Farmer's appropriation of system of rice intensification practices in water-scarce irrigation schemes in Northern Tanzania

This research article published by Springer Nature Switzerland AG.,2021The system of rice intensification (SRI), advocates new ways of rice cultivation which challenges farmers’ knowledge and skills to the extent that they are required to learn, experiment and integrate new principles to suit their specific needs and agro-ecological conditions. This study was conducted to evaluate farmers’ appropriation to SRI; first, a survey was conducted to explore farmers’ adjustments of SRI. Second, yield and water productivity of the integrated system were assessed by setting up an experiment in the farmers’ plots. Whereby four treatments representing farmers’ adaptations of SRI practises were assessed: continuous flooding (F1) with two 21 days old seedlings at 15 × 15 cm spacing. The other three were under intermittent irrigation with two 21 days seedlings at 20 × 20 cm (F2), one 21 days seedling at 20 × 20 (F3) and one 15 days seedling at 25 × 25 cm spacing. Yields obtained were 4.8, 8.5, 8.2 and 9.2 tons/ha for F1, F2, F3 and F4, respectively. Water productivity (WP) of 0.15, 0.39, 0.35 and 0.51 kg/m3 was obtained for F1, F2, F3 and F4, respectively. Water saving under SRI practise was 34.3%, 28.9% and 45.1% for F2, F3 and F4, respectively. Two seedlings 21 days old at 20 × 20 cm with intermittent irrigation are recommended for this area as it ensures a sufficient number of plants, relatively higher yields and a reduced considerable amount of irrigation water. The findings show that the integration of SRI into the local rice farming system has the potential to improve yields and water productivity of irrigation schemes

Analysis of Intra and Interseasonal Rainfall Variability and Its Effects on Pearl Millet Yield in a Semiarid Agroclimate: Significance of Scattered Fields and Tied Ridges

Establishing food security in sub-Saharan African countries requires a comprehensive and high resolution understanding of the driving factors of crop production. Poor soil and adverse climate conditions are among the major drivers of poor regional crop production. Drought and rainfall variability challenges are not fully being addressed by rainfed producers in semiarid areas. In this study, we analysed the spatiotemporal rainfall variability (STRV) and its effects on pearl millet yield using two seasons of data collected from 38 rain gauge stations scattered randomly in farm plots within a 1500 ha area of semiarid central Tanzania. The STRV effects on pearl millet yield under flat and tied ridge management were analysed. Our results show that seasonal rainfall can vary significantly for neighboring fields at distances of less than 200 m, which impacts yield. The STRV for daily rainfall was found to be more critical than for total seasonal rainfall amounts. Scattering fields can help farmers avoid total harvest loss by obtaining at least some yield from the areas that received adequate rain. The use of tied ridges is recommended to conserve soil moisture and improve yields more than flat cultivation in semiarid areas.Peer Reviewe

Combining biochar with low rate of chemical fertiliser boosts maize biomass yield, regardless of tillage system, under humid conditions

Biochar application to soils increases biomass and crop yields, especially with rates higher than 100 t ha−1. Yet, there is limited knowledge on the combined effect of biochar and chemical fertiliser under different tillage systems. The objective of this study is to investigate the effect of maize-cob biochar (BC) (rates of 5 and 10 t ha−1) combined with chemical fertiliser micro-dosing (MD) at a rate of 25% of the recommended quantity on total shoot dry matter (DM) and plant height of maize cultivated under flat (F) and tied-ridge (R) practices during a humid season in Tanzania. The results indicate that combining 5 t ha−1 BC with 25% MD increases DM at harvest by 83% (4.16 t ha−1) compared to the control (2.27 t ha−1) and was in the same range as the DM obtained from the treatment with the recommended fertiliser rate (100% FD). The treatments with single applications of 25% MD, 5 t ha−1 BC, and 10 t ha−1 BC only tended to exceed the control of DM yield. Therefore, we recommend that small-scale farmers aiming at DM for livestock or grain yield with limited access to chemical fertilisers to combine biochar with 25% MD, rather than applying biochar or low chemical fertiliser rates alone