马铃薯植株高度对FAO-56修正作物系数和实测作物系数的响应差别

摘要

This study was conducted to establish a simple convenient method for calculating crop coefficient, and provide a certain basis for the research of the em-pirical formula for calculating crop coefficient with plant height which could be mea-sured conveniently with regional differences, especial y for the establishment of accu-rate irrigation schedule of potato in Yunnan. By the field experiment on potato under the condition of drip irrigation, it was found that the models of plant height with corrected FAO-56-recommended K and measured K were a quartic polynomial and a cubic polynomial, respectively, and the polynomial of potato plant height with measured crop coefficient was simpler with higher degree of fitting; and the differ-ences between the period with the highest change rate of potato plant height and the periods with the greatest FAO-56-recommended K and measured K exhibited a differences of 3 d. In conclusion: In the future study of simple or empirical formula calculation of crop coefficient, plant height should be considered as a main depen-dent variable in that the calculation result would be closer to the measured crop coefficient with the problem of regional difference existing in the FAO method solved and the formula might be simpler; and the irrigation time of potato should be 3 d earlier than the irrigation time determined according to the corrected FAO-56-recom-mended crop coefficient , especial y in the key water requirement stages of potato.%为研究计算作物系数寻找到简单便捷方法，通过便于测量及具有地域差异性的植株高度来计算作物系数经验公式研究提供一定基础；同时为云南地区马铃薯植株精准灌溉制度提供研究基础及其参考。通过滴灌条件下大田种植马铃薯试验研究方法，试验数据拟合植株高度与 FAO-56修正 K值、实测 K值的模型，分别为四次多项式和三次多项式，马铃薯植株高度与实测作物系数多项式更简单且拟合度更高；分析马铃薯植株高度变化速率最快时期分别与 FAO-56修正 K值和实测 k值最大时期相差天数，为3 d。得出：(1)在今后研究简单作物计算中，植株高度是一个主导因变量，它能解决FAO-56 K值的地域差异性，用植株高度计算 K值将会更接近实测 K值及其计算式会更简单，为简单方法提供依据。(2)通过FAO-56修正K值研究马铃薯作物需水及其灌溉制度，在灌溉时间上，通过 FAO-56计算出来确定的灌溉时间，尤其是在马铃薯需水关键期，应提前3d进行灌溉。