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To Learn About Industrial Hemp Production

On March 17, 2018

In 2017 Penn State obtained a permit from the PA Department of Agriculture to evaluate industrial hemp as a crop. Extension Agronomist Greg Roth explained that  some management variables were evaluated including variety, N fertility, planting date, and seeding rate associated with good production practices for hemp grown for seed.  Field plots were established at the Russell Larson Research Farm near Pine Grove Mills in Centre County, Pennsylvania using chisel plowing followed by several secondary tillage passes to destroy weeds that emerged over a three week period. Most trials were planted on June 6.

In the variety trial, six varieties from http://www.hempgenetics.com/index.html (CFX-2, CFX-1, CRS-1, Picolo, Katani, and Grandi) were evaluated at three planting dates. In general, the taller lines, CFX-2, CFX-1, CRS-1 yielded more (1206 lb/a) than the shorter lines Picolo, Katani, and Grandi (1029 lb/a).  This could have been a result of their better competitiveness with weeds in our environment.   We planted on June 6, 13 and 21 and yields declined slightly from 1216 to 1078 lb/a with the last planting date.  The crop took 82 to 86 days from planting to harvest, so it was a relatively short season crop.  As planting was delayed, the plant height was reduced from an average of 36 to 25 inches.  We concluded that planting a taller line early is the best way to maximize yield and plant height.  Planting one of the taller lines in late May in this area might be ideal.

In the fertility trial, five N rates were applied that totaled 0, 50, 100, 150 and 200 pounds of N applied at planting to the variety CRS-1.  Yields in this trial increased from 960 lb/a in the check plots to 1770 at the 100 pound rate and were maximized at the 150 lb/acre treatment at 1850 lb/a. In the seeding rate trial, five seeding rates of 15, 20, 25, 30, and 45 pounds per acre were evaluated with the varieties CRS-1, Grandi and Picolo.  Yields of the taller variety CRS-1 were maximized at 30 lbs/acre while the shorter Grandi and Picolo lines needed 45 lb/acre to maximize yields.
Weeds were one of our biggest challenges.  We planted most of the trial in 15 inch rows but had a demonstration area that was drilled in narrow rows.  That appeared to help reduce weed pressure.  There are no herbicides labeled for hemp in the US so we needed to rely on tillage and competition.

Based on our experience, drilling a taller line at 30 lb/acre in late May and fertilizing with 150 pounds of N might be a good management strategy.  We plant to repeat this study again in 2018 with some modifications in the protocol to reflect what we learned in 2017.  We will also be conducting a herbicide evaluation.

We also evaluated some no-tillage establishment and that appeared to work well.  We harvested the crop with a non rotary combine and did not have any problem.  Some other permit holders reported problems with harvesting taller varieties, especially with a rotary combine. We concluded management details are important and that it should be possible to grow yields of 1500 to 2000 lb/acre of seed with good management.  Hemp can also be grown for fiber and cannabinols (CBDs).  When growing for these end uses, different management tactics need to be deployed.

To Learn About Burcucumber Management In Corn And Soybeans

Burcucumber (Sicyos angulatus), a native to North America, continues to be a serious weed problem in agronomic crops throughout the Northeast.  Extension Agronomist Dwight Lingenfelter explains this weed was originally found along stream banks and other damp, shady areas, now burcucumber has invaded river bottom and upland fields. Burcucumber seed are the size of a watermelon seed, can germinate from mid-May through September, and the seedlings can emerge from up to six inches deep.  Because burcucumber germinates throughout the season, it is difficult to control with herbicides that lack residual activity. Penn State weed scientists conducted several studies on burcucumber in the late 1990s. Many of those research findings are still relevant today. Since then, other universities also have conducted field studies that provide additional insight into the management of burcucumber.
The first step in management is to prevent burcucumber seed spread by thoroughly cleaning tillage and harvesting equipment before leaving infested fields. Encourage aggressive crop growth through good cultural practices such as maintaining adequate soil fertility, choosing appropriate high-yielding crop varieties, and regularly scouting for and managing pests. Include in the rotation crops that provide early competition such as alfalfa or small grains. Include no-till in fields that are infested with burcucumber. Research suggests that no-till allows burcucumber seed to remain near the soil surface, thus allowing germination to occur over a shorter time period and more uniformly which reduces the number of germination flushes. This also improves herbicide effectiveness and performance. Tillage buries some seeds at lower depths which causes a season-long germination pattern to occur. With a lack of residual control, these later emerging seedlings can be difficult to manage. Harvest burcucumber infested fields for silage to prevent viable seed production. Studies at Penn State have shown that immature burcucumber seed that is cream/tan-colored can be effectively killed by the ensiling process. Once the seeds turn dark brown or black, they are difficult to kill.

