Study On The Potential Productivity,Comparative Efficiency And Rational Intensity Of Winter Wheat——Maize Double Cropping System In Hebei

The potential productivity, the degree of developing potential productivity, limiting factors for development of potential productivity and rational intensity of winter wheat- maize(W-M) double cropping system were studied. The potential productivity of W-M cropping system at different planting districts in Hebei was definited. The rational aim of developing potential productivity was proposed. Further, the way and the rational intensity for improving the comparative efficiency of W-M cropping system and achieving the rational aim of developing potential productivity were proposed. An Ithink model was established to compute the potential productivity of W-M system. The simulated results as follows: The potential photothermal productivity is 19780.5-22 105.5 kg/hm2 in l-Iebei. It is 22105.5 kg/hm2 in the planting district of the Middle-Hebei, 19780.5 kg/hm2 in the planting district of the East-Hebei, 20362.5 kglhm2 in the planting district of the South-Hebei and 21262.5 kg/bin2 in Heilonggarig planting district. Forty percent of the potential photothermal productivity can develop because of the rain restrictions in Hebei. Under the local resource conditions, the potential resource productivity is 18789.7 kg/bin2 in the planting district of the Middle-l-Iebei, 16417.8 kg/bin2 in the planting district of the East-Hebei, 16290.0 kg/bin2 in the planting district of the South-Hebei and 15309.0 kglhm2 in Heilonggang planting district. There are appreciable gaps between different potential productivities. The potential photothermal productivity is the biggest of all, then the Max actual productivity, the potential resource productivity and the actual productivity. The actual development degree of W-M cropping system is 48.4-54.5% in Hebei and the rational ecological development degree is 72.2-84.7%, so the developing potential.is great. Giving attiontion to the social profitability, the economic utility and the ecological benefit, the aim of developing potential productivity was proposed under the conditions of the actual level of technology and price. The results as follows: the aim is 14994.0 kglhm2 in the planting district of the Middle-Hebei, 14135.4 kg/bin2 in the planting district of the East- Hebei, 14563.0 kg/bin2 in the planting district of the South-Hebei and 13876.5 kg/bin in the Heilonggang planting district. Under conditions of the actual technology and price, the economic efficiency of W-M system is best in the wheat-field cropping systems in Hebei and it has comparative advantage. While evaluating by composite economic indicators, the W-M cropping system has comparative inferior position in field cropping system. Basing on the resource advantage and the comparative advantage, we can improve the economic utility and the comparative advantage in cropping system by improving properly the yield, regulating the distribution of W-M cropping system and cultivate composition. Technology, fertilizer and irrigation are most important for the potential yield. Technological innovation may improve the potential productivity and the actual productivity. The sixty-three percent of increasing yield was attributed to the technology innovate during the 1980-1999. The thirty-seven point eight percent of the potential resource productivity can develop by fertilizer, and thirty-five percent of the potential resource productivity can develop by irrigation. The intensification of technology is the best way to develop the potential productivity. Now, the input should be intensifie...