Non-rice crops in rice-based farming systems in mainland Southeast Asia

In the five countries of Mainland Southeast Asia (MSEA) that are the focus of this review, there is no questioning the importance of rice within the landscape, in the farming systems, in the diet, and even in cultural terms. Currently, an area of about 32 million ha is cultivated to rice each year (FAOSTAT, 2014), although with multiple rice cropping – with an annual rice cropping intensity ranging from about 1.8 in Vietnam to not much over 1.1 in Laos – the actual area that is planted to rice at some time in any one year is about 22 million ha. The importance of rice cultivation is very clear when these figures are compared to the total and arable land areas of these countries. Of the total land area of about 190 million ha in the five countries, about 19%, or 36 million ha, is regarded as arable. Thus about 60% of the land categorized as arable is planted to rice at some time in any year. While this emphasizes the importance of rice farming, it does not mean that non-rice crops, whether annual or perennial, are not important to the multitude of farming households or to the overall economies of the region. The cultivation of non-rice crops is affected by the available natural resources, particularly climate and soils, by changing market demands, by labour- and capital-availability, by the specific interests of farmers, and, as is critical to this review, by changes in the area and methods of rice production. Examples of all of these factors affecting non-rice crops in cropping systems will be outlined in this chapter.