全球变化知识资源中心

The Central Dry Zone (CDZ) of Myanmar is home to an estimated 12 million people, provides 35% of Myanmar's grain cropping, but is underdeveloped and food-insecure. We examined the cropping systems of the CDZ to understand the biophysical drivers of those systems, the need for change to improve productivity and sustain ability, and how future research and extension might be framed to best serve the rural communities. Data were sourced from (i) published empirical studies and web-based documents produced by the Myanmar Government and international agencies and (ii) a face to face survey of 190 Central Dry Zone farmers. Our analysis indicates that CDZ cropping systems have low productivity which threatens sustainability and future production. Farmers practice traditional cultivation and remove crop residues to use as animal feed, which together deplete soil organic matter reserves and expose the soil to physical degradation. The soils are generally coarse-textured with low water retention, high leaching potential and nutritionally deficient. Nutrient inputs from farm-yard manure and mineral fertiliser are also low. As a consequence, crop nutrient deficiencies are widespread across the CDZ and a major productivity constraint. Mineral-fertiliser use is increasing however, but farmers are conscious of the need for high-quality advice on how best to use these inputs. A narrow range of crops is grown in the CDZ with ca. 80% of the land used to grow pulse and oilseed legumes and sesame and sunflower, but few cereals. The lack of crop diversity exposes farmers to market price fluctuations and the lack of balance between broadleaf and cereal crops results in disease and yield loss. Climate changes further threaten the sustainability and economic viability of grain cropping with increasing temperatures, more erratic rainfall and fewer but more intense rainfall events during the monsoon. Consequences are more floods and dry periods and increased risk of soil erosion. The imperative now is to transition the upland cropping of Myanmar's CDZ to embrace the basic elements of conservation agriculture, i.e. crop diversity, effective weed control, in situ retention of crop residues, optimised crop nutrition and minimal-to-zero soil disturbance, to sustainably increase crop water use-efficiency and system productivity.