Modelling of production systems for estimating dairy and beef cattle production based on floar of solar and fuel energy.

比较了几种不同种植方式和放牧草地的光能固定效果和生物量生产的能量输出与燃料利用的辅助能量输入的比值，在低施肥水平的农户管理条件下，牲畜可利用牧草（牧草有效）的生物量产量为1400 ~ 6700 kg/ha/年。这些值对应于从年太阳能输入到放牧牛可用的牧草的固定能量的转换效率的0.20%。牛以平均0.5 kg/头/天的体重增加（日增重）的速率生长。将日增重换算成单位面积放牧草地的能量产量，可以计算出养牛生产对太阳能总投入的效率。放牧草地的光能固定效率较低，但能量输出与燃料能输入的比值较高。管理良好的放牧牧场的生物质能源产量对农场的燃料能源输入的比例，而不降低太阳能固定的效率的高价值。每投入1 KJ的燃料能，在水稻籽粒中产生0.5KJ，在玉米、燕麦等土壤作物的青贮饲料中产生2.5KJ，在放牧草地中产生6.2- 8.6KJ。

Efficiencies of solar energy fixation and the ratios of energy output by biomass production to subsidiary energy input by fuel use were compared among several types of cropping and grazed oasture.The biomass yield of herbage available for animals (herbage available) is ranging from 1400 to 6700 kg/ha/year under the conditions of farmer's management with low level of fertilizer application. These values correspond to 0.20 % of the conversion efficiency from the annual solar energy input to the fixed energy of the herbage available for grazing cattle.The cattle grew at the rate of 0.5 kg/head/day in body weight gain (daily gain) on an average. Converting the daily gain into the energy yield per unit area of the grazed pasture, we can calculate the efficiency of cattle production to the total input of solar energy. The value of efficiency was only 0.0029 % on an average.Grazed pasture showed lower efficiencies of solar energy fixation, but higher ratios of energy output to fuel energy input. Well managed grazing pasture gave a high value of the ratio of biomass energy yield against on-the-farm fuel energy input without reducing the efficiency of solar energy fixation. Input of 1 KJ of fuel energy on-the-farm produced 0.5 KJ in rice grain, 2.5 KJ in silage of soiling crops such as corn and oat and 6.2-8.6 KJ in grazed pasture.