• Energy Research

AbstractIncreasing demand for land to ensure human food security in the future has already impelled agricultural production into marginal areas. The environmental conditions found there have a more pronounced impact on agricultural productivity than in the systems used so far under favourable conditions. In addition to this challenge, climate change is expected to increase the unreliability of weather conditions (through increased variability and occurrence of extremes) for farmers considerably. This unreliability is even more serious in developing countries’ farming system where food security is vulnerable. Current efforts in digitalization offer great possibilities to improve farmers` decision‐making processes. A wide range of online tools and smartphone applications is available to support both agricultural extension services and smallholder farmers alike. These apps are often parameterized and validated to certain environments and are troubled when applied to new geographical locations and different environmental conditions. We have conducted field trials to demonstrate potential methods to close knowledge gaps in the data background for one of these apps, RiceAdvice, concerning three key aspects: shifting of cropping calendar, adjustment of fertilizer management and genotype selection. Sites in Ethiopia, Madagascar and Rwanda were selected to represent altitudinal gradients, with overlapping elevations reflecting differences in temperature to enable cross‐country comparisons. Planting dates were distributed throughout three calendar years, with continuous iterative planting dates taking place in Madagascar, in‐ and off‐season planting dates in Rwanda with different fertilizer applications, and one planting date during each rainy season in Ethiopia with different management options. With these trials, we have been able to identify key data sets needed for the adaptation of agricultural decision support tools to new environments. These include the assessment of climatic constraints on innovations to cropping calendars (e.g. double cropping), informed selection of alternative varieties able to complete crucial parts of their phenological development to avoid temperature‐related stress inducing, for example spikelet sterility in rice in late development stages and the effectivity of potential innovations in fertilizer management strategies.

ABSTRACTRice production in sub-Saharan Africa (SSA) has increaed ten-fold since 1961, whereas its consumption has exceeded the production and the regional self-sufficiency rate is only 48% in 2020. Increase in rice production has come mainly from increased harvested area. Yield increase has been limited and the current average yield in SSA is around 2 t ha−1. This paper aims to provide the status quo of (i) current rice production and its challenges, (ii) selected achievements in rice agronomy research mainly by the Africa Rice Center and its partners, and (iii) perspectives for future research on rice agronomy in SSA. The major problems confronting rice production include low yield in rainfed environments, accounting for 70% of the total rice harvested area. Rainfed rice yields are strongly affected by climate extremes such as water stresses, soil-related constraints, and sub-optimum natural resource management and crop management practices by smallholder farmers including poor water management, and suboptimal use of fertilizers, herbicides, and machineries. For alleviating these constraints, a wide range of technologies have been developed and introduced over the last three decades. These include water conservation technologies in rainfed and irrigated lowland rice, site-specific nutrient management practices, decision support tools such as crop growth simulation models, and labor-saving technologies. We conclude that further research efforts are needed to develop locally adapted agronomic solutions for sustainable intensification, especially in rainfed rice to enhance the resilience to climate change and increase land and labor productivity and sustainability of rice cultivation in SSA.