Marian Wesołowski

Cover cropping influences physico-chemical soil properties under direct drilling soybean

In seeking effective methods to prevent soil degradation, conservation tillage plays an important protective role. Apart from significantly reducing production costs, cover crops contributes to beneficial changes in the soil environment. A three-year field experiment included three cover crops (winter rye, winter oilseed rape, and white mustard) subjected to mulching or desiccation and to the action of a herbicide at three rates (100%, 75%, and 50%). The study evaluated soil moisture and the content of organic matter, phosphorus, potassium, and magnesium in two soil layers (0–15 cm and 15–30 cm). Cover cropping had a positive effect on soil organic matter content. More organic matter (by 4.7%) was recorded in the topsoil layer (0–15 cm). Among the cover crops most favorable effect on the content of organic matter in the soil had white mustard (an increase of 14.2%) compared to the control. Moreover, rye and white mustard mulch increased the soil content of phosphorus and magnesium, while oilseed rape mulch increased the potassium content. At the critical growth stages (the flowering/pod set) of soybean (Glycine max (L.) Merril), soil moisture was dependent on mulching treatment and soil layers.

Intensywność mechanicznych zabiegów pielęgnacyjnych a zasób nasion chwastów w glebie [The intensity of mechanical cultivation measures vs. the amount of weed seeds in the soil]

The effect of the number of mechanical operations in sugar beets plantation on the amount and species composition of weed seeds in the 0–5 cm deep layer of the loessial soil was studied. It has been proved that reduction in the number of weed seeds depends upon both the frequency of weeding-out operations and the level of agrotechnic. The highest decrease in the number of fruit and weed seeds was caused by eightfold weed removal which took place during the period from emergence phase to the joining of sugar beet rows. Application of increased mineral fertilization, microelements, fungicides, and insecticides caused the number of weed seeds to be reduced by 5,9%, in comparison to extensive agrotechnical level.

The effect of herbicides on Chenopodium album L. phenology in fodder beet, spring wheat and faba bean crops

The objective of the study was to determine the time of occurrence of the emergence, budding, fruiting and seed shedding stages, as well as the degree of advancement of the white goosefoot fruiting and diaspores shedding stages in fodder beet, spring wheat and faba bean crops under mechanical and chemical weed control. Phenological observations were conducted in the years 2000-2002 at 10-day intervals, starting from the day of crop sowing on alluvial soil made of light loam. Chemically weed controlled objects were treated with herbicides: fodder beet - lenacil 80%; spring wheat - MCPA 30% + dicamba 4%; faba bean - linuron 50%. It was proven that the times of occurrence and the scale of the studied phenological stages of white goosefoot depended on the crop species, the in-crop weed control method and the pattern of weather conditions in the study years. White goosefoot had the most favourable conditions of growth in the fodder beet crop. The herbicides in the fodder beet and faba bean crops delayed the emergence and the time of occurrence of successive white goosefoot growth stages. These agents also decreased the degree of diaspores shedding by the weed species studied. The most white goosefoot specimens shed fruits on the mechanically weed controlled plots. The diaspores dissemination was promoted by a warm and moist growing season.