Poland has generally favourable conditions for agricultural production, despite low-and-medium quality soils, which are most common, and an insufficient precipitation and water deficit in some regions. A serious threat to agricultural production is inadequate environmental protection. On the other hand, the prevailing semi-intensive agricultural production and advantageous environmental conditions in many parts of Poland encourage high quality foodstuffs. The last few years have recorded a substantial progress in environmental protection. Polish farms are generally smaller and less productive than their counterparts in Germany, France and Denmark. Considerable differences across Poland are still observed in farm size, crop yields and productivity of farm animals. Poland, with its high employment in agriculture, is a leading country in the production of vegetables and produces more vegetables per capita than Germany, Denmark and France, and in fruit production comes second right after France. Polish agriculture with its semi-intensive character and low consumption of mineral fertilizers and other chemicals is already, to some extent, close to ecological agriculture and many of its products are of high quality. All that creates a high potential for agricultural exports, especially to the neighbouring countries, e.g. Germany, and for agrotourism.

The 1999-2001 research evaluated the applicability of red clover for mountain meadow undersowing and drew on ‘Raba’ cultivar clover and ecotype of low-highland-region origin. While preparing the meadow for undersowing, 30-40 % of sward was damaged with heavy tractor-drawn harrow and rotary cultivator. The red clover ecotype adapted much better to meadow sward than the cultivar; the ecotype share in the yield was over two-fold higher than the share of ‘Raba’. The presence of clovers in the meadow sward was most favourable in the second and third research years when the objects exposed to 30 kg N·ha-1 yielded at a similar level to that of natural sward fertilised with 100 kg N·ha-1. The plant matter which included clovers showed also a higher dry matter digestibility which increased by 1 % with every 10 % of clover share in the yield.

The aim of the present research was to define selected enzymatic activities and hydrolysis of starch, cellulose, chitin, pectins, proteins and dissolution of Ca3(PO4)2 of Actinomycetes of Streptomyces isolated from soil and potato rhizosphere. The size of hydrolysis zones of the substrates researched as a consequence of enzymatic activities showed a high activity of the Streptomyces strains tested. The greatest number of strains used starch and cellulose (CMC-Na medium) as their source of carbon and gelatine. The lowest number of isolates used pectins on pH 5.2 medium and cellulose powder. The production of chitynase in all the Actinomycetes was quite common (75 %), like the ability to dissolve Ca3(PO4)2 (70 % of strains).

The study covered traditional ‘Bardo’ and self-completing ‘Katon’ white lupin cultivars over 1998-2000 at the Mochełek Experiment Station. ‘Bardo’ cultivar yielded significantly higher than ‘Katon’. Urea applied together with MgSO4 (B) did not affect the seed yield of any cultivar studied. The addition of multi-nutrient Ekolist to the mixture of urea and MgSO4 (C) increased significantly the seed yield of ‘Bardo’, only. Chemical plant protection with Merpan and Ronilan (E) was the only one that resulted in the significantly highest seed yield of ‘Katon’. Neither foliar plant fertilisation nor chemical control affected the total protein content in seeds and their viability significantly.

The paper covers a yielding analysis, the share of potato in the total crop structure and environmental conditions for three groups of communes in the region of Doły Jasielsko-Sanockie. The research revealed that the area analysed showed conditions favourable for agricultural production, including potato cultivation. An average tuber yield amounted to 18.1 t·ha-1 and was by 1.7 t·ha-1 higher than the national average. Similarly the share of potato in the total crop structure, which reached 17.7 %, was by 5.9 % higher than the national average. The regression analysis showed that both the cultivation area and the yield were positively correlated with environmental conditions and the stock of pigs and cattle.

The 1996-2000 experiments carried out on very good rye soil complex in four Experiment Stations of the Research Centre for Cultivar Testing evaluated yielding, protein content and yields, yield stability and a reaction to moisture level of 10 pea cultivars representing various morphological and economic types. The general-use cultivars yields, that is of ‘Agra’, ‘Rola’, ‘Piast’, ‘Set’ and ‘Tambo’, did not differ significantly, while a precipitation deficit affected tendrils-leaved cultivars: ‘Piast’ and ‘Agra’ showed a tendency to seed and protein yields increases. The fodder cultivars, ‘Wiato’ and ‘Idol’, yielded similarly to general-use cultivars, yet with a lower yield stability. The yield stability of the seed and green-crop fodder cultivars, ‘Kormoran’, ‘Kier’ and ‘Roch’, was higher than other cultivars.

