Horticulture Notes January 2012

As we start a new year in 2012 a new growing season beckons and there are many issues that will face you as growers.  I want to highlight the two important issues of peat reduction in growing media and precision water management in horticultural crops, that are being investigated and demonstrated at CAFRE’s Greenmount Campus.

Cut flower lilies are currently grown in Northern Ireland in plastic crates using peat based substrate. Reducing the amount of peat used would reduce the cost of production and would also develop more environmentally sustainable growing practices. We have been demonstrating the reduction of peat at CAFRE, Greenmount Campus by three methods;

CAFRE Horticulture Technologist Teresa Maguire and Cut Flower Development Adviser David Davidson with 2011 lily trials demonstrating the reduction of peat

My colleague, Teresa Maguire, Horticulture Technologist has been working closely with me during 2011 to demonstrate that lilies can be grown successfully using peat that has been used to grow three previous crops of lilies.  This was achieved by simply layering the three-times previously used peat in the bottom of plastic growing crates which made up 50 percent of the total growing media that the lily bulbs were grown in and then placing new growing media on top of the reused media. This simple practice could be easily replicated on-farm by lily growers to reduce their use of peat and thus reduce their growing costs.  

We also found that lilies could be grown successfully both in composted green waste and in in-vessel composted food waste mixed with 25 percent peat. The initial findings of a trial conducted in 2011 also indicated that lilies could be grown successfully in a shallower depth of compost than is currently being used by growers in Northern Ireland.  

How do you know when your crop has received sufficient water to maintain healthy growth? Current practice in the irrigation of horticultural crops tends to be down to the experience of the grower. There is a risk of this approach being a bit hit or miss for example crops may require additional watering or there could be wastage if too much is applied. Today there are a range of hand held moisture sensors available which give an immediate digital readout of the percentage moisture content of any growing medium. Such a device gives an accurate picture of how well the crop is being watered.  Modern overhead watering sprinklers, and ground level watering systems such as drippers or seep hose can also help cut down the amount of water going to waste during irrigation by more accurately directing water to the crop root zone.

Technology currently exists that allows watering of crops based on the moisture content of the growing substrate (measured by a moisture sensor) and the requirements of the crop which allows very accurate irrigation of crops to be achieved. A moisture sensor will measure percentage moisture and send this information to a controller which triggers watering of the crop to maintain a preset moisture level typically set somewhere between 20 and 40 percent depending on the requirements of the crop in order to maintain healthy crop growth.

The Precision Water Management project managed by my colleague Cathal Ellis, Renewable Energy Technologist (Horticulture) at CAFRE Greenmount Campus demonstrates the ability of the available technologies to irrigate based purely on crop requirement. This approach provides the crop with timely and optimum volume of irrigation whilst limiting runoff/wastage. Our project work has indicated that the irrigation of containerised plants can be very accurately controlled within moisture limits set by the operator, thus reducing wastage of water and fertiliser through runoff.

CAFRE Technologist Cathal Ellis demonstrating precision water management trials to strawberry growers