Herbicides are essential in a burcucumber management program, but use them in combination with other control methods. One-pass herbicide programs will not work. Effective management must include both pre and post (foliar-applied) herbicides. Post programs that include effective foliar and residual herbicides will enhance season-long control. Several corn herbicides provide good control of burcucumber and they are most effective on young seedlings rather than larger plants. Include herbicides that have residual activity to control new burcucumber flushes. Post herbicides provide the best burcucumber control. In corn, if possible, include at least 1.5 pounds of atrazine in the herbicide program for residual control. Other effective herbicides include prosulfuron (Peak or Spirit), primisulfuron (Beacon), mesotrione (Callisto), and glyphosate. In addition, other Group 6 herbicides such as bromoxynil (Maestro/Buctril) are effective for controlling emerged plants. Some two-pass programs that have proven effective include the use of products such as Lumax, Lexar, Acuron, Corvus + atrazine, or Balance Flexx + atrazine preemergence followed by glyphosate plus Sprit or Callisto applied postemergence. Other post options include: atrazine, dicamba/Status, NorthStar, Halex GT, Maestro, and Liberty 280. Prosulfuron (Peak), a component of Spirit, provided the best season-long control of burcucumber in Penn State field research. For example, tank-mixing Peak at 0.25 oz/A with Spirit (1 oz) typically improves and extends control but watch out for long recrop restrictions.
Burcucumber may be easier to manage in soybeans than in corn simply because you can better monitor control and apply herbicides later in soybeans than in corn. Split-applications might be necessary for best control of later emerging burcucumber seedlings. The most effective herbicides for control in soybean are glyphosate plus a residual product like chlorimuron (Classic). More than one post application may be necessary. Liberty 280 also has activity in LibertyLink varieties.
Wet weather, especially late in the season, is ideal for burcucumber seeds to continue germinating and become a problem in corn and soybean fields. Since it is so late in the season, burcucumber vines usually don’t get above the crop canopy and often go unnoticed. At this late stage in corn, there are few options for managing this troublesome weed. Glyphosate, Gramoxone, Impact/Armezon, and 2,4-D are the only typical pre-harvest herbicides that have some activity. However, Beacon (applied before tassel emergence) and Maestro (formerly Buctril) can also be sprayed until tassel to slow burcucumber. As harvest-time, the pre-harvest applications are targeting grain production prior to a frost and really are intended just to allow combine harvest of the crop. Gramoxone is probably the most effective of these options at this time.
In soybeans, of the available harvest aids, only glyphosate, Gramoxone, and Clarity would have any activity on burcucumber. Again, Gramoxone is probably the most effective of these treatments for burcucumber suppression.
In summary here are the key points to burcucumber management. First avoid spreading the seed via harvest or tillage equipment. Use no-till practices to keep the seeds on the soil surface and plant shorter season corn varieties to allow earlier silage harvest. Remember ensiling kills green/immature burcucumber seed. Two-pass programs that include effective foliar and residual herbicides are required for season-long control. Pre-harvest burcucumber control is usually not effective.
Quote Of The Week: “For myself I am an optimist — it does not seem to be much use being anything else.” Winston Churchill