![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
The effects of two nutrient rates (Nutricote at 1.0 or 3.0 kg/m3 of potting mix), three plant densities (128, 256, and 384 tubers/m2), and three stem pruning/leaf removal treatments on tuber weight and the incidence of secondary tuber production in Sandersonia aurantiaca (Hook.) were assessed in a factorial experiment. The pruning/leaf removal treatments were an unpruned control, stem pruning just below the lowest flower at early flowering, and a leaf removal treatment (leaves stripped from below the lowest flower at early flowering). Secondary tuber formation was significantly affected by both nutrient rate and plant density, but not by the pruning treatments. The higher plant density reduced mean secondary tuber formation from 75 to 45%, and the lower nutrient rate decreased secondary tuber numbers from 64 to 55%. There was no significant interaction between plant density and nutrient rate. At the lowest density and high nutrient rate the incidence of secondary tubers was 79% compared to 38% at the highest density and low nutrient rate. Commercially, this is still unacceptably high. Mean daughter tuber weight, including the weight of tubers with attached secondary tubers, was reduced at the lower nutrient rate (14.4–11.8 g), with increasing plant density (15.6, 12.8, 10.9 g) and with pruning (14.7 g in the uncut control compared with 10.3 g in the pruned treatment). Leaf area per plant was reduced both at the lower nutrient rate and by the pruning/leaf removal treatment, but it was not affected by density. The reduced tuber weight with increased plant density was probably the result of to greater levels of interplant shading.