Rooting of apple-tree layers m.9 depending on substrate for hilling

Abstract

The article is devoted to the investigation of the influence of mulching materials on the parameters of root system of the layers of apple-tree clonal rootstock M.9 type. Propagation of planting material for intensive apple orchards is based on highquality vegetatively propagated rootstock material, which is obtained from the mother plants. High efficiency of mother plants is achieved by hilling with an organic substrate, which improves root formation, creating favorable air, heat and water regimes at the base of a shoot, and significantly increases the rooting of the layers. The use of sawdust contributes to the development of the root system of layers. Since the sawdust requires an annual update, it is relevant to find a substitute for them and reduce their use, in particular through the use of polyurethane pellets. In 2012-2014 the research was conducted in the training and production department of Uman National University of Horticulture.  In 2002 the mother plantation of rootstock M.9 T337 was laid down with the virus-free plants in the way of horizontal layers with the scheme of planting 1.4 x 0.33 m. The soil of the experimental plot was black earth podzolized heavy loam with humus content of 3.5%; pH of the salt extract is 5.9. There were 10.8 mg / 100 g of easily hydrolyzed nitrogen (according to Kornfield), 11.9 – mobile phosphorus and 10.1 mg/100 g of exchangeable potassium (according to Chirikov) in the arable soil layer. The soil density is 1.18-1.20 g/cm3, the lowest field moisture capacity is 30.3% and 28.6% in arable and subsoil layers, respectively. The relief of the experimental plot was flat with an insignificant southern slope; the subsoil waters were located at a depth of 10-15 m.
The influence of a mixture of hardwood sawdust (with the exception of oak) with the addition of 25, 50 or 75% of foam-polystyrene granules with a diameter of 0.3–0.8 cm on the development of the root system of the layers was studied.  The first hilling was performed with a mixture of sawdust with granules at a shoot height of 20 cm, and the next two hillings - up to a height of 40 cm - was carried out with sawdust. The replication of the experiment was fourfold with a randomized arrangement of the plots; at each registration plot there were 10 recorded mother plants. Recordings and observations were conducted by generally accepted methods. The statistical processing of the results was carried out by the dispersion and correlation analysis of program "Statistica". It has been established that the greatest length and number of roots of M.9 layers are achieved at the first hilling of mother plants with polystyrene foam granules, which exceeds the result of using sawdust by 21.0–62.7%, respectively. With an increase in the proportion of granules in the mixture with sawdust, the indicators, in general, increase linearly. The length of the root system of layers M.9 depends on the applied substrate (influence of a factor is 92%) with a maximum value when hilling with a mixture of sawdust with 75% of polystyrene foam granules.