feed it to genetically-improved stall-fed cows, from which they produce manure. They apply the manure along with chemical fertilizers to fields planted with hybrid maize varieties and often intercropped with nitrogen-fixing legumes. This integrated maize-livestock farming system is more labor-intensive and land-saving than the traditional farming system, in which livestock is grazed without much interaction with crop farming.

It is worth noting that this highly complex farming system is indigenous and represents a novel combination of technologies that has not been researched as a system so that the best combination of inputs and the optimum timing of their application is unknown.

# **7.2 Rice**

A series of empirical studies of rice farming were conducted based on household data collected in Mozambique, Tanzania, Uganda, Ghana, and Senegal published in Otsuka and Larson (2016). As the studies reveal, rice is a promising crop in Africa and one well suited to technologies currently used in Asia (Otsuka and Larson, 2013; Estudillo and Otsuka, 2013; and Nakano et al., 2013).

In the Senegal River Valley, paddy yields average 4.5 tons per hectare, highest among the five countries studied. Rice farmers in the Senegal River Valley have access to an irrigation facility with ample supply of water, adopt Asian-type semi-dwarf modern varieties, apply chemical fertilizers amply, and practice improved management such as bunding, leveling, and straight-row planting (Sakurai, 2016). Yields are comparable with yields observed in Asia’s irrigated areas in the late 1980s (David and Otsuka, 1994). Irrigated yields in Tanzania were lower, averaging 3.7 tons per hectare, partly because of lower quality irrigation facilities and partly because of the incomplete adoption of improved management practices (Nakano et al., 2016). Irrigated yields in Mozambique ranged between 1.6 to 2.0 tons per hectare, well below the average of 2.2 tons in SSA (FAOSTAT, 2015). This lower yield can be attributed to low-quality irrigation facilities, inadequate chemical fertilizer application, the use of old varieties, and the low adoption of improved management practices (Kajisa, 2016). Thus, it is clear that irrigation alone is not sufficient to achieve high rice yields.

Njeru et al. (2016) observed paddy yields as high as 5 tons per hectare in the Mwea irrigation scheme in Kenya, where improved management practices were widely adopted, even though high-quality but low-yielding basmati varieties are grown. In some areas of the Mwea irrigation scheme, where varieties developed by IRRI were grown, yields of 8 tons per hectare were obtained. It is thus possible to achieve high yields in irrigated areas in Africa if improved varieties and chemical fertilizer are combined with improved management practices.

Still, achieving a sweeping revolution in rice will require improvements in rainfed rice yields, since 85 percent of lowland paddy field in SSA is rainfed (Balasubramanian et al., 2007). Rainfed yields ranged from 0.8-1.0 ton per hectare in Mozambique, 2.0 tons in Ghana, and 2.3-2.5 tons per hectare in Uganda. The higher average yields in Uganda are close to the average yield in rainfed areas in Asia in the late 1980s (David and Otsuka, 1994). It is important to note that management training programs were not implemented in Mozambique, but were in rainfed areas in Uganda and Ghana.

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