For the 2016 growing season, The XY Hemp Corporation grew a cover crop of peas and faba beans. The term cover crop is used to describe a crop that is not grown to harvest, but instead to cover the soil to prevent erosion, add organic material to the soil, suppress weeds by increasing competition for light and moisture, and create a habitat for beneficial insects and microorganisms. For legumes crops, like ours, there is the additional benefit of nitrogen fixing in the roots of the plants. Another term, which is commonly used to describe this process, is a green manure crop or a plough down crop. These practices are different than summerfallow, where a field is left bare between cash crops and the soil is vulnerable to erosion or excess water.
Our primary motivation for the cover crop is to fix nitrogen in our soil to prepare for the 2017 hemp crop. In 2015, we also struggled with wild oats and so weed suppression is another goal for the cover crop. The 2016 cover crop (and 2017 hemp crop) is in the field next to our 2015 hemp crop. The last crop grown on the new field was oats and our soil tests revealed that there were similar levels of nitrogen in each field following the hemp crop and following the oats crop. This means that we need to fix as much nitrogen as possible in our 2016 field to support the growth of the 2017 hemp crop.
To do this, we planted a combination of 40/10 peas and faba beans. This combination was determined after conversations with our farming partners Al and Hélène, our hemp farming mentor Larry Marshall, and various organic agrologists and seed suppliers. The faba beans were chosen because they will fix a lot of nitrogen in the soil, but they do not provide very good weed competition and they need a lot of moisture, which is not ideal if the growing season is dry. On the other hand, the peas provide better weed competition and do not require as much moisture. In order to hedge against either weather outcome, we decided to grow a 50/50 blend of peas and faba beans.
Our final strategy to increase our soil’s nitrogen content organically, in a single growing season, was to ask Al and Hélène to graze their cattle on our cover crop before ploughing (or discing) the plants and manure into the dirt. While Al and Hélène have a relatively small herd – this type of manure spreading is best done by flash grazing a large herd – the additional nitrogen from the manure, and the weed suppression from cattle gazing on wild oats, should be beneficial overall.
In late June, Nordrick’s Norsask Seeds delivered our blended peas and faba beans to Breadroot Farm and Al was able to seed the cover crop. The seeds were treated with an organic inoculant to help the plants germinate and establish in the soil. This was quite effective, as both the peas and beans grew well together and there is a lot of plant material for grazing and working into the soil. When Hélène left for a conference in Montreal, the faba beans were taller than the peas, but when she returned, the peas had overtaken the beans. As you can see above, the crop was about three-quarters the height of the yearlings when they were released into the field to graze.
Al and Hélène tested the cattle in a small area (about 10 acres) to ensure that the peas and beans did not cause bloat in the livestock. To the contrary, the yearlings quite like the peas and appear to have healthy digestion from the perfectly round patties they are leaving on the field. On August 21, Al and Hélène opened up the rest of the field to the yearlings, who have been eating the peas and the wild oats, but leaving the faba beans for the most part. This is ideal for us, as the peas should be disced-in now because pods are already formed, while the faba beans can continue growing and fixing nitrogen. The cattle have been a very effective way to selectively mow down the cover crop. As they trample the crop, they are also starting the decomposition process, which will continue to mineralize the nutrients in the soil through the fall, winter and spring. The success of this strategy is a true triumph for the XY Hemp Corporation and we are hopeful that it will be reflected in the health of our 2017 hemp crop.