Peanuts will often do well if given the time to fully develop and then dug in a timely manner.
By David Jordan, Extension Agronomist, North Carolina State University
Peanuts are one of the most resilient crops grown in the United States and around the world. While there are some predictable characteristics of peanut in terms of maturity and its impact on yield and market grades, when this predictable window will occur can be surprising.
The value of delaying digging until optimum maturity is achieved is well established, and researchers, Extension specialists, consultants and agents have worked hard to help growers predict the best time to dig. For example, at 30 cents per pound, digging one week early can prevent a grower from making an additional $162 per acre (see Table 1). This amount of money covers much of the estimated cost for control of disease, insects and weeds for a typical farmer in the Virginia- Carolina region.
Flexibility Pays Dividends
Growers get antsy in the V-C region because of the possibility of tropical weather patterns, cooler temperatures that can reduce field drying once fields are wet in the fall, potential pod shed for Virginia types and the chances of freeze damage. Some growers dig early because of these risks. Digging at this often elusive “place” brings the greatest economic return.
This may seem like textbook fine-tuning but being as timely as possible and hitting the yield/market grade peak will increase income. There is often a point in peanut development and maturation of pods where yield has plateaued but market grades can still improve. Of the many inputs growers can invest in, having digging and harvesting equipment that allows one as much flexibility as possible in digging will pay dividends in many years.
There is often a dilemma between letting peanuts mature fully and digging early because disease is present. While each disease impacts vine health and subsequent pod retention and yield differently, data, with respect to interactions of disease and digging date, remind us of how important near complete disease control and timely digging can be (see Table 2). In these studies, the highest yield was noted when peanuts were allowed to stay in the field until mid-October and when an effective spray program was in place.
Weather Always A Factor
While peanut response to digging date is often predictable, occasionally peanut response to planting and digging can be surprising. In North Carolina, planting in May will routinely out yield Juneplanted peanuts even when peanuts are given as much time as possible to reach maturity prior to digging. But results can be surprising depending on stress early in the season and can also point out how averages can be deceiving.
In the first three years of a study, peanut yields were considerably higher when planted around May 5 or May 25 compared with planting around June 8 (see Table 3). However, in the final year of the experiment, peanuts planted in early June did much better than those planted in May.
While initially shocking, weather conditions at this location went a long way to explain the results. From 2009 to 2011, rainfall and temperatures were relatively good for flower and peg development for the May-planted peanuts. In these years, the early planted peanuts did well, and, on average, yielded about 1,000 pounds more than the best digging date for the June plantings.
In 2012, peanut planted June 8 yielded just over 1,300 pounds per acre more than peanut planted in May with optimum digging. Dry conditions for most of late May through early to mid-July negatively impacted flowering and pegging and were a detriment to the May-planted peanuts. Weather from mid-July through the entire season was near perfect for peanut growth and development.
Images of peanuts taken in late August appear to have more pods for the June plantings compared with May plantings. Temperatures for the first 10 days in October moderated, helping peanut planted in June continue to make up ground (see Table 3). Images of pods from 2012 in late August show more pods when planted in June compared to May, most likely as a result of hot, dry weather and the negative impact on flowering and pegging in late May and June.
Timeliness Is The Key
Each of us can draw our own conclusions from these data sets. Each time I discuss them with Extension agents, I walk away with a slightly different perspective that will be helpful the next time someone asks a question about planting dates and digging dates. Today, my takehome message (and it is an obvious and well-established one) that timely digging is essential in optimizing yields, grades and income. What also continues to be well-established is that a considerable amount of peanuts continue to be dug on the early side, reducing income in many cases. And, peanuts are resilient and we should never give up on them.
For maximum yield, grade and income:
• Timely digging is essential.
• Protect vines from disease, insects
• Don’t give up on peanuts!
Protection Of Vines
Another obvious message is how the protection of vines from disease provides the greatest yield and flexibility in obtaining that yield in terms of digging. Finally, peanuts can be unpredictable when it comes to response to digging and planting. We can expect lower-than-desired yields if a weed, disease or insect problem is allowed to take its toll, and often we are not that surprised when it happens. But when peanuts are protected from the biotic stresses, we are often positively surprised at how well they do if we give them time to fully develop and mature and then dig them in a timely manner.
As my technician faithfully points out, you can plant a lot more peanuts in a few weeks than you can dig in a few weeks. In general, 30 and 40 acres at 10 hours a day at three miles per hour can be dug with four- and six-row diggers. A big question for growers is how their digging capacity satisfies not only the perfect fall but also the falls that are imperfect when it comes to getting the job done.
Without digging capacity, the fine-tuning and timely digging is not possible, and so is the extra and “free” income that goes with it.