This project was a pilot study to quantify agronomic characteristics of some forage brassicas and to educate farmers about the economic potential of these species. The project was a partnership between Cornell Cooperative Extension of St. Lawrence County and organic farms in northern New York.
In 2009, research plots were established at four sites to investigate yield potential of these crops, comparing different varieties and different establishment methods.
In 2010, research plots were established at two sites to investigate yield potential of different varieties of forage brassica crops.
Information about brassica production was disseminated to producers in field days and fact sheets were developed.
Due to the high variability between plots, the analysis of variance indicated no significant differences between varieties. For purposes of suggesting the yield potential of the crops under good conditions, yields are reported from the highest-yielding plot for each variety (since for most varieties at least one plot of the three was situated in a reasonably productive environment). Tables 1, 2 and 3 are provided.
High quality forages have been recognized as a key to sustainable production of ruminant animals. With volatile fuel prices and environmental concerns about fossil fuel use, grazing is an increasingly desirable alternative to mechanical harvest of forages.
Highly productive grazing animals under intensive rotational management will often not be able to consume enough digestible energy from perennial grass and legume forages to meet their energy demands for optimum production. Typically these animals are supplemented with high-energy feeds such as grains, which have significant economic and environmental costs, but can provide a more balanced diet when properly implemented.
Another challenge in managing grazing systems is the fluctuation in pasture productivity throughout the growing season. Productivity of the cool season grasses used in the northeast typically peaks early with a “spring flush” of pasture in May and June, followed by a “summer slump” in the warmest months and another increase in early fall followed by decline in the late fall.
This project strives to increase the economic and environmental sustainability of grazing systems by researching grazing crops that have a high energy density and will improve the distribution of forage productions throughout the year. As the economic viability of grazing improves, adoption of grazing practices will increase, thus increasing the overall sustainability of agriculture in the region.
Forage brassicas, crops of the family Brassicaceae such as rape, kale, mustards, turnip, radish, and swede (rutabaga), are usually palatable and have high levels of digestible energy for ruminants. These crops can be productive during the summer slump or during the late fall. There is little recent experience with these crops in northern New York. With numerous new cultivars on the market, there is a need to investigate the ability of these crops to improve the energy density and seasonal distribution of forages on grazing farms in the Northeast.
There are many unanswered questions about economically optimal methods of using forage brassicas, especially in Northeastern climate and soils. There are many varieties with diverse growth habits to choose from, and there are diverse agronomic recommendations from different sources. It is not clear whether the recommendations are actually based on research data, nor whether they are applicable in this climate. Planting date recommendations are particularly inconsistent, with early spring planting and mid-summer (late July) planting being the most common. There are few data about yield potential (none from the colder parts of the Northeast) and it is not clear whether the value of these crops will outweigh the costs incurred in producing them. No-till planting could be a low cost method of establishment if it is found to be effective.
This project was intended to shed light on some of the gaps in information available about the agronomic performance and requirements of these crops in northern NY.
The original project objectives are given below, each followed by a brief explanation of whether the objective was achieved:
- Quantify yield and forage quality of several varieties across the range of forage brassica types (rape, kale, mustard, turnip, radish, swede, and/or hybrids of these). In the course of several field trials, yield and forage quality were estimated for many varieties. However, due to problems in some of the trials, the data are not as complete as anticipated.Compare yield and forage quality of forage brassicas when planted at different times. Observations about productivity at different planting times were recorded. However, due to the need to minimize complexity in the experimental designs, direct comparison of different planting times in a statistically valid way was not possible.
Evaluate establishment of brassicas using minimal tillage into pasture compared to conventional tillage. No-till establishment of brassicas into pastures was compared relative to conventional tillage.
Compare conventional tillage establishment of brassicas with and without a nurse crop of oats. Observations about productivity with and without a nurse crop of oats were collected. However establishment with and without a nurse crop of oats could not be directly compared.
Compare no-till establishment of brassicas with and without a vinegar spray for suppression of competing vegetation. It was clearly demonstrated that vinegar spray is not sufficient to suppress competing vegetation in a pasture for no-till establishment of brassicas.
