Contour hedgerow intercropping in the mountains of China: a review

Abstract

Hedgerow intercropping systems were introduced in China in early 1990s. Achievements in research and extension of contour hedgerow intercropping in China during the past 15 years are reviewed here. Results reported in over 70 published papers have shown that hedgerow intercropping contributes to soil and water conservation, soil fertility amelioration, land productivity improvement, bioterrace formation, and gives more options for income generation based on local resources in mountain areas. Research and demonstration works on contour hedgerow systems have achieved success by integrating local resources and needs into the system, especially in the dry valleys of the upper reaches of the Yangtze River, and the Three Gorges region. Contour hedgerow intercropping has attracted the attention of researchers, policy-makers, and farmers, and has been taken as an alternative to implementation of the Grain for Green policy, and ecological reconstruction and restoration today. To date, hedgerow intercropping has been demonstrated and applied practically on sloping land in more than six provinces of China, particularly Sichuan, Guizhou, Shanxi, Shaanxi, as well as in the Three Gorges region of Chongqing and Hubei Province. The intercropping system has also been practiced as an optimized technology for conserving farming on sloping lands, improving cash income, and reducing agricultural risks in depressed mountainous regions in southwest and northern China over recent years. Some misunderstandings and problems in studies and extension of the system in China are summarized and clarified, and some recommendations for further research and expansion of the system are also presented in this paper.

Tree species and pruning regime affect crop yield on bench terraces in SW Uganda

“…Contour planting of trees has also proved successful in limiting runoff and erosion and improving fertility on hillslopes under a wide range of climatic conditions in China (Sun et al 2008). …”

“…However, agroforestry does not always provide a solution, as negative interactions may occur due to competition with adjacent crops (Ong et al 2006(Ong et al , 2007Sun et al 2008). Some reports suggest there is little competition on bench terraces due to spatial or temporal separation of the trees and crops (Cooper et al 1996), although farmers have reported that trees may compete with adjacent crops (Wajja-Musukwe et al 1997;Sun et al 2008).…”

“…Some reports suggest there is little competition on bench terraces due to spatial or temporal separation of the trees and crops (Cooper et al 1996), although farmers have reported that trees may compete with adjacent crops (Wajja-Musukwe et al 1997;Sun et al 2008). This is important as crop production on the lower terrace is vital for food security during the first 2-3 years after planting while farmers await the benefits of trees grown on the upper terrace.…”

Effects of long-term fertilization and mulch on soil fertility in contour hedgerow systems: A case study on steeplands from the Three Gorges Area, China

“…Crops are produced in the alley-like spaces between the hedgerows (Sun et al 2008). Hedgerows can reduce the generation of runoff, and can intercept eroded sediments from the upper slopes so that soil fertility can be conserved (Lal 1989a).…”

“…Shen (1998) and Zhao et al (2004) reported that bio-terraces can form on 15-25°slopes after 4-7 years by planting hedgerows. The cost of bio-terraces is only 3-17% of that of engineered terraces, and they are also much more stable (Sun et al 2008). However, due to the limited soil depth in the Three Gorges Area, this type of terrace is often associated with high spatial variability in soil fertility and crop responses.…”