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以往,根据遥感资料估算作物产量,多数用的是经验方法。本文提出了一种具有生物学基础的水稻估产模式。该模式包括两项基础性的工作。(1)利用Baerema在澳大利亚新南威尔士州的Riveri-na地区,在水稻整个生长季中获得的三个水稻品种、两种播种方式(空播和拖拉机播)共6组实测的叶面积指数值LAI,通过LAI与积温间关系的分析,得到一条规一化的LAI曲线,称叶面积指数轨线(LAI trajectory)(2)根据太阳辐射在植冠层内的传输理论,利用实测的水稻叶角分布和常规日射资料,用模拟计算的方法,得到水稻冠层对光合有效辐射PAR日截获率IPAR_d与LAI间的关系。并用实测资料对此作了检验,结果表明模拟计算结果是可取的。由此,我们只要知道了水稻扬花前不久某一天的LAI,利用上述两项基本关系及当地的辐射、温度资料,便可推算植冠层从扬花到生理成熟期间对光合有效辐射的截获总量TIPAR,进而再假定水稻的灌浆直接取决于对PAR的总截获量TIPAR,根据水稻籽粒产量与光能截获间的转换效率,便能估算水稻产量。
In the past, crop yields were estimated from remote sensing data, mostly using empirical methods. This paper presents a biologically based rice yield model. The model includes two basic tasks. (1) Using the three rice cultivars obtained by Baerema in the Riveri-na region of New South Wales, Australia during the entire growing season, two groups of seeding methods (air-sowing and tractor sowing) were used to measure six measured leaf area index values LAI. Through the analysis of the relation between LAI and accumulated temperature, a normalized LAI curve is obtained, which is called as LAI trajectory. (2) According to the transmission theory of solar radiation in the canopy layer, using the measured rice leaf Angle distribution and conventional data of solar radiation, the interception rate of photosynthetic active radiation (PAR) IPAR_d and LAI between rice canopy and rice canopy were obtained by means of simulation calculation. The test results show that the simulation results are desirable. Thus, as long as we know the LAI of a certain day just before flowering, we can calculate the total amount of photosynthetically active radiation intercepted from flowering to physiological maturity using the above two basic relationships and local radiation and temperature data TIPAR, and then assume that the rice filling directly depends on the total intercepted amount of TIPAR to PAR, and rice yield can be estimated according to the conversion efficiency between rice grain yield and light interception.