Canopy Cover and Leaf Area Index Relationships for Wheat, Triticale, and Corn

Previously collected data sets that would bc useful for calibrating and validating Aqua Crop contain only leaf area index (LAI) data but could be used if relationships were available relating LAI to canopy cover (CC). The objective of this experiment was to determine relationships between LAI and CC for corn (Zea mays L.), winter wheat (Triticum aestivum L.), and spring triticale (x Triticosecale spp.) grown under dryland or very limited irrigation conditions. The LAI and CC data were collected during 2010 and 2011 at Akron, CO, and Sidney, NE, using a plant canopy analyzer and point analysis of above-canopy digital photographs. Strong relationships were found between LAI and CC that followed the exponential rise to a maximum form. The relationship for corn was similar to a previously published relationship for LAI <2 m(2) m(-2) but predicted lower CC for greater LAI. Relationships for wheat and triticalc were similar to each other.