after the research results of rice crop farmers in eight countries are summarized by IRRI, classified by traditional and improved varieties, irrigated and rain-fed fields, and rainy and dry seasons for countries which supplied data, as shown in Table 1. (5)
(1) Three factors of improved varieties, increased fertilization and irrigation: Technological essential of the Green Revolution is Biological-Chemical Technology (BC Technology), and it is certain that if the three basic factors which yield the best volume per hectare are accomplished, such as high yielding improved varieties as the bio-technology element, chemical fertilizer which results from the chemical industry developments, and irrigation facilities are in place to raise the effectiveness of both BC technologies, it will become complete.
(2) Increased fertilization and increased yield of improved varieties: High yields in the Philippines result from an average of more than 150 kilograms of fertilizer per hectare, but at the other end of the spectrum, Cambodia is much lower at 40 kilos per hectare using the same improved varieties and irrigation conditions.
(3) Low fertilization and low yields of the traditional varieties: The average amount of fertilizer used is quite low for the traditional varieties, and the yield from rain fed fields is also low for all countries.
(4) Price ratio between fertilizers and rice, and investing in fertilizers: If the price ratio is more than 200% greater, the investment in fertilizers is low (in Philippines, Thailand, Nepal etc.).
(5) Effect of irrigation on improved varieties: The yield from irrigated fields is clearly higher that rain fed fields (in Philippines, Indonesia etc.).
(6) Effect of irrigation on traditional varieties: The difference of the yield is not clear (Cambodia).
(7) High yield from improved varieties/Irrigated fields in the dry season: The yield is high if there is sufficient water supply and sunshine as the volume of the improved varieties from the irrigated fields in the dry season is high compared to the rainy season (Philippines and Bangladesh).
