Influence of agriculture on soil water quality in the karst region of Lithuania

✍ Scribed by V. Morkunas; A. Rudzianskaite; P. Sukys

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 317 KB
• Volume: 54
• Category: Article
• ISSN: 1531-0353
• DOI: 10.1002/ird.179

✦ Synopsis

This article presents the results of studies on lysimeters and drainage carried out in the karst zone of Lithuania. The studies included the estimation of the changes of water quality in a soil profile of moraine loam and sandy loam soils in respect of the land usage and fertilization intensity. Fluctuations of N-NO 3 concentrations contained in soil water mainly depend on N losses through the yield (r 2 ¼ 0.78). The highest N concentrations (up to 28.7 mg l À1 ) were observed in the fields where potatoes were grown; six times lower N concentrations occurred in the fields of barley with undercrop and the lowest N concentrations (up to 5.1 mg l À1 ) were determined in fields of perennial grass. This was because N losses with the yield of potatoes are 1.7-2.0 times less than its losses with barley and even 3.0-4.5 times less than N losses with perennial grass. Efficient application of fertilizers results in decreased N-NO 3 and TP concentrations contained in soil water (r 2 ¼ 0.27-0.56 and r 2 ¼ 0.18-0.57 respectively).

Compared to the field of perennial grass, the arable land contained even 9 times higher N-NO 3 concentrations and 2.6 times lower TP concentrations in the whole soil profile. However, when migrating into deeper soil layers in arable land, N-NO 3 concentrations decrease, while in the field of perennial grass the lowest N-NO 3 concentrations occur in the root zone of plants. TP concentrations tend to decrease in deeper soil layers in arable land as well as in the field of perennial grass.

The selection of proper land use in studied soils is a particularly important factor. In order to reduce N-NO 3 leaching, the area of perennial grass might be increased, however this may result in higher TP concentrations. Moreover, it is precarious to leave tilled land for the period abundant in water (winter and spring).