The paper analyses the effect of the main agronomic factors, including sowing rate, method and date, nitrogen fertilisation and cultivar-specific properties, on the number of winter wheat ears per area unit, as one of the most essential yielding components. A stand management method offered depends on the sowing pattern and aims at obtaining a maximum number of ears and hence a high yield.

The aim of the present studies of 1998-2000 was to define selected physical properties of soil following three winter wheat pre-sowing. The properties researched were much affected by the precipitation and the pre-sowing schemes. Replacing traditional with direct sowing increased the soil moisture, decreased the total porosity and the capillary porosity and increased the bulk density compactness of the topsoil. However high precipitation significantly modified the soil properties.

The physical properties of soil defined over winter wheat flowering depended on the weather conditions, first of all on precipitation. The soil moisture in ploughless and in traditional cultivation were similar, while wheat sowing in white clover mulch significantly lowered the moisture of the topsoil, especially in the lowest precipitation year. Direct wheat sowing, as compared with traditional cultivation, significantly lowered the total soil porosity and increased its capillary porosity, the bulk density and the soil compactness. The wheat intercrop sowing affected the total porosity and the bulk density, similarly to traditional cultivation, while the capillary porosity – to ploughless sowing. The cultivation without pre-sow ploughing, in the 0-10 cm layer, decreased, while in the 10-20 cm increased the topsoil compactness as compared with that observed in traditional cultivation. Yet greater soil compactness of the deeper layer was observed due to wheat sowing in white clover mulch, significantly higher both as compared to that observed in the traditional sowing and that in direct sowing.

Over 1984-1994 field experiments which aimed at defining the effect of nitrogen fertilisation on the yield of grain and protein in winter barley were carried out at the Research Station of the University of Technology and Agriculture in Bydgoszcz, located at Mochełek in the vicinity of Bydgoszcz. The experiment factor consisted of 4 levels of nitrogen fertilisation: 0, 60, 120 and 180 kg N.ha^-1. Increasing nitrogen fertilisation resulted in, for an average of 10 years, significant increases in grain and total protein yields as well as in the total nitrogen content in grain up to 120 kg N.ha^-1. The application of 180 kg N.ha^-1 decreased the grain yield, caused a breakdown in an increase dynamics for total protein yield and substantially increased the total nitrogen content in grain. The results obtained show that weather conditions in subsequent research years modified considerably the effect of nitrogen fertilisation on the winter barley characteristics studied.

The pot experiment was set up on soil sampled from topsoil of the podzolic soil of the slightly-loamy-sand grain size composition. The soil was very acid with a low available phosphorus content and a very low content of available forms of magnesium and potassium. Prior to the experiment, half of the soil material was limed with CaCO₃. The other experiment factors included nitrogen (NH₄NO₃) and phosphorus fertilisation (Ca(H₂PO₄)₂ and Ca₃(PO₄)₂). Liming, nitrogen and phosphorus fertilisation increased the contents of available phosphorus and of mineral phosphorus fractions. The fertilisation with superphosphate increased the content of phosphates easily soluble and ferric, while the content of calcium phosphates depended on the fertilisation with rock phosphate meal.

In a pot experiment very-acid soil liming increased the ‘Start’ spring barley yield. The plants grown on acid soil accumulated a greater amount of phosphorus in grain, straw and roots than in limed soil. Liming and nitrogen and phosphorus fertilisation enhanced the uptake and use of phosphorus by plants whose uptake was greater from triple superphosphate than from rock phosphate meal. The use of phosphorus was also greater from superphosphate than from meal, irrespective if the fertilisers applied onto acid or limed soil.

The 1997-1999 research investigated the health status of stem base of winter rye cultivated after spring cereals in pure stand, their mixtures and mixtures with yellow lupin. The lowest infection with Fusarium spp. was recorded after oats, the highest – after barley. The lowest infection with Pseudocercosporella herpotrichoides and Rhizoctonia spp. was observed after oats and oats with lupin, while the highest after triticale and oats with triticale. The pathogens occurring on stem base were represented mostly by Fusarium spp., especially F. avenaceum. The rye grain yield as affected by the forecrop did not differ significantly.

The investigations were conducted in the years 1999-2000 on medium-heavy soil. Five maize cultivars were mowed at the height of 10-15 cm and 40 cm higher. It was found that increasing the mowing height to approximately 55 cm lowered the whole plant yield by 16%, while the dry matter yield by 8.9%. At the high mowing height the silage value was higher, which was observed in an increase in the dry matter content in the whole plants by 3.1%, while the percentage of ears in the fresh matter increased by 6.8% and in the dry matter – by 5.2%, respectively. In spite of high variability in earliness, the cultivars investigated did not differ significantly in dry matter contents at harvest. However, considerable differences were observed in the dry matter yields and the percentage of ears. Medium-late cultivars ‘Magister’ and ‘San’ yielded higher with more advantageous structure that the early cultivar, ‘Rasant’.

