Enclosing two samples for your analysis this year. These two samples were taken 150 miles apart.
Sample #2 is taken from a piece of property that we own in the Oregon High Desert. We’re starting a small native grassland restoration program there and want to know what we have to start with. Soil is subject to extreme erosion and 10” rain per year.
Sample #1 is from our hay field. The field is naturalized grass and legumes. We are no longer grazing sheep, but instead have shifted our focus to growing nutrient-specific hay for our pleasure horses. Here are some specifics that we are trying to achieve:
As the soil has become more fertile through remineralization, vetch and clover are threatening to choke out the grass. We wish to discourage the growth of the legumes, and encourage the growth of the grasses.
It is not that the legumes are undesirable nutritionally. The vetch has become so rampant that it is almost impossible for the disc mower to cut through it, and because of our increasingly wet and cold springs, it is nearly impossible to cure, making the hay musty.
We also lost our hay crop this year, partially on account of the vetch. It grew so long and heavy that it forced the grass to the ground in June rains, where it began to rot. We were forced to mow the field and let the hay lie on the ground, which leads me to the next subject.
Our organic matter content seems to be on the rise again. Last year it was 11% (OM, not necessarily humus). This year, because there is a MASSIVE amount of OM from the ruined hay, I am wondering if we are going to need a more liberal dose of nitrogen to help digest it all. This leads me to the next issue.
Despite applications of copper sulphate to apparently adequate soil levels, our copper uptake in the grass continues to fall while the molybdenum continues to rise. The Cu level in the last hay crop was 3ppm, and the moly was 4ppm. The ratio of Cu:Mo needs to be as much as 10:1 for animal health. Obviously we need to unlock the Cu somehow, to get it into the grass. I am also hoping that better Cu uptake will help the grass resist lodging. I am guessing the OM is trapping the Cu and making it unavailable. This ongoing low copper issue has been fatal to some of my stock. I am very wary of adding any more Cu to the soil – prefer to see if managing the OM will correct the problem.
Potassium is a subject of extreme concern, as most grass hay has far too much potassium in it for idle/light work horses. An idle horse needs only .8% K in the diet, and most grass hays run far higher than that. Our last hay crop was 1.7%, which is quite a good level, but we have starved the K down in the soil quite a bit, which hasn’t had the least effect on yield. So we prefer to try keeping the K in the low-to-mid range of base saturation requirements. On the other hand, we also request that you examine the Na to make a recommendation for salt application. We applied Redmond salt at 150 lb/acre one year, and that brought the animal nutrient level of Na up to .25%, which is the bottom of the NRC requirement. I know that K and Na have to be in the right proportions. The Na level in the fall fresh forage that year had dropped to negligible levels, so I’m sure the Na can use topping up again, especially with our excessive rainfall.
Another real problem we have is pushing the Mg up into the grass. The hay is more or less meeting minimum NRC requirements, but it is constantly suppressed in comparison to Ca and especially K. I strongly believe that this is a function of the cold spring/early summer soil, and wondering if you can recommend a biostimulant that might help us push more Mg into the plants.
Just as an aside, regarding Ca, Mg and K uptake, we used to have lamb livers analyzed when we were raising sheep. The livers were chronically low in Ca in particular, and Mg tended to be borderline, while K was always off the charts. These lambs were always harvested at the end of June, at the peak of the grass growth. These numbers are particularly damaging to metabolism. It doesn't show so much in young livestock, but eventually produces metabolic disease in longer lived animals such as horses.
The other mineral that the hay is chronically low in is zinc. We have not applied any to the soil, and I believe it’s probably time.
I am enclosing a copy of a blog article I wrote, comparing some Eastern Oregon (rained on) commercially grown orchard grass hay, with our home grown stuff, which hopefully shows the type of nutrition we are trying to coax out of the grass.
Looking forward to receiving your advice!
Barb Lee
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