Kształtowanie się plonu i jakości bulw ziemniaka pod wpływem zmianowania i ochrony roślin

The findings of the study concern potatoes cultivated in crop rotation and monoculture at the Production and Experimental Station at Bałcyny near Ostróda since 1973. The static field experiment was carried out on lessive soil, quality class IIIb–IVa. During a 6-year investigation cycle covering the years 1993–1998, a very early Orlik cultivar was cultivated in a crop rotation: potato (on manure) – oat – fibrous flax – winter rye – faba bean – winter triticale – stubble intercrop, and in the 21st to 26th monoculture, interrupted with an intercrop – Phacelia tanacetifolia for underplough. Three levels of plantation protection were used: 0 – no protection (control), H – with herbicide protection, H+F – with herbicide and fungicide protection. The soil cultivation, fertilization and plant protection were carried out in accordance with agrotechnical recommendations of the IUNG of Puławy. Manure in a dose of 30 t ha-1 was used once in the rotation, while in potato monoculture – 15 t ha-1 both under the 1993 and 1996 crops. Manure, together with comminuted Phacelia biomass, was covered with pre-winter ploughing. Potato fertilization was 220 kg of NPK, including 80 kg N ha-1. The experiment was conducted within a system of random blocks with replications. The size of planting and harvest plots was 27 m2. The study indicates that eelwormresistant, very early Orlik potato cultivar achieved a high tuber yield in the crop rotation – 36.4 t ha-1 on average, while the commercial crop (tubers > 40 mm) exceeded 90%. In the multiyear monoculture, the tuber yield was 23.3 t, while the percentage of the commercial fraction constituted around 80%. The use of herbicides in the potato monoculture is recommended for reducing the weeds typical of potato, while in the crop rotation it is unnecessary and depends on the soil culture. Irrespective of the rotation system, fungicides caused an insignificant increase in the tuber yield, but a significant increase in the content of both starch and the commercial fraction of tubers in the protection of the plantation of the very early potato