Evaluating effects of selected water conservation techniques and manure on sorghum yields and rainwater use efficiency in dry region of Zimbabwe.

Sorghum production in semi-arid areas of Zimbabwe is constrained by low and erratic rainfall, low fertility and soil moisture stress. Sorghum grain yields ranges from 0.2 to 0.4 t ha-1 in sandy-to-sandy loam soils respectively. The objective of the study was to assess cattle manure and rainwater harvesting techniques in improving sorghum grain yield in a semi-arid region of Zimbabwe. The experiment used a randomised complete block design with rainwater harvesting technique as a main treatment factor at three levels. Sub-plot factor was cattle manure at five levels (0, 2.5, 5, 10 and 15 t ha-1) and two sorghum varieties (Macia and SV1) as sub-sub plot factor. Sorghum grain yields were improved significantly (p < 0.05) for both varieties using tied contours. Increasing application rates of cattle manure, showed significant increase (p < 0.05) in sorghum grain yield over the control (0 t ha-1). Tied contour had higher grain yield (1.15 t ha-1) with the use of Macia variety. Stover yield was highly influenced by rainwater harvesting method of tied contour (p < 0.05) compared with infiltration pit and standard contour. Increase in application levels of cattle manure show significant (p < 0.05) increase in stover yields. Tied contour had the highest (3.11 kg ha-1 mm-1) rainwater use efficiency which show significant differences (p < 0.05) from infiltration pits and standard contour. Interaction of tied contour and different rates of cattle manure showed significant increments in rainwater use efficiency with increases in manure application rates. Tied contours, 15 t ha-1 cattle manure and Macia variety are potential strategy to achieve climate smart agriculture and improve food security in semi-arid areas. Sorghum production in marginalised areas can be productive with adoption of tested techniques.

Rainwater harvesting and Leucaena leucocephala biomass rates effects on soil moisture, water use efficiency and Sorghum bicolor [(L.) Moench] productivity in a semi-arid area in Zimbabwe.

BACKGROUND: Sorghum is one of the major staple crops in Sub Saharan Africa but its production is mainly limited by moisture stress, frequent droughts and soil infertility, especially in the smallholder farming systems. This raises the need to develop climate smart options to improve sorghum production. The objective was to assess the effects of rainwater harvesting and use of different Leucaena leucocephala biomass rates on soil moisture content, rainwater use efficiency, and stover and grain yields in two sorghum varieties (Macia and SV1). The experiment was laid as a randomized complete block design in split-split plot arrangement from 2017/2018 to 2019/2020 season. RESULTS: The results show that tied contour (TC) and infiltration pits (IPs) significantly (P < 0.05) increased soil moisture content than standard contour (SC). Soil moisture content increased gradually with the increase in soil depth (20-40 cm > 0-20 cm), with 2018/2019 season having the maximum soil moisture content. Soil moisture content also increased with the increase in application rates of Leucaena biomass. Grain and stover yields were significantly (P < 0.05) increased by all Leucaena biomass application rates with higher yield observed in 2018/2019 season. SC had significantly lower grain and stover yields at all Leucaena biomass application rates. TC and IPs had comparable rainwater use efficiency compared to SC. Rainwater use efficiency increased with application rates of Leucaena biomass across all seasons and varieties. CONCLUSION: TC and IPs are better adaptive mechanisms against drought spells in semi-arid areas and can be combined with 10 t ha-1 of Leucaena biomass due to better yield increments realized. © 2022 Society of Chemical Industry.

Estimativa da correção do coeficiente de retorno de esgoto sanitário em habitações com sistemas de aproveitamento de água pluvial: estudo de caso da cidade de Bauru, SP / Estimate of the correction of sewage return rate in housing with rain water recovery systems: case study of Bauru city, SP, Brazil

RESUMO O coeficiente de retorno (f) da rede coletora de esgoto, que apresenta quociente dado pelos volumes água/esgoto micromedidos, é empregado no projeto e na gestão do sistema de coleta de esgoto sanitário. As fontes de suprimento de água alternativas, tais como águas de reúso e de aproveitamento pluvial, não estão contempladas por f. O presente artigo teve o objetivo de aplicar metodologias para avaliar o potencial do lançamento de água pluvial no sistema de coleta e transporte de esgoto sanitário por meio de práticas de aproveitamento, na cidade de Bauru/SP. As variáveis de interesse foram parametrizadas utilizando o número de habitantes. Foi usado procedimento amostral para a determinação das áreas de telhado disponíveis. Os resultados apontam para correções de f (f corrigido ) na faixa de 0,86 e 1,14.

ABSTRACT The return coefficient (f) of the sewage disposal system, which presents the ratio given by the volume of wastewater by the public supply system water volume is employed in the design and management of sanitary sewer collection system. The use of alternative sources, such as reuse and rainwater harvesting, are not considered by f. This article aims at applying the methodology to evaluate the potential release of rainwater in the collection and transportation of sanitary sewage system through recovery practices in Bauru city/SP. Variables were quoted by means of number of inhabitants. The statistical sampling procedure was applied for roof area determination. Results pointed out for f correction (f corrected ) values varying from 0,86 to 1.14 for Bauru city.