Generate data for use in partial budgeting to evaluate the financial viability of forage brassicas in farming operations. The yield and quality data that were obtained will be valuable for any farm manager evaluating the financial viability of forage brassicas. A sample partial budget was developed.
Establish several instances of brassica trials using different tillage and seeding methods for demonstration to interested farmers. Brassica crops were demonstrated to interested farmers at four different field days.
This project was focused on collection of data in field trials. There were five distinct trials in 2009 on four farms, and two distinct trials in 2010 on two farms.
The following methods are more or less common for all. The different trials (and deviations from common methods) will be described below.
- Soil was sampled and tested prior to plot establishment. Each collaborating farm was responsible for providing their own fertility amendments, and as such they made their own decisions. The Cornell Cooperative Extension Learning Farm (ELF) applied fertilizer and lime according to Cornell University recommendations.Field preparation and planting equipment was determined by the individual farm and varied among trials.
Seeds were either drilled or broadcast. Those drilled were at a depth of half an inch. Seeding rates were calibrated to 2 lbs/acre for swede and turnip, 13 lbs/acre for forage radish, and 4 lbs/acre for all other types, unless specified otherwise by the distributor.
Plots were a minimum of 20 feet long by the width of a single pass of the seed drill used at that site (ranging from 5-8 feet). Treatments were replicated three times within a site in a randomized complete block design.
Yields were estimated by a scissor cut three randomly located quadrats (at least 0.75 m2 each) from each plot for yield measurements. Yield of brassica plants was measured separate from yield of other species in the quadrat. Sampled forage was weighed wet, then oven-dried and weighed again, and results reported as dry biomass. Radish, swede and turnip had leafy biomass and root biomass measured and analyzed separately. After quadrat harvest, the collaborating farmers harvested plots by grazing. In the case of crops that could sustain multiple harvest events, quadrat samples were collected and weighed each time.
Yield data were evaluated with Analysis of Variance using the SPSS statistical software (GLM procedure), followed by Tukey’s HSD for multiple comparisons.
Several suppliers were asked to send seed to be included in variety trials. Suppliers could specify whether they wanted the variety to be planted in early spring (April 20-May 20) or in mid-summer (July 20-August 1) or both. The suppliers were Ampac and PPG (in 2009 and 2010),and Limagrain and Barenbrug (in 2010 only). The varieties included in each trial are shown in Table 1. Chicory (2009 ELF) and fodder beet (2010 ELF) were included in trials in some cases; even though they are not strictly brassicas, they are sometimes marketed in the same category as brassicas by seed companies, and they might be of interest to similar audiences.
A sample of fresh forage of each variety was sent to Dairy One forage analysis lab for basic wet chemistry forage quality analysis. More detailed analysis was done on a subset of samples to estimate parameters for use in feed ration formulation models. Because they were not replicated, forage quality analysis results were not subjected to statistical analysis, but are presented as estimates for informational purposes and economic analysis.
2009 ELF Spring Variety Trial
Trial was established at the ELF, Canton, NY on May 15, 2009. Seeds were broadcast followed by cultipacker. Crop quadrat yields were collected on two different harvest dates, based on recommendations from literature and/or dealers : July 9 for Appin, Graza, Hunter, Pasja and Oasis and August 28 for New York, Winfred, and Bonar. Quality samples were taken from each variety at time of harvest, with samples for Kestrel kale and Dominion swede collected on September 11. The plan was for a third harvest in late October for regrowth of those crops, plus the first harvest of Kestrel kale and Dominion swede. However, sheep broke into the plot and cleaned it off prior to that harvest. In order to get a rough estimate of yield potential for Dominion Swede, on October 30, some data were collected on what remained of one of the Dominion Swede plots that had been grazed less heavily, leaving partially grazed bulbs in the ground. The diameter of each remaining bulb in each of three quadrats was measured at ground level, and a shape algorithm (based on some surviving complete bulbs) was used to estimate the volume of the bulbs from the diameter at ground level. This was multiplied by an estimate of the bulb density (mass per unit volume, based on surviving bulbs) and an estimate of the leaf to bulb ratio (based on earlier data collection during sampling for quality) to estimate total yield.
