Determining the Optimum Quality Harvest Stage of Male-Sterile BMR Forage Sorghum

Progress report for ONE20-367

Project Type: Partnership
Funds awarded in 2020: $13,351.00
Projected End Date: 07/31/2021
Grant Recipient: Advanced Ag Systems LLC
Region: Northeast
State: New York
Project Leader:
Thomas Kilcer
Advanced Ag Systems LLC
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Project Information


Short season BMR sorghum has been tested and produces high yields and quality to replace corn silage (1,10). It has many advantages over corn silage especially for organic farms. In balanced rations, BMR sorghum sp. can produce the same milk as corn silage but with higher components and greater feed conversion efficiency (1).
Sorghum sp. stalks will lodge as the grain head fills – a major limit to farmer adoption. Male sterile – either sorghum or sorghum-Sudan – gave some of the highest yields in PI’s trials and had the best standability with no maturing seed to bring the plant down and had higher digestibility than their seeded counterparts. Photosynthetic energy in male-sterile continues to build in the plant cells and is not translocated to the seed sink. Unfortunately, with no grain we have no indicator for the optimum time to harvest male-sterile types. Sorghum breeders cannot tell farmers the optimum harvest time for a crop without seeds. This knowledge is critical to determine varietal season length for our farms and for the farmers to harvest at the optimum time to support profitable milk production.
A BMR male-sterile sorghum will be planted on Dutch Hollow farm. From the boot stage and continuing for 6 weeks, 6 replicate samples each week will be ensiled in vacuum-sealed bags. Cumberland Valley Analytical Lab will analyze for quality components. Utilizing CNCPS model, the data will determine the optimum harvest window. This information will be disseminated through contacts with multipliers in agribusiness, Extension, and consultants.

Project Objectives:

The project seeks to both quantify and qualify the forage nutritional quality component changes of a male sterile bmr sorghum from boot stage to 35% dry matter silage stage to determine the optimum harvest window. Lyons et al 2019 Dairy Science(10), clearly determined the components for a fertile seeded BMR brachytic dwarf sorghum. Because there is no pollination in the male-sterile, there is no carbohydrate sink to pull photosynthetic nutrients from the cells in the rest of the plant and convert them to starch in the seed. This has the potential to dramatically shift both the amounts and the components of the digestible portion of the plant. This could have a significant impact on the makeup and profitability of utilizing the forage as a major component of the dairy ration. The analysis of changing forage quality components over time will tell us when is the optimum time to harvest; how big the harvest window is for dairy forage; and if there is any stoppage or loss of nutrients past a certain point in the fall with this crop. As farms, especially organic farms, increasingly switch to male-sterile genetics, this project will significantly increase their success in utilizing the forage.


Winter forage acres, needs to be planted early for high yield and soil protection, but directly reduces the corn season (8,9). There is no short-season BMR (Brown Mid Rib = high digestibility) corn. Short season BMR sorghum has been tested and produces high yields and quality to replace corn silage (10). Work by the PI and documented by Dr. Chase (Professor Emeritus, Dairy Nutrition, Cornell) is that with proper balancing, BMR sorghum sp. can produce the same milk as corn silage. Work at Miner Institute on BMR sorghum-Sudan also documented the same milk production as corn silage but with higher components and greater feed conversion efficiency (1).
Dairy/livestock farmers are turning to BMR forage sorghum species for benefits superior to corn. Corn seed is increasingly expensive to grow. Genetic rootworm resistance is failing, and disease controls require expensive fungicides. Sorghum is $100/acre cheaper to grow on just seed cost. Sorghum species eliminates corn rootworm for following corn crops, and is deer-proof. Organic corn silage requires multiple cultivations which leave the soil vulnerable to erosion. Cultivation, critical for organic corn silage success, is at the same time that organic haylage needs to be made. Thus, the haylage is often late, severely limiting the profit potential of the organic farm. Optimum sorghum planting is in drilled narrow rows (PI’s replicated research found 18% higher yield compared 30-inch row) quickly canopies to prevent erosion, shade out weeds, and maximize sunlight interception in our short season. Based on our work, sorghum-Sudan’s rapid emergence and dense stands utilizing a stale seedbed is replacing corn silage on organic farms without cultivation to control weeds. Thus, more organic farms are switching to BMR sorghum-Sudan as their energy forage.
The PI’s research has found that most sorghum and especially sorghum-Sudan stalks, even the Brachytic dwarf type, will lodge as the grain fills – a major limit to farmer adoption. The research found that of the BMR, the male-sterile – either sorghum or sorghum-Sudan – without a seed head, gave some of the highest yields and had the best standability with no maturing seed weight to bring the plant down. In paired comparisons, the male-sterile had higher digestibility than their seeded counterparts. Photosynthetic energy continues to build in the plant cells and was not translocated to the seed sink. Unfortunately, with no grain we have no indicator for the optimum time to harvest male-sterile types. Sorghum breeders cannot tell farmers the optimum harvest time for a crop without seeds. This knowledge is critical to determine varietal season length for our farms and for the farmers to harvest at the optimum time to support profitable milk production.
The solution is to plant a BMR male-sterile sorghum on the Dutch Hollow farm. Beginning at boot stage in August, and continuing for 6 weeks; six replicate samples will be taken, chopped, inoculated and vacuum sealed for fermentation. Samples will be sent to Cumberland Valley Analytical Lab for analysis of quality components. The data will determine the optimum harvest date.


