In this six-year research study the effect of nonwoven polypropylene covering on the quantity and quality of early potato yield was estimated. The use of nonwoven polypropylene covers resulted in an increase in the tuber yield and smaller yield variability in the various years, when compared with the traditional cultivation, especially at a very early date of potato harvest. In the cultivation with nonwoven polypropylene covering, the marketable tuber yield 60 days a�er planting was higher by 23.34% on average and 75 days a�er planting by 10.92% in the six-year period of the study, compared with the cultivation with no plant covering. The higher profitable effect of covering was obtained in the years with cold spring. The cultivation method of the potato did not affect the chemical composition of the tubers harvested a�er 60 days from planting. A�er 75 days from planting the tubers of potato cultivated under nonwoven polypropylene covers contained, on average, more dry ma�er and starch by 0.81% and 0.85%, respectively.Keywords: early potato; nonwoven polypropylene cover; yield; tuber quality PLANT SOIL ENVIRON., 51, 2005 (5): 226-231 227 60 kg P 2 O 5 and 90 kg K 2 O for potatoes harvested 60 days after planting and 90 kg N, 90 kg P 2 O 5 and 135 kg K 2 O per 1 ha in the case of potatoes harvested 75 days after planting. Immediately after planting and before covering the herbicide was applied (linuron -trade name Afalon 450 SC). The material used in the experiment was nonwoven polypropylene of 17 g/m 2 weight (trade name Pegas Agro 17). The cover was removed 2 weeks after plant emergence. The total and marketable yield of tubers (diameter above 30 mm) was estimated. For laboratory studies, 50 tubers of different size, according to the proportional participation in the yield of each plot were sampled. The dry matter, starch (using the polarimetric method), total protein (using the Kjeldahl method) and vitamin C (using the Pijanowski method) contents in potato tubers were determined (Rutkowska 1981). Chemical analyses were made on fresh material just after the harvest.The results of the experiment were analysed statistically by means of analysis of variance. The significance of differences was veryfied using the Tukey's test at P = 0.05. The yield and the content of examined components in potato tubers were characterized by the mean, standard deviation and variability coefficient (%).In the six-year period of the study, only in 1998 and 2002 were the climatic conditions favourable for potato cultivation for the early crop (Table 1). In 1997, a very cold April and a long-lasting snow cover made it impossible to plant the potatoes early. RESULTS AND DISCUSSIONDiverse climatic conditions during the potato vegetation period significantly affected the tuber yield. The yield variability after 60 days from planting was higher than that obtained after 75 days from planting. The variability of marketable tuber yield was higher than that of total tuber yield, particularly at the earlier date of potato harvest (Tabl...

SummaryThe effect of three methods of soil mulching: autumn or spring ploughing and leaving mulch as a cover crop on the soil surface without incorporation till the end of cabbage growth on the contents of selected nutrients in red cabbage and onion was investigated. The following plants were used as intercropped mulches: phacelia, vetch, serradella and oat. Mulching effects were compared to a non-mulched control as well as a farmyard manure application at the rate of 40 t·ha -1 . Nutrient content in both vegetable species depended on weather conditions and varied in study years. Accumulation of dry matter in cabbage was favoured by phacelia and oat mulches, irrespective of the date of ploughing. Non-incorporated oat and autumn-incorporated phacelia increased dry matter content in onion. An increase in the protein content in cabbage was observed when following serradella and vetch mulches. The protein content in onion cultivated in the second year following mulching did not change significantly as a result of the influence of examined factors. Among an the mulches taken into study, serradella and oat increased the content of vitamin C in cabbage. Similarly, autumn-or spring-incorporated oat mulch and non-incorporated serradella mulch increased the content of vitamin C in onion.