Roselilly Farm uses a conservative and measured approach to fertilizers. We are comfortable departing from the organic movement's policies in important ways.
The organic movement claims that chemical fertilizers encourage excessive growth of plants, and that, in using the nutrients supplied in the fertilizer, they over-use other nutrients – the trace elements – and leave the soil depleted. They also claim that chemical fertilizers destroy the life of the soil, killing the microflora and fauna and depleting its organic matter.
We agree that chemical fertilizers are highly concentrated, and that it is therefore easy to apply too much of it. Naturally, if you over-apply fertilizer, the harm described above will follow.
However, we do not agree that chemical fertilizers are harmful if they are applied at the correct dose rates to rectify deficiencies. We agree that the soil's organic matter is extremely important. It gives the soil good structure, which encourages root penetration and makes the nutrients available to the plants. But the requirements of the microfauna and flora for nutrients are very similar to those of plants, so if the plants are suffering from a deficiency of, say, phosphorus, the soil bacteria and fungi, etc., will be too. Therefore we believe that if, in those circumstances, you enhance the supply of phosphorus, the microbial life will benefit just as much as the plants. We sample the soils of our different fields regularly, and have them analyzed by UVM, and we make sure that our application rates of fertilizer are well within UVM’s recommendations.
Not only do we argue that simulated fertilizers can be beneficial to soils, but we have also found downsides to using manure as fertilizer. Transporting manure bulk is a big problem. This was illustrated by an on-the-farm case study last year. We applied chemical fertilizer to seven hay fields, comprising about 20 acres. A single spreader full of fertilizer was sufficient, and it took about four hours. In contrast, the owners of one of the fields we lease would not allow us to spread fertilizer on their field, only manure. This field is only about four acres, a mile from the farm, including a steep hill. That fertilization task took 11 trips over three days, with the tractor at full throttle going up the hill. It also meant running heavy machinery over the soil a great deal more, which is not good for it. Overall, the much smaller task required 20 gallons of diesel and much more tractor time. The cost to the environment was therefore considerable.
For these reasons, and under certain circumstances, the limited use of fertilizers makes sense in this part of Vermont. Roselily Farm will continue to use all the manure we generate in the fields of our own farm, but will consider fuel use and soil damage when fertilizing requires travel -- or other complexities.