Water quality of a lowland stream in a New Zealand dairy farming catchment

Abstract

A small stream in a predominantly dairying catchment in the Waikato region of New Zealand was monitored for 2 years at three sites. Total nitrogen (TN) concentrations were up to 7.09 g m -3in winter, with the bulk comprising nitrate nitrogen (NO -3 -N). During summer NO -3 -N was near zero and TN mostly comprised organic nitrogen. Maximum concentrations of total phosphorus (TP) and dissolved reactive phosphorus (DRP) were 1.64 and 0.555 g m -3 , respectively, and peaks coincided with spring and autumn applications of phosphorus fertiliser. Ammoniacal nitrogen concentrations exceeded 1 g m -3 on several occasions and mean concentrations at the three sites were 0.165-0.272 g m -3 . Faecal coliform and enterococci bacteria concentrations were 64-26000 and 7-23000 cfuper 100 Received 23 March 1999; accepted 23 June 1999 ml, respectively. Specific yields of TN and NO -3 -N (35.3 and 30.7 kg ha yr -1 , respectively) were much greater than any previously reported for New Zealand pasture catchments, whereas TP and DRP yields (1.16 and 0.54 kg ha yr -1 , respectively) were more in accord with other studies. Greater use of land treatment of liquid wastes will reduce stream inputs of faecal organisms, NH 4 -N and P. M99015

Diffuse contributions dominate over point sources of soluble nutrients in two sub-catchments of the Manawatu River, New Zealand

“…These mechanisms occur over all flow categories and may differ in their relative contribution as flows increase or decrease. If the outcome sought is reduced diffuse source inputs at low flows, consideration should be given to methods that reduce direct diffuse source inputs such as stock access to water (Quinn et al 2009) and poorly managed farm dairy effluent (Houlbrooke et al 2004(Houlbrooke et al , 2008, including leakage from effluent ponds (Wilcock et al 1999;Roygard 2009). Direct diffuse source inputs are obvious mechanisms for nutrient transport; another major pathway is via groundwater.…”

Nitrous oxide generation, denitrification, and nitrate removal in a seepage wetland intercepting surface and subsurface flows from a grazed dairy catchment

“…Because the wetland soils likely included eroded materials from the adjacent Allophanic volcanic soils of the paddocks, there is potential for some portion of the dosed NO 3 À to be subject to anionic sorption (Magesan et al 1998). However, considerable NO 3 À leaching has been observed in the paddock soils (Wilcock et al 1999), suggesting that any sorption is likely to account for a limited proportion of the NO 3 À removal. Uptake of NO 3 À by wetland plants in our study appears to be plausible even over a short period of 48 h, particularly because the vegetation appeared to be N-deficient at the time of the experiment.…”

Trends in water quality of five dairy farming streams in response to adoption of best practice and benefits of long-term monitoring at the catchment scale

“…The Inchbonnie and Waikakahi catchments were dominated by free-draining stony soils, in contrast to the Bog Burn catchment where poorly draining silt-loams were underlain with extensive mole and pipe drainage networks ). Toenepi and Waiokura catchment soils were dominantly volcanic silt loams (Wilcock et al 1999). …”

“…pdf [accessed 15 May 2012]). A consequence of increased stocking rates has been a concomitant increase in nutrient leakages from farm systems and increased inputs of sediment and faecal microbes to aquatic ecosystems (Ledgard et al 1999;Quinn et al 2009;Wilcock et al 1999Wilcock et al , 2007. Land use changes from sheep and beef cattle grazing to more intensive dairy farming have caused marked deterioration in the water quality of New Zealand's low-elevation streams and rivers (Larned et al 2004;Howard-Williams et al 2011).…”