New Zealand Journal of Agricultural Research abstracts

---

Short communication 

Land application of farm dairy effluent: results from a case study, Wairarapa, New Zealand

R. M. Hawke
S. A. Summers

School of Earth Sciences
Victoria University of Wellington
Wellington, New Zealand

Abstract  This case study examines the effects of 6 years of farm dairy effluent (FDE) irrigation on the upper 40 cm of a Greytown silt loam, Wairarapa, New Zealand. Physical and chemical soil properties were measured, i.e., particle size distribution, porosity, dry bulk density, field-saturated hydraulic conductivity, total carbon, total Kjeldahl nitrogen, pH, total and Olsen phosphorus, cation exchange capacity, and concentrations of exchangeable cations (K⁺, Na⁺, Ca²⁺, Mg²⁺). While the concentrations of total carbon and total Kjeldahl nitrogen were generally low at all depths, the application of effluent has caused a significant increase in their concentrations in the upper 10 cm of the profile. The concentration of exchangeable cations has been similarly increased in the upper 10 cm of the profile. The soil has very low phosphorus retention, however effluent application has increased both total and Olsen phosphorus to 40 cm depth. Most of the changes in soil properties have led us to believe that current application rates and pasture production can be maintained and that FDE application has improved the soil’s long-term fertility or ‘soil quality’, especially in the upper 10 cm of the profile. However, there is no evidence to suggest that current application rates are sustainable in terms of other environmental effects (e.g., nitrate leaching).

Keywords  dairy; effluent; soil; Wairarapa

A03001; Received 23 December 2002; accepted 1 September 2003; online publication date 5 November 2003
New Zealand Journal of Agricultural Research, 2003, Vol. 46: 339–346
0028–8233/03/4604–0339 $7.00/0 © The Royal Society of New Zealand 2003

PDF file of entire paper: Print-quality (67K) |screen-quality (43K)

---

This year's abstracts | Journal home page | All abstracts | Publishing home page