Two high-input and two low-input crop-management systems, one reference treatment with field crop rotation, and one long-term moderately treated pasture were studied and compared in respect to nitrogen (N) and phosphorus (P) flow and balance. The experiment was conducted on tile-drained plots covered by Endocalcari-Endohypogleyic Cambisols. The least Nmin (mineral nitrogen) leaching losses were registered in the pasture. The high-input management systems did not consistently result in larger losses of Nmin [mainly nitrate (NO 3 )-N] and Ptot (total phosphorus) in the drainage water. The leaching of Nmin depended more on amount of the drainage water leaving the site, soil organic matter/humus, and soil Ntot content (positive correlation) as well as the content of water-stable aggregates (negative correlation). The higher concentrations of Ptot in drainage runoff in the organic (ORG1) treatment and pasture during the second rotation might be conditioned of ley root system impact. Ptot leaching was positively correlated to the available P 2 O 5 -AL in the topsoil. Negative N field balance was determined in all the treatments, except ORG2 and LTP in 1995-1999, whereas it was negative only in the reference plots (REF) in the 2001-2003 rotation because of the increased crop residues and drier climatic conditions. Phosphorus balance was slightly negative in the ORG1 and reference treatments during both rotations.

No abstract

The geography of border regions is not only determined by geopolitical issues, but also by physical factors, cultural traditions, economic activities and demographic change. Twenty‐five years ago, the rural landscapes in the Šilutė (Lithuania) and Slavsk (Russia) administrative districts, which are located in the Nemunas river delta area, were dominated by agriculture, based on polder systems. Subsequently, agriculture has shrunk and some agricultural land has been abandoned. As a result of migration, the total and rural populations in Slavsk district have remained the same as 25 years ago. In Šilutė district, the total and rural populations have been decreasing each year since 1990–1991. Traditional agriculture in Šilutė district is supplemented by organic farms and, in parallel with commercial fisheries, recreational fishing has increased. Rural tourism, water and nature tourism and other recreational activities have also increased, particularly in Rusnė Island and Nemunas Delta Regional Park territory (Lithuania's part of the delta). Protected areas have increased four‐fold since 1991–1992, while there has been a negligible increase in built‐up areas in the whole delta region. Though recreation and tourism are less developed in Slavsk district, and small and medium enterprises are fewer than in Šilutė district, the rural landscape is evidently changing in the whole region. It is transforming from a traditional agricultural–fishery region to a multifunctional region that is focused on increasing conservation and recreational activities.

The aim of this research was to compare a few crop management systems in respect of potassium leaching in order to reduce the leaching losses. Research was carried out on an Endocalcari-Endohypogleyic Cambisol (CMg-n-wcan) at the experimental site of Lithuanian Institute of Agriculture (currently -Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry). The focus was on the search for factors responsible for leaching, including precipitation amount and rate, and selected soil properties. The highest potassium cation (K + ) leaching with drainage runoff 3.8 kg ha -1 year -1 was determined in the conventional system with high K inorganic fertilization level as compared with 1.9 kg ha -1 year -1 in the treatment with zero fertilization (reference) during the first research period in 1995-1999. However, later, after a few changes in experimental design and under the drier conditions, leaching of K + was low and similar in all crop management treatments on the arable plots (approx. 1.6 kg ha -1 year -1 ). The rate of K and N fertilizers positively influenced the leaching of K + only during the normal and wet years with precipitation rate >450-600 mm. The content of soil aggregates <0.25 mm in topsoil positively correlated with K + leaching losses during the first research period (P < 0.01). During the whole research period the precipitation rate was the factor from the main effects, which explained 64% of the K + leaching variance. The final model explained 76% of K + leaching variance for all data and 65 ± 16% on cross-validation data, showing relatively high and stable accuracy of predictions. Among the variables, the interaction of precipitation rate and content of humus, the interaction between the precipitation rate and content of soil aggregates <0.25 mm were the most important, each explaining more than 60% of the variance of K + leaching losses.

The causal relationship of changes in nitrogen and phosphorus concentrations in the Akmena-Danė River and its largest tributary, the Eketė River, was analysed for the period 1999–2014. Results showed that the annual concentrations of NH4-N and PO4-P significantly decreased in the Eketė River over the research period. NH4-N also significantly decreased in the Akmena-Danė River. This was mostly due to the shrinkage of agriculture, i.e., the reduction in agricultural land area, total farm and animal numbers and other agricultural activities. The effect of other factors such as air temperature, precipitation rate, shift of precipitation maximum from warm to cold season, drainage runoff from the large tile-drained areas, soil types and the slight increase in forested land was also examined.