farmmanagement
variables (fertilisation, distance to household, and crop diversity)were collected. Canonical Correspondence
Analyses (CCA) with permutation rank tests identified driving factors of alterations in nutrient
concentrations.
Maize grain had higher correlations with soil factors (CCA N 80%), than cassava tuber (76%) or matooke fruit
(39%). In contrast, corresponding correlations to management factors were much lower (8–39%). The main soil
properties affecting food nutrients were organic matter and texture. Surprisingly, pH did not play an important
role. A positive association of crop diversity with nutrient concentration and yield in lower fertility areas was observed. Considering, food nutrient composition, apart fromyield, as response variables in agronomic trials (e.g.
fertilisation or soil improvement strategies), would contribute towards discounting the notion that crops growing
on fertile soils always produce healthy and high quality foods
Description
Keywords
Food composition, Human nutrition, Yields, Soil fertility, Farm management
Citation
Fischer, S., Hilger, T., Piepho, H. P., Jordan, I., Karungi, J., Towett, E., ... & Cadisch, G. (2020). Soil and farm management effects on yield and nutrient concentrations of food crops in East Africa. Science of the Total Environment, 716, 137078. https://doi.org/10.1016/j.scitotenv.2020.137078