Effects of combining in-situ rainwater harvesting technologies and organic manure on soil moisture and maize performance in Morogoro, Tanzania

Tanzania is among the Sub-Saharan Africa countries that experience water scarcity. Water scarcity is caused by unreliable rainfall and prolonged drought which greatly affects both soil moisture and crop productivity. The study was conducted to assess the practices used by small-scale farmers to cope with water scarcity, and effect of combining in-situ Rain Water Harvesting technologies with organic manure on soil moisture storage and maize performance. The experiment was carried out in Morogoro municipality at Sokoine University of Agriculture farm. The experimental design was a Randomized Complete Block Design (RCBD) with eight treatments replicated thrice. For two seasons the treatments were conventional cultivation without manure (T1), mulching without manure (T2), furrows without manure (T3), Zai pits without manure (T4), Zai pits with manure (T5), mulching with manure (T6), furrows with manure (T7) and conventional cultivation with manure (T8). Soil moisture was taken at 0-20 cm and 20-40 cm depth every week. Yield and biomass data were taken at the end of the season. Household survey was conducted at Gairo district. Subsquently from the field trials, soil moisture content, yield and biomass data generated were subjected to analysis of variance (ANOVA) using SAS version 8. Statistical Package for Social Scientists (SPSS) was used to analyze data from the questionnaires. Results showed that coping strategies for water scarcity varied significantly between the study villages (p= 0.001). Further, there were significant differences (p=0.05) among treatments on moisture retention at soil depth of 0 – 20 cm and 20 – 40 cm which ranged from 9.72% - 16.16% and 13.52% - 17.67%, respectively. The treatment with the highest soil moisture value was mulching without manure (16.16%) at 0 – 20 cm and 17.67% at 20 – 40 cm. There were significant differences (p=0.001) among treatments on maize yield and biomass produced. Conventional practice had lowest maize yield (3.18 t/ha) compared to other treatments. Mulching was a good in-situ rainwater harvesting technique when combined with organic manure as it resulted in highest maize yield (5.05 t/ha) in comparison with the conventional practice. There is thus a need to combine in-situ rainwater harvesting technologies and organic manure application for effective moisture storage as well as high grain yield. These results will be used to guide researchers and other stakeholders.