Optimizing Livelihood and Environmental Benefits from Crop Residues in Smallholder Crop-Livestock Systems in Southern Africa
Sustainable forms of intensification are needed to address the low and stagnant production of farming systems in southern Africa. More efficient use of croplivestock interactions can contribute to this in this context the effective use of crop residues is becoming increasingly important and also contested. Crop residues left on the field for mulching are expected to bring longterm environmental benefits but when fed to livestock they provide farmers with shortterm livelihood benefits. This study aims at better understanding the diversity of farming systems and uses of crop residues, in particular the tradeoffs in using the residues for soil amendment versus livestock feed. It is part of a global comparison with sites along a human and livestock population density gradient across subSaharan Africa and South Asia. This southern Africa study represents the most extensive case of semiarid areas with lowest biomass production. Three sites were compared, at different levels of agricultural intensification, extent of croplivestock integration and use of crop residues. 1. Mzimba in Northern Malawi intensified crop oriented production. 2. Nkayi in southwest Zimbabwe integrated croplivestock systems. 3. Changara in Tete province in Central Mozambique extensive croplivestock farming. Across the three sites, crop residues are clearly needed as livestock feed. In Nkayi and Changara low crop yields and low biomass production against the existing demand from livestock prevents farmers from using residues for purposes other than livestock feed. The practice of collecting and kraal feeding residues in Nkayi illustrates that the pressure on residues is at a level where farmers start privatizing residues in order to ensure their individual benefits. When feeding crop residues in the kraal, farmers also increase the amount of manure for soil fertility improvement. Even in Mzimba, with higher residue production and lower livestock ownership, very few farmers retain the residues to achieve real impact on soil health. Although farmers see soil fertility as a critical constraint, they have limited residues to spare for mulching. The tradeoffs of reallocating crop residues from livestock feed to mulching for soil amendment will be high as long as alternative feed technologies and access to input and output markets are not developed. The tradeoffs will be lower in areas with higher biomass production and less competition with livestock. Technical options need to increase biomass on existing croplands, addressing feed shortages and the need for soil amendment concurrently. Viable institutional structures and appropriate policies need to support this intensification processes through better access to inputs, knowledge and markets. The pathways for sustainable intensification and more efficient crop residue utilization need to be developed within the local context. We found strong growth potential for livestockoriented agricultural development in extensive areas (Changara), strengthening crop and livestock integration to support intensification in areas like Nkayi, and enhancing croplivestock integration for more efficient resource utilization where biomass is less limiting (Mzimba).