The paper presents the results of 2000-2003 investigations which aimed at comparing the yielding and profitability of cultivating table potato fertilized with intercrop and straw. The experiment involved two factors: intercrop fertilization (control treatment, birdsfoot trefoil, birdsfoot trefoil + Italian ryegrass, phacelia, phacelia in a form of mulch), straw fertilization (without straw, with straw). In the first year after applying organic fertilization table potatoes were cultivated. During harvest there was determined the total yield and the commercial yield of potato tubers. There was also performed an economic evaluation of table potato cultivation under varied organic fertilization. The following were calculated: the production value, direct production costs and gross margin. The highest total and commercial yield of potato tubers was obtained from combinations fertilized with a mixture of birdsfoot trefoil with Italian ryegrass and birdsfoot trefoil with straw. The lowest direct production costs were incurred for potato fertilization with phacelia in a from of mulch, birdsfoot trefoil and a mixture of birdsfoot trefoil with Italian ryegrass. The best production and economic results were recorded due to the fertilization of table potato with a mixture of birdsfoot trefoil with Italian ryegrass and birdsfoot trefoil with straw.

Summary. The plant material taken for the study was collected from maize fields in Denmark. In total, maize cobs were collected from 58 fields of 15 farms (9 organic and 6 traditional ones). The plant material (97 samples) was divided according to the following criteria: maize cultivars, effective temperature sum (ETS) during growing period, type of farm (traditional and organic farms). The dry matter content of maize cob samples was determined as well as starch, neutral detergent fiber (NDF) and acid detergent fiber (ADF), phosphorus and magnesium content. The dry matter content was negatively correlated with NDF and ADF, but positively correlated with starch. A highly negative correlation of starch content with NDF and ADF was found.

The aim of the present research was to determine the biomass yield and health status of three legume species: serradella, pea and yellow lupin, grown in stubble intercrop, after spring barley. Fields experiments were carried out at the Experiment Station of the Faculty of Agriculture at Mochełek, in the vicinity of Bydgoszcz, on light soil, of very good rye complex soil, over 2002-2004. Of the crops studied, the greatest amount of the total dry matter was produced by yellow lupin (3.31 t·ha^-1), and the least – by serradella (2.43 t·ha^-1). Pea produced the greatest aboveground biomass yield, while yellow lupin – significantly greater post-harvest residue mass than serradella and pea. There was observed a relatively low infection of the root crown and roots in serradella, slightly higher – in yellow lupin and pea. The main reason of the disease symptoms observed were Fusarium genus fungi, especially F. solani. There was found no significant effect of intercrops on the chemical composition of soil.

Field experiments were carried out over 2002-2004, at the Experiment Station of the Faculty of Agriculture at Mochełek, in the vicinity of Bydgoszcz. The aim of the present research was to determine the content and accumulation of macronutrients in the biomass of three legume species: serradella, pea and yellow lupin, grown in stubble intercrop, after spring barley on light soil. The plants accumulated considerable amounts of nitrogen (62.1-90.9 kg·ha^-1) and potassium (66.2-85.4 kg·ha^-1) in the biomass. The other nutrients (P, Ca and Mg) were accumulated in the biomass of papilionaceous plants in low amounts. The most valuable as for the potential of macronutrient use in the biomass was yellow lupin which accumulated significantly higher mass of potassium, phosphorus and magnesium than serradella and pea.

The aim of the present research was to determine the after-effect of legumes: serradella, pea and yellow lupin, grown in stubble intercrop, for spring wheat. Field experiments were carried out at the Experiment Station of the Faculty of Agriculture at Mochełek, in the vicinity of Bydgoszcz, over 2003-2005. The papilionaceous plants researched considerably enhanced the stand for spring wheat. A positive effect of the ploughed-in biomass was seen by increasing the density of spikes and the grain and straw yield. There was found no significant effect of the plants researched on the number of grains per spike and 1000 grain weight of spring wheat grown after them. The after-effect of the intercrop of pea and serradella was stronger when the entire biomass produced was used for green fertilizer. In the case of yellow lupin, to obtain a maximum effect, it was enough to plough in post-harvest residue only.