Winter Hardy Small Cereal Cover Crops for Grazing and Silage in Nebraska

Final report for GNC20-296

Project Type: Graduate Student
Funds awarded in 2020: $14,389.00
Projected End Date: 09/30/2021
Grant Recipients: University of Nebraska Lincoln; University of Nebraska Lincoln
Region: North Central
State: Nebraska
Graduate Student:
Faculty Advisor:
Dr. Mary Drewnoski
University of Nebraska Lincoln
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Project Information

Summary:

Producers using integrated cropping and cattle systems identified a need to research options for dealing with early spring and late fall forage deficiencies. This project, “Winter Hardy Small Cereal Cover Crops for Grazing and Silage in Nebraska” will evaluate the opportunity for cereal rye, winter wheat or winter triticale to fill these gaps. The use of these small grains may be a way to provide inexpensive, high quality forage and improve sustainability of cropping systems in the North Central Region. Cereal rye is the most commonly planted cover crop in corn and soybean systems. Winter wheat and winter triticale are also sometimes used. These species all have the potential to produce forage that can either be grazed in the early spring before perennial pastures are ready for grazing or can be cut for silage and used as a source of forage in the fall and winter. However, they will likely differ in growth pattern and thus timing of when they are ready to graze or harvest in the spring.  Therefore an objective of this project is to investigate the grazing potential of three species, including the timing of the start of grazing and nutritive value of forage as measured by cattle gain. Another objective is to compare these species for spring silage production. To better understand how each species may fit into a crop rotation the relative timing of maturation of each species coupled with the yield and nutritive value at various maturity stages will be evaluated. This information will better equip producers when making cover crop species choices and management decisions for their operation.

Project Objectives:

This study will:

  • Directly compare cereal rye, winter wheat and winter triticale as a source of early spring grazing to provide an understanding of the relative timing that grazing can be initiated, the carrying capacity and nutritive value of forage
  • Evaluate the relative timing of maturation of cereal rye, winter wheat, and winter triticale as well as yield and nutritive value at various maturity stages to better understand how each species may fit into a crop rotation and feeding system

As a result:

  • Nebraska Extension will be able to provide research based information to producers about the use of winter hardy small cereals for early spring grazing or silage production
  • Producers will be more confident in making decisions regarding the selection and use of winter hardy small cereals for early spring grazing or silage production

Cooperators

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  • Dr. Daren Redfearn, Mary E Drewnoski

Research

Materials and methods:

Grazing of winter hardy small cereals

A 7.3-ha field, located at the Eastern Nebraska Research Center (ENREC) of the University of Nebraska-Lincoln located near Mead, Nebraska, was utilized during this research. The land aforementioned was enrolled in dryland, continuous soybean cropping system. The soybeans used were a Group 1, short-season variety planted on May 15 with 76-cm row spacing. Three treatments, cereal rye, winter triticale, and winter wheat, were employed on the soybean ground after harvest, each having three replicates (n = 3).  Cereal rye was seeded at approximately 99 kg/ha to target 84 kg of pure live seed (PLS) per ha using a variety-not-stated (VNS), costing $0.51 per kg. Winter triticale was seeded at approximately 121 kg/ha to target 112 kg PLS/ha using the NT11406 variety, costing $0.70 per kg. Pronghorn winter wheat was seeded at approximately 114 kg/ha to achieve 112 kg PLS/ha, costing $0.53 per kg. This study targeted the same number of seed to germinate per ha; therefore, cereal rye, having a smaller seed, received fewer kg/ha in seed.

Soybeans were harvested on September 10 with the small grain forages being planted using a no-till drill on September 15 with 17.8 cm row spacing. The small grain forages received no fertilizer, because it was assumed the soybean crop left behind enough nitrogen to satisfy them. The 7.3-ha were split into 0.81 ha paddocks (experimental units). The 0.81 ha paddocks were assigned randomly to treatment, planted to species and then divided into 2, 0.4 ha paddocks in order to allow rotational grazing between the two paddocks within the experimental unit. When each species reached a height of 12.7 cm, cattle were moved to a 0.4-ha and allowed to graze forage down to a height of 5 cm before being rotated to the other half. Grazing continued until forage biomass limited intake or until the scheduled pull date of May 10. Remaining forages were then terminated using herbicide in order to prepare for soybean planting.

