VFRC Publications - Page 11

Whereas fertilizers are meant to be taken up by agricultural crops only, a substantial portion of the nutrients are lost, adversely affecting both ecosystem and human well-being alike. Losses may range from only 20% to about 80% and remain substantial even under the most efficient agricultural production systems, which are often highly knowledge intensive. Fertilizer overuse contributes to eutrophication and climate change. Fertilizer underuse, however, leads to soil degradation, poverty and hunger; and the low yields result in encroachment into biodiversity-rich ecosystems in search for new, fertile agricultural land (Figure 2). The use of fertilizers in low production systems can be profitable on average, but it tends to be more risky, which creates a disincentive for farmers to adopt fertilizers.7 Risk, such as due to rainfall variability, is a cause of perpetuating poverty. Interventions to reduce risks include a more favorable price ratio of fertilizer to crop product, risk-reducing strategies like drought-resistant varieties, integrated water management and also insurance schemes. Fertilizers designed to cope with erratic conditions resulting in increased uptake efficiency and stronger yield response are an as-of-yet unexplored avenue. Biol Fertil Soils (2015) 51:897-911 DOI 10.1007/s00374-015-1039-7 ed Rainf lizers ti + fer CrossMark REVIEW Revisiting fertilisers and fertilisation strategies for improved nutrient uptake by plants ed Rainf izers il – fert Prem S. Bindraban1 • Christian Dimpka1 • Latha Nagarajan2 • Amit Roy2 • Rudy Rabbinge3 Figure 2. Maize yields have remained stagnant on the African continent (dots are annual yields from 1960 to 2005).8 The picture (courtesy Marcel Gabila) shows the compelling evidence that it is not the amount of water through rainfall that limits yields, but the poor fertility of the soil. 7