The researches were carried out from 2002-2007 in the upper reaches of the Šušvė River, a Nevėžis tributary, at the pig enterprise Limited company (LTD) 'Litpirma' breeding near the township of Šiaulėnai. LTD 'Litpirma' has been operating since 1978 and produces 25 thousand fattening pigs per year, along with an associated 56 thousand m3 organic fertilizers (liquid manure, slurry and solid manure), which are spread on surrounding agricultural fields. This article presents the impact of a large pig breeding company on the river water quality and quantifies the leaching of nitrogen, phosphorus and potassium (NPK). It is based on the water quality research data collected from an 11.6 km section of the Šušvė River, both upstream and downstream of Šiaulėnai, regarding the drainage water outflow from the fertilized fields and from Šiaulėnai domestic wastewater. Drainage water from 728 ha of fields that have been fertilized with organic fertilizers carry an average of 11.4 tons of nitrogen, 0.073 tons of phosphorus and 5.53 tons of potassium. Changes in NPK quantities carried by this section of the Šušvė were calculated as follows: total nitrogen increased by an average of 83 tons yrE–1 (58%), potassium by 51 tons yrE-1 (54%) and the smallest increase, for total phosphorus, by 1.2 tons yrE-1 (48%). All of these pollutants leached into the river during the cold season (to 60% total phosphorus and to 88% total nitrogen) when there was no vegetative growth. A wet year affects the quantities of leached NPK.

The article analyses the seasonal nitrogen variation in drainage water, when the plants in the field crop rotation are fertilized with slurry during different seasons. The investigations were carried out in 2001-2003 in Juodkiškis experimental site of the Lithuanian Water Management Institute. The investigations established that the largest amounts of nitrogen are leached out in spring and in winter. In the autumn fertilized variant 38.8% more of this element was leached out in winter and spring compared with the variant fertilized in spring. During autumn nitrogen leaching was also 21% higher from the variant fertilized in autumn. It was established that the fertilization rate and dissolved inorganic nitrogen (DIN) supply in soil have influence on the concentrations of this element. During the cold season nitrogen concentrations in drainage water, when plants had been fertilized with slurry in spring, were more affected by the supply of dissolved inorganic nitrogen in soil more compared with the rate of fertilization; and if fertilization had been performed in autumn - the concentrations were more affected by the fertilization rate. In warm season both the fertilization rate and the supply of dissolved inorganic nitrogen in soil had similar influence on the concentrations of nitrogen in the drainage water in both treatments. Meteorological conditions affect nitrogen leaching a lot. During the cold season a greater amount of nitrogen is leached out when the air temperature is higher and during the warm season - when more precipitation falls.

Field experiments were carried out at the Experimental Station of Vytautas Magnus University (54º52′ N, 23º49′ E) in Lithuania. Winter wheat was grown on the background of N150P90K90 mineral fertilization and was additionally foliar-fertilized with different concentrations of amino acid solutions (0.5-3.0%) at stem elongation and heading stages. The study was aimed to establish protein content as well as quantitative and qualitative distribution of amino acids in winter wheat grain as influenced by fertilization with different concentrations of amino acids. Experimental evidence showed that solutions with different concentrations of amino acids applied at winter wheat stem elongation and heading stages increased grain protein content and total amino acids contents. Plants, fertilized with amino acids solutions at stem elongation stage accumulated higher protein content by on average 4.8%, at heading stage by 4.5% compared with the grain protein content of plants that had not received amino acids fertilization. The total amino acids content in winter wheat grain in response to amino acids applied at stem elongation stage increased by on average 2.0 g kg-1, at heading stage by 5.3 g kg-1. Nonessential and essential amino acids content in winter wheat grain was significantly increased by 2.5 and 3.0% amino acids solutions, applied at stem elongation stage by 0.5, 1.0, 1.5% amino acids solutions applied at heading stage. Winter wheat fertilization with amino acids solutions at stem elongation stage mostly increased the content of glutamic acid, at heading stage mostly increased the contents of glutamic, aspartic, valine, isoleucine, leucine, phenylalanine, methionine, threonine and lysine acids.

In 1999-2003, the investigations were carried out in Juodkiskis study object of Water Management Institute of Lithuanian University of Agriculture. Study scheme is composed of three treatments: treatment I -slurry applied, treatment II - mineral fertilizers applied; treatment III - no fertilization. Test field is drained, drain spacing is 15 m; draining depth is 1.2 m. During the crop rotation the following plants were grown: spring wheat with undercrop, red clover (1st year of use), red clover (2nd year of use), sugar beet, and spring rape. The objective of studies was to determine the effect of cultivated crops on drainage water quality. As the study results have show, N total concentrations contained in drainage water increased due to higher fertilization rates and inorganic nitrogen accumulated in the soil. Neither fertilization nor amount of mobile phosphorous contained in the soil made any effect on Ptotal concentrations in drainage water. In arable land, Ntotal concentrations contained in drainage water were 2.3 times higher than those in drainage water of the field, where red clover was grown. Ptotal concentrations were higher in the field with red clover. According to the rates determined in Lithuania, drainage water is not polluted with phosphorus, while average annual Ntotal concentrations exceeded the maximum allowable (MAC) when spring wheat with undercrop and sugar beet was grown.