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  • Brian Chittenden - Producer


Materials and methods:

Before this proposal begins, in late May – early June, when soil temperatures are over 60 F, and the forecast is for increasingly warmer weather, a field of male-sterile bmr sorghum (Richardson Seed: donated seed) will be drilled in 8 inch row spacing on the Dutch Hollow farm, at a target of 10 lbs. seed/acre. The site was chosen to be away from any random source of sorghum pollen that would compromise the research project. The seed will be treated with a herbicide safener so appropriate broad leaf and annual grass control herbicide can be applied immediately after planting to control weeds. (This is not an organic trial although the resulting forage quality data is directly useable for organic farms growing male-sterile varieties). A one-harvest system will be used as research (2) has found single harvest more than double the yield and cuts the harvesting cost almost in half compared to a multi-cut system. For this proposal, when the plants reach the boot stage, once each week after, for 6 weeks, randomized 6 plants will be selected and each chopped (PI’s mini chopper). A one-time harvest of 6 stalks of nearby corn silage at 50% milk line, will also be chopped, ensiled, and analyzed for comparison. Each chopped plant will be treated with an inoculant (Chr. Hansen Silo Solve MC) and using our present commercial sealer, vacuum sealed for fermentation. After 3 weeks of fermentation the sample from that week will be shipped to Cumberland Valley Analytical Laboratory (6 shipments). This sequential shipping is necessary so there is not a difference in the amount of fermentation between the first week’s samples taken and the final weeks samples taken. The forage analysis components to be analyzed was a decision made with input from Dr. Larry Chase, Nutritionist, Cornell University, and Matt Michonski, manager, CVAS Labs. Each sample will be analyzed for NIR+ which will give Dry Matter, Moisture, Crude Protein, ADFCP, NDFCP, Soluble Protein, ADF, NDF, Lignin, Starch, Sugar, Fat, Ash, Calcium (Ca), Phosphorus (P), Magnesium (Mg), and Potassium (K) and pH on ensiled forage. Calculated values will be provided for Available Protein, Adjusted Protein, Degradable Protein, NEl, NEm, NEg (OARDC Summative Energy Equation), NSC and NFC. It will provide 30 hr NDF Digestibility with Kd rate, an NIR evaluation of fermentation acids, as well as a uNDF at 30 hrs, a uNDF at 120 hrs and 240 hrs, total fatty acids, and soluble fiber. This option also includes a soil contamination probability index of low, medium, or high for forages. A nitrate probability is reported as low, medium, or high. For corn silage, the NIR Plus Option provides 12 hr NDF digestibility and 7 hr (4mm) starch digestibility. Each NIR+ sample is $28.70. The normal NIR may give erroneous numbers for sugar and cellular starch. As the male-sterile plant is not mobilizing cellular starch and sugar and sending it to a fertile seed sink, it accumulates in the plant forage cells the longer the plant is growing past flower emergence. One of the companies that market a male sterile bmr sorghum said they had measured as high as 20% sugar on a dry matter basis at harvest. The PI experienced these high numbers in some of his male-sterile research samples. Because the sugar and starch amounts are far outside the norm of regular forage crops, the algorithm results for the NIR analysis would not be accurate so a wet chemistry analysis is needed to accurately capture what is going on in the plant as it approaches harvest. To that end each sorghum sample will have wet chemistry Water Soluble Carbohydrate sugar measured at $12.00/sample. For the cellular starch a wet chemistry Ethanol Washed Starch at $13.50/sample analysis will be used. The ethanol would remove the free sugars and then they will measure the glucose that remains in the starch fraction to get an accurate measure. Without the ethanol wash the lab may end up double-counting the sugar that would appear as starch. The total analysis cost for each of the 42 samples (36 sorghum and 6 corn silage) is $54.20/sample
At each harvest date, an 8-inch row x 12 ft, 1-inch long area (1/6000 of acre) will also be harvested at three locations to determine the silage yield at that date. Height and phenological stages will be noted for each harvest date.
The resulting data will be statistically analyzed (6 reps/harvest date x 6 harvest dates) utilizing Statgraphics software (presently licensed to use) to determine both mean and statistically significant differences of the components at each date and again across dates. The means of each component of each harvest date will be entered into the CNCPS model to determine the impact on potential milk-producing ability of that forage over harvest dates. This will give us the optimum harvest time.