Forage heights were collected using a disc-plate meter. Ten heights were randomly collected across each 0.4 ha and then averaged. Forage height was recorded when 50% of the leaves under the disc touched the plate. Paddock heights were used to determine the start of grazing and when to rotate among the two paddocks within the experimental unit.

Forage biomass samples were collected right before each grazing period began (before cattle entered) and immediately after the grazing period ended (after cattle left) in each 0.4-ha paddock. Three samples were collected randomly across each 0.4-ha paddock. Samples areas were 0.49 m2 with forage being clipped to ground height. Pre-graze biomasses samples were used to determine the amount of forage available when grazing periods began. Post-graze biomasses were then collected to determine the forage amount remaining after a grazing period ended. Enclosures were placed in areas of average pre-graze biomass to account for forage growth during the grazing period. and one sample would be collected from the enclosure area at the end of each grazing period. Enclosures were moved with each rotation. Samples were dried in a 60° C forced air oven until a constant weight was reached in order to determine dry matter (DM) content. The cover crop samples were then used to calculate forage yield in kg/ha on a DM basis.

Forage disappearance was calculated by subtracting post-graze biomass from enclosure biomass divided by the number of grazing steers divided by the number of grazing days. Forage disappearance per steer per day is attributed to both cattle consumption and trampling. Rye, triticale, and wheat pre-graze biomass samples were also used to determine forage nutritive quality. After being dried in 60° C forced air oven, samples were ground through a 1-mm screen Cyclone Mill. Samples were dried for 24 hours to determine DM. Organic matter (OM) was then determined by burning samples at 600° C for 6 hours in a muffle furnace. Samples were analyzed for neutral detergent fiber (NDF), acid detergent fiber (ADF), and in-vitro dry matter digestibility (IVDMD) using methods described in Vogel et al (1999) utilizing the ANKOM A2000 Fiber Analyzer and DaisyII Incubator (ANKOM Technology Corporation). Rumen fluid was collected from ruminally fistulated steers (Bos taurus) that were offered a diet containing 70% bromegrass hay and 30% concentrate which containing distillers grains, dry rolled corn, mineral supplement. Lastly, forage crude protein (CP) was determined using a TrueSpec micro analyzer (LECO Corp.).

Fifty-two growing steers (305 kg SD ± 5 kg) were utilized during this study. Steers were limit fed in a feedlot for 8 days before and after taking part in the trial in order to equalize gut fill. Initial and ending weights were taken pre-feeding during the last three days of each limit feeding period (Watson, et al., 2013). While in the feedlot, steers received a diet of 50% Sweet Brand and 50% alfalfa hay at a 2% of body weight DM intake. It was estimated that cattle ADG was 1 lb/d during the limit feeding period and this gain was removed from the steer BW. Steers were stratified by weight and assigned randomly to experimental unit. Six steers were stocked per experimental unit for a stocking density of approximately 2,288 kg BW/ha.

Silage:

Twelve 11 ft x 80 ft  plots were randomly assigned to one of 3 treatments (n = 4 replicates per treatment):  winter wheat, cereal rye, and  winter triticale, . Plots were seeded with the small grain cereals in late October. All plots received 60 lb/ac of nitrogen  applied in the spring.

The forage was harvested at 4 different stages: boot, anthesis, milk, and soft dough. Crops were cut by a harvester at 3 to 4 inch height and allowed to wilt to a target of 65% dry matter (DM) before being packed into five-gallon buckets.  A Koster Moisture Tester was used to measure forage moisture content in the field. Samples were taken at packing and oven dried to determine actual DM content at packing. Silos were left to ensile for 45 days before being opened and sampled.

A series of lab analyses was conducted on the samples post fermentation to evaluate the feeding value and how well the silage was preserved. Dry matter was determined by placing the ground samples in a forced air oven for 12-24 h at 105°C. Subsequent organic matter (OM) was determined by placing the samples in a muffle furnace for 6 h at 600°C (AOAC, 1999).  Crude protein content, silage pH and fermentation end products (lactic acid, acetic acid, butyric acid and ammonia) were measured at Dairyland Laboratories.

