The paper presents main development challenges of Polish agriculture and food economy in the process of integration with European Communities. The author tries to diagnose the current economic situation of food producers against the changing Common Agricultural Policy. A future model of European Rural Policy in 2008 and its influence on Polish rural society is discussed. At the end of the publication one can find SWOT analysis of Polish food economy in transition period and some practical conclusions for domestic agricultural policy.

The split-plot design experiment, in four replications, investigated 2 variables: I – fertilization – post-harvest residues and post-harvest residues with straw, II – liming – 0; 0.7; 1.4; 2.1 (CaO t·ha^-1). The winter wheat cultivated after under-ploughed winter rape straw, as compared to that without straw, showed a lower number of overwintered plants, of grains per ear, grain weight per ear, grain yield, protein yield and crop energetic value. Liming did not compensate for the yield decrease caused by a negative effect of under-ploughed winter rape straw on winter wheat grain yield.

The split-plot design experiment, in four replications, investigated 2 variables, I – fertilization – post-harvest residues and post-harvest residues with under-ploughed straw, II – ammonium nitrate – 0; 25; 50; 75 (N kg·ha^-1). The winter wheat cultivated after under-ploughed winter rape straw, as compared to that without straw, showed a lower number of overwintered plants, of grains per ear, grain weight per ear, grain yield, protein yield and crop energetic value. Nitrogen fertilization did not compensate fully for the yield decrease caused by a negative effect of under-ploughed winter rape straw on winter wheat grain yield.

The 1998-2001 study evaluated the productivity of spring barley, over selected development stages, cultivated in various crop rotations and in monoculture. It was shown that dry matter yields of overground plant parts and roots were over each development stage significantly higher in crop rotations than in monoculture. The share of roots in the total dry matter of barley was highest over full tillering to opening of leaf sheaths. The cultivation of spring barley in monoculture significantly increased the occurrence of take-all disease as compared with crop rotations with a 25 and 50% share of spring barley. All that decreased the ear density, grain weight per ear and 1000 grain weight and, as a result, decreased the field productivity.

The 1998-2000 experiments investigated the effect of plough and ploughless tillage systems and varied fertilization and chemical control levels on winter rye residues weight and chemical composition. It was observed that a greater dry matter of winter rye roots was accumulated in 0-10 cm soil layer, as compared with 10-20 and 20-30 cm layers. The winter rye objects intensively fertilized and chemically controlled recorded significantly more post-harvest residues. The plough-tillage objects showed that winter rye roots accumulated more total nitrogen, potassium and magnesium as compared to ploughless tillage. The content of total nitrogen and potassium in rye roots was greater for objects with basic fertilization and chemical control. A greater content of phosphorus in stubble and mulch was recorded for ploughless tillage and potassium – plough tillage. As for the basic fertilization, stubble and mulch of winter rye contained significantly more total nitrogen and phosphorus than the intensively fertilized and chemically-controlled plots.

The present studies define the sugar-maize nitrogen requirements, delivered as pre-sowing fertilization or complementary foliar and soil nutrition. The usefulness of multiple fertilizers for sugar-maize top-dressing has also been defined. It has been shown that increase in pre-sowing nitrogen dose from 30 to 60 kg N·ha^-1 resulted in any significant yield increase in cobs neither with nor without covering leaves, nor did it increase the percentage of 1^st class cobs and their length, and the number of grains in a cob. However either top dressing or watering with 18 kg N·ha^-1 in the form of urea solution or else with multiple fertilizers, such as Florovit, Basfoliar 6-12-6, Basfoliar 36 Extra and Florogama K, increased the yield of cobs with and without covering leaves, yield of 1^st class cobs and the number of grains per cob.

The three-year field experiment determined a reaction of four potato cultivars to herbicides and their mixtures prior to and after emergence. The herbicides caused plant damage, but the changes were temporary and did not deteriorate the yield. A stronger negative reaction to herbicides was noted for Ibis and Irga (2.7 and 2.6 points according to the 1-9 scale, respectively) than for Mila and Arkadia cultivars (2.4 and 2.2 points, respectively).

24-year (1972-1995) data provided by COBORU (Centre for Cultivar Testing) showed the spatial and time distribution of medium-late and late potato cultivars development stages. A greater variation over 1972-1995, even five-fold, was recorded for duration of potato phenophases than for their dates. The period from potato planting to harvest in Poland shows almost a three-week spatial variation and a significant tendency to get longer, mainly due to earlier planting, emergence and flowering. The dates and duration of respective development stages significantly affect the successive phenophases. Earlier dates and phenophases and the time series can help the forecast of respective dates and duration of phases for medium-late and late potato cultivars across Poland.

