Agriculture is an important activity in both Bagamoyo and Rufiji Delta. About 65 percent of the people in Bagamoyo and over 70 percent in Rufiji Delta consider farming their first priority. Main crops grown include paddy rice, cassava, cashew nut, coconut, maize, banana, simsim, millet, sweet potatoes, fruits, vegetables, and legumes. In the Rufiji Delta, cultivation of rice is very important for the survival of the people, to the extent that farmers believe “without paddy cultivation, many people would have died here.”6 Rice is harvested twice a year in some of the areas.
Agriculture remains small-scale due to economic, social, ecological, and institutional problems. Forty percent of the farmers cultivate 1 to 2 acres, about 30 percent cultivate 2 acres, and 30 percent cultivate 3 to 5 acres. In the Rufiji Delta, farms are much smaller and fragmented. In both Bagamoyo and Rufiji, farmers stated that they expanded their farms because they needed to increase incomes, to get more yields, and to be able to support big families. These responses indicate some of the driving forces behind the expansion of farms at the local level. However, in Bagamoyo, only 25 percent of the people expanded their farms by about 2 acres within the last five years, while in Rufiji Delta, only 30 percent were able to expand by 0.5 acres within the same period. Overall, about 70 percent of the farmers in Bagamoyo and Rufiji were unable to expand their farms due to shortage of land and farm implements.
Thus, at a local level, expansion of agricultural area is a direct cause of habitat change. New farms are being opened up in the Rufiji Delta although such expansion is illegal because the government has prohibited further clearing. Farmers are advised by the government to plant mangroves in their paddy farms and are allowed to cultivate paddy until the mangroves have grown up. Then the farmers must vacate the area. This policy has garnered strong criticism from the farmers. One farmer in Mfisini village said, “We are really surprised by this government, we do not know what they are thinking about us. We are required to plant mangroves in our paddy farms, will they send us food in future?” Farmers have not been told where to go after the mangroves in their rice fields have grown up.
Some of the most crucial ecological problems for agriculture include inadequate land, inadequate fertility (for Bagamoyo), diseases (for cashew nut and coconut), vermin, and pests. Likewise, agriculture causes ecological damage. Crabs found in the sediment affect rice seedlings. Farmers respond by using DDT to kill the crabs (Semesi, 1991), but it also kills other species. Farmers in the Rufiji Delta continue to use DDT perhaps due to lack of alternatives for dealing with the problem or due to ignorance of its effects. Agriculture is also affected by natural processes. For example, Rufiji River changed course some years ago, resulting in changed patterns of erosion, deposition, and salt penetration into different parts of the Delta. Some rice farmers reacted to these changes by clearing mangroves and introducing rice into areas that now experience less salinity (Sandlund, et al, 1997).
Shifting cultivation was a major agricultural system in the Rufiji Delta but has become less common as the land shortage has worsened. Under shifting cultivation, yields are initially high in a newly opened rice field in the mangroves, but decline after the third year, and the field is abandoned due to weed invasion by the seventh year (Rufiji Environmental Management Project, 1998). This practice led to clearing of mangroves every time a new field was opened. Shifting cultivation is still a threat to the mangroves despite the ban on expansion and opening of new farms in the Delta.