Application of TAMSAT-ALERT soil moisture forecasts for planting date decision support in Africa

Abstract

Deciding when to plant is critical for smallholders in Africa. If they plant too early, farmers risk seedling death if the rains are not established; if they plant too late, there will not be enough rain to sustain the crop through critical development periods. In this study, we present a new decision support tool (DST) that accounts for the trade-off in the risks of early and late planting through advisories based on both short- and long-range forecasts of crop water availability. Unlike most existing operational systems, which are based solely on rainfall, the DST presented here uses ensemble forecasts of soil moisture to estimate the optimal planting date at a local scale. Evaluations using >30,000 observations of planting date and yield in Kenya, Rwanda, Uganda, Zambia and Malawi demonstrate that that planting at the optimal time would increase yield by 7–10% overall, and up to 20% for late planting farmers. The DST has been piloted by One Acre Fund for the 2019–2020, 2020–2021, and 2021–2022 seasons and there is strong demand for the service to be extended further. We conclude from the evaluations and pilots that the planting date DST has the potential to strengthen farmer decision making and hence their resilience to climate variability and change.

A computationally light-weight model for ensemble forecasting of environmental hazard: General TAMSAT-ALERT v1.2.1

“…The original TAMSAT-ALERT implementation was designed as a framework for producing ensemble crop yield forecasts (Asfaw et al 2018). Following the publication of the original TAMSAT-ALERT method, there was interest from the 115 agricultural and humanitarian sectors in wider application to drought forecasting and agricultural decision support (Boult et al 2020, Black et al 2023). These subsequent applications did not require significant development of the underlying methodology for the framework, and so there was no need to develop a new model.…”

“…Previous work on the TAMSAT-ALERT method has described how the system can be used for agricultural and drought forecasting (Asfaw et al 2018;Boult et al 2020, Black et al 2024 and to short term decision support (Black et al 2023).…”

Variability of rainy season onsets over East Africa

“…Such systematic analysis of the credibility and salience of onset information and the further enhancement of co-production processes are therefore a key priority. This is especially so given the demand for climate information and indeed the ongoing development of agricultural decision support tools ingesting forecast information targeted at local-level stakeholders (e.g., Black et al, 2023).…”

The potential value of seasonal drought forecasts in the context of climate change: A case study of the African elephant conservation sector

“…Forecasts are not just useful for disaster management. Indeed, a number of decision support tools have been developed that enable stakeholders to utilise long and short term forecasts in their routine decision‐making—improving resilience to variability in the weather (Black et al, 2023). It follows from the previous discussion that robust systems for early warning are key to adapting to a climate in which drought is more common.…”