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Little River, TX | A lot depends on your philosophy.
All my sampling is well in advance of any fertilizer application.
I sample the first year back into alfalfa as a fertility QC, and the last year of a stand for the next alfalfa fertility plan. I assume a 5 year stand 30 tons total yield. All the fertilizers considered needed for the life of the stand is incorporated prior to planting. I also fallow the field the year prior to planting back to alfalfa to recharge deep moisture. This is essentially alfalfa following alfalfa, with a year fallow rotation.
Bermudagrass being a persisting perennial they are tested every 3 years.
My fields are long and narrow, with good access from the sides. I divide each field into three equal segments and collect three each, separately identified samples. The results are compared and then averaged. Yes I sample usually in May. I pay $16.60 per soil sample for Olsen chemistry and free lime determination. Plant analysis is $18 per sample plus $18 for molybdenum, and $6 for chlorine. Usually basic plus chlorine for the during the first season, and basic plus moly for the last sample.
Along the way I have had separate measured CEC testing, at $17.10 /sample. I have built a data base of CEC values and now use an averaged 37 meq/100 g for my alfalfa ground and an averaged 50 meq/100 g for my grass hay fields. I multiply the averaged CEC value by some magic numbers to determine the critical and sufficient levels of K & Mg. It is a given the calcium is excessive on my calcareous & 8 pH clay soils.
For comparison, I look for 400 to 600 ppm K soil report to assure adequate potassium uptake by the crop. At 300 ppm K the plant analysis will be down close to 1.00% K, the stand will thin out drastically during the summer our droughts. Ideal, for yield and persistance, plant analysis is 2.78% K.
I realize our climate, soil, and management needs are not typical Corn Belt. I do not expect what works here will transfer directly and completely to the Mid West. I do mention what works here so you all can consider a different methodology. Some of which just might work for your climate, soil, and management.
At the same time our best and brightest have not had any success with no till systems.
First cutting is late March early April. Second cutting is usually early to mid May. Depending on weather cooperation. I sample at the second cutting to avoid having a luxury indication for the minerals, as they have had all winter to gather in nutrients. This is after all Central Texas and we seldom have a frost that penetrates an inch of soil. Our Alfalfa is FD 7, 8, or 9, and remain green all winter. Frosted back alfalfa will regrow.
As you may gather I fertilize one field for alfalfa each year, not each field each year. The people up in Oklahoma have data to show a stand will produce more over the life of the stand with a single prior to planting fertilizer application. From what I see on my farm they are correct.
A side note, I want the first years hay to test close to 3.00% K, to give the first year plants a better chance to survive our summer drought.
The bermudagrass, The nitrogen is applied according to past applications adjusted for amount removed as hay. With a 50 meq/100g CEC nitrogen just does not leach away. Half of what ever is applied in year one is available for year one's crop, plus half of any residual. There is always a good bit of residual. For the bermudagrass soil and plant analysis I evaluate the major, minor, and micro nutrients, excluding any nitrogen test results. A challenge or advantage not available to sandy soils.
All bets are off for 2007.
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When to fertilize new alfalfa
