Rainwater harvesting agriculture in Gansu Province, people's Republic of China

While the problem of soil erosion in China's semi-arid northwestern provinces receives the lion's share of national and international attention, farmers here are generally more concerned about the availability of water. Since groundwater resources are often unavailable, farmers of the region must rely on rainfall to supply their crops and household needs. Precipitation is low (250-550 mm) and droughts are a common occurrence. Before the revolution of 1 943, drought often brought famine in itf wake. During severe dry spells in recent years, the Chinese government has hati to ship in water and grain to villagers by truck. In terms of agricultural production, the problem is more the intensity and timing than the scarcity of rainfall. Rainfall tends to be concentrated in the form of intense thunderstorms which cause tremendous amounts of erosion. Moreover, approximately 60% of the annual precipitation occurs in the three months between July and September, which is not when crops need rainfall the most (Yang 1990). In the prevailing rain-fed farming system, the limiting period is from May until the beginning of rhe rainy season in July (Li et al 1996). Crops which are planted in late March …