Crop Diversification in the Asia-Pacific region - United Nations in ...

coupled with better management practices. In most of the countries, estimated area plantedto HYVs has increased as shown in Table 1.Table 1. Estimated Areas planted to HYVs and Hybrid Rice(percentage of total rice areas) in Major Rice-Producing Countries of AsiaCountryBangladeshIndiaIndonesiaMyanmarPhilippinesSri LankaVietnamChina1989 1997HYVs 1 Hybrid Rice 2 HYVs Hybrid Rice 340.7--65.0--62.0--70.0Neg73.0--85.0--51.9--51.9--88.5--93.0--90.0--95.0------85.0Neg--50.045.050.01 IRRI, 19952 Yuan, 19963 FAO estimate (Neg = hybrid rice was planted to about 120,000 ha in Indiaand about 180,000 ha in Vietnam)Among other cereals, the highest coverage under modern varieties is for wheat. It isestimated that more than 70 percent of the wheat acreage in major wheat producing countries(Bangladesh, China, India and Pakistan) is under improved varieties. In other crops, use ofimproved varieties is not extensive, but there is plenty of scope as farmers are quiteresponsive to the new varieties and have increasingly adopted them as and when they arereleased for cultivation.4.5 Protected AgricultureThe most recent addition to crop diversification is the introduction of crop productionunder controlled environments. This concept known as protected agriculture has made rapidheadway, becoming popular among middle income agriculturists. Protected agriculture orcontrolled environment agriculture is the modification of the natural environment to achieveoptimum plant growth. In these systems various factors of the environment such as air,temperature, humidity, atmospheric gas composition, nutrient factors etc., are controlled.These technological developments coupled with use of high quality crop varieties areintegrated into a system of agricultural production, which is referred to as protectedagriculture.The main forms of protected agriculture include the use of mulches, row covers andpoly-tunnels. It has been a common practice to use organic mulches such as straw, deadleaves, coir dust etc., to modify the environment to make soil more favourable (weed andmoisture control) for plant growth. However, in the recent past these low cost agronomicpractices have received less attention from the farmers. Plastic mulches are also used for theproduction of high-value crops and pineapple plantations in Hawaii. Plastic mulches withdrip irrigation are widely used as irrigation water and fertilizers (fertigation) could be appliedtogether with the added advantage of reducing cost of production. Row covers have alsobeen used since the 1950’s. These are polyester sheets stretched over rows of plants as seen162