Biomass in crop-livestock systems in the context of the livestock revolution uri icon

abstract

  • Mixed crop-livestock systems are the dominant source of livelihood supporting morethan 80% of people living in the developing world and producing 50% of worldcereals, around 34% of the global beef production and about 30% of global milkproduction. However, mixed systems are coming under increasing pressure with theirhuman population predicted to increase from 1,099 million in 2000 to 1,670 millionpeople in 2030 and their cattle population to increase from 230 million to317 million from 2000 to 2030. Coupled with this increase in human and livestockpopulations, cereal yields have been stagnating in sub-Saharan Africa (SSA) for thelast 40 years (in contrast to growth rates of 1.5-2% per year for the rest of thedeveloping world), with most increase in overall cereal production arising fromexpansion of arable land. Such trends cannot be maintained as land suitable forcropping is scarce, and additional cropland might also be more marginal and subjectto greater climatic risks. There is increasing pressure on biomass in mixed systems andthere are strong needs to find ways out of this ??biomass trap?? through increasingoverall biomass yield and fodder quality and through increasing the efficiency oflivestock production. Biomass from crop residues (CR) is used as a feed resource andas mulch to improve crop yields. Biomass is becoming scarcer and competition for CRis becoming more severe. This is reflected in changes of CR use from grazing toharvesting and storage, longer distances across which CR are transported andtransacted and decreasing CR to grain ratios. The predicted increase in demand forlivestock products, the so-called livestock revolution, will further fuel feed demand andincrease the usage of CR for livestock feeding. Use of CR for mulch and conservationagriculture demands about 2 to 3 tons of CR per hectare which is often equal to theirtotal yield under rain-fed conditions in the semi-arid tropics. Multidimensional cropimprovement can mitigate competition for biomass by increasing CR quantity and byimproving fodder quality. Increased CR yield will facilitate partitioning of CR betweenlivestock and soil improvement and improved CR fodder quality will supportintensification of livestock production where more animal sourced foods (ASF) can beproduced with less feed. It is important to realize that feed biomass requirement is verycontext specific and decreases with increasing per unit animal productivity

publication date

  • 2013