Researchers at the International Maize and Wheat Improvement Center (CIMMYT) analysed potential trade-offs in maize residue use as soil mulch and livestock feed in mixed crop-livestock systems in Kenya. Based on survey data, researchers found that both the proportion and quantity of maize residue used for soil mulch and livestock feed are strongly affected by agro-ecology and livestock holding. Farmer knowledge about alternative use of crop residues and farmer perception of soil erosion risk positively affect the amount of residue farmers retain on maize plots. Results imply that crop residue use as soil mulch in conservation agriculture is challenged in mixed crop-livestock systems and particularly by smallholder farmers owning cross-bred and exotic dairy animals. In general, reducing the demand for crop residues as livestock feed through the introduction of alternative feed sources, better extension services on the use of crop residue as soil mulch and designing agro-ecology specific strategies and interventions could facilitate the adoption and expansion of CA-based practices in mixed crop-livestock systems.

The whole document is available from the AgEcon website

SLP East Africa team continues presenting preliminary results of the project on crop residue trade-offs. This time Kindu Mekonnen (ILRI-Ethiopia) will present a poster at the CIALCA International Conference held next week in Rwanda. The presented study concludes that “the three study sites in east Africa are found at different crop-livestock intensification level because of variability in rainfall, adoption of crop and livestock technologies, and access to input/output markets. Dealing with some of the constraints that affect crop and livestock production could lead to a more sustainable intensification of crop-livestock farming in the East African highlands”.

This poster is available from Slideshare

Kindu Mekonnen, SLP associate researcher of the East Africa team writes:

“Biomass is a crucial resource for smallholder farmers. Crop residues form an important source of biomass but there are competing demands for its use. The key trade-off is between use of crop residue for feeding of livestock and retaining residues on the field to sustain soil fertility. This issue has formed the basis of a global research project on trade-offs in residue use in smallholder systems. In East Africa, the research has focused on two sites in Ethiopia and one in Kenya.

As part of this research a village survey was conducted each site with the objective understanding diversified and competing uses of crop residues; analyze past trends of uses of crop residues; and identify production and utilization constraints of crop residues. A total of 8 villages per site were surveyed in two sites in Ethiopia (Kobo and Nekemte) and one site in western Kenya (Kakamega).

The most important findings from the research so far are (1) The use of crop residues for animal feed (stall feeding and direct grazing) surpassed the other competing uses in all the sites; (2) The practice of mulching crop fields using crop residues has declined in the last 10 years in the three sites because of competing use of the resources for various services and products; (3) Soil/land related problems, weed, insect and pests, high input/low output prices, poor distribution of rainfall/drought and lack of information/services are some of the constraints associated with low crop productivity and production of crop residues; and (4) Lack of modern crop residue processing technologies limited the efficient utilization of crop residues in the three sites.

The pressure on residue use and the decline in its use as a mulch raise serious concerns for system sustainability. Our next task will be to look at policy, institutional and technical options for reducing pressure on biomass in smallholder systems for the long term benefit of poor smallholders.

We will present this work at the International Congress: Water 2011– Integrated water resources management in tropical and subtropical dry-lands. The congress will be held from 19 to 26 September 2011 in Mekele, Ethiopia. The title of our presentation is “Competing uses, dynamics, and production and utilization constraints of crop residues in East Africa: Implications for conservation agriculture”.

This presentation is available from Slideshare

by Place F, Roothaert R, Maina L, Franzel S, Sinja J and Wanjiku J.

The objective of this study is twofold, to demonstrate (1) the effects of fodder shrubs on milk production and their value at the household and regional level and (2) the contribution of research by the World Agroforestry Centre toward strengthening the impact of fodder shrubs. The study is a synthesis of previous studies related to dissemination, adoption and impact combined with two new analyses, one quantitatively measuring the impact of the shrubs through econometric analysis and the other a qualitative analysis to better understand constraints on adoption and gender issues related to participation and control of benefits from fodder shrubs. Among the study findings are that fodder shrubs have been widely adopted in East Africa, by an estimated 205,000 smallholder dairy farmers by 2005. Women were active in planting shrubs, as monitoring found almost half of planters to be women. Several studies have confirmed that shrubs do have an impact on milk production. While feeding trials have found that 1 kilogram of calliandra increases milk production by 0.6–0.8 kilograms, a new survey of farmers’ perceptions in Kenya found the effect to be about half as large after controlling for the effects of breeds, season and other feeds. Whether the effect is the lower or higher estimate, the overall impact of theshrubs in terms of additional net income from milk is high, at US$19.7 million to $29.6 million in Kenya alone over the past 15 years.

Full report in pdf

An interesting study by Wageningen University which unfortunately ignores completely livestock in the system, crop residues playing a major as feed. System specific trade-off analyses are certainly needed to assess competitive use of crop residues to either feed animals, maintain soil productivity or produce energy looking both at short and long term impacts on livelihoods and system productivity.