MACROELEMENTS CONCENTRATION IN PLUM TREE LEAVES AND SOIL IN RESPONSE TO ORCHARD FLOOR MANAGEMENT

The aim of the study was to determine the influence of various methods of orchard floor management on extractable mactronutrients concentration in plum leaves and orchard soil. Study carried out between 2013 and 2015. Standard mineral fertilization on experimental plots was applied. Trees of ‘Valjevka’ plum (Prunus domestica L.), grafted onto Myrobalan seedlings (Prunus cerasifera Ehrh. var. divaricata Ledeb.), were planted in the spring of 2008. From 2009 to 2015, the following methods of soil cultivation under tree canopies were introduced: control with limited weeding around tree trunks; spraying with foliar herbicides; mulching with organic waste, i.e. straw with compost; mechanical soil cultivation with the use of rotary cultivators and hoe; weed mowing. The method of soil cultivation had influence on leaf concentration of phosphorus, potassium, magnesium and calcium, as well as soil concentration content of phosphorus, potassium, and magnesium in particular years of the study or as three-year mean. Orchard floor management did not affect leaf nitrogen concentration in any way. The results showed that regular weed control in the evaluated type of orchard is not necessary for properly supplying plum trees with macronutrients.

Soil Nitrogen and Weed Biodiversity: An Assessment under Two Orchard Floor Management Practices in a Nitrogen Vulnerable Zone in Italy

Nowadays, understory vegetation along the tree row is considered a vital source of agroecosystem services and functional biodiversity improvement in the fruit orchard. Hence, current orchard floor management systems encourage practicing a more sustainable approach that supports vegetation cover rather than keeping bare soil herbicide use, or tillage. A two-year field trial was conducted using two different ground management techniques; integrated mowing (mower and brush or disc) and herbicide (glyphosate) in two commercial apple and peach orchards in a nitrogen vulnerable zone (NVZ) of the Marche region, Italy. This study aimed to evaluate the effects of these practices on soil N status, weed abundance, percent of soil cover, and dry weed biomass production. Weed management systems had no significant effect on soil organic matter and N availability; however, an improvement was noticed under integrated mowing when compared to the one treated with herbicides. Integrated mowing had a significant effect on species richness, soil coverage, and weed biomass production, which was approximately 2-times higher than in the herbicide-treated plots. The overall results showed that integrated mowing maintained a balance in the soil N status of both orchards, while supporting above-ground weed biodiversity and soil protection.

Plum Cultivar Evaluation on Myrobalan Rootstock in Lithuania

Twenty plum cultivars on Myrobalan (Prunus cerasifera Ehrh.) seedling rootstock were tested in 2012–2017 at the Institute of Horticulture of the Lithuanian Research Centre for Agriculture and Forestry. Plum trees were spaced at 4.5 × 2.5 m and trained as spindles. Orchard floor management included frequent mowing of grass in the alleyways with herbicide strips along tree rows. ‘Duke of Edinburgh’, ‘Kijevas Vēlā’, ‘Dąbrowicka Prune’, ‘Čačanska Najbolje’, ‘and ‘Štaro Vengrinė’ cultivars were the most vigorous plum trees at the end of 6th year. Their trunk diameter achieved 92–96 mm. ‘Valor’, ‘Queen Victoria’, ‘Herman’, ‘Čačanska Najbolje’, ‘Favorita del Sultano’, ‘Ave’, and ‘Jubileum’ cultivars had the lowest trunk diameter — 72–78 mm. The highest cumulative yield of four fruiting years was recorded for ‘Kometa’ and ‘Violeta’ cultivars, respectively, 43.0 and 46.5 kg/tree. ‘Favorita del Sultano’, ‘Rausvė’, and ‘Kijevas Vēlā’ produced the largest fruits — 52–60 g. The smallest fruit occurred on ‘Dąbrowicka Prune’ and ‘Herman’ cultivars, respectively, 22 and 25 g. ‘Dąbrowicka Prune’ had the highest soluble solids content (SSC) — 19.5%. The least SSC was recorded in ‘Kometa’, ‘Violeta’ and ‘Herman’ fruits — 10.6–11.8%. ‘Renklod Rannij Doneckij’, ‘Čačanska Najbolje’, and ‘Valor’ cultivars had the highest fruit flesh firmness.