Author Archives: Maria Balota

Midsummer peanut updates for Virginia

According with the FSA, 26,323 acres of peanut were planted this year in Virginia; and the crop progresses well so far. The early May planted peanuts are getting close to the full seed growth stage (two pictures of peanut pods and seed are provided here)

Peanut pod and seed at full seed stage.

Peanut plants and pods on Aug-7-17 and planted in early May.

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However, in some sandy fields plants have become yellowish lately. It is difficult to guess the reason for the yellow color. It could be caused by poor inoculation or nitrogen fixing due to drought or water standing; manganese deficiency, which is relatively easy to identify (a picture of manganese deficiency is provided here)

Peanut leaves with manganese deficiency.

; but also acidic soils, which are predominant in south-eastern Virginia. Soil pH directly affects plant growth through its effects on the availability of all nutrients. For example, soils with pH less than 6 may become deficient in calcium, magnesium, phosphorus, potassium, and molybdenum. Molybdenum is essential in biological nitrogen fixation and, even though the nodule numbers may seem sufficient, the result, tissue nitrogen content, may be limited.  Gypsum does not alter soil pH; only lime can be used for that, and dolomitic limestone is the desired product as it provides calcium and magnesium. The traditional recommended pH range for peanut land is 5.8 to 6.2, but more towards 6.2 when Virginia-type peanuts are planted. In addition, limestone moves very slowly into the soil, therefore applying limestone early in the planting process and tilling it into the root zone (top 7 inches) is important. Rainfall amount, application of fertilizers containing ammonium or urea, sulfur containing ingredients, and decomposition of organic matter (previous crop residue) also adds to soil acidity. Soil sampling should be taken in the fall and, if the test results indicate a need for limestone, for best results it should be applied in the fall or winter months. If applied just prior to planting and soil is dry, lime will have little effect on the pH.

Going back to the yellow plant color, the best approach for knowing and not just guessing what causes it is to take soil and tissue samples and send to a laboratory for determining the soil pH and tissue nutrient content. The table below shows the sufficiency levels for macro and micronutrients of the peanut vines. It is recommended that 50 whole shoots throughout the field, or problematic areas, should be combined in one sample prior to or at bloom stage.

Macronutrients

%

Micronutrients

ppm

Nitrogen (N) 3.50-4.50 Iron (Fe) 60-300
Phosphorus (P) 0.25-0.50 Manganese (Mn) 60-350
Potassium (K) 1.70-3.00 Boron (B) 25-60
Calcium (Ca) 1.25-2.00 Copper (Cu) 5-20
Magnesium (Mg) 0.30-0.80 Zinc (Zn) 25-60
Sulfur (S) 0.20-0.35 Molybdenum (Mo) 0.10-5.00

 

Manganese (1 pound per acre) and boron (up to 0.5 pounds per acre) are regular applications in peanut production during summer, but nitrogen can also be applied if the tissue analysis indicates the need. Rate of 60 to 120 pounds per acre elemental nitrogen (or 285 to 571 pounds per acre of ammonium sulfate) can be applied, depending on the test results; and it is worth applying even at this time (August). After all, there are two more months of peanut growth. Increasingly more fields seem to require potash applications. Peanut is efficient at scavenging phosphorus and potassium left in the soil from previous crops, but for some reason potassium is getting slim each year. An application of 100 pounds per acre of potash may correct that deficiency.

Knowing the history of each field for yield and crop growth, can help to anticipate where nutritional problems may occur and allow for preventive measures even before symptoms are visible. Drone technology can be used to derive soil maps for pH, moisture and yield of each crop in rotation, so that precise locations within a field where problematic spots exist can be known and independently managed using the variable rate technology (VRT). The VRT consists of a control system on an application equipment, planters, sprayers, and spreaders, which allows grower to achieve site-specific application rates of inputs. To work, prescription maps need to be generated and uploaded to the computer within the machine cab that has the VRT. Drones can be used to generated these maps. For example, the last picture in this story shows an image of the soil moisture distribution of a field at the Tidewater AREC. The image was taken before peanut planting with an infra-red camera on a drone; the drone purchased not long ago with funding from the Virginia Peanut Board, the shellers, and Virginia Crop Improvement Association. In the image, the darker the blue the more soil water was available; green color indicated dryer soil sections with the driest spots being colored in yellow and red and located in the patches adjacent to the field.

Pre-plant field image taken with an infra-red camera from a drone showing soil moisture distribution.

Potential applications of this technology can help growers to use variable seeding rates and depths depending on the available soil moisture at planting, and monitor irrigation needs throughout the growing season.

Planning for Planting Date and Seeding Rate for 2017 Peanut Season in Virginia

There may be more peanut and cotton acreage planted in the V-C region this year than in 2016; and growers may wonder what crop to start planting first and which one last. These are legitimate concerns and we may have, at least in part, answers.

For peanut, mid-May planting seems to carry least risk compared with late April to early May or late May to early June plantings. This is quite common knowledge gathered through extensive research at the Tidewater Agricultural Research and Extension Center in Suffolk VA and Peanut Belt Research Station in Lewiston NC.  However, researchers agree that all depends on the weather. For example, research I did in 2009, a relatively cool and wet year with 17 inches of rainfall from May through the end of August, clearly showed that April 20 planting resulted in a statistically significant yield reduction of 780 pounds per acre in comparison with a May 15 planting. At the state level, average yield in Virginia in 2009 was 3700 pounds per acre, similar with the average yield in 2016. Year 2010 was hot and dry with less than an inch precipitation in June, July and August combined. In this year, state average yield was only 1800 pounds per acre and our results indicated that April 15 planting of Bailey resulted in substantially more yield than late May (May 21) planting. The majority of other peanut commercial cultivars tested in that year responded in a similar way; but there were a few exceptions like Sugg, Gregory, and the runner Georgia 09B, which performed well when planted on May 3, but still low when plated on May 21.  The first two weeks in May (maybe end of April too with good thrips control) may be best for peanut planting if April and May are warm with constant daily temperatures of 65 °F or more, sunny days, and night temperatures of 45 °F or more, and soil has “right” moisture; if moisture is excessive, the soil is probably cool. If April and May are cool and wet like last year, maybe waiting for after mid-May to plant peanut is the best option. Varieties seem to respond differently to planting time, but information on the new high oleic cultivars needs investigation.

In 2011 and 2012, I looked at how combination of planting date, seeding rate and tillage affects peanut yield. Results from these years were also dependent upon the specific weather conditions of each year. Across the state, both years were “good” years for peanut, with state averages of 4100 and 4200 pounds per acre; but in 2011, the hurricane in August dropped 18 inches of water at one time, and weather was considerably warmer than in 2012. In 2011, planting on April 25, May 5 or May 23 did not significantly changed yield, in particular when 5 or 6 seeds per foot-row were seeded. Some yield reductions were observed when only 3 seeds per foot were used. However, in 2012 Bailey yielded approximately 1000 pounds per acre more when planted on May 12 in comparison with April 30 and May 23 or June 1; and yields were about 100 pounds per acre greater in conventional versus strip till.

We concluded that the optimum time for peanut planting in Virginