The Science Learning Hub team understands the importance of covering all science disciplines within our content. Before beginning this collection of resources on soil and farming, we were aware that chemistry was an area that needed some attention. Find out below how our writer, Barb Ryan, went about this.

Barb Ryan - writer

I was also asked if I could do something on farming since it is the backbone industry of New Zealand’s economy and most New Zealand children have had some experience related to farming – even if it’s just to stay on a friend’s or relative’s farm.

I began to think about how I could combine chemistry and farming. After talking to a few people, I realised that not only did soil chemistry combine farming and chemistry but that environmental issues concerning nutrients from the soil (nitrates and phosphates in particular) were hugely topical.

My colleague, Angela Schipper, joined me to develop these new resources. With her background and knowledge of soil chemistry, she worked on the soil articles and some of the activities.

The issues

The environmental problem underlies these resources. It appears that intensified farming in our country has brought about the imbalance of the nutrient cycles – particularly the nitrogen cycle. More nitrates are available in the soil than can be used. Nitrates are soluble and can be easily washed into waterways. Nitrates and phosphates (also leached into waterways) contribute to eutrophication – the degradation of streams and lakes (Farming and environmental pollution). Excess nitrogen also contributes to greenhouse gases. These issues and possible solutions developed by scientists are explored.

The scientists

I contacted scientists Ross Monaghan and Selai Letica from Invermay because we wanted some South Island coverage. They were investigating some interesting ideas for solving the nutrient loss problem. These ideas related to their knowledge of the nitrogen cycle and how to use the cycle to inhibit the production of nitrates.

Professor Louis Schipper is Angela’s husband. He is also a scientist at the University of Waikato, working to reduce nutrient run-off. Louis has developed a system that works to use nitrates before they get into waterways (denitrification beds). He was also happy to be involved with the Science Learning Hub.

Nutrient cycles

I knew very little about soil chemistry and nutrient cycles when I started out. I quickly realised that, in order to understand the scientists’ work, I needed to get familiar with the nitrogen and phosphorus cycles. Some of the work at Invermay – through scientist Richard McDowell – involved the phosphorus cycle and explored farming practices that could reduce phosphorus leaching. It’s true that these cycles are very complex, but the scientists helped me to present the most important parts of the cycles in a simple way. This helps us to understand the main aspects of the cycles.

Activities– very practical…

Angela and Louis had previously written a practical resource book on nitrogen for teachers of senior students in the USA (Soil, Water and Land Use: Understanding Nitrogen Interaction – A Soil and Water Education Project Kit). They were happy for me to use and rewrite many of these experiments.

It was fun trialling some of these experiments. They are ‘hands on’, easy to do and really help with the learning. I still have a Winogradsky column in my garage – a soda bottle full of mud growing colourful bands of bacteria (Growing soil microbes). Angela told me she set up one of these columns in a new entrant room (5-year-olds) and that the writing from the students was incredible! It’s a great activity for developing observational skills.

… and explores others’ points of view

There is also an activity that focuses on discussing issues (Farming and environmental issues). Since there has been awareness of environmental pollution caused by nutrient loss, there has been debate between environmentalists concerned about water and air quality and farmers who not only need to earn a living but supply food and goods to the rest of us. Students explore these issues within a framework – learning to understand issues from various points of view.

    Published 8 August 2013