2009 ELF Summer Variety Trial
Trial was established at Extension Learning Farm, Canton, NY, on August 12, 2009. Planting was delayed due to wet weather. This trial was established with a no-till drill into a glyphosate-killed sod. Sheep broke into the plots and ate everything before any data were collected.
2009 Crowe Farm Summer Variety Trial
Trial was established at Crowe Farm, Heuvelton, NY on August 13, 2009. Planting was delayed from the planned late July planting due to wet weather and wet soil. Oats were drilled into the entire plot area, and seeds were broadcast after oat planting, with no incorporation. Yield data were obtained from a single “representative” quadrat in each plot, harvested on October 16.
2010 ELF Spring Variety Trial
Trial was established at Extension Learning Farm, Canton, NY on May 15, 2010. Plots were planted with a drill, and stand establishment was good for most varieties. Quadrat yield estimates were obtained on two harvest dates; July 30 for turnips (except New York) and rapes, and October 26 for all crops (including a second harvest on regrowth of summer harvested crops). After the quadrat harvest on July 30, plots were cleaned off with a Carter forage harvester, as no grazing animals were available. Fresh biomass yields were measured from the Carter harvester.
2010 Zufall Summer Variety Trial
Trial was established at Zufall family Farm in Lisbon, NY on August 6, 2010. Plots were field-scale, planted with a drill into prepared soil. Quadrat yield estimates were obtained on November 2, 2010.
The establishment trial was to be carried out with spring planting at the Laing Farm and with summer planting at the Tuttle Farm. The treatments were:
• No-till planting, no chemical treatment
• No-till planting, plus 5% acetic acid (vinegar) spray for suppression of competing vegetation pre-emergence.
• Conventional till (disk harrow and cultipacker), no oats nurse crop
• Conventional till, using oats as a nurse crop.
To minimize small plot maneuvering with tillage equipment, the tillage treatments were main plots (replicated three times) and the vinegar or oats were sub-plots. Crop species were planted as sub-sub plots. No till planting was preceded by heavy grazing pressure and close mowing to weaken the existing vegetation. Due to the clear results in 2009 suggesting that no-till establishment with organic management practices represented an unacceptable risk of failure, the establishment trials were not repeated in 2010.
2009 Spring Establishment Trial
Trial was planted at Laing Family Farm, Potsdam NY on May 13, 2009. Cows broke through the fence a few days before the planned harvest and cleaned up the plots, so no data was collected, but the observational results (the complete failure of no-till establishment regardless of vinegar treatment) were clear.
2009 Summer Establishment Trial
Trial was planted at Tuttle Farm, Malone, NY on August 8, 2009. Due to miscommunication with farmer about availability of tillable land, only no-till half of trial was established. Establishment of brassicas was again a nearly complete failure regardless of vinegar application. No yield data were collected due to the obvious absence of brassica plants.
Yield estimates for each trial are summarized in Table 2. Forage quality data are summarized in Tables 3a, 3b, and 3b. Observational notes and data quirks for each individual trial and for individual crop varieties are discussed in the following sub-section.
Mild weather conditions were ideal for brassica crop growth, and yields were good. Broadcast establishment was found to be less than ideal because it was difficult to get uniform seed distribution at the low seeding rates.
Grazing after the first harvest was probably more severe than it should have been, as the plots were small relative to the number of sheep and it was overgrazed within 24 hours. As a result, regrowth seemed to be substantially impaired. This, combined with our inability to collect data for frequent harvests, probably biased the yield results against varieties that depend on multiple harvests to optimize yield.
There was some uncertainty about optimal harvest timing. The harvest dates were based on published suggestions about time to first harvest for different types of crops, but there was (and remains) significant ambiguity in the literature about how to evaluate whether the crops in a specific situation are ready to harvest. For example, it is commonly written that forage rapes should not be harvested until the leaves turn red. However, there is no good explanation for this and based on our observations and conversations with seed company representatives, it is probably incorrect. The late summer harvest was probably later than it ideally should have been. New York Turnip developed a leaf disease and leaves had begun to senesce by the time of the late summer harvest. Bonar and Winfred rapes and Kestrel Kale had also begun to senesce on lower leaves, though the plants were still healthy. As a result of the two different harvest dates, the varieties cannot be compared directly. This was anticipated and seemed unavoidable in the experimental design, but in retrospect they could probably all have been harvested simultaneously at the earlier date or at an intermediate date. Harvest timing remains one of the more confusing aspects of brassica management.
