Protecting our crucial soils

Protecting our crucial soils

Bala Tikkisetty

Good soils are at the heart of agricultural enterprise in the Waikato region.

Waikato Regional Council’s soil quality monitoring programme measures soil properties such as soil compaction, nutrient status, biological activity, soil carbon and organic matter at 152 sites, with about 30 sites sampled annually. The sites cover a range of soils supporting various land uses.

The main soil quality issues identified are compaction, excessive phosphorous and nitrogen (N) on dairy and cropping land, and declining carbon, mainly on cropping land.

The good news is that some of the emerging data trends suggest that there is an improvement in some soil quality indicators, most likely the result of good land management practices undertaken by our farming community.

But some measures in various areas are still causing concern, with improvements needed.

That’s because minimising human-induced soil erosion and maintaining good soil quality are essential for maintaining so-called soil “ecosystem services”, such as nutrient and water buffering, productive capacity, assimilating waste, and minimising impacts of sediment and other contaminants on water bodies.

The transformation of so-called “natural capital” - namely soil, plants and animals, air and water into resources that people value and use - is at the heart of what’s meant when we refer to ecosystem services.

The concept is gaining more attention nationally as we see environmental pressure increasingly applied to resources, such as soil health, that we once took for granted.

There are a number of practices that help support and improve our soils, and which provide clear benefits including:

• avoiding over grazing and heavy grazing in wet weather (leading to compaction)

• avoiding under or over-fertilisation

• appropriate use of pesticides and other agrochemicals

• managing pasture to maintain complete soil cover

• careful application of farm dairy effluent to optimise organic matter and avoid saturation .

There is also benefit in protecting on-farm wetlands, which deliver a wide range of ecosystem services, such as improving water quality, flood regulation, coastal protection, and providing recreational opportunities and fish habitat.

A suite of tools called functional land management seeks to optimise the agronomic and environmental returns from land and relies on the multi-functionality of soils. It focuses on soil functions that are specifically related to agricultural land use. They are:

• primary production

• water purification and regulation

• carbon cycling and storage

• functional and intrinsic biodiversity

• nutrient cycling

New research is currently focussed on nutrient cycling in soil, such as the ability of soils to recycle N, carbon and phosphorus and how this can best be managed.

To reduce N leaching from soils, the research is seeking to understand mechanisms for N retention in soil and how to manipulate soil processes to enhance de-nitrification. As soil microbes are the key agents for nutrient cycling, scientists are focussing on determining the impacts of soil management on soil microbial activity.

Waikato Regional Council is strongly committed to working with the wider farming community to increase the understanding of soil ecosystems services and ways in which farmers can manage them both to benefit their business, and to protect or enhance the natural capital on which it is based.

This work has already resulted in production of the menus of practices to improve water quality. They identify farming solutions and provide assessments of their effectiveness in managing various contaminants from farm land. The online version of the menus can be found atwww.farmmenus.org.nz.

The council will be keeping a close eye on the new research and providing advice to the farming community when we know more.

• Bala Tikkisetty is a sustainable agriculture advisor at Waikato Regional Council. Contact him on 0800 800 401 or bala.tikkisetty@waikatoregion.govt.nz.

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