| Oasis is the typical agriculture system in inland regions where more than 95 % population live in and more than 90 % matter and energy production were made from. Shihezi oasis includes four sub-oases, Shizongchang (SZC), Xiayedi (XYD), Anjihai and Mosuowan (MSW), and mainly depends on Manas River. At present, many problems such as secondary salinization of cropland, land desertification and soil chemical pollution have seriously threatened the sustainability of oasis agriculture system as a result of the absence of knowledge of agricultural system and poor management.By using the methods of combining investigations and experiments, the research was conducted to identify the characteristics of energy, economics and matter in oasis agriculture system and main results were gained as following:1. Fertilizer was the main aritficial energy input and 77.6%-90.8% of the total artificial energy input was fertilizer energy for the three sub-oasises. Among the crop production systems, maize production has the highest total energy output (307.6±15.5GJ/ha) and net energy output (260.5±16.8GJ/ha), but cotton production has the lowest (110.5±5.0GJ/ha and 51.7±7.6GJ/ha), respectively. The order of energy utilization efficiency of crops was ranged: alfalfa>grape>maize>wheat≈tomato>cotton; and energy input per hectare of crop production system of the three sub-oasises were ranged: shizongchang>xiayedi>mosuowan, and order of the total energy input was XYD>SZC>MSW. Crop production system of XYD sub-oasis has the highest net energy output and that of SZC sub-oasis has the lowest one as a result of excessive energy input. The net energy output of cotton were 37.3% in XYD, 65.6% in MSW and 21.1% in SZC which net energy output of winter wheat was 54.0%, 19.5% and 43.8% respectively. About 30.0% of net energy output came from tomato growth in SZC.2. For the financing input of each crop production systems, 43.4%-49.3% of the total financing input of cotton producion was used by labour, and fertilizer and irrigation was took second place. The main inputs for the wheat production were fertilizer, seed and fertilizer, about 82.1%±0.2% of the total financing input was used by those. The series of total input was ranged: fertilizer>irrigation>machine in XYD and MSW, and this was ranged: irrigation>machine>fertilizer in SZC. The half of the financing input was used to purchase fertilizer and the rest of that was used by irrigation, chamical and machine, and about 82% of the total financing input was used by fertilizer, irrigation and chamical. The main input in alfalfa production was irrigation, machine and fertilizer, and 86% of the total financing input was used by those. For tomato production, about 57.9% of total financing input was used by labour. Maize production has the highest total economic output and net economic income among the crops, 9.0×10~4Y/ha and 3.7×10~4￥/ha, respectively. And cotton production took second place, about 2.5×10~4￥/ha and 1.3×10~4￥/ha, respectively. Maize production has the highest ratio of economic output and input, and wheat production has the lowest one. SZC has higher financing input and total output of the crop production among the three sub-oasises, and XYD was the lowest one. But the series of net incomes of the three sub-oasises were ranged: MSW>XYD>SZC. Cotton was the main income resource for the three areas, and the propotion were 93%, 88% and 62% respectively.3. The highest crop was corn and the lowest ones were cotton, alfalfa and wheat in water use efficiency based on economic yield, total economic input and net economic income. The cotton was lower than alfalfa by the percent of 49.2% and 72.1% separately in the water use efficiency based on total energy output and net energy output. Among three oasis sub-system, the water use efficiency based on yield of SZC is 3.42￥/ha, morn than MSW 1.5 times, and XYD was the lowest; the water use efficiency based on economic net income of MSW was 3.83￥/ha, morn than SZC 0.25 times. There were few different between XYD and SZC in the water use efficiency based on net economic income. The average value was 1.94￥/ha lower than MSW by the percent of 13.2%. XYD similar with MSW was higher than SZC by the percent of 15.3% and 49.9% in the water use efficiency based on total energy output and net energy output, separately.4. The soil organic carbon density of 0-40cm in cotton land is the highest, and in the alfalfa land, the content of total nitrogen,available nitrogen,total phosphorus,available phosphorus are highest. The content of soil organic carbon,total nitrogen,available nitrogen,total phosphorus,available phosphorus which sequence in sub-oasis is: SZC>MSW>XYD. And in MSW, the output/input of nitrogen is the highest of 0.77, which in SZC is 0.69, XYD is 0.43. The differences of the output and input ratio of phosphorus were not significant between the three sub-oasises.5. The forage of the three sub-oasises could supplied occupied 13.0%±2.2% of the total metabolizability energy livestocks needed. And the ratio of net output of the livestock production and the crop production is 9.8%±1.6%.6. Among the environmental loading ratio of different crops, alfalfa is lowest, cotton is hignest, and the sustainalbility index is just the contrary. To the environmental loading ratio, SZC is highest and MSW is lowest, but the sustainalbility index of SZC is not more than the half of the MSW.Agro-system of Shihezi Oasis is dominated by cotton production, maintained by irrigation, drived by fertilizer and is absent of livestock production, which show three "high" properties of high input of energy, water and fertilizers, high output of crop products and high risk of environment and market. Crop production system is characteristized both by intensive input of labor and input of capital and technique. Because of poor forage crop production, the crop production is diffcult to be integrated with livestock production. The forage maize and alfalfa show good benefit of economy and ecology (e.g. high energy use efficiency and water use efficiency) ahd thereby could play an important role in optimization of cropping structure together with reduce of cotton planted area.
|
PDF Full Text Request