Effect of Humisol on survival and growth of nursery grafted walnut (Juglans regia L.) plants

The effect of Humisol organic fertiliser (150 g humic acid/l + 20 g/l mineral nutrients) on plant survival and growth of five walnut cultivars grown over a period of two years in the nursery were evaluated. Walnut plants treated with Humisol at the total annual rate of 0.75 ml/plant had a significantly higher survival rate in the first year, greater height and diameter in both years, and a higher percentage of first-class plants at the end of the second year, as compared to untreated control plants. Soil application of Humisol led to better performance of nursery grafted plants, compared to foliar application. Nursery plants receiving 1.5 ml Humisol per year through both soil and foliar application exhibited the best performance in the parameters analysed. In the first year, a decrease in plant growth rate in all treatments was observed in August and September; in the second year, growth rate started to significantly decline in the second half of August.