Methods described by (Tilley & Terry, 1963) were used to determine in vitro organic matter digestibility (IVOMD) with 48 h incubation. Methods were modified by adding urea to the McDougall’s buffer (McDougall, 1948) at a rate of 1 g urea/L buffer solution, to ensure adequate N was available for microbes in the rumen fluid (Weiss, 1994). Blanks were included in the in vitro run to adjust for any feed particles that might have come from the inoculum. After incubation, the Whatman 541 filter paper (22 µm pore size) plus samples was placed in crucibles and heated in a muffle furnace for 6-h at 600°C (AOAC, 1999). Two runs were conducted and five hay standards with known in vivo (total tract) digestibility (51-60% range) were used to adjust IVOMD values. Forage digestibility was expressed using digestible organic matter (DOM) and calculated as: DOM= OM x IVOMD.

 

Research results and discussion:

Grazing

In year 1, were no differences in carrying capacity or growing steer gains when grazing cereal rye, winter wheat, or winter triticale prior to soybean planting. Gains of calves was quite high averaging 4.0 lb/d. These calves were previously managed on corn residue with supplementation and were gaining about 1 lb/d. Thus some of this gain was due to compensatory growth. Cereal rye did result in the ability to start grazing about a week earlier than the other two species.  In year 2, there were no major differences in initial growth and thus timing of the start of grazing was similar across species. However, calves grazing rye gained (2.98 lb/d) more than those grazing triticale (1.38 lb/d) and wheat (1.79 lb/d), which did not differ.  A dry cold spring resulted in reduced forage growth and the calves were likely limited in forage intake. It can be concluded that all three species can provide high quality forage, if managed to maintain it in a vegetative state. To accomplish this relatively high stocking rates and a rotational grazing system is needed. Rye may offer an advantage due to more growth earlier in the spring in some years.  

Silage

Dry matter yield of rye and triticale did not differ except at soft dough stage where triticale was greater than rye. Triticale yield was greater than wheat at pollination and soft dough, with rye being greater than wheat only at soft dough. In terms of energy content, measured as digestible organic matter (DOM) after fermentation, rye and wheat did not differ and were both greater than triticale. Across all species, boot stage had the greatest DOM concentration, followed by pollination then soft dough with milk having the lowest energy content. Crude protein (CP) of all species decreased with increasing maturity. There were minor differences in CP concentration among species, with rye being greater than triticale at boot, pollination, and soft dough but not differing from wheat. When energy and protein content were combined with dry matter yield and evaluated on a yield of DOM and CP per acre, rye and triticale had greater nutrient yields than wheat.

A two year study was conducted to investigate the grazing potential of the three species in Eastern Nebraska, including the timing of the start of grazing and nutritive value of forage as measured by growing steer gain. Timing of the start of grazing was based on a 5 inch target height. Calves (700 lb) were stocked at 3 calves per acre and rotationally grazed in a two paddock system with the goal of keeping the forage between 2 and 8 inches. In year 1, were no differences in carrying capacity or growing steer gains when grazing cereal rye, winter wheat, or winter triticale prior to soybean planting. Gains of calves was quite high averaging 4.0 lb/d. These calves were previously managed on corn residue with supplementation and were gaining about 1 lb/d. Thus some of this gain was due to compensatory growth. Cereal rye did result in the ability to start grazing about a week earlier than the other two species.  In year 2, there were no major differences in initial growth and thus timing of the start of grazing. However, calves grazing rye gained (2.98 lb/d) more than those grazing triticale (1.38 lb/d) and wheat (1.79 lb/d), which did not differ.  A dry cold spring resulted in reduced forage growth and the calves were likely limited in forage intake. It can be concluded that all three species can provide high quality forage, if managed to maintain it in a vegetative state. To accomplish this relatively high stocking rates and a rotational grazing system is needed. Rye may offer an advantage due to more growth earlier in the spring in some years.  

