The Effect of Sulfur-Containing Humic Acid on Yield and Nutrient Uptake in Olive Fruit

Abstract

The combined application of organic and mineral fertilizers can be a proper way of nutrition management to increase the yield and quality and to mitigate environmental impacts of chemicals and the pertaining costs. The impact of different rates of sulfur-containing humic acid was studied on yield and nutrient uptake of the fruits of olive “Zard” three-year-old trees in a trial based on a Randomized Complete Block Design with three replications in Shariati College of Tehran, Iran. The studied treatment was sulfur-containing humic acid at four rates of 0, 20, 25 and 30 kg·ha−1, which was applied at two stages. The highest fresh weight, dry weight, chlorophyll b, carotenoid, N and Cu contents were related to humic acid rate of 20 kg·ha−1. The highest fruit length, chlorophyll a and total chlorophyll were observed in control. The highest K, Fe and Mn contents were obtained from plants treated with 30 kg·ha−1 humic acid. Plants treated with 25 kg·ha−1 exhibited the highest P and Zn contents. All in all, the application of sulfur-containing humic acid at different rates had favorable impacts on quantitative and qualitative traits of olive fruits.