Tea Bag Index - a simple scientific method to test microbial activity in your soils
The tea bag index (TBI) is a very low-tech, low-cost scientific tool that allows you to test the microbial activity in your soil.
The Tea Bag Index experiment is easy: You take one green and one rooibos tea bag (everybody has to use the same brand). You weigh them, bury them 8 cm deep in the soil and after 3 months, you take them out, dry them and weigh them again. The weight loss will tell you how quickly plant material decomposes at the burial location.
Decomposition is a critical function performed by soil microbes that recycles nutrients, forms humus and stores carbon. It is important to understand decomposition so we can improve soil nutrient status and take carbon out of the atmosphere.
The Tea Bag Index is a cheap and easy way to help you better understand microbial life in the soil on your farm. You can compare different materials (e.g. different pastures, different crops) or the same material in different soils/fields or at different times of year, or a combination. You can find a good explanation of how and why it works here. You can also hear more about it in this month’s episode of Farmerama, listen here.
Sun Surveyor App - use sun and shade elements to guide decisions whilst out in the field
One of the most important resources on our farm is the sun (as is true on most farms). All of our buildings have passive solar design at their core, and the sun’s movements are always central to everything we create on the farm. The sun's positioning (and the length of shadows) in each season help us to determine the placement of a water tank, or where to plant the lettuces in the Summer.
The Sun Surveyor App makes it easy to foresee exactly where the sun will be at any time of day, any day of the year, at an exact location that you specify and calculate the shadows caused by any objects in the area. This makes it the perfect tool to use when you are out and about in the field and want to use passive solar/permaculture design principles to plant a stand of trees or determine the location of a new polytunnel.
The lite version is free and you can get pretty much all the information you need. The full version is £8 and makes it a bit easier as you can use your phone’s camera to see the sun position superposed on your surroundings.
Featured farmer: Nick Green from Incredible Farm, Todmorden
We are excited to feature Nick because he is extremely resourceful and always looking for low-cost and easy options for making his small farm run effectively.
1.Can you tell us a bit about you and your farming setup?
We are a small community farm, started 6 years ago with the intention of re-inventing tiny family scale agriculture. Motivations are climate change, food security, sustainability etc.
We are on a 5 acre plot, deep in a Pennine valley with plans to expand. We have several businesses within the whole: a veg business; a fruit tree nursery where we sell trees to community groups etc; and a teaching business where we seem to be developing a USP of alternative provision – for the ones who fit better into an outdoor setting than a school.
We also have a nano dairy, of 3 jersey cows, and are working towards sales of unpasteurised milk. Two pigs lap up the whey from cheesemaking and apple pulp from cider making from the nearly 1000 trees we planted 8 years ago.
We have nominal support locally, but the real support is young people coming to stay and work on the farm, for food and accommodation, from all over the world. Often the BEST people and future leaders. We have a strong sense of changing lives, globally.
2.Can you tell us the story of the latest tool you added to your farming setup? What works? what doesn't work?
This summer we made two new gadgets. A solar fruit drier, out of the polytunnel front door (we take it off in summer) vented with a solar fan. But the key to its success is slates: Black, heat absorbing and we had them already!
The other is a development of a simple milking machine we bought. We successively replaced the parts until we had the capacity we needed, and it ran on 12V from our solar supply. The cows like it, we like it, it’s easy to use, simple and cheap.
3.What is the most important tool you use? What's so good about it?
Probably the most useful thing we have is a supply of re used black one ton water tanks (IBC’s). We use them for all sorts: chopped in half for movable grow beds; for water storage that stores heat passively in the polytunnels; chopped down to make a hay feeder for the cows; to drag stuff around the farm; for a duck pond, or a gosling nursery; we even just use them for drinking water storage!
If you want to hear more about Nick's tools or ideas you can get in touch through Incredible Farm facebook or twitter, or send us any questions and we will pass them on.