Results From a Curiosity Trial

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Impact of Time of Vine Mowing and Digging Date on Peanut Yield

How will peanuts respond to mowing prior to digging? This question stems from the excessive vegetation often observed with Bailey. Apogee and guidance systems can help growers overcome the difficulty in seeing rows and staying in the correct place in the field as they dig. However, Apogee is expensive and many growers have not invested in guidance systems.

In addition to difficulty in seeing rows adequately for digging, the excessive vine growth can cause pod loss due the high volume of plant material (vines, pods, roots) going through the digger and inverter. This is especially noticeable because pods are pressed tightly against the inverter bars. Would mowing help reduce these losses without negatively affecting yield, and if so, what interval between mowing and digging is acceptable?

We conducted three tests designed to answer these questions. Our goal was to have two digging dates and three mowing treatments. The first digging date was designed for optimum maturity followed by a second digging date one week later. The mowing treatments included a non-mowed control versus mowing 1 and 2 weeks prior to the first digging date (see photograph). In small-plot research we generally can track rows even without Apogee or a guidance system. Having alleys often helps the person digging adjust slightly when needed, and this most likely eliminates positive effects of mowing grower might experience in large fields.

Disease was controlled well in these trials, so positive impacts of greater air flow resulting in less disease most likely was not a factor (the peanut canopy was healthy throughout the duration of the trials.) However, weather conditions and other logistical issues kept us from holding tightly to the digging schedule (see dates for mowing and digging in the table.) We may have learned more by not being able to hold to that schedule.

At Rocky Mount with the variety Sugg, we saw no difference in yield when comparing digging dates or mowing treatments (see table). With Bailey at this location (planted at the opposite end of the field), we did see a difference in digging date but no negative impact of mowing (see table). Maturity relative to when we initiated digging most likely varied due to planting date and location in the field. At Lewiston we did see a major impact of mowing and possibly an interaction of mowing and digging date (see table). If you recall we had poor digging and combining conditions in early and mid-October and this delayed our last digging date. The result was peanuts staying in the field much longer than intended, especially when peanuts were mowed two weeks before the first digging date. Mowing lowered yield in this case. Some of these results are obvious. As with any management strategy that impacts the plant’s ability to hold pods (disease control and physical damage to foliage), a delay in digging after mowing due to unforeseen circumstances can have a major (and negative) impact on yield. We did not anticipate delays in digging (September 28 and Oct 9, these dates were several days to almost two weeks later than initially designed due primary weather conditions.)

Once vines are mowed, the time of digging is set from the plant’s perspective but might not occur based on the farmer’s ability to be timely with digging. That is when mowing becomes a problem. So, if a farmer has rank vines and wants to mow to help facilitate digging, weather and soil conditions need to be favorable for the next week for digging and digging needs to occur in that window of time. Anything beyond a week is a risk because of unknown weather and soil conditions that are created because of weather. There are only a handful of people that would mow to facilitate digging.

peanut mowing trial

Treatment Description Mowing Date Digging Date Yield (lbs/acre)
Rocky Mount (Sugg)
1 Not mowed No Sep 25 4901 a
2 Mowed 5 days before digging Sep 20 Sep 25 4829 a
3 Mowed 12 days before digging Sep 13 Sep 25 5179 a
4 No mowing No Oct 2 5385 a
5 Mowed 12 days before digging Sep 20 Oct 2 5175 a
6 Mowed 19 days before digging Sep 13 Oct 2 5508 a
Rocky Mount (Bailey)
1 Not mowed No Sep 25 4462 b
2 Mowed 5 days before digging Sep 20 Sep 25 4477 b
3 Mowed 12 days before digging Sep 13 Sep 25 4960 ab
4 No mowing No Oct 2 5402 a
5 Mowed 12 days before digging Sep 20 Oct 2 5625 a
6 Mowed 19 days before digging Sep 13 Oct 2 5581 a
Lewiston-Woodville (Bailey)
1 Not mowed No Sep 28 5601 a
2 Mowed 8 days before digging Sep 20 Sep 28 5411 a
3 Mowed 18 days before digging Sep 10 Sep 28 4566 bc
4 No mowing No Oct 9 5101 ab
5 Mowed 19 days before digging Sep 20 Oct 9 4387 c
6 Mowed 29 days before digging Sep 10 Oct 9 3655 d

Article first appeared as North Carolina Peanut Note (PNNC-2014-015)