The 1992-1996 experiments defined the effect of organic fertilisation (farmyard manure, after harvest residue and the total mass of intercrop) and mineral fertilisation (0, 400, 600 kg NPK?ha^-1) on field emergence, final stand, yield and quality of sugar beet root. The highest root and leaf yield was obtained when fertilised with the total mass of black medic and mixture of black medic and Italian ryegrass, yet the biological and technological sugar yield – when fertilised with the total mass mixture of black medic and Italian ryegrass and also when fertilised with farmyard manure. The increase in the mineral fertilisation caused an essential increase in the root and leaf yield yet the decrease in the final stand of sugar beet and the quality of roots. Fertilisation of sugar beet with 400 kg NPK?ha^-1 resulted in the biggest field emergence and technological sugar yield.

The present paper covers the 1990-1999 research into potato yielding and crop structure under natural conditions in the Świętokrzyskie Province. The average potato yield amounted to 15.2 t.ha^-1 and was similar to the national average. The tuber yield increased with enhanced natural conditions, soil in specific. Low yields were recorded in the communes whose natural conditions were slightly favourable or unfavourable. An average share of potato in the total crop structure on arable land was 17.5% and was 6.34% higher, as compared to the national average. The natural conditions more favourable to the agricultural production decreased the total potato plantation area; potato plantation area was most considerable in the communes of low soil quality, in the north of the province which, when maintaining the present system of set-aside in the EU, could expect subsidies.

The research investigated the effect of weather conditions on stem length of ten pea cultivars. The correlation between stem length and some economic value features was defined. The correlation between of weather conditions on stem length was much more considerable in general-use and seed-and-fodder cultivars than in seed and green-crop cultivars. The relationships between the feature tested and the 1000 seed weight and lodging was recorded in a few cultivars only. The highest seed yields of the general-use cultivars coincided with the stem length ranging from 70 to 95 cm and that of the seed fodder cultivars between 90 and 110 cm.

The field experiment was carried out as a split plot over 1996-1998 and included alfalfa cultivars of different origin (Canadian: ‘Mohawk’ and ‘I Roqvois’; American: ‘Legend’ and Polish: ‘Radius’) harvested with 3- and 4-cuts. The highest yields of dry matter, total protein and true protein were recorded in: ‘I Roqvois’ and ‘Radius’ (3-cut harvest) and ‘I Roqvois’, ‘Mohawk’ and ‘Legend’ (4-cut harvest). The results suggest a potential for cultivating alfalfa cultivars: ‘I Roqvois’, ‘Mohawk’ and ‘Legend’ in the south-eastern Poland.

The 1996-1998 research investigated the quality of alfalfa cultivars of different origin (Canadian: ‘Mohawk’ and ‘I Roqvois’; American: ‘Legend’ and Polish: ‘Radius’). The greatest share of dry matter was recorded in the third and fourth regrowth. The greatest content of the total and true protein was recorded in ‘Legend’ and in plants of the fourth cut. The cultivars researched showed adequate nutritive content of P, K, and Mg as well as an excessive content of Ca.

The study evaluated the technique and date of nettle plantation setting as well as estimated the optimum plant harvest date. The plantation was set up vegetatively (from underground rhizomes) or generatively (seed sowing) on three autumn dates in the first decade of September, October and November 1991 and in spring in the first decade of April 1992. The plants were harvested at three development stages: vegetative (before bud-forming), full budding and full flowering. The results showed that the plantation set up vegetatively generated higher yields of fresh and dry matter than that set up generatively. Early autumn (first decade of September) can be accepted as optimum date for rhizome setting and late autumn (November or October) for seed sowing. Moreover, it was observed that although higher plant yields were achieved at later development stages, plants had lower leaf share.

The study estimated chemical composition (total and true protein, crude fibre and ash as well as mineral components: P, K, Ca, Mg) in overground parts of nettle (Urtica dioica L.). Samples were collected on a field plantation from plants harvested at three development stages: before budding (vegetative phase), full budding and full flowering. The results show that later harvest decreased both protein forms and some mineral components (P, K, Mg) and increased crude fibre and Ca content. Along with the harvest delay, fewer differences between total and true protein content were recorded, all of which points out that plants transform nitrogen taken from the soil into protein much more easily. Nettle leaves as compared to stalks revealed much higher protein, ash, phosphorus and calcium content yet a clearly lower level of crude fibre.