Since sheep broke into the plots and ate everything before the final planned harvest, full season yield data were not obtained.
Planting was delayed due to wet weather. This trial was established with a no-till drill into a sod that had been sprayed with glyphosate 5 days earlier. This establishment method seemed reasonably successful overall, though it appeared that it would have worked better had a longer time elapsed between spraying the sod and planting, as there was still significant green leaf matter in the sod at planting. Sheep broke into the plots and ate everything before any data were collected.
Planting was delayed due to wet weather and wet soil. The plot area chosen by the farm owner was poorly drained and the brassicas grew unevenly. The oat intercrop appeared to be a rational practice in these conditions, as the oats provided good quality forage dry matter more quickly than did the brassicas in these conditions. Due to late planting and cool conditions, brassica plants were smaller at harvest than would have been desirable.
Stand establishment was good for most varieties. However, problems with weed control and poor drainage caused significant yield loss to much of the trial area. The ability of these crops to withstand less than ideal conditions was severely tested. Two varieties had very poor stand establishment, probably due to seed quality issues. The plots included a fodder beet variety, which had poor stand establishment (presumably due in part to non-availability of the correct planting equipment), but which appeared to have significant potential for high yield and high quality nonetheless. Due to the high variability between plots, the analysis of variance indicated no significant differences between varieties. For purposes of suggesting the yield potential of the crops under good conditions, yields are reported from the highest-yielding plot for each variety (since for most varieties at least one plot of the three was situated in a reasonably productive environment).
Stand establishment was good for most varieties, although again two varieties appeared to have seed quality issues. Productivity was very uneven. Several varieties appeared to suffer from excessively high planting densities, and variable soil fertility also appeared to be a factor in uneven productivity. The crop was grazed by dairy cattle in November. Palatability was apparently very high, and milk production increased during the grazing period. Utilization of bulbs was initially low, but after a learning period, cattle returned to graze the bulbs and final utilization was high. This trial was the only opportunity to test the Ethiopian Cabbage and the Barenbrug varieties.
The most consistent and potentially useful observation in the variety trials was noting a distinction between varieties with storage organs (i.e. turnips with bulbs, swedes, and marrowstem kales) and those without significant carbohydrate storage capacity (i.e. the rapes, some kales, and the bulbless “grazing turnips” like Hunter, Pasja, and T-Raptor). Varieties with storage organs had the highest dry matter yields and the most favorable energy to protein ratios for lactating dairy animals or finishing meat animals. Turnip and swede bulbs had energy concentrations comparable to ear corn.
Presumably the biological explanation for the higher yield potential of storage varieties is that these varieties have a “bank” into which they can sequester carbohydrates as they photosynthesize. In contrast, the bulbless varieties can only put carbohydrates to work in making new leaves, but as the new leaves shades the old leaves, the older leaves die and fall off, leading to little net accumulation of biomass past a certain level of growth. These bulbless varieties are commonly sold with a suggestion that they can be grazed multiple times, regrowing well in between. If they are regrazed at an optimal interval and to the appropriate residual level so that there is little “idling” of photosynthetic capacity, it may be possible for the yields of these varieties to compete with those of the bulbing varieties. However, given these crops’ sensitivity to overgrazing and trampling, achieving this would require very careful management and probably good luck.
The disadvantage of the bulbed crops is that the bulb may be difficult to utilize fully. In sandy, unfrozen soils, cattle often seem to be able to pull turnips out of the ground. Sheep are more likely to eat the turnip bulbs in situ, often chewing off all that is accessible, but leaving the bottom portion of the bulb in the soil. Either way there is probably significant ingestion of soil, which is not optimal. In heavier soils or frozen soils, pulling the bulbs out is more difficult and utilization will be limited to what animals can chew off with their teeth. While this is roughly 70% of a typical turnip bulb (depending on the variety), it still represents some utilization loss. Swedes have a larger proportion of of their bulb above ground, while marrowstem kales (e.g. Caledonian) provide almost the best of both worlds by placing the storage organ (a swollen stem) completely above ground. Due to its structural function, however, the kale stem is somewhat higher in indigestible fiber than a turnip or swede bulb.
