The aim of the paper was to evaluate the efficiency of nitrogen from ammonium saltpeter as related to the formulation of phosphorus fertilizer under maize grain cropping. Maize was grown in monoculture throughout the consecutive years 2003- -2007. A two factorial field experiment was established at a farm located in Nowa Wieś Królewska (52^o26’ N; 17^o57’ E) on a slightly acidic soil, moderately rich in phosphorus. Experimental factors were as follows: (i) chemical formulation of the fertilizer, (partially acidulated phosphate rock – PAPR, simple superphosphate – SSP and triple superphosphate – TSP), (ii) nitrogen rate: 80 and 140 kg N·ha^-1; a phosphorus unfertilized treatment was also considered. The type of phosphorus fertilizer did not differentiate nitrogen uptake, but the lack of phosphorus at the applied rate has induced a decrease in nitrogen accumulation in the aboveground biomass, on average by 8%. Phosphorus fertilization at the rate 26.4 kg P·ha^-1 was the main determinant of nitrogen uptake by the kernels. Nitrogen recovery (R) from the fertilizers as well as its agronomical (AE) and physiological (PE) efficiency were significantly lower in treatments where phosphorus was not applied. Furthermore, it was found a positive effect of sulphur from simple superphosphate on the AE after the application of 80 kg N·ha^-1. The R values did not depend on the chemical formulation of phosphorus in the fertilizer and amounted on average to 74 and 59% for the rates 80 and 140 kg N·ha^-1, respectively, whereas for the treatment without P, these values varied within the range 46-54%.

The paper deals with evaluating the yield and yield structure elements of winter durum wheat lines (Triticum durum Desf.) under conditions of varied levels of chemical protection. The field experiments were carried out in 2006-2008 on the Experimental Farm Felin, University of Life Sciences, Lublin. Examinations involved 3 lines of durum wheat (STH 716, 717, 725) achieved from Plant Breeding Station in Strzelce as well as common wheat Tonacja cv. for comparison. The second factor consisted of 2 levels of chemical protection: I – minimum (seed dressing Oxafun T 75 DS/WS and herbicide Chwastox Trio 540 SL); II – complex (seed dressing, herbicides Puma Uniwersal 069 EW and Chwastox Trio 540 SL, fungicide Alert 375 SC, growth regulator Stabilan 750 SL and insecticide Decis 2,5 EC). Obtained results allowed for concluding that when comparing with minimum protection, the increase in wheat grain yields by 1.08 t·ha^-1 was recorded on complex-protected treatments, regardless of compared lines and varieties. Lower yield of durum wheat as compared to common wheat resulted first of all from lower spike density per area unit. A positive influence of chemical protection on spike number and grain number per spike was observed. Durum wheat lines were characterized by high grain vitreousness.

In 2005-2007, in a field experiment, the yield and quality of the thyme herb of the Polish cultivar Słoneczko in organic farming were tested. The experiment was established on six different organic farms and one conventional farm in Poland. The following features were evaluated: fresh and dried herb yield, stem fraction in herb, essential oil content, and microbiological purity. Only from one organic farm in Słońsk thyme herb yield was higher compared with the yield from conventional cultivation, although it contained a high amount of stems. Organic thyme herb was characterized by a high content of essential oil. Evaluation of microbiological purity showed that herb contamination from both types of cultivation did not exceed the standard for raw materials treated with hot water.

In 2005-2007, in a field experiment, the yield and quality of the basil herb of the Polish cultivar Kasia in organic farming were tested. The experiment was established on six organic farms and one conventional farm in different location in Poland. The following features were evaluated: fresh and dried herb yield, stem fraction in herb, seed yield, weight of 1000 seeds, essential oil content, macro- and microelements content and microbiological purity. Only from one organic farm in Słońsk basil herb was yield higher compared with the yield from conventional cultivation, although it contained a high amount of stems. Organic basil herb was characterized by a high content of essential oil and an increased content of macro- and microelements. Evaluation of microbiological purity showed that herb contamination from both types of cultivation did not exceed the standard for raw materials treated with hot water.

A field experiment was established at the Experimental and Didactic Station in Swadzim near Poznań over 2004-2007 (52^o26’ N; 16^o45’ E). The experiment was carried out in a ‘split-plot’ design with 3 research factors in 4 field replications. 2 types of maize hybrids, 6 doses of nitrogen and magnesium doses (including methods of their applications) were examined. The effect of these research factors on the proportion of nutrients and raw material energy value of two types of maize hybrids grown for ear silage were assessed. The hybrid of stay-green type contained less crude fibre but more crude fat in dry matter of ears as compared with the traditional hybrid. The largest amounts of net energy concentration, net energy yield, digestible protein yield and total protein yield were obtained by applying a nitrogen dose of 120 kg N·ha^-1. Fertilizing maize with N + Mg (in rows and by broadcasting), an increase in total protein yield was obtained in relation to the treatments with N fertilization only.

Field experiment was carried out on the Didactic and Experimental Farm in Swadzim (52°26’ N; 16°45’ E) near Poznań, in the years 2004-2007. The three-factorial experiment was established in “split-plot” design with 4 replications. The reaction of two maize hybrid types on the application of 6 nitrogen doses and magnesium fertilization was studied. The influence of the studied factors on the content of chloroplast pigments in maize leaf blades in the phase of ear blooming (BBCH 67) was estimated. A greater content of chlorophyll a and a + b expressed in SPAD units was found in maize leaf blades of the stay-green type, as compared with leaf blades of the conventional Anjou 258 hybrid. Concentration of chlorophyll a and a + b was increasing in a linear way in the nitrogen range from 0 to 120 kg N·ha^-1, while the amount of chlorophyll expressed in SPAD units ranged from 0 to 150 kg N·ha-1. The stay-green type hybrid showed to be better nourished with nitrogen, on the basis of chlorophyll content in maize leaf blades, in the phase of ear blooming (BBCH 67), in comparison with the conventional hybrid and, at the same time, a lower nitrogen fertilization was needed. A simultaneous fertilization with magnesium increased the content of chloroplast pigments, in comparison with the application of nitrogen only. With the increase in the assimilation area of a single maize plant and of a maize stand (LAI indicator), the chlorophyll concentration in leaf blades was decreasing in a linear way.