Silage yield and nutritive value of cereal rye, triticale, and wheat harvested at boot, pollination, milk and soft dough was evaluated also over the two years. Dry matter yield of rye and triticale did not differ except at soft dough stage where triticale was greater than rye. Triticale yield was greater than wheat at pollination and soft dough, with rye being greater than wheat only at soft dough. In terms of energy content, measured as digestible organic matter (DOM) after fermentation, rye and wheat did not differ and were both greater than triticale. Across all species, boot stage had the greatest DOM concentration, followed by pollination then soft dough with milk having the lowest energy content. Crude protein (CP) of all species decreased with increasing maturity. There were minor differences in CP concentration among species, with rye being greater than triticale at boot, pollination, and soft dough but not differing from wheat. When energy and protein content were combined with dry matter yield and evaluated on a yield of DOM and CP per acre, rye and triticale had greater nutrient yields than wheat. It appears that triticale had slightly greater DM yield with slightly lower digestibility (energy) and protein content while rye had slightly lesser yields with slightly greater digestibility and protein content. For high quality forage, harvest at pollination appeared to have increased yield without sacrificing nutritive value. For maximized yield, harvesting at soft dough is a better option.

Participation Summary
18 Farmers participating in research

Educational & Outreach Activities

20 Consultations
10 Webinars / talks / presentations

Participation Summary:

371 Farmers
48 Ag professionals participated
Education/outreach description:

A total of 9 presentations were given at educational events targeted toward producers. This includes 6 virtual workshops focused on the use of cover crops, 2 of which were hosted by Nebraska Extension, 1 hosted by Nebraska Cattlemen, 1 hosted by Missouri Extension, 1 hosted by Iowa Extension and 1 hosted by the Practical Farmers of Iowa.  Presentations were given at 4 in person events, 2 hosted by Nebraska and 2 hosted by Nebraska Extension in conjunction with South Dakota Extension.

Two presentations were recorded and posted on Nebraska Extension BeefWatch YouTube channel "Winter hardy cover crops for spring grazing and silage" has received 261 views and "What every feedlot needs to know about cover crops" has received 339 views.

 

Project Outcomes

18 New working collaborations
Project outcomes:

The use of these small grains is a way to provide inexpensive, high quality forage and improve sustainability of cropping systems in the North Central Region.

When grazing, all three species can provide high quality forage, if managed to maintain it in a vegetative state. To accomplish this relatively high stocking rates and a rotational grazing system is needed. Rye may offer an advantage due to more growth earlier in the spring in some years.  

When the species were evaluated for silage production potential there were very minor differences. Triticale had slightly greater DM yield with slightly lower digestibility (energy) and protein content while rye had slightly lesser yields with slightly greater digestibility and protein content. For high quality forage, harvest at pollination results in increased yield without sacrificing nutritive value. For maximized yield, harvesting at soft dough is a better option.

Knowledge Gained:

During the course of the project, I learned that cover crops can benefit the soil and also support livestock. Thus it is possible for CC to produce environmental benefits and income at the same time. Producing multiple agricultural products, in these ways, on the same piece of ground safely enhances land output while increasing diversity and improving soil health.

Recommendations:

We surveyed 18 producers to understand their experiences including the challenges and lessons they have learned when making small grain silage. In 2021, we also collected small grain silage samples both at harvest and post-fermentation from these producers.  The majority of the producers were using cereal rye with triticale being the second most common species. A common challenge mentioned by producers was getting the timing of silage harvested correct. “Weather and custom harvest crew availability always a challenge.  We do not have as much control on harvest timing as we would like.”  Indeed 37% of the samples were too wet (below 30% DM) when placed in the silo, despite most of the producers indicating that they wilted the forage. This suggests there is a need to assist producers with moisture management (determining how long to wilt and how to easily asses moisture of the crop during wilting).

When asked “What questions would you like to have answered that you feel could improve your management and harvest of small grain silage?” It was indicated that there is “not a lot of readily available information” suggesting a need for more small grain silage specific extension programming.  A common theme in their questions was about growth stage impacts on yield and quality. “Would like to have a better understanding of the protein change and TDN change as the crop matures.”  Legumes also came up in several responses, “How does inclusion of a legume affect feed quality, yield and timing?”

This project will help to answer their questions about growth stage impacts on yield and quality. We are currently working on extension material to provide guidance to producers about this question. However, questions about inclusion of legumes needs further exploration.

Information Products

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.