On returning from a trip through the "Parkland" region of Manitoba, Canada, we had questions about the hemp harvesting observed. After a bit of Googling, we found this helpful provincial government site. Being a professional resource, of course, the site offered no explanation as to why the hemp seed pods had been harvested and the fibrous main stems left to stand, porcupine-like in the last warm days of fall. A few weeks later help arrived. An earlier email to the Parkland Industrial Hemp Growers Coop had been passed along to a local agricultural agent, who kindly responded to all of our naÃ¯ve questions, including these: + 1. Do wildlife, waterfowl especially, frequent the fields and eat seeds as they do on other Manitoba crops? If so, do they then become confused and fly North in the fall (kidding about that part)? + 2. How might you compare soil conservation outcomes of hemp rotated lands to lands rotated only with traditional crops. + 3. How energy intensive is the hemp planting and harvest compared to the other common Manitoba crops? As with all questions hempish, the 'devil is in the details.' Have a look at some excerpts from the helpful reply we recieved.
"The fields this year were about 5 to 7 feet tall on average. When combining for [hemp] grain, a combine with a straight header is used. For most crops it means the crop is combined at about 10 to 25% moisture and is cut usually as high as the header will allow. This height depends on the type of machine and how high they allow the header to go up and also how high the crop is. Generally 2.5 to 3.5 feet of stalk is left in the field.
In an ideal world, the 3 feet of remaining stalk would be cut at ground level by a machine (swather) to windrow it so it could be baled so it could be removed from the field to a fibre processor. Producers would normally do this anytime from right after combining until the next spring depending on their work load. Unfortunately, at present there is not a fibre processor so the stalk are not harvested. Presently with out a processor, the length of time the stalks have to stay in the field is unknown. This will have an impact on how soon after combining the crop could be cut. Parkland Industrial Hemp Growers are in the process of trying to raise equity to build a fibre processing plant in Dauphin, Mb.
I don't think it has been observed that wildlife like or dislike the hemp compared to any other crop. In the fall we generally do not see them in the fields as I think the stalks are too hard on them — for example a deer. Water fowl do not like it as once they are down in the stubble it is very hard for them to fly out.
Soil Conservation — I would say it is a crop comparable to most other crops. Manitoba especially has gone to a minimum and zero tillage system of cropping. This means there is very little tillage and a lot of the stubble and plant material is left on the top of the ground (eg wheat). This protects the soil from blowing away. With hemp, depending on what the farmer does to clean up the stubble, there might in fact be a higher exposure of the soil to wind erosion. Without a market for the fibre, the farmer really does not have any option but to get rid of the fibre/stubble so he can crop the field the next year. The stubble because of the high fibre content would stay in the field for 3 to 5 years. The fine fibres then can wrap on equipment wheel, bearings etc and cause undo expense and repairs. With out a market, most of the fields are burned to get rid of the fibre. This leaves no trash on the field to protect from erosion. If the farmer uses much tillage after burning, the field would be like summer fallow and could be prone to erosion from wind.
Energy use for production is probably the same as any other crop like wheat or Canola. There is limited research but Tillage and seeding practices are suggested to be the same as for a good crop of wheat of canola. One difference would be in the use of herbicides. If a hemp crop gets off to a good start, it can out compete weeds so weed control costs would be less. The energy used to make the herbicide would translate into less energy being used for hemp production. On the other hand, hemp grain will always be combined at 10 to 25% moisture so drying of the grain is necessary which would likely off set the herbicide saving.
Closing comments from TH:
Much appreciation to the Manitoba ag agent for answering our questions so thoroughly and sensibly. It would be a great benefit to the environment if the local coop were able to complete its fiber processing plant. If anyone would like to be in contact with the coop working to add Manitoba fiber processing capability, their web site is here.
Our trip from Wisconsin USA to Winnipegoses, Manitoba Canada was thought provoking. In the near future, we also hope to do a post comparing the sharptail grouse populations of Manitoba to those of North Dakota, as a function of agricultural acres held in conservation reserve. If anyone has ideas or references on this topic, please email them to john-at-treehugger.com or else leave a comment here.