One of the five labs that I work with provides small plastic-lined paper bags for their customers to put their soil samples in. The person submitting the soil for analysis fills out the field’s and farm’s specifics on one side of the bag. On another side of the bag there’s a sales pitch: “Test — don’t guess. A soil test is one’s best single guide in determining the strength of each link of the plant nutrient chain. The weak link sets the ceiling on crop link potential. A soil test identifies the weak link or links.” Making assumptions about the nutrient status of one’s soils — and forages, for that matter — is, gently stated, very high on the silly scale.
A couple generalities about manure’s benefits are in order here. First — with four-legged animals — manures that are forage-based tend to run lower in phosphorus (P), compared to concentrate-based manures from ruminants and swine. This is because, as a rule of thumb, P levels in grains run about twice as much as P levels in forages; for example, a mixed mostly grass hay crop commonly tests about 0.2 percent P, while shell corn tests about 0.4 percent P (both values on a dry matter basis). Secondly, poultry manures tend to run higher in P than they do potassium (K). Poultry manures are much more grain-based, than forage-based. Forages run much higher in K than grains do.
As I wrote in a column last month, raw poultry manure runs (by analysis) around 4 percent nitrogen, 3 percent phosphate, and 2 percent potash. Fields that get fed abundant poultry manure can be expected to suffer reduced potash levels, at some point. Typical raw cow manures average about 1 percent nitrogen, 0.5 percent phosphate, and 1 percent potash. So in theory the proper blend of poultry and ruminant manures would be adequate for many crop scenarios. That said, there’s little or no room for guess-work. We need the services of skilled technicians at soils and forage labs to isolate the weak links in the food production chain.
Just how safe a practice is guessing about soil nutrition? The answer to that question reminds me of the response meteorologists give when asked: where’s the safest place to be in a trailer home during a tornado? Answer: there’s no safe place. Similarly, when it comes to not knowing the nutritional make-up of your soils (and your crops), ignorance isn’t bliss — and one can argue that it’s not safe, when you consider everything at stake. It seems that I travel more by air in recent years. When boarding a plane — if the door to the cockpit is open — I like to quickly look at all the gauges and instruments on the control panel. All those electronic tools are serving an important function. Is there room for any quesswork? — not if I’m on that plane.
In 1958 I remember reading an article in Life Magazine, that dealt with the discovery of a World War II bomber, specifically a B-24D Liberator aircraft, whose wreckage had just been discovered in the Sahara desert. I’ll quote from a write-up on www.warhistoryonline.com, dealing with the lost “Lib”: “The wreckage of a USAAF (United States Army Air Forces) plane that went missing during its first and last mission in the Second World War was discovered in a North African desert. In early November 1958, an oil exploration team from Britain was flying over the Libyan desert, when they unexpectedly spotted the wreckage of a plane in the middle of the desert. A ground team was quickly dispatched to the crash site to investigate the wreckage. It was later revealed that it was the wreckage of a ‘B-24D Liberator’ from the Second World War, also known as the ‘Lady Be Good.’ The plane flew for the first time on a bombing mission in Italy in 1943 but lost radio contact shortly after entering a sandstorm.” The comparatively recent website account lined up with what I recall from the Life article. The dry desert conditions made possible the recovery of the remains of all aircrew members, who had parachuted from the aircraft that had run out of fuel.
I never forgot that Life article. My memory was further refreshed during a lecture dealing with flight safety, that I attended while on Air Force active duty in 1971. The speaker, a battle-seasoned fighter pilot, actually led into his talk with a scripture: Proverbs 14:12 King James Version: “There is a way which seemeth right unto a man, but the end thereof are the ways of death.” With that “in-your-face” Bible quote, this pilot (a Navy commander) was just trying to get aircrews to pay attention to their instruments. Then he mentioned the ill-fated “Lady Be Good” incident. Aided by dry desert conditions, aircraft accident investigators — almost 16 years after the Lib crashed — were able to determine that all the aircraft’s instruments were functional. What happened was that the pilot and co-pilot didn’t believe the compass when it said they were flying south, further into the desert. They assumed they were flying north, toward safety. So they kept flying south using dead (literally) reckoning, until the fuel gauge pushed empty. They trusted that gauge, but it was too late.
A little extreme illustration on my part? You bet. But I’m on a roll. Last week I picked up eight soil samples from a total of three dairy farmers. These men had taken advantage of a short-lived thaw and sampled the mud. I picked up the samples, brought them home, air-dried them on newspaper in our sun-lit porch, then screened them precisely. I mailed them to the soils lab in Ithaca, and should have results back by the time you read this. All three dairymen are “off-grid” — but somehow embraced modern laboratory technology to learn what’s in their soils (or not).