Let’s flash back to 1966 and our family’s Greene County, NY, hillside farm where my dad wanted to purchase a new tractor. He was told he should expect to pay $100 per horsepower. He bought a new green 70-hp diesel tractor for about $7,000; he also bought a 250-gallon fuel tank and filled it up with 20-cent diesel. Good hybrid seed corn cost about $15/bag. He also had ag lime delivered and spread for $10/ton.
Returning to the present, two growers with whom I work both just told me that new tractors typically cost about $1,000/hp. Diesel delivered to the farm runs about $3.31/gallon. Non-genetically engineered (non-GMO) seed corn was priced at $200/bag. GMO corn costs about $300/bag. Fertilizer prices have varied all over the board (partly due to geopolitical messes) but they’re still several times higher than they were 58 years ago.
Ag lime increased in price also, to about $30/ton delivered; add another $10 for spreading. Lime price went up 200%, fuel price went up over 1,500% and non-GMO seed corn increased over 1,200%.
From one of these growers, who also runs a feed and seed business, I learned that a set of tires for their 350 hp tractor, with rear dual tires, cost them $2,400. Of the inputs just listed, the only one that hasn’t kept pace with – or surpassed – inflation is ag lime.
With the idea that higher yields per acre minimize the acreage one must harvest in order to yield a certain targeted total tonnage, it’s a no-brainer that improving yield per acre reduces tractor and worker hours. It will take a lot more equipment time – and human time – to harvest 200 acres yielding three tons of dry matter (DM) per acre than harvesting 100 acres yielding six tons DM/acre. Total harvest is the same in both scenarios.
I apologize for repeating the yield-enhancing benefits of applying proper amounts of ag lime – amounts determined by soil test results. The stunning cost of these non-lime inputs causes deep-thinking growers to capitalize on the least expensive input to optimize the performance of more costly inputs.
With huge geopolitical uncertainty in the world – particularly relating to fertilizer ingredient costs – not liming when soil tests indicate the need to is a bad idea. Failure to soil test to determine lime needs is just as bad an idea. With a soil pH of 7.0, nitrogen utilization is 100% – a figure which is halved when pH plunges into the low 5s. When soil testing, use a lab that gives base saturation percentages (BSPs). A BSP of less than 10% for magnesium will indicate the need for a dolomitic (hi-mag) lime rather than high-calcium lime. BSP is also necessary to determine the balance existing between different soil nutrients.
Some folks believe that if fertilizer price drops a fair amount, reduced efficiency of soil amendment utilization – associated with lowered pH – is an acceptable trade-off. People thinking that way forget the benefit of lime as a provider of nutrients Ca and Mg, in addition to its trait as a pH regulator. Plant nutrients, once rendered unavailable, are just as useless to the targeted plants whether they cost $500/ton or $1,000/ton. I refer to my own crop nutrient availability demonstration, conducted during my service as a field crops Extension agent in the mid-1970s.
Working with a cooperating farmer in Otsego County, NY, I divided a gently sloping upland field into three equal parcels. Soil test results recommended four tons of 70% ENV (effective neutralizing value) hi-cal lime per acre. The pH was in the mid-5s. A commercial fertilizer blend of 300 lbs./acre of 15-15-15 analysis would take care of the N, phosphate and potash needs.
Under the guidance of Cornell’s Agronomy Department, I altered the lime application rate. They told me that if I applied half the recommended lime rate on a corn planting, I could expect 75% of the yield increase associated with full lime application. One parcel received 4 tons/acre of lime, one parcel received 2 tons/acre and one parcel received zero lime.
The corn piece with zero fertilizer yielded 11 tons/acre of 35% dry matter (DM) silage. The two-ton lime recipient yielded 17 tons silage/acre. The 4-ton recipient yielded 19 tons silage/acre. According to my math, those professors’ yield forecast was spot on. They cautioned me that the short-changed corn parcels should get the rest of what they were owed lime-wise in the next couple years.
Let me now attempt to couple field crop production with climatology. We know that tillage tends to increase carbon dioxide emissions from the soil. It does so by introducing oxygen to soil, which then reacts with organic matter (58% carbon), liberating carbon dioxide – our planet’s most prevalent greenhouse gas (GHG). Here’s what happens next:
Solar radiation hits Earth’s surface. But the more GHGs that are in the upper atmosphere, the more sun energy stays trapped closer to the planet rather than deflecting back into space. Oceans cover about three-quarters of Earth’s surface, absorbing the vast majority of that trapped solar radiation heat. Such extra energy forces water to evaporate, but this water doesn’t go straight, vertically, up into our atmosphere. Like water going down a drain does so in a spiral fashion, that’s how water vapor rises from ocean’s surface – in a spiral fashion. The more this extra trapped solar energy hits the water – and stays – the higher the resulting sea surface temperature (SST), compliments of GHGs.
Higher SSTs predispose us to higher wind velocities. When sustained surface winds in this spiral hit 74 mph, that weather event earns the title “hurricane.” It’s not much of a stretch to say that lime applications indirectly reduce land needing to be tilled. This in turn reduces carbon dioxide emissions, which, in turn, helps reduce the severity of tropical storms.
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