根钻和图像法测定棉麦套种及单种作物根长密度的精确性研究

【目的】研究田间根钻取样结合计算机图像软件分析方法测定棉麦套种及单种作物根长密度的精确性。【方法】结合田间根钻取样,分别用图像法(DT-SCAN图像软件分析法)和直尺法(常规人工直尺测量法)测量根长密度,通过2002―2013年试验获得的3423对根长密度数据分析图像法的精确性,使用根均方差描述图像法测定值(模拟值)与直尺法测定值(观测值)之间的一致性。【结果】2种方法测定根长密度的相关性较好,图像法的精确性较高。对可能影响图像法精确性的因素分析表明:(1)在不同种植模式下图像法的精确性表现为小麦单种模式棉花单种模式麦棉套种模式;(2)随着土壤深度增加,图像法的精确性增加;(3)在麦棉套种模式下图像法的精确性从麦幅到棉幅逐渐提高,在小麦单种模式下行上大于行间,在棉花单种模式下行上小于行间;(4)在棉花开花前图像法的精确性表现为棉花单种模式大于麦棉套种模式,在棉花开花后表现为棉花单种模式小于麦棉套种模式。【结论】田间根钻取样结合计算机图像软件分析方法测定棉麦套(单)种作物根长密度的精确性较高,该方法成本低、测定速度快,能更好地扫描并分析计算棉花的细小侧根,具有较强的先进性和较高的可靠性。

Improved Accuracy of Root Length Density Measurements for a Wheat and Cotton Intercropping System or Monocultures by Combining Root Auger Sampling and Image Analysis Methods

[Objective] The study objective was to improve the accuracy of root length density measurements for a wheat and cotton intercropping system or monocultures using a method that combines field root auger sampling and computer image analysis. [Method] Following field root auger sampling, root length density was measured using an imaging method (DT-SCAN image analysis software) or a ruler (conventional measurement method). The accuracy of the imaging method was assessed using 3423 pairs of root length density data collected from 2002 to 2013. The consistency between the imaging method data (simulated data) and ruler measurements was assessed according to the root mean square error. [Results] The results of the imaging method were correlated with the ruler measurements, although the imaging method was more accurate. Subsequent analyses revealed that in the wheat and cotton intercropping system or monocultures, the accuracy of the imaging method was higher for wheat monocultures than cotton monocultures. Additionally, the accuracy was higher for cotton monocultures than the wheat and cotton intercropping system. Furthermore, the accuracy of the imaging method improved as increasing depths. For the intercropping of wheat and cotton, the accuracy of the imaging method improved from wheat to cotton rows. More accurate data showed: the imaging method accuracy of the wheat rows were higher than the between-wheat rows for wheat monocultures, and that of the between-cotton rows were higher than the cotton rows in cotton monocultures. Regarding the influence of cotton growth periods, the imaging method data for cotton monocultures were more accurate than the data for the wheat and cotton intercropping system before flowering. However, the opposite trend was observed after flowering. [Conclusion] The accuracy of the root length density measurements for the wheat and cotton intercropping system or monocultures increased by combining field root auger samples and an imaging method. This improved method is inexpensive, fast, and enables more accurate analyses of fine lateral roots.