Fertiliser Trees for Sustainable Food Security in the Maize-Based Production Systems of East and Southern Africa

Abstract

-The negative effects of soil fertility depletion on food security, especially among smallholder farmers in Africa, is of economic importance, and may be worsened by climate change and rising global fertiliser prices. Substantial efforts and investment have gone into development of alternative soil fertility management options. These include vigorous research and development of N-fixing plants or "fertiliser trees", that has been on-going in the last two decades in East and Southern Africa. In this paper, we review several studies conducted both on-station and on-farm and synthesise the results in terms of improvements in soil physical, chemical and biological properties, and crop yield in response to fertiliser trees. Our major findings are that (1) fertiliser trees add more than 60 kg N ha −1 per year through biological nitrogen fixation (BNF); (2) nutrient contributions from fertiliser tree biomass can reduce the requirement for mineral N fertiliser by 75%, translating to huge savings on mineral fertilisers; (3) fertiliser trees were also shown to substantially increase crop yield. A meta-analysis has further provided conclusive evidence that with good management, fertiliser trees can double maize yields compared with local farmer practices of maize cultivation without addition of external fertilisation. (4) Financial analyses showed that fertiliser tree systems are profitable and also have higher net returns than the farmers' de facto practice, i.e. continuous maize cropping without fertiliser. We conclude that widespread adoption and scaling up of fertiliser trees can reduce the amount of mineral fertiliser needed, maintain the soil ecosystem, and positively impact on the livelihoods of farm households in southern Africa.

Crop Residue Management and Soil Health with Changing Climate in Smallholders Farming: A Subtropical Indian Perspective

“…Hobbs and Govaerts, (2010) observed that CA results in improved soil physical and biological health, better nutrient cycling and crop growth as well as increasing water infiltration (Ranging from 45 to 87% increase in infiltration rate with CA compared to conventional practices) and soil penetration by roots, which allows crops to better adapt to lower rainfall and make better use of water. Akinnifesi et al, (2011) reported that some fertilizer trees can add up to 60 kg N/ha/yr, reduce the need for mineral fertilizers by 75% and substantially increase crop yield. In some conditions (East and Southern Africa), the use of fertilizer trees can double maize yield and, thus, enhance profit and net returns Akinnifesi et al, (2011).…”

“…Akinnifesi et al, (2011) reported that some fertilizer trees can add up to 60 kg N/ha/yr, reduce the need for mineral fertilizers by 75% and substantially increase crop yield. In some conditions (East and Southern Africa), the use of fertilizer trees can double maize yield and, thus, enhance profit and net returns Akinnifesi et al, (2011).…”

Climate Strategic Soil Management

“…There are numerous proven options of enhancing the WUE, and their adoption must be promoted through soil governance. Improving soil fertility by establishing fertilizer trees [112] can also improve WUE in drought-prone agroecosystems.…”

“…Fertilizer trees, grown as agroforestry systems, can restore soil fertility and productivity. Akinnifesi et al [112] reported that some fertilizer trees can add up to 60 kg N/ha/yr, reduce the need for mineral fertilizers by 75% and substantially increase crop yield. In some conditions (East and Southern Africa), the use of fertilizer trees can double maize yield and, thus, enhance profit and net returns [112].…”

“…Akinnifesi et al [112] reported that some fertilizer trees can add up to 60 kg N/ha/yr, reduce the need for mineral fertilizers by 75% and substantially increase crop yield. In some conditions (East and Southern Africa), the use of fertilizer trees can double maize yield and, thus, enhance profit and net returns [112]. Some commonly used fertilizer trees include Faidherbia, Gliricidia, Leucaena, Sesbania, perennial pigeon pea, acacia, Tephrosia and numerous others.…”