PROJECT RESULTS

Development of Hemp Production and Processing Quality

Table of Contents:

• Background and Objectives
• Procedure and Project Activities
• Results and Discussion
• Conclusions

ARDI Project:

Total Approved:

Date Approved:

Project Status:

#98-108

$67,600

May 26, 1998

Completed June, 2000

Background and Objectives:

Commercial industrial hemp cultivation became legal in 1998, under regulations administered by Health Canada. Although hemp has traditionally been considered mainly as a fibre crop, its grain has demonstrated nutritive and potential therapeutic or nutraceutical value, and the experience reported in this document contributes to hemp’s development as a grain or dual-purpose crop.

Research trials in Manitoba and elsewhere have demonstrated that available cultivars are adaptable. These trials have provided rudimentary production recommendations and given preliminary indications of yield and quality. However, successful establishment of hemp as a new crop in Manitoba continues to depends on at least two key factors:

1. Development of markets and processing capability to meet those markets.
2. Development of agronomic practices for consistently profitable production.

This project took place during the 1998 and 1999 growing seasons and sought to address both of these factors. Specifically, the objectives were to provide baseline information on commercial yield and quality expectations and to begin investigating management and environmental factors affecting yield and quality.

Procedure and Project Activities:

Data were gathered during the 1998 and 1999 growing seasons from:

• grower fields and experiences, through direct observation and a survey of growers;
• an equipment trial, consisting of the set up and testing of a stripper header on Prairie Hemp Ltd.’s behalf by the Prairie Agricultural Machinery Institute;
• laboratory analyses, consisting of grain samples submitted to Dr. Roman Przybylski (Dept. of Foods and Nutrition, Univ. of Manitoba) for analysis of composition, fatty acids, anti-oxidants, and amino acids;
• and a designed field experiment, examining the effect of harvest timing on yield, quality, and composition of hemp grain.

Results and Discussion:

Overview of Seasons

Due to delays in licensing and seed availability, seeding dates in 1998 ranged from late May to mid-June. Fedora 19 was the variety grown. Excessive moisture conditions in late June/early July resulted in drowned out or stunted patches in numerous fields; other yield limiting factors included Sclerotinia and lodging. Numerous harvest approaches were attempted, and harvest experiences ranged from good to very poor – harvest timing and technique emerged as one of the most significant production issues. Despite the problems encountered, yields were relatively higher than anticipated, with generally good growing conditions and an open fall.

In 1999, seeding generally took place between mid-May and early June; although at least two fields were sown very early in May. Most growers associated with the study grew Fasamo, but some experience with Fedora 19 and USO 31 was also gained. Cold conditions resulted in slow, unsatisfactory emergence, and portions of at least one of these fields were later resown. In addition, Sclerotinia was evident in several fields, with elongated sclerotia appearing in the screenings of several lots. The sclerotia tended to be present in lots harvested on the dry side. This suggested that when the stalk was green it remained intact through the combine and did not release sclerotia, while when the stalk was drier it was more brittle and hurds and sclerotia were released in the threshing process. Harvesting difficulties were fewer than in 1998—the experiences of 1998 led to better timing in 1999, and consequently fewer problems.

General Agronomic Considerations

Actual yield results exceeded expectations, with most fields producing in excess of 500 clean/dry lb/acre, and some producing in excess of 1000 lb/acre. There is a significant impact of environment and management on yield outcome, and our studies and experience suggest that field selection and seeding are important, as is harvest timing and technique. Other factors such as fertility are likely important as well, but a field-scale trial we planned for 1999 could not be accomplished because of overly wet spring seeding conditions at the planned location.

Sclerotinia is frequently observed, with plants killed due to stem rot, and sclerotia sometimes being present in harvested grain. The economic consequence of Sclerotinia in hemp grain production is not known. There were also establishment problems that were related mainly to excess moisture and to overpacking at seeding time, especially on heavier-textured soils. Where establishment was poor, weed competition became significant, despite hemp’s reputation for competitive growth; and poor stands were associated with below average yields.

Harvesting proved to be one of the most significant factors in achieving a favorable outcome. Delayed harvest resulted in high shelling losses and frequent difficulties with stalk/fibre wrapping on combine bearings, pulleys, chains, and shafts. Relatively early harvest provided higher yields and fewer combining difficulties, as green stalk material tended to travel through the combine and remain relatively intact compared with dry stalk material. Some types of combines were clearly superior for use in combining hemp grain, in particular, conventional cylinder types with draper headers. In conjunction with PAMI, under this ARDI project, we evaluated the use of a stripper header. While conditions were inadvertently less than satisfactory for a fully conclusive trial, the experience suggested that the stripper header was worthy of further investigation for hemp grain and seed production.

Quality Considerations

Oil content averaged 28.4 (± 2.0%) in 1998 and 30.9 (± 1.2%) in 1999. The range was from 25.5 to 33.1% overall. Gamma-linolenic and stearidonic acids ranged from 2.1 to 4.2% and 0.7 to 1.8%, respectively. The ratio of omega 6:omega 3 fatty acids, often claimed to be an "ideal" 3.0, ranged from 2.2 to 3.4. Polyunsaturated fatty acid content ranged from 72.9 to 82.7%. The variability was found from field to field, year to year, and variety to variety. While this could not be demonstrated to be statistically significant, there is enough variation to be of concern from a processing perspective.

Optimum Harvest Timing Trial

As moisture declined from c. 40% into the low 20% range, yield continued to increase, on average 48 lb/acre/day; test weight increased by approximately 12% and tocopherols (anti-oxidants) steadily increased in the oil. Gamma-linolenic acid levels decreased between the first and second harvest dates, but not thereafter. As moisture dropped below approx. 25%, range shattering risk increased dramatically, and a single windy day resulted in a loss of at least 25% of the grain.

Conclusions:

Successful establishment of hemp as a new crop in Manitoba continues to depend on development of markets and processing capability to meet those markets and development of agronomic practices for consistently profitable production. However, this project has provided valuable baseline information on commercial yield and quality expectations and an investigation into management and environmental factors affecting yield and quality.

Most significantly, this investigation has provided detailed profiles of seed composition for several varieties, to assist the fledgling industry in establishing processing parameters and reasonable expectations of yield and quality. Another outcome of this project is a more objective basis for harvest management, with a better understanding of yield formation, risks of loss, and effects of timing on critical quality concerns (such as levels of gamma-linolenic acid and anti-oxidants). Therefore, better recommendations can be made for harvest timing and technique in order to achieve optimum yield and quality. 

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