Inoculant Questions

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Phone Question about Inoculants:

A grower planted on twin rows and applied half of the rate of inoculant under each row of the twins. In other words, each row of the twin row pattern has half of what each row in a single row pattern would have. In my view when planting in twins each of the rows needs a full rate, equal to the rate used in single row plantings. This is why the expense for twins is twice as much as singles when it comes to inoculant (but still very inexpensive when looking at a $900/acre peanut budget.) The question is whether or not the farmer should do something right now, about 30 days after planting and 21 days after peanuts have emerged.

There is a lag time between emergence and nodule formulation. Generally it will take about 40 or so days to begin seeing nodules and maybe even a little longer to know how effective nodulation is. The farmer is interested in knifing in nitrogen right now. My recommendation is to hold off on doing anything, especially given the farmer is interested in trying to knife in nitrogen between the twins (7-9 inches.) Seems to me this is a very precise operation, there is a chance the peanuts could be damaged with the equipment or the concentrated fertilizer and we don’t know what the half rate of inoculant will do. Companies often establish the 1X rate of something with some buffer. This is true for pesticides and for fertilizers and other products. In many situations a 1/2X rate will perform as well as a 1X rate when it comes to inoculant and other fertilizers and actually with many pesticides. But knowing when the 1/2X and 1X will perform the same is the biggest challenge. We have noticed this is gypsum studies. In many cases the 1/2X and 1X rate increase yields and grades virtually the same compared with the no-gypsum control. But there are times where the 1X is definitely better than the 1/2X and we have not been able to predict this with gypsum. So from a risk management standpoint applying the 1X is the best thing to do. In the case I a rambling on about with inoculant, there is a good chance the 1/2X will do an adequate job. My recommendation would be to not do anything to the peanuts until a few weeks from now and then make an assessment of nodulation and whether the nodulation will be adequate. At that point the farmer may not need the nitrogen but it is not too late to add it (ammonium sulfate as a broadcast) if nodulation is poor.

Article first appeared as North Carolina Peanut Note (PNNC-2014-071)