Research results and discussion:

With the help of Brian Chittenden of Dutch Hollow Farm, and support by Northeast SARE grant and Richardson’s Seed, we established a four-acre field in the Hudson Valley, just south of Albany NY. We went from a colder than normal spring to a warmer than normal summer in May.  The planting was in by May 25, earlier than normal but into warm soil with warm weather forecasted.   We would like to report an outstanding crop – the reality is that it was the worst crop of sorghum I had grown in 40 years.  Extreme dry weather limited initial emergence and prevented most of the herbicide from being activated.  An error in tillage left most of the roots in the top two inches of soil.  30% of the stand was foxtail. Our variety was a low yielding in-bred we deliberately selected in order to achieve heading by the beginning of August and enough weeks post heading before frost. Our yield from the normal parts of the field was about 12 tons of 35% DM silage.  We are hoping to rerun this experiment in 2021 with a normal high yielding hybrid that is presently being grown in South America. Fortunately, we had several blocks in the field that emerged normal and had good weed control which allowed realistic sampling. We sampled starting at boot stage on August 10, and continued on a weekly basis until a killing frost on September 21.  This was one week later than the SARE proposal and was funded by a Texas Sorghum Seed company Richardson’s seed.  This was fortuitous in that the extra week showed a major increase in the quality components we were studying in this project.

The harvest and processing went very well in that we used a Chr Hansen SiloSolve MC inoculant.  Across all dry matter levels, it dropped the pH to 3.65 and there was no butyric in any of the samples.  If our theory of waiting after heading to increase the forage quality proved out; it would have the immediate benefit of a high dry matter forage for more efficient harvest and fermentation. The dry matter increased during that 7 weeks 56% which means farmers are hauling more forage and less water.  It also increased the success of fermentation and decreases or eliminates leachate which was historically a problem with sorghum sp. crops.  

The Chr Hansen company wanted to test two of their inoculants on this crop and so we ran a parallel funded (by Chr Hansen) study on their inoculants.  This was beneficial in that we were able to use their SiloSolve MC results in addition to our own SARE results which were also treated with the MC.  Thus, it gave us 12 reps per harvest date, greatly strengthening the statistical reliability of our analysis at no cost to SARE.

The results of the forage analysis were compiled for each harvest date.  Dr. Larry Chase inputted them into the Cornell Net Carbohydrate and Protein Systems model to determine the pounds of milk supported by metabolizable energy and metabolizable protein. 


Research conclusions:

Two clear results came from this project.  First, bmr sorghum in a properly balanced ration will support the same milk as corn silage with less protein supplementation, and slightly more corn grain supplementation.  Dr. Chase’s analysis showed that sorghum silage is NOT corn silage and the nutritionists need to rebalance the rations for higher fiber feeding.  The second result is that the quality components increased tremendously the longer after heading that we waited.  From boot stage to the 7 th week after, the cellular (forage) sugar increased 500% to 18.85% of the dry matter of the forage. Rumen available sugar is critical to high milk protein levels.   Utilizing sorghum forage with its slow release will avoid sub clinical acidosis that happens when other sugar sources are dumped into the rumen.  In addition, the digestible components Non-Structural carbohydrate increased 185% and the Non-Fiber Carbohydrate increased 71%.  These components making up increasing amounts of the dry matter, drove the NDF (fiber) levels down on a dry matter basis which allowed for more pounds of sorghum to be incorporated in the diet from the 6th and 7th harvest dates, reducing the cost of the ration even further.

The economic impact of increasing quality components is still being evaluated.




Participation Summary
1 Farmer participating in research

Education & Outreach Activities and Participation Summary

5 Consultations
1 Curricula, factsheets or educational tools
1 Published press articles, newsletters

Participation Summary

Education/outreach description:

Jan 2021 Sorghum alternativeThe research results will reach farm-level decisions through multipronged media efforts targeting farmers, agribusiness and consultant multipliers for maximum impact at the farm and in farm numbers. The data and results will be incorporated into articles published in agricultural newsletters and agricultural magazines to directly raise awareness and knowledge among the farmer growers and dairy nutritionists. Presentations will be given to agribusiness and consultants at venues such as the Northeast Region Certified Crop Advisors training. These groups of individuals will multiply the SARE on-farm results through their outreach effort directly to the farm community. A presentation will be developed on the findings of the research and the recommendations and put on the web to allow 24/7 access by farmers, nutritionists, and agronomists across the state. This latter outreach has been used successfully by the PI in YouTube presentations on winter forage and bmr forage sorghum (11, 12).

Learning Outcomes

Key areas in which farmers reported changes in knowledge, attitude, skills and/or awareness:

The project is just beginning its outreach with the newsletter on 1/4/2021.  Four farmers have contacted me for further information.  The outreach effort is just beginning.

Project Outcomes

2 Grants applied for that built upon this project
2 Grants received that built upon this project
$3,553.00 Dollar amount of grants received that built upon this project
2 New working collaborations
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.