基于观测与模拟结合的疏勒河流域辣椒灌溉制度优化

    Irrigation optimization of pepper in Shule River Basin based on observation and simulation

    • 摘要: 集成秸秆沼气先进技术提高工程经济性是秸秆沼气工程可持续发展的关键。为进一步提高秸秆沼气发酵效果,提升沼气工程运行效益,该研究针对秸秆预处理、秸秆厌氧发酵、搅拌优化、沼液回流等关键环节进行了研究和分析,提出了“秸秆青贮-秸秆微好氧水解预处理-优化搅拌CSTR中温厌氧发酵-沼液近全量回流”的秸秆沼气工程集成技术。通过对河北省三河市天龙规模化生物天然气工程1#发酵罐启动过程进行监测与分析,表明该集成技术在实际运行过程中,秸秆干物质产气量可达555.78 m3/t,沼气中CH4体积分数保持在56%左右,H2S体积分数稳定在162×10(6左右,工程启动运行效果良好。上述结果表明,该本研究所提出的秸秆沼气集成技术在实际工程运行中可取得稳定、高效地运行效果。

       

      Abstract: Abstract: In order to overcome the barriers on conducting field irrigation experiments including limited number of treatments and level setting, a large number of influencing factors as well as the high cost of human and material resources, this paper establishes an irrigation scheduling analysis method through combination of field observation and numerical simulation. The method was applied to analyze the water consumption characteristics and irrigation scheduling of pepper under the condition of border irrigation in the Shule River Basin. Field observations included soil volumetric moisture content, crop plant height, meteorological data, and soil physical parameters. The Hydrus-1D model was adopted in the method to simulate the water movement process during crop growth period. The calibration and verification of the model were conducted by using data of measured soil volumetric moisture content in the first and second half of pepper growth period, respectively. RMSE (root mean square error) and RMSD (root mean square deviation) were used to quantitatively evaluate the performance of the model. RMSE reflected the average degree of absolute error between the simulated value and the measured value. RMSD was the standardization of RMSE, and reflected the degree of deviation between the simulated value and the measured value. The calibrated and validated model was used to analyze the water consumption law of the crop growth process, and numerical experiments of the irrigation scheduling scenario were conducted to find the better irrigation scheduling with minimum water stress and deep percolation. The amount of water stress was defined as the cumulative amount of soil water content less than 60% of field capacity in the maximum root layer. The results of the method application showed that the total water consumption of pepper during the whole growth period was 456.76 mm under current irrigation scheduling. The ranking of average daily water consumption intensity was swelling stage > fruit setting stage > flowering stage > maturity stage > seedling stage. The results also showed that there was serious deep percolation loss, and water stress occurred in several growth periods, for the amount of deep percolation in the current scheduling during the whole growth period was 171.56 mm and that of water stress was 39.46 mm. In order to obtain the better irrigation scheduling, 96 new scenarios for irrigation scheduling were developed, which included 6 irrigation amounts for each application and 16 irrigation time intervals. With the increase of TIA (total irrigation amount), WC (water consumption) showed an increasing trend, and then became steady, and the range of TIA for WC peaks was 950-1 120 mm. WS (water stress) showed a trend of rapidly decreasing with the increase of TIA, and became extremely small after TIA exceeded 750 mm. With the increase of TIA, DP (deep percolation) showed a trend of slowly increasing first and then rapidly increasing linearly. According to the principle of minimum amount of deep percolation and water stress, taking into account the operating intensity and acceptability of the farmers, this paper proposed that the border irrigation scheduling of pepper in Shule River Basin should be: 525 mm for the total irrigation amount, 9 times irrigation per year, 30-day interval between 2 irrigations in the seedling period, 15-day interval in other growth periods, and 45-80 mm for the irrigation amounts for each application. In practice, it can be adjusted according to specific climatic conditions and soil moisture monitoring.

       

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