Advertisements for rapes often claim that they will regrow for multiple grazings (though some vendors are clear that this is not their strong point when compared to the leafy turnips). It was observed that the regrowth potential of most of these crops, but especially rapes, are extremely sensitive to the extent of grazing. When Bonar and WInfred were grazed by sheep in 2009, the sheep left the stems and bit off the leaves. It was noted that grazed plants regrew much better than those that had been hand-harvested (in quadrats) by cutting 3 inches above the ground. In the 2010 ELF study, the first cutting was removed with a Carter Harvester after quadrat harvests, but one strip was left uncut in one of the Winfred plots. This strip was sampled for yield at the fall harvest time, and was found to yield about 3.5 times more than the total (summer + fall) yield in the area that had been cut in the same plot. In the 2010 Zufall trial, hungry cattle mowed down the rapes to a few inches above the ground, so claims that rapes will regrow should be evaluated carefully.
Future researchers on grazing topics should pay special attention to the potential for data loss from grazing animals if fencing is inadequate. It may be common on farms for interior fencing to be imperfect on the assumption that if animals get out it isn’t a big problem, as long as they stay within the perimeter fence. In a research situation with a highly palatable crop, care should be taken that the fence is firmly planted, has a good charge, and preferably has more than one strand. As brassicas are also palatable to deer, fencing should be adequate to deter them if they are in the area.
Appin Turnip is notable in a number of respects. It consistently had among the highest yields in any trial. The seed is relatively easy to source. It has a sizeable bulb and it has multiple shoots on a bulb, giving it a unique capacity for leafy regrowth compared to most other bulb turnips. In order to make use of the regrowth potential, care must be taken not to allow overgrazing.
Barabas Turnip and Barkant Turnip both yielded well in the Zufall 2010 trial but had very different qualities. It is possible that they were inadvertently switched and mislabeled at some point. Barkant is described in Barenbrug literature as being a “tankard” type, which means the bulb is more or less cylindrical, significantly taller than it is wide. Barabas is given a more generic description. In our trials, the crop labeled “Barabas” was a tankard type, while “Barkant” was a more typical turnip shape. “Barabas” had very low germination rates, but the sparse populations allowed it to grow huge bulbs and ultimately lead the trial in estimated yield. Because of its high bulb to leaf ratio, it had among the highest energy to protein ratios in all the trials. The tankard shaped bulb, which sticks up out of the soil, is reputed to improve utilization in situations where the livestock would not be able to pull bulbs out of the ground.
Bonar Rape was the highest yielding rape in some trials (Zufall 2010, ELF 2010, Crowe 2009) and a very close second highest yielding rape in the ELF 2009 trial. In all the 2009 trials it was very similar in size, shape, and yield to Winfred, but it seemed to be somewhat more reliable than Winfred in 2010.
Caledonia Kale is a marrowstem kale, meaning it has a swollen stem which stores carbohydrates. Seed was not available to test in 2009. Based on the ELF 2010 trial (and the anecdotes of Tim Darbishire, who provided the seed), it appears to have very high yield and quality potential, yielding about 4 tons per acre of dry matter in one plot, about 55% of which is the carbohydrate-storing stem. However, it is slower to get started than turnips and rapes, so in the short season Zufall 2010 trial it yielded poorly.
Dominion Swede is the only forage swede variety able to be sourced for these trials. Unfortunately good examples of its yield potential have yet to be measured. It was expected to have a very high yield potential in the 2009 ELF spring trial, based on the very large heavy bulbs it developed. As noted above, it was grazed before a good yield sample could be obtained. However, extrapolation from the aftermath of grazing suggests a potential yield of about 3.4 tons of high energy dry matter per acre. Due to its very high bulb to leaf ratio (about 88% of total biomass is the bulb, by one sample estimate, compared to only about 30-40% for turnips), it probably is the most effective of the brassica crops, perhaps alongside fodder beet, at functioning as a replacement for grain in the ration. Like kale, it is slower to get started than turnips and rapes and needs a full season to develop its potential. Dominion did not distinguish itself in the 2010 ELF trial, probably due to its slow starting, which would make it less competitive with weeds in the early season.
Dwarf Essex Rape has seed that is very easy to find, and is often used for wildlife plots. It is indeed dwarf, and yields were low in the Zufall 2010 trial. The seed was contaminated with about 5% of some kind of turnip.
Graza Radish consistently underperformed in our trials. While it has a (smallish) carbohydrate storing root, the root was very difficult to pull out and did not extend above the ground, so was not generally grazeable. The root penetrates deeply and may have some value in aerating compacted soils. The seed company representative suggests its strength is in its resistance to being pulled out by grazing, resilience to trampling and regrowth after grazing, and thus it may shine in a situation where it would be valued for repeated grazing rounds.
Hunter Leaf Turnip is supposedly a variety selected from Pasja, and they strongly resemble each other. They also seem to have similar yields. In most cases Hunter yields trended higher than Pasja by a small amount.
Maestro (aka Robbos) Fodder Beet had very poor establishment in the ELF 2010 trial. Fodder beets are reputedly somewhat more management intensive than the brassica crops, requiring planting with a row-crop planter and (due to its very slow start) requiring either selective herbicides or mechanical weed control. In regions where they are commonly grown, yields are quite high (about 6 tons dry matter per acre in Britain). Our plots were planted later than ideal and without the correct equipment, but if the yields of individual plants or small groups of plants could be extrapolated to the whole plot (i.e. by throwing out quadrats without any crop plants), the yield potential of this crop seems to be relatively high. The roots are very high in sugars, making it a potentially valuable crop for finishing animals or lactating dairy animals where energy is limiting. According to Tim Darbishire (Limagrain dealer), they are traditionally grazed by cattle in the fall, then pigs are turned in and any roots which remain underground are eaten by the pigs.
Maris Kestrel Kale was not harvested in yield sampling in the ELF 2009 trial due to early sheep grazing. It appeared to yield similarly to Winfred and Bonar in that trial. It did not yield particularly well in the ELF 2010 trial.
New York Bulb Turnip was a strong yielder in most of the trials.
Oasis Chicory is not technically a brassica, but was included in 2009 as a curiosity because it is often on the same page as brassicas in seed catalogs. It is a perennial that can regrow after close grazing. It is reputed to have anthelmintic properties for sheep. Sheep found it highly palatable, grazing it off before starting on other brassicas. The yield at any given cutting was low compared to the brassicas, but it shines when it is grazed repeatedly. Chicory is typically sown with clover and grasses to boost yield and quality of a perennial pasture.
Pasja Leaf Turnip as noted above is very similar to Hunter.
PG 584 Ethiopian Cabbage is a widely unfamiliar addition to the study. There is very little published information available about Ethiopian Cabbage. It has a structure similar to the forage rapes (tall stem with leaves), though the leaves look different from the rapes. The stem seems to be more fibrous than the rape stems.
Winfred Rape had quite variable performance. As noted above, its ability to regrow seems to be especially sensitive to harvest method.
Those crops not mentioned above (Interval , Barnapoli, Barsica, Pinfold, Rangiora, and T-Raptor) did not particularly distinguish themselves in the conditions of the 2010 studies. As those conditions are not necessarily representative of other situations which might be reasonably expected, these varieties are probably all worth further research.
There was no apparent difference between establishment success in conventional tillage with or without a nurse crop of oats, but the oats provided some additional biomass. Vinegar gave a short term impression of complete vegetation control (leaf necrosis), but perennial grasses and clovers quickly grew out of the damage. Establishment was an almost complete failure in the no-till plots, regardless of vinegar applications. Cows broke through the fence a few days before the planned harvest and cleaned up the plots, so no data were collected, but the observational results were clear. The farmer was impressed with the obvious palatability of the brassicas and plans to grow them again.
In the summer trial, vinegar again resulted in almost complete leaf necrosis, but again the grasses recovered, though not as completely as in the spring. Establishment of brassicas was again nearly a complete failure regardless of vinegar application. No yield data were collected due to the obvious absence of brassica plants.
Brassica crops may be appropriate for certain situations, but are not necessarily appropriate for every farm. Based on experience in these trials, as well as literature review and conversations with others who have more experience with brassicas, the following summary recommendations are offered beyond what is commonly found in fact sheets:
- Some brassicas have strong yield potential, but they are very sensitive to environmental conditions and may be somewhat unreliable agronomically. It would be unwise for a farmer to rely too heavily on a certain yield expectation until he or she has significant experience with the agronomic requirements of a particular variety.There are at least three other reasons to avoid brassicas except in cases where they are truly the best option: (a) metabolic issues from inclusion at too high of a rate in the diet, (b) tainting of flavor in milk or meat if not managed correctly, and (c) providing a spacious refuge and breeding ground for pests and diseases of brassica crops which are very difficult and costly to manage for the vegetable farmers in your neighborhood.
Generally speaking, a farmer would be wise to focus management attention on maximizing yield, quality, and utilization of intensively managed perennial pastures, only diverting attention to annuals when those efforts reach a plateau.
Generally speaking, it is probably not cost effective to kill a perfectly good perennial pasture in order to plant brassicas. Brassicas and other annuals may, however, have a place in a rotational sequence when a perennial pasture needs to be killed in order to be renovated and replaced with a higher quality forage seeding. Having a break between sod crops can help control diseases, pests, and weeds endemic to sods.
The most valuable role of brassicas in a rotation should be as a replacement for grain or grain crop silages as an energy supplement to other grass- or clover-based pastures. This may be most likely to be cost effective when either (a) grain prices are unusually high and the farmer does not have equipment for harvesting and storing home-grown grains or silages, or (b)the farmer gets a price premium for a grain-free (aka grass-fed/grass-finished) product. Use of brassicas to replace forage volume on cool-season perennial pastures during the summer slump seems too risky and low-yielding compared to summer annual grasses like sorghum-sudangrass, millets, or grazing corn. Similarly, brassicas should not be used alone in an attempt to increase forage volume in late fall and early winter. However due to their cold hardiness and standability in snow, they may have a useful role as a supplement during that period, to improve the average quality of a ration based on stockpiled perennial grasses or corn aftermath.
Use of brassicas which do not have a carbohydrate storage organ (either a bulb or a swollen stem) is not advised. The quality parameters of brassica leaves are good, but not sufficiently different from those of high quality clover-grass pastures to justify the expense and risk of sowing brassicas. It is the energy storage organs which are capable of improving the energy to protein ratio in rations for livestock with high energy needs (i.e. lactating dairy or finishing meat animals). In addition, under conditions like those in our trials, or where the farmer doesn’t want to take the risk of attempting multiple grazings, the crops with storage organs had higher yield potential.
Some fact sheets fail to mention the critical importance of avoiding an excessively high seeding rate. Many farmers will not take the time to calibrate their seeding equipment and will have little experience with such small seeds at such low rates. Brassicas are auto-toxic and total yields are reduced when plants are too crowded. This is doubly critical for varieties where a bulb is anticipated.
Statements from seed companies which suggest that crops can be grazed multiple times should be treated with caution. While it is not impossible, grazing management must be skillful to make sure that crops are not trampled, pulled up, or overgrazed. A rule of thumb for the leaves is “take half, leave half.”
- This work has increased awareness of brassica crops as a source of digestible energy for grazing animals among farmers in St. Lawrence and Franklin counties.Data were obtained indicating potential yield and quality of seventeen varieties under varying conditions.
An improved understanding of the agronomic conditions necessary for good brassica crop production, and of the risks and benefits of these crops has been gained, and will be shared with others in a variety of contexts.
Brassicas are not a panacea and may not be appropriate crops for many farms, but this research demonstrates that brassicas may have a valuable role in certain situations.
Education & Outreach Activities and Participation Summary
- Field Workshops were held July 30 and 31, 2009 at Extension Learning farm, drawing a total of 15 interested farmers. Spring planted brassica yield data were discussed, and attending farmers got to see what the plants looked like.A field workshop, cosponsored with NOFA and the Cornell Organic Dairy Initiative, was held September 18, 2009 at the Crowe Farm, with 35 people in attendance (30 farmers/agribusiness, 5 presenters/organizers). Results of spring variety trial at ELF were discussed, attendees got to see plants in the field and samples of larger plants from ELF.
