Population Stand Monitoring Of Cane Using Coefficient Of Variance Of Canopy Reflectance-Based Vegetation Index Readings.

The type of planting materials and seeding rate can influence early cane (Saccharum sp) stand population, number of millable stalk, and overall cane yield. Current methods for determining plant population and number of millable stalks are by manual counting or plot weight method. The use of remote sensing technique offers an advantage in terms of time and labor but is a relatively new concept in energy cane production. In 2012, a field experiment was initiated at the LSU AgCenter Sugar Research Station in St. Gabriel, LA to (1) establish the relationship between early plant stand population and number of millable stalks, and (2) determine if coefficient of variance (CV) among canopy reflectance-based vegetation index (VI) readings is related to plant stand population and number of millable stalks. Treatments were arranged in a split plot in randomized complete block design with four replications. Two planting schemes were designated as the main plot (whole stalk and billets) and six varieties as sub-plot (Ho 02-113, US 72-114, Ho 06-9001, Ho 06-9002, L 01-299, L 03-371).  Population count was done one and two months after planting, and the following spring along with the collection of canopy reflectance readings using 2- and 4- band handheld GreenSeeker^TM active sensors. Population count of billet-planted cane was 152% higher than the whole stalk-planted cane two months after planting. The early population stand advantage of billet-planted cane was translated to a higher millable stalk count compared with the whole stalk-planted cane at the grand growth phase. The population stand at tillering stage of both billet- and whole stalk-planted cane had a slightly strong positive relationship with millable stalk count with r² values of 0.43 and 0.42, respectively.  Weak positive relationships between CV of the VI readings and actual plant population at tillering stage were obtained with r² values of 0.22 and 0.26 for whole stalk- and billet-planted cane, respectively. The initial results of this study showed some indications that CV of VI readings had relations with cane population stands. Additional data is needed to confirm these initial findings.