Yielding of winter wheat was evaluated based on 30-year results of cultivartesting experiment carried out by the Research Centre for Cultivar Testing at Seroczyn (latitude = 52o 00’, longitude = 21o 56’) over 1970-2000. The average yield for all the cultivars tested constituted the basic unit for analysis. The climate observations for a given research period were conducted in the same location as the experiment. The analysis of precipitation and of the energy factor, namely potential plant evapotranspiration, showed their high variability over research years. The variability of winter wheat grain yield was mostly affected by weather extremes, inflicting on stress conditions over specific plant development phases which, consequently, limit their yielding potential. Both the water shortages due to long rainless periods, (of about 20 days) as well as heavy daily precipitation (over 20 mm) or stormy precipitation at the end of the vegetation period are mostly responsible for yield decreases.

Plants of ‘Teo’, traditional yellow lupin cultivar were treated with different growth regulators over 1998-2000 at the Mochełek Experiment Station. Growing doses of citokinin, gibberellin and their mixture enhanced the total protein accumulation in yellow lupin seeds. The impact of growth regulators and/or their mixtures on the crude fat content was inconsiderable and changeable with years. The crude fibre content decreased with an increase in doses of gibberellin and of gibberellin and auxin mixture as well as in the dose of three-growth regulator mixture which also decreased the content of ash and increased the content of P, K, Mg and Ca. The impact of Ekolist on the chemical composition of seeds and their viability was lower than of the growth regulators studied.

The content of water in maize kernels at the time of harvest, not affected by the earliness of cultivar, is considerably affected by the weather over the vegetation period, particularly in July and August. This relationship concerns mainly early and mid-early cultivars. Water content in kernels of mid-late cultivar, on the other hand, depends, on the temperature and total precipitation over the vegetation period. The length of the vegetation period of early cultivar and mid-early cultivar depends on the temperature and precipitation over maize growth and development. The weather, however, has the greatest influence during the summer months, July through August, especially the total precipitation, and, in turn, affects the length of the vegetation of mid-late cultivar.

The 1996-1999 research investigated the health status of stem base of winter wheat cultivated after spring cereals in pure stand, their mixtures and mixtures with pea. The forecrop showed the greatest impact on the plant infection with Gaeumannomyces graminis, followed by Fusarium spp. The lowest number of plants infected by G. graminis was observed after oats and oats with pea. Infection by Fusarium spp. was the lowest after oats with barley, however the highest after triticale. The pathogens occurring on stem base were represented mostly by Fusarium spp., especially F. avenaceum.

Over 1995-1997 a two-factor experiment was carried out which aimed at defining whether and to what extent magnesium fertilisation affects the ‘Mila’ potato processing value straight after their full maturity and to what extent the value is modified by the Mg doses due to storage over autumn and winter. The experiment included the following factors: evaluation dates, after harvest and after 6-month storage, and 5 levels of magnesium fertilisation (9, 21, 30, 42, 51 kg Mg·ha-1) when exposed to a fixed fertilisation with nitrogen, phosphorus and potassium. In the experiment selected quality characteristics were determined and dry matter, starch, reducing sugars, and the quality of chips and crisps were evaluated. The highest quality was found in chips and crisps, produced from potato tubers fertilised with 51 kg of Mg·ha-1. Tuber storage significantly lowered the applicability of tubers to thermal processing.

The research was conducted in 1997 and 1999 in the Agricultural Experiment Station at Swojec in the vicinity of Wrocław. The aim of the present research was to evaluate the effect of simplified tillage and direct sowing for two nitrogen fertilisation levels on the degree of spring wheat infection with pathogenic fungi inflicting on foot-rot complex. The main reason of the diseases of the wheat culm base were Fusarium fungi, especially: F. culmorum, F. avenaceum, Rhizoctonia cerealis and Bipolaris sorokiniana. Simplified tillage did not affect the degree of the plant infection. However a lower level of nitrogen fertilisation (100 kg of N·ha-1) was favourable to the development of fungi of the Fusarium genus. Additionally such a nitrogen dose showed a considerable increase in the number of F. culmorum, and 200 kg of N·ha–1 F. avenaceum was more frequent.

The present study tested the effect of tansy phacelia (1) and white mustard (2) water solutions (A – 0, B – 0.1 %, C – 1.0 %, D – 10.0 %) on the germination energy and the length of cereal seedlings. The results showed that the water solution affected more the cereal seedling length than the germination energy, while water solution concentrations mainly inhibited the characteristics researched. Winter-wheat germination energy differed least, while seedling length – most; oat was most affected by high water-solution concentrations.