Should you plant a cover crop? No one likes hearing this, but the answer is – it depends.
In most perennial crops, such as tree fruit and small fruit, cover crops provide mostly advantages and almost no disadvantages. In filberts, this needs some forethought, and that is why it depends. Let’s look at the possible disadvantages first.
In the early years, during the establishment of the orchard, a cover crop can be risky if the orchard is non-irrigated. A cover crop, or any intercrop for that matter, can easily compete for water, to the detriment of the filbert trees. Young trees are vulnerable at this time, they don’t compete for water very well, and they can be easily set back, damaged or killed, as a result of competition for water. If you don’t have irrigation, don’t risk your trees.
In producing orchards, the “floor” of the orchard must be as smooth as possible to facilitate sweeping, windrowing and harvesting. During these operations, cover crops would be in the way. Repeated use of a flail is best to remove cover crops. Do this well ahead of time. Also, in older orchards (probably unlikely, given the ubiquitous effects of Eastern Filbert Blight over the past several years), especially in the multi-trunk format, the foliage tended to reach right over the alleyways. The light underneath tended to be dim, so the chances of establishing cover crops were low.
Now for the potential advantages of cover crops. During the non-producing years of an establishing orchard, if you have irrigation, the chances of establishing cover crops are good. With what looks like huge bare alleyways, there is every good reason to grow something there until the commencement of the intense floor operations of a mature production orchard. In the interim years, while waiting for your trees to grow to their full height and foliage and reach full production, why not grow cover crops and reap the benefits? (an alternate idea is to “intercrop”, meaning grow another crop to use the available space and gain some revenue – but that is a topic for another time).
One of the major benefits from cover crops is erosion control. If your orchard is prone to erosion, under certain conditions rivulets can become minor gullies quickly in heavy rainfall. In the early life of a filbert planting, before you need to worry about grooming the orchard floor in preparation of harvesting, there is no reason not to establish a cover crop for erosion control. The roots will do a good job of holding the soil in place. Second, you can use nitrogen-fixing legume cover crops to add nitrogen to the soil. This is an inexpensive source of nitrogen. Filberts take much of their nitrogen requirement from the soil reservoir, much more efficiently than from top-dressed nitrogen fertilizer. Third, cover crops help combat compaction; especially grasses. Filbert orchards are vulnerable to compaction because of the amount of truck and tractor traffic they are exposed to over time.
Cover Crop Seed under our Richardson Seed brand is available at TerraLink. Seed blends tend to do better than individual species. Here are some choices: