Browsing by Author "Hilger, Thomas"
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Item Can Occurrence and Distribution of Ground Beetles (Carabidae) Be Influenced by the Coffee Farming System in the Mount Elgon Region of Uganda?(Neotropical Entomology, 2021) Raphael Ijala, Anthony; Kyamanywa, Samuel; Cherukut, Scola; Sebatta, Christopher; Hilger, Thomas; Karungi, JeninahThe Mount Elgon region of Uganda has coffee farmlands distributed along the slopes of the mountain, in a mosaic of differing crop combinations, and semi-natural vegetation. Thus, there are parcels of varying microclimate that create disparities in occurrence of key insect functional groups. The study quantified the occurrence of Carabidae in 72 coffee farmlands categorized by altitude: low (1400–1499 m.a.s.l), mid (1500–1679 m.a.s.l), and high (1680–2100 m.a.s.l); and farming system: coffee monocrop, coffee+annual crops, coffee+banana, and coffee+banana+shade trees. The results revealed highly significant effects of altitude, farming systems, and the interaction of the two on occurrence of three Carabidae genera (Anisodactylus, Chlaenius, and Harpalus.). The abundance of Harpalus spp. was higher at lower altitudes in coffee monocropped farming systems; Anisodactylus spp. were more abundant at higher altitudes in coffee+annual crop systems; and Chlaenius spp. were highest in the coffee+banana+shade tree system at mid altitudes. The belowground microclimate parameters of soil moisture, pH, EC; and the aboveground diversity of semi-natural vegetation explained some of the differences in occurrence of the different Carabidae genera. This distinctiveness in preference of different genera in the same family hinders collective recommendations but looks to a more pragmatic strategy in nurturing diversity on a holistic scale.Item Soil and farm management effects on yield and nutrient concentrations of food crops in East Africa(Science of the Total Environment, 2020) Fischer, Sahrah; Hilger, Thomas; Piepho, Hans-Peter; Jordan, Irmgard; Karungi, Jeninah; Towett, Erick; Shepherd, Keith; Cadisch, GeorgCrops 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