There was determined a profitability of early crop potato production for Aster and Drop cultivars cultivated with the traditional method and under agrotextile cover. The method of incomplete calculations was used. The production profitability was calculated as the ratio of production value to costs. The production costs were 51% to 73% higher for the agrotextile-cover cultivation, which increased the production profitability in the cold-spring year. The profitability index ranged from 312% to 581%. In the warmer spring years the agrotextile-cover production profitability was lower, as compared to traditional cultivation. The cultivation of Aster was more profitable.

The experiment aimed at determining the fungal infection of pea and yellow lupin seeds from plants grown under water and mineral stresses. The results showed that water stress increased the fungal infection of pea and yellow lupin seeds, as compared with the control. A lowered health status was also seen in seeds from plants exposed to a lowered-to-¼-of-the optimal fertilization with phosphorus, potassium and magnesium. It was observed that the greatest fungal infection was recorded on the seed coat, lower – cotyledons and the lowest – embryonic axis.

The present paper presents the results of a three-year experiment on a good rye complex soil which investigated the yielding potential of five lentil cultivars and the content of five basic organic compounds and minerals in seeds. The highest yield was recorded for Izka cultivar and Krak 2 strain. The highest content of protein was found in Anita seeds. The cultivar, just like the Canadian genotype, contained the greatest amount of nitrogen-free extractable compounds. The seeds of Anita and Izka showed the most favourable content of basic macro- and microelements. ’Anita’ and ’Izka’, developed at the Lublin and Cracow Agricultural Universities, are the first domestic lentil cultivars.

A pot experiment with soya bean, Warszawska cultivar, was established on specific brown soil. Soya bean was sprayed with solutions of auxins – IBA, NAA and their mixture IBA + NAA (each solution: the concentration of 20 mg·dm^–3), twice in the vegetation period, when exposed to fixed NPKMg fertilisation, against the control (distilled water spraying). Both auxins increased the seed weight; greater increases were due to IBA application, as compared with the control. IBA also enhanced the concentration of nitrogen in seeds by approximately 7%, hence a 46.2% increase in nitrogen uptake. Synthetic auxins favourably modified the distribution of nitrogen, phosphorus, potassium, sodium, calcium and magnesium in the above-ground soya bean organs, which intensified the removal of, especially, phosphorus and nitrogen from pod-shells, leaves and stems to seeds.

The effect of differentiated pre-sow ploughing depth (30, 20 and 10 cm) and weed control method (mechanical, chemical, combined mechanical and chemical) on the overwintering, weed infestation, yield and quality of seeds of oilseed rape was tested. Shallower ploughing worsened the main traits of the autumn condition of rape plants. Rape plants treated chemically had better-formed rosettes than those treated mechanically. Ploughing made to the depth of 30 and 20 cm did not significantly differentiate the yield of rape plants. However, a significant decrease (9-13%) in the yield occurred when the ploughing depth went down to 10 cm. The highest yield was obtained from the rape controlled chemically against weeds. The yield-protective effect of the combined mechanical and chemical weed control was comparable to that of mechanical method.

The aim of the studies was to evaluate the persistence of perennial ryegrass in the pasture sward. The studies were carried out over 1994-2000 on black earth and muck-and-peat soil at Sosnowica. The share of perennial ryegrass in the pasture sward changed depending on the sequence of regrowth, habitat moisture and temperature course in the autumn-and-winter period. Irrespective of the soil type, the highest winter damage of perennial ryegrass and greatest reduction in the share of the species were recorded in the sward following 1995/1996 and 1996/1997 winters.

Late autumn observed a very high content of nitrogen, the lowest for the 60-90 cm layer (4.3 mg·kg^-1). In early spring, however, the highest content of nitrate nitrogen was recorded in soil sampled from the greatest depth. The content of ammonium nitrogen for each date was highest in the soil sampled from topsoil. Undersown oleiferous radish significantly decreased N-NO₃ content (by 19%) in the second half of September, as compared with faba bean in pure stand. Over an intensive growth of winter wheat, the content of mineral nitrogen due to mineralization of ploughed radish biomass was significantly higher after self-completing faba bean with the undersown crop as compared to no-faba bean combination.

The species composition, number and distribution of weed seeds sampled from three layers of soil for different tillage systems have been investigated. A total of 22 weed species was recorded. The ploughless and direct sowing objects showed the occurrence of weed seeds which were not recorded in plough tillage. Both for tillage systems and for respective soil layers, the greatest share of seeds (from 77 to 84%) was accounted for by three species: Chenopodium album L., Stellaria media Vill. and Viola arvensis Murr. Irrespective of the soil layer depth, the greatest total number of seeds was recorded in plough objects, slightly fewer in ploughless and significantly less – in direct sowing. In all the tillage systems the greatest number of seeds was recorded in the topsoil and significantly less – in deeper layers.