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

Abstract

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).

Investigation of Water Quality in the Agricultural Area of Lithuanian Karst Region

“…The highest concentration of nitrate nitrogen (NO 3 -N) was found when growing potatoes and lower one was found when growing perennial grasses (Figure 3). However, concentration of total phosphorus (TP) increases in drainage water when growing perennial grasses [17,18].…”

“…Higher amount of nitrogen and phosphorus are leached out in winter and spring periods [18]. The peak concentrations of nitrate nitrogen occurred in winter and spring (due to the higher run-off) and at the onset of run-off after a dry period (due to the leaching of nitrogen that was not used during the dry period) [22].…”

Analysis of annual and seasonal total nitrogen pollution in the Mūša catchment

“…H. Pauliukevičius using AGNPS model to investigate the relationship between the territorial distribution of agricultural land and water quality in the Nevėžis catchment has established that variation of agricultural land area can increase or decrease nitrogen load from 1.5 to 2 times within the river catchment [9], [10]. This was proved by the other scientists who investigated the runoff of biogenic matter into the water courses of the karst region [11][12][13]. They established that it was important to evaluate the type of agricultural land and suggest that the least amount of nitrate nitrogen is leached from pasture and the largest amount -from arable land.…”

Hydrology and water quality across gradients of agricultural intensity in the Little River watershed area, New Brunswick, Canada

“…Compared with other land uses, agriculture and associated activities are more closely related to N and P loads to the environment (Novotny 1989;Cartwright et al 1991;Morkunas et al 2005;Oenema et al 2005;Dukes and Evans 2006) that lead to water quality issues. Intensification of agricultural activities has led to more frequent applications and increased amounts of fertilizers and pesticides.…”

“…It is important to understand the relative contribution of contaminants from agricultural and forested area at the watershed level. Although some research has been done to evaluate the impacts of agriculture on water quality (Norton and Fisher 2000;Hecky et al 2003;Morkunas et al 2005;Dukes and Evans 2006) at different temporal and spatial levels, the complexity of the impacts (affected by both field and landscape variables) requires a long-term robust time-series data collection at multiple-scale watersheds to carry out more efficient evaluation by using statistical modeling.…”