OK Conservation Commission Educator Update
As we continue our discussion of soil nutrients resulting from hay feeding, it’s important to understand how the various nutrients are partitioned as they get excreted by the cow. Well-known grazier and consultant, Jim Gerrish, has written some articles titled Feeding Hay to Improve Your Land, from which I will draw a few insights here. As it is often the most limiting nutrient, Gerrish hones in heavily on Nitrogen (N). N is tied directly to the protein content of the hay, with protein, on average, containing 16% N. Livestock will usually excrete 85-95% of the N consumed. If the hay has the exact amount of protein the animal needs, then about half the N will be excreted in the feces and half in the urine. Any excess N ingested by the animal due to hay protein content greater than their requirement will be excreted in the urine. It is important to note that N in manure is released slowly as the piles decompose, but N in urine is highly soluble and readily available to plants. In summary, the protein content of your hay and the amount fed per acre will determine how much N is being applied to our soils. On concentrated hay feeding areas, we often have an overload of N being applied via urine that will essentially be “wasted fertilizer” and lost to runoff or volatilization. In terms of Phosphorus (P), Gerrish points out that almost all of it is excreted through manure. This is good in that it is a longer-lasting organic source of P, but feeding hay in a manner that results in good manure distribution is still important. Also, if feeding is concentrated to areas with high runoff potential, much of it can still be lost through erosion and may contribute to water pollution if there are streams or ponds nearby. I highly recommend that you read Gerrish’s articles and view the charts and figures he has presented. Your perspective on hay feeding will be challenged for the better.
Potassium (K) is a nutrient we have not yet discussed. Last month I referenced Dr. Greg Halich from Kentucky, and I would like to do that once again. He states that “10% of the K secreted by cattle is in the dung”, meaning a high percentage of it is in the urine and easily lost through volatilization or leaching if hay is fed in a concentrated feeding area (Halich, 2019).
In his article, Dr. Halich mentioned some other research that I thought would be beneficial to include here. A study on nutrient retention in feedlots found that out of all N that passed through cattle, 57-67% was lost to volatilization, 5-19% was lost to surface runoff, and 10-15 percent was leached into the soil. Only 9-19% was left in the manure by the time it was to be spread. Yes, this was in a feedlot, but if we are feeding in a concentrated area on pasture for extended periods of time, we can expect wastes like this to occur. In contrast, if we can feed in a different place each day, we decrease the risk of overwhelming our soils with more nutrients than they can hold onto and more good is derived from the nutrients we’ve recycled through livestock. Another study observed nutrient increases in bale-grazed pastures in Canada. Bale grazing is a technique where bales are set out on pasture before winter and fed in a planned, controlled manner, somewhat like rotational grazing. When comparing bale grazing to dry-lot feeding and spreading manure on pastures, the following was found. Inorganic N was 187% higher and extractable K was 185% higher in the bale-grazed pastures. P levels did not differ between pastures since most of the P is tied up in the manure. Forage growth over the next 2 years was 127% higher in the bale-grazed pastures and protein levels of that forage were 74% higher. Unrolling hay can lead to the same results and maybe even better nutrient distribution. We just have to be aware of soil compaction when unrolling hay during wet periods. Bale grazing in high densities works well in Canada where the ground stays frozen for long periods of time, but in Oklahoma, we would need to space bales further apart in order to lessen the pugging effect during wet weather. Feeding at lower densities would mean less nutrients contributed per acre, but spread over more acres.
Winter feeding is often one of the largest costs for cow/calf producers. Let’s get more bang for our buck by efficiently using feed as our fertilizer.
Oh, and IT’S BETTER FOR OUR SOIL LIFE THAN SYNTHETIC FERTILIZERS!
Sources:
Gerrish, J. (2019, February 25). Feeding Hay to Improve Your Land – Parts 1-6. https://tannachtonfarm.com/2019/03/10/feeding-hay-to-improve-your-land-part-1/
Halich, G. (2019, January 30) Fertilizer value of hay feeding. Progressive Forage. https://www.progressiveforage.com/forage-production/management/fertilizer-value-of-hay-feeding
The Underground Herd, Part 4
Soil health advocate and guru, Nicole Masters, has written a book in which she describes the soil ecosystem and lays out strategies to regenerate farming systems. One chapter specifically describes the underground “livestock” and the vital role they play in our existence on earth. For the next several months, we are highlighting the different soil organisms and what they do, as explained in Masters’ book, For the Love of Soil.
This month, let’s look at NEMATODES.
Nematodes can be viewed as non-segmented worms, and, compared to bacteria, they are quite large, ranging from 300 microns to a just visible 2.5 mm. We often hear about “bad” nematodes, the root feeders and parasites, when, in reality, these only make up around 5% of all nematode species. The damage they cause can be considerable when soil systems are out of balance, but most nematode families are beneficial and contribute to good soil structure. In addition to creating passageways between soil aggregates, nematodes also keep microbial populations in check and help drive the nitrogen cycle.
Nematodes are grouped by what they eat, and they live in areas where their food concentrates. Depending on the species and, thus, mouth part anatomy, nematodes may feed on algae and organic matter, fungi, bacteria, or each other.
Finally, Masters likens nematodes to “canaries in the mines of soil health”. Since certain groups of nematodes are more vulnerable to disturbance and pollution than other organisms, their absence may be a method for assessing soil integrity and health. Low nematode levels are often associated with reduction in the following: plant nitrogen, disease and pest suppression, soil structure development, and root health.
The following link will provide more information on soil nematodes as well as pictures.
https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/soils/health/biology/?cid=nrcs142p2_053866” data-auth=”NotApplicable”>Soil Nematodes | NRCS Soils (usda.gov)
Source: Masters, N. (2019). For the Love of Soil. Printable Reality.
Oklahoma Soil Health is a community of partners that includes Oklahoma agencies, higher learning institutions, non-profits, and private citizens and companies, pooling resources to learn about and educate Oklahomans about how and why improving soil health benefits us all, including our agricultural production systems, food, air, and water quality. These occasional updates share information on soil health and upcoming soil health educational events in Oklahoma.
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