Results of the ELF 2009 spring variety trial were presented to roughly 40 people at the statewide NYCO/Organic Dairy and Field Crops PWT meeting on December 10, 2009.
A demonstration plot of summer annual species including turnips, kale, and swede was planted at the ELF in 2011. This was shown to an audience of 15, and results of the 2009 and 2010 trials briefly discussed, at a Field Day cosponsored with Dairy Grazing Services on July 26, 2011, and at a field day on August 27, 2011.
An invitation was extended to speak about brassicas at the Cornell Sheep and Goat Symposium on October 29, 2011.
A fact sheet has been developed and will be published in CCE newsletters in northern NY and made available to CCE personnel around NY.
Partial budgeting can be used to evaluate the potential value of brassica crops as a replacement for corn grain in the ration. Partial budgeting evaluates only those costs and returns that will change between two scenarios being compared. Any costs that are the same in the two scenarios are ignored. There are many good resources on partial budgeting on the world wide web. The example below will compare growing an acre of Dominion Swede to an acre of corn silage. Initially, an estimate of the value of each crop is required and can be found using the FEEDVAL spreadsheet from the University of Wisconsin (http://www.uwex.edu/ces/dairynutrition/documents/FEEDVALComparative.xls ) .
This spreadsheet provides a simple way to estimate the value of a crop with a given quality profile, assuming it will be used to replace some quantity of corn and/or soybean meal. Because on many grazing farms with well-managed pastures, protein is abundant but energy is limiting, the price of soybean meal in the FEEDVAL spreadsheet was set to zero, so the prices better reflect the ability of the crops to replace only corn in the diet. Estimates are shown for both Dominion Swede (a full season crop) and New York Turnip (which could potentially be planted after taking off a small grain forage crop).
Corn @ $7.50/bu
New York Turnip at 2 ton DM/A tops; 1 ton DM/A bulbs
Dominion Swede at .5 ton DM/A tops; 3 ton DM/A bulb,
Corn Silage@ 15 ton/acre at 33% DM
Turnip bulb worth $12.36/100 lb DM, tops worth $9.42/100 lb DM.
One acre of New York Turnip is worth $642.
Dominion Swede bulb worth $13.98/100 lb DM, tops worth $10.62/100 lb DM.
One acre of Dominion Swede is worth $945.
Value of corn silage: $12.23/100 lb DM
One acre of corn silage is worth $1223/Acre.
The Partial Budget Analysis is shown in Table 4.
In this market, due to the higher yield of the corn, it is difficult for swede to compete with corn, except, as noted above, if there are particular circumstances (product marketing claims or equipment restrictions) that make it preferable to corn. Each individual farm should compute its own costs and returns. Another factor which might influence the equation would include the ability to include shorter duration brassicas like turnips in a multiple-cropping rotation with, for example, a small grain like oats or triticale. Also, the quality of other feeds in the ration and production goals will make a difference in the actual value of the feeds being compared. Note, for example, that corn silage has much higher fiber content than swede, so the swede may be a more precise replacement for corn grain (a better comparison might be with corn snaplage). These issues should be discussed with a nutrition consultant for the farm.
In conversations with farmers, they have demonstrated increased awareness of risks and benefits of brassicas. Phone calls and emails have been received from farmers both in St. Lawrence County and from other areas looking for more information about brassicas. There has been success toward the goal for farmers to make more educated decisions about these crops. Since it is not recommended, based on these results, that farmers make radical changes to their practices, it is difficult to quantify farmer adoption.
Areas needing additional study
- Impacts of harvest timing on yield and quality, rules of thumb for deciding when to graze the crops.Impacts of grazing intensity on regrowth and total season yield of brassica crops.
Continued evaluation of varieties across environmental conditions, especially swedes and kales which did not have reliable data in 2009 and 2010 trials. It is anticipated that some useful yield estimates from swede and kale will result from demonstration plots planted at ELF in 2011.
Better understanding of the impact of seeding rate on yield and quality.
Evaluation of other summer annual crops (e.g. millet, BMR grazing corn, BMR sorghum X sudangrass) which could fill a similar niche with less risk.