This report presents the results of a baseline survey that was carried out in nine wards of Chihota communal area, Zimbabwe. This survey is part of the Chihota Soil Fertility project which is a pilot ...study to expose farmers in this area to a range of 'best-bet' soil fertility improvement technologies and to get their assessment of these technologies in their own terms. The aims of this survey are twofold: to enhance our understanding of farmers' problems and perceptions and to serve as a control against which the impact of the Chihota Soil Fertility project will be compared. The survey covers the following aspects: household characteristics, landholdings, crops grown, soil fertility practices, field characteristics and management, history of use of soil fertility practices, and knowledge about these practices. The unit of analysis used here was the household. Households were classified into three categories: a) male-headed households, female -headed households with male adults (males 18 years and older), female -headed households without male adults (no males above 18 years old). The results show that the farming systems in Chihota are maize-based, even though garden production and non-agricultural labour are important sources of income and subsistence. These systems do not seem to have changed dramatically in the last twenty years. There are some important gender differences among households in terms of the assets they control and the agricultural management they implement. Farming households use a range of soil fertility improvement practices, both organic and inorganic. Some of these are traditional while others have been introduced in the last two decades. Even though most farmers in this area have been in contact with extension, and they have good knowledge about certain soil improvement practices, there seem to be many knowledge gaps in the use of others, including some traditional organic ones. There are opportunities to improve farmers' knowledge with technical information that is relevant and easy to use.
Major constraints to increasing the productivity of crop production in semi-arid areas are shortages of draught animal power (DAP) and labour, combined with variable soil moisture and at times ...excessive weed growth. Farmers, research and extension staff have been developing and testing innovative moisture conserving crop establishment and weeding practices for a maize. based cropping system in semi-arid Zimbabwe. This paper, the third of three, provides a socio-economic evaluation of those practices, selected by farmers as suitable to their circumstances. This has involved on-farm trials and a process of farmer testing on typical granitic soil catenas. Evaluation has been based on criteria farmers consider important, yields, labour and draught animal requirements. Results indicate that rip and open plough furrow plant practices increase productivity benefiting those who have access to adequate DAP and labour. Reduced demand for DAP may release DAP for more timely use by those reliant on borrowing or sharing arrangements. Hand hoe weeding techniques usually outperform the ox-cultivator or plough confirming a need for improving the use of such implements. It is also recognised that farmers should be encouraged to experiment to identify those methods most suitable for their circumstances. Programmes for this are in place for next season.
Farmers' taxonomies as a participatory diagnostic tool: Soil fertility management in Chihota, Zimbabwe Bellon, M.R. (Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico, DF (Mexico)); Gambara, P. (Department of Agricultural, Technical and Extension Services (Agritex), Marondera (Zimbabwe)); Gatsi, T (Department of Research and Specialist Services, Harare (Zimbabwe)) ...
Soil Fertility Network for Maize-Based Cropping Systems in Malawi and Zimbabwe,
19/Aug
4
Publication
Soil infertility is a major constraint to food production in the communal areas of Zimbabwe. Smallholders in the region recognise the problems of low soil fertility and have devised ways of coping ...with them. This study describes the use of farmers' taxonomies of themselves and their soils to identify and understand the options they have, and the constraints they face, to manage poor soil fertility in Chihota, a sub-humid communal area of north central Zimbabwe. It is part of an effort by the Soil Fertility Network for Maize-Based Cropping Systems in Malawi and Zimbabwe (Soil Fert Net), a grouping of agricultural researchers and extensionists working on improved soil fertility technologies, towards more integration with farmers to expose them to promising technologies, get feedback on their merits and feasibility, and help farmers experiment with them. The results show that these farmers have relatively sophisticated taxonomies, which provide a good picture of the resources, constraints, and concerns they have about soil infertility and ways to manage it. The taxonomies are an important framework for integration of technical interventions with farmers' requirements, systems, and circumstances.
Background
MMV390048 is an aminopyridine plasmodial PI4K inhibitor, selected as a Plasmodium blood‐stage schizonticide for a next generation of malaria treatments to overcome resistance to current ...therapies. MMV390048 showed an acceptable preclinical safety profile and progressed up to Phase 2a clinical trials. However, embryofetal studies revealed adverse developmental toxicity signals, including diaphragmatic hernias and cardiovascular malformations in rats but not rabbits.
Methods
In vivo exposures of free plasma concentrations of compound in rats were assessed in relation to in vitro human kinase inhibition by MMV390048, using the ADP‐Glo™ Kinase Assay.
Results
We demonstrate a potential link between the malformations seen in the embryofetal developmental (EFD) studies and inhibition of the mammalian PI4Kβ paralogue, as well as inhibition of the off‐target kinases MAP4K4 and MINK1. PI3Kγ may also play a role in the embryofetal toxicity as its in vitro inhibition is covered by in vivo exposure. The exposures in the rabbit embryofetal development studies did not reach concentrations likely to cause PI4K inhibition. Overall, we hypothesize that the in vivo malformations observed could be due to inhibition of the PI4K target in combination with the off‐targets, MAP4K4 and MINK1. However, these relationships are by association and not mechanistically proven.
Conclusions
Deciphering if the EFD effects are dependent on PI4K inhibition, and/or via inhibition of other off‐target kinases will require the generation of novel, more potent, and more specific PI4K inhibitors.
Near-infrared emission in the 885–915 nm region was observed for two distinct Nd3+ centres that co-exist in hexagonal wurtzite ZnO:1 mol%Nd3+:10 mol%Li+ powders. The powder samples were prepared by ...sintering in air at 950 °C and the emission, attributed to the 4F3/2 → 4I9/2 transitions of Nd3+ ions, was measured in the 10–75 K temperature range. The sharp and well-resolved Nd3+ emission transitions are present in Nd3+-Li+ co-doped samples only, and the intensity increases with Li+ concentration. X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy were used for structural, morphology and compositional assessments of the samples. Atomistic modelling using GULP shows two favourable Nd3+-Li+ substitutional positions, in consistence with the experimental findings.
•Structure and surface morphology of sintered ZnO:Nd3+:Li+ powders were determined.•Spectroscopy of the two Nd3+-Li+ centres present in ZnO powders is presented.•Crystal-field levels for 2G7/2;4G5/2, 4F3/2 and 4I9/2 multiplets of Nd3+ were deduced.•Proposed centre configurations were obtained from modelling calculations.
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