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The effects of anthropogenic (nitrogen fertilization) and natural [soil texture, pH content of humus, ammonium nitrogen (N-NH4), and the available forms of phosphorus (P), potassium (K), magnesium (Mg)] factors on nitrate nitrogen (NO3-N) content and distribution were shown. The dependencies between these factors and the content of NO3-N in soil were estimated in three soil layers: 0-30 cm; 31-60 cm; 61-90 cm. The research was carried out in 2004-2006, and the soil samples were taken from 411 places throughout eastern Poland in two seasons: spring and autumn. The concentration of NO3-N significantly depended on the year of investigation, season of the year, and depth of sampling. Distribution of NO3-N in the soil profile indicates possibility of NO3 leaching during winter and early spring. The results also provide evidence that application of more than the optimum N rate considerably increases NO3-N, especially in soil with low humus content. [ABSTRACT FROM AUTHOR]

Field studies were conducted in the years 2003-2005 in the Experimental Farm of the University of Life Sciences in Lublin. Beans from four cultivars - 'Paulista' and 'Hit' (green pods) and 'Korona' and 'Galopka' (yellow pods) - were grown on fawn soil, formed of loess deposits, on chalky marls, containing 1.4% organic substances on average. There were six sowing terms, every 6-7 days starting from the middle of May to the end of June. French bean harvest was performed once, when about 75% of the pods on the plants were in the phase of technological maturity, which fell between the third ten days of July and the first ten days of September. From the plot and plant the number and yield of the pods were determined: total, marketable and non-marketable small pods, unshapely and overripe pods, as well as those with symptoms of disease. The highest total and marketable pod yields - on average, 15.45 and 11.06 t ha-1, respectively - were obtained from plants sown in the first ten days of June, whereas the lowest - 12.54 and 9.54 t ha-1 - were from those sown in the middle of May. As a result of performing a one-time French bean pod harvest, the share of non-marketable pod yield in the total yield was on a similar level (24-28%), depending on the growing term. Variability was demonstrated in the share of particular non-marketable yield fractions (small pods, undersized, unshapely, and overripe pods, as well as those with disease symptoms), depending on the sowing date. Growing four French bean cultivars from sowing in the period from the middle of May to the end of June allowed us to extend the period of fresh pod harvest to six or seven weeks. [ABSTRACT FROM AUTHOR]