Skip to main content

Trends in soil quality monitoring data in the Waikato region 1995-2015

TR 2017/26

Report: TR 2017/26

Prepared by: Matthew Taylor (Waikato Regional Council), Neil Cox (NeilStat Ltd), Ray Littler (University of Waikato) and John Drewry (Greater Wellington Regional Council).

About this report

Waikato Regional Council monitors the life supporting capacity of soil to determine whether current practices will meet the foreseeable needs of future generations and identify any changes in the ability of the soil to sustain environmental quality. This report presents data and statistical modelling on trends in meeting the seven soil quality targets by soil quality sites for different land uses for the period 1995-2016 and the main soil quality issues facing the Waikato Region.

Overall, 10% of managed soil quality sampling sites corrected for land area in the region met all seven indicators in 2015, down from a high of 17% in 2006. The main soil quality issues identified in the Waikato region are soil compaction, excessive nutrients and loss of soil organic matter (SOM) with the associated decrease in biological activity of microorganisms. However, the magnitude of each issue varies with land use.

Read or download the report

Trends in soil quality monitoring data in the Waikato region 1995-2015 [PDF, 1.6 MB]

Contents

  Executive summary
  Recommendations
1 Introduction
1.1 Regional programme objectives
1.2 The Soil Quality Monitoring Programme has three key objectives:
1.3 Reasons for soil monitoring
1.4 Soil monitoring programme design
2 Soil monitoring programme method
2.1 Sampling and analysis
2.2 Statistical analysis
3 Soil quality results
3.1 Changes in bulk density 1995-2015
3.2 Changes in macroporosity @ -10 kPa 1995-2015
3.3 Changes in Olsen P 1995-2015
3.4 Changes in total N 1995-2015
3.5 Changes in AMN 1995-2015
3.6 Changes in total C 1995-2015
3.7 Changes in pH 1995-2015
4 Discussion
4.1 Pastoral land
4.2 Arable land
4.3 Horticulture
4.4 Forestry
4.5 Conversion of forestry to pasture on pumice soils
4.6 Soil acidification
5 Conclusions
6 References
Appendix I: Determining the number of nationally representative samples
Appendix II: Required laboratory methods for soil quality monitoring
Appendix III: Soil quality target ranges
Appendix IV Statistical analysis
Appendix V Results of 2015-16 soil quality monitoring
Appendix VI Results for all 150 soil quality monitoring sites