Harnessing net primary productivity data for monitoring sustainable development of agriculture

This study was undertaken to assess the utility of remotely sensed net primary productivity (NPP) data to measure agricultural sustainability by applying a new methodology that captures spatial variability and trends in total NPP and in NPP removed at harvest. The sustainable intensification of agriculture is widely promoted as a means for achieving the Sustainable Development Goals (SDGs) and transitioning toward a more productive, sustainable, and inclusive agriculture, particularity in fragile environments. Yet critics claim that the 17 SDGs and 169 targets are immeasurable and unmanageable. We propose adoption of satellite-estimated, time-series NPP data to monitor agricultural intensification and sustainability, as it is one indicator potentially valuable across several SDGs. To illustrate, we present a unique monitoring framework and a novel indicator, the agricultural appropriation of net primary productivity (AANPP) and analyze spatial trends in NPP and AANPP across the continent of Africa. AANPP focuses on the proportion of total crop NPP removed at harvest. We estimate AANPP by overlaying remotely sensed satellite imagery with rasterized crop production data at 10-by-10-kilometer spatial resolution; we explore variation in NPP and AANPP in terms of food and ecological security. The spatial distribution of NPP and AANPP illustrates the dominance of cropping systems as spatial drivers of NPP across many regions in West and East Africa, as well as in the fertile river valleys across North Africa and the Sahel, where access to irrigation and other technological inputs are inflating AANPP relative to NPP. A comparison of 2000 and 2005 datasets showed increasing AANPP in African countries south of the Sahara—particularly in Mozambique, Angola, and Zambia—whereas NPP either held stable or decreased considerably. This pattern was especially evident subnationally in Ethiopia. Such trends highlight increasing vulnerability of populations to food and ecological insecurity. When combined with other indicators and time-series data, the significance of NPP and the capacity of spatially explicit datasets have far-reaching implications for monitoring the progress of sustainable development in a post-2015 world.