Soil aggregation with various cover crops in Ginkgo biloba L. plantations

Abstract

Ginkgo biloba is an exotic plant for Ukraine that is nowadays becoming popular for parks and landscape gardening. Raw materials (leaves) of these plants are used as medicinal, and in the context of organic production has pharmaceutical significance. At Sumy National Agrarian University fields Ginkgo biloba is grown by seedling method, young seedlings are transplanted into the open ground, in an area where the plants are grown without chemical synthetic fertilizers and pesticides. Row spacing between Ginkgo plants is 3 m and in case of high temperature and dry growing season the survival rate is reduced. The use of cover crops in the rows of Ginkgo biloba can help the plant cope with temperature stress, regulate the structural and nutrient status of the soil. We conducted one experiment with some common cover crops for Forest-steppe of Ukraine such as a phacelia, white clover, red clover, ryegrass, sainfoin, white mustard during growing seasons 2019‒2020. Sites planted in the spring between the rows of Ginkgo. At the end of August, soil samples to a depth of 0‒10, 10‒20, 20‒30 cm were collected to determine the structural and aggregate composition. These samples after reaching the air-dry state were sieved (dry method) and determined the percentage of soil particles with different diameters and structural coefficient soil. The percentage of agronomically valuable structure depended on the mechanical tillage on the site without and with cover crops, weather conditions. In the site without cover crops with mechanical tillage for weed control, the highest percentage of aggregates with a diameter of 10‒0.25 mm and coefficient of structure in layers of 0‒10 and 20‒30 cm was obtained. White mustard and white clover cover crops have shown the best result in good soil aggregation in the 0‒10 cm layer. In the layer of 10‒20 cm, the coefficient of structure was the highest in sites with white clover, respectively agronomically valuable structure was 69.6 %, slightly less with mustard 68.3 % and sainfoin 68.8 %. In a layer of 20‒30 cm sainfoin and clover among other cover crops showed the best result, the coefficient of structure was 2.7. Lastly, further research is needed to choose the best cover crop for Ginkgo biloba young plantations which help the plants to pass strongly through to environmental stressful condition. Additional researches are needed for cover crops selection and their mixtures, terms of sowings, times of cutting should be studied.