Field edge rainwater harvesting and inorganic fertilizers for improved sorghum (Sorghum bicolor L.) yields in semi-arid farming regions of Marange, Zimbabwe

Abstract

Sorghum (Sorghum bicolor L.) is mainly cultivated in marginal areas of Zimbabwe, where soil fertility is poor and rainfall is low, erratic, and poorly distributed, leading to low yields. The study aimed to determine the effect of tied contour (TC) and in-contour infiltration pits (IP) rainwater harvesting (RWH) methods and varying nitrogen fertilizer application rates on the yield of two sorghum varieties, Macia and Sc Sila. A split-split plot experiment was laid out, with the main plot factor being the RWH method, the subplot factor being sorghum variety, the subsub plot factor being nitrogen application, and the sub-sub-sub plot factor being the plant distance from the RWH method. The experiment was done at Mt Zonwe's small-scale farming community in the Mutare region from 2016/17 to 2018/19. The results revealed that TC and IP increased the gravimetric water content (gwc) of the soil. The gwc decreased gradually as the distance from the rainwater RWH method increased (0-5 m > 5-10 m > 10-15 m), with the 2016/17 season having the maximum gwc. In all seasons, TC and IP yielded much more sorghum grain than standard contour (SC). Sorghum grain production was significantly greater at all nitrogen application rates and consistently higher at all plant distances from the RWH method in the 2016/17 season with more rainfall. In comparison to TC and IP, the SC had significantly lower grain yield at all nitrogen application rates. At all plant distances from the RWH method, TC and IP had significantly higher grain production than SC in each variety of sorghum.

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

“…This water increase in soil moisture availability to crops during dry periods and dry spell, improved crop growth and sorghum grain yield. This coincides with findings by other researchers 7,11,16,37 who reported higher grain yield from TC and IPs compared to SC using different varieties from those used in this study. Higher yields from TC and IPs could be attributed to improved water retention which prolongs soil moisture, increasing crop growth and sorghum grain yield.…”

Evaluation of different rainwater harvesting techniques for improved maize productivity in semi‐arid regions of Zimbabwe with sandy soils

“…Using results from this study, farmers in the study area now prefer the use of TCs and infiltration pits because these techniques harvest runoff, reduce land degradation and increase soil moisture which boost crop production (Kubiku, Nyamadzawo, et al, 2022). TC technique was welcomed by several farmers in the region basing on findings from other researchers in Zimbabwe by Nyamadzawo et al (2015), Kubiku, Mandumbu, et al (2022) and Kugedera et al (2022b) who all reported higher results from TC in semi‐arid regions of Zimbabwe.…”

“…Infiltration pits combined with TR and PH performed better than STDC integrated with PH and TR. This may have been caused by poor water harvesting of STDC which disposed‐off runoff from the field resulting in moisture stress which deliberately affected grain filling stage and movement of photosynthetic carbohydrates from leaves to grain hence lower yields (Kubiku, Mandumbu, et al, 2022; Kugedera, Nyamadzawo, Mandumbu, Nyamangara, 2022; Kugedera et al, 2022a). Nyamadzawo et al (2015) reported that TC can be the cheapest option for farmers which if combined by other cheaper options like TR can boost maize grain yields since the construction of BAS is labour intensive (Masaka et al, 2019; Marumbi et al, 2020).…”

Enhancing Sorghum bicolor (L.) grain yield with the use of field edge rainwater harvesting and NPK fertiliser in a dry region of Zimbabwe

“…Agriculture in dry regions across Africa is characterised by low inputs and outputs especially in smallholder farming environments (Desta et al, 2022; Kubiku et al, 2022b). Many smallholder farming environments in Africa are associated with low and erratic rainfall which is sometimes accompanied with heavy downpours causing soil erosion, surface runoff and crusting (Chilagane et al, 2020; Kugedera et al, 2022d).…”

“…Improving sorghum grain yields above 800 kg ha −1 makes smallholder farmers’ food secure and reduce poverty. Macia is a sorghum variety which is widely grown in semi‐arid region of Zimbabwe and thrives well under harsh conditions (Kubiku et al, 2022b). The variety has yield potential of 3–6 t ha −1 under commercial production and matures early.…”