Jaroslav Tomasek

Reply of mulch systems on weeds and yield components in potatoes

Surface mulch is an important factor of soil protection technology in the cultivation of potatoes. Presented herein are the results of three years (2009–2011) of field trials at two sites (Leskovice and Uhřiněves), where two cultivars (Finka and Katka) were grown. Three mulching treatments (grass mulch after planting, grass mulch before germination and black polypropylene mulch textile) were used in the study. The weight of marketable tubers (tuber over 40 mm) and tuber size distribution were influenced significantly by mulching. The application of grass mulch on surface of the row ensured a 20.5–24.8% increase of weight of marketable tubers and higher occurrence of tubers over 56 mm (resp. tubers 56–60 mm and over 60 mm). There was no consistent effect of grass mulch on the aboveground biomass of weeds. Higher occurrences of larvae of Colorado potato beetle was found on the plots with black polypropylene textile in warmer site Uhřiněves.

Potatoes (Solanum tuberosum L.)

In the area of potato production, targeted research solving concrete and actual problems of potato producers runs on Czech University of Life Sciences in Prague. In the last few years, we were focused on the production of new potatoes designated for early harvest, and we were focused on capitalization of yielding and qualitative characteristics of colored potato variety. These findings were further utilized and transferred to the system of organic farming. Firstly, we watched the influence of organic farming on yield and quality of tubers. Ecological ways of cultivation had strong negative influences on yield (decrease of 36%). From qualitative characteristics, organic farming increased the content of polyphenols by 10.2%, decreased the content of nitrates by 11.0%, and decreased the content of reducing sugars by 22.0%. We also evaluated the possibilities and impacts of mulch on potato cultivation. The mulch on top of ridges affected the temperature of soil (it increased the temperature by 0.2–0.6 °C under black mulching nonwoven fabric, and it decreased by 0.5–0.8 °C under herbal mulch). The mulch also affected soil humidity (herbal mulch decreased the soil humidity) and adjust weed infestation (20 to 92% lower), soil erosion (95% lower), the occurrence of Colorado beetle (the number of larvae was 22.8% lower with herbal mulch and 88.7% higher with mulching textile), and late blight in potato vegetation.

Stimulation sorghum seed leading to enlargement of optimum conditions during germination and emergence

The ways to improve the vitality of sorghum seed after treatment with Lexin and M-Sunagreen were tested in laboratory conditions. These methods of seed stimulation were also tested in field conditions. All experiments were carried out in 2011–2013. Positive results after using the presented formulations for testing of germination were observed not only in laboratory conditions but also in field experiments. Seeds stimulated by Lexin reached statistically higher germination (95%) compared to control (91.5%) with the shortest medium time of germination (3.5 days) versus control seeds (4.3 days). Higher, faster and smoother germination of stimulated seeds resulted in higher average number of plants per m2 (about 2.1 plants/1 m2 in Lexin compared to control seeds) and thereby contributed to higher average yields up to two tons of dry matter per hectare.