Spatial variability of maize leaf area and relationship with yield

Leaf area is an important factor affecting crop yield. However, leaf area has spatial variability and the relationship between leaf area and yield have scale dependence. For these reasons, we establish multifractal model of maize (Zea mays L.) leaf area and joint multifractal model of maize leaf area and yield. The experiment was carried at the Xiangyang base of Northeast Agricultural University. The size of experimental plot was 9,216 m2 which included 64 sampling points. The spatial and temporal variability of maize leaf area was studied with traditional statistics and multifractal methods, and the relationship between maize leaf area and yield at multiple scales was analyzed with the joint multifractal method. Multifractal theory can effectively characterize spatial and temporal variability of maize leaf area and multiscale relationship between leaf area and yield. Maize leaf area exhibited a moderate degree of variation which first decreased then increased with the change in the growth stage, and spatial variability at different growth stages was mainly caused by low leaf area values . At the observed scale, axis weight per ear, ear weight, and grain weight per ear were most significantly related to maize leaf area at the milk, filling, and jointing stages; at the multiscale level, axis weight per ear was most significantly related to maize leaf area at the tasseling, filling, milk, and jointing stages, and ear weight and grain weight per ear were most significantly related to maize leaf area at the tasseling, filling and ripening stages. Core Ideas Maize leaf area had moderate variation at different stages in this region. Degree of maize leaf area variation first decreased and then increased with growth stage. Spatial variability of maize leaf area at various stages was mainly caused by low leaf area value. Multiscale analysis could reveal deep relationship between maize leaf area and yield.