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Little River, TX | It is both interesting and informative. I do have a few observations.
You might look at the total pounds of nitrogen added to crop lands compared to total nitrogen removed with the crop.
A number of years ago a big thing was made of all the nitrogen applied in the Texas Winter Garden Area. Hot until it was pointed out that more nitrogen was being shipped out in crops than was being applied in the area. This did not fit the politically correct party line and met with some disapproval in some academic circles. I suspect all that data is now lost. Volatilized? Leached? Contributed to nitrates in the water??
It should be pointed out that a number of standard values for soil elements are really regional not universal.
Slide 13's soil calcium might be different with a soil that is 8,000 ppm Ca plus 10% free calcium carbonate.
A danger: For the farms that NEED tiled drainage to attain any productivity may be hurting with the drainage slides.
Might put crop agriculture under similar restrictions to confinement livestock operations, where any water that falls on a farm must stay on that farm. All that nutrient rich water out flow will have to be applied to land with according to a nutrient application schedule. Only drain tile out flow that is low enough in nutrients to be a neutral factor would be Permitted. Key Word Permitted! PERMITTED!
My 8 th grade math on slide 37 indicates, to me, the alfalfa is roughly 16% CP. A Dairy Quality alfalfa hay at 24% CP hay might contain 77 lbs of Nitrogen.
Slide 43 graph is nice to look at and may apply to Corn Belt corn, but in hay the yield to plant level for phosphate is a reasonably classic bell curve, while for potassium there is a wide spread for the optimal yield to plant potassium percentages.
Slide 50, I hope your verbal presentation illuminates what the P & N in excess refers to. The slide is just numbers.
Slide 51, probably in the Eastern Pennsylvania dark green county I visited a testing Lab on an AFGC annual Conference and there the dairies were testing their soil, testing their crops for feed value and nutrients, then they tested the animal waste, tested the water coming onto their farms and tested the water leaving their farms. This was close to 30 years ago. Those Amish Dairy Farmers were not contributing to the Delaware or Chesapeake pollution problems. They had the numbers to prove it. They also tested their well water.
Unless of course we were being fed a line of bovine scat.
Slide 78 is a good slide.
Slide 79 obviously does not apply for calcareous soils. Need an asterisks to denote that regional difference.
I liked the hint that organic might eliminate or at least reduce the need for mineral fertilizers. That might be valid, but I do not see locally available animal waste in sufficient quantities to support the crops being grown HERE. Plus not all commercial crops end up as an animal waste. Think Cotton.
A very interesting presentation, and I expect very appropriate for the area your school draws students from. You might mention to any students that might in their future be engaged in agriculture in an area where their regional truths are different.
Back to slide 13, there are a few who insist they will grow Azaleas in these soils. It is possible just as it is possible to grow blue berries in this soil, but it is very labor intensive and prohibitively expensive. | |
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Presentation on nutrient cycling
