Soil parameters, onion growth, physiology, biochemical and mineral nutrient composition in response to colored polythene film mulches

Abstract

The present study evaluated the effect of different colored plastic mulching viz. olive polythene film (OPF), silver polythene film (SPF), white polythene film (WPF), black polythene film (BPF) and blue polythene film (BLPF) on soil properties, growth, physiology, biochemical and mineral nutrient composition in onion bulbs. Soil properties at 0–10 cm depth are variably affected by colored polythene film mulches. The highest values of soil moisture and pH were found when covered with a silver film, whereas black film provided the higher temperature among other types of film. The contents of nitrogen, phosphorus, potassium, and sulfur in the soils were slightly enhanced by mulching. Fresh biomass of shoot, bulb, and root was enhanced by silver colored mulching due to suitable moisture conditions, temperature and nutrients in the root zone. Plant height, number of leaves, bulb diameter and bulb length, were also remarkably increased after mulching where also the utmost values of dry biomass of shoot, bulb, and root were found. Under different colored polythene film mulches, a significant difference was found only for blue-yellow chromaticity (b*) while lightness (L*) and green-red chromaticity (a*) of onion skin did not affect significantly. With the mulching of olive colored polythene film, the skin of onion bulbs exhibited maximum b* values in compare to all mulches and control. Sugars, pyruvate and mineral nutrient concentration in onion bulbs also increased in all colored mulches whereas silver film provided the utmost value almost in all. Comparing all results, silver color polythene mulching is found to be the best choice for better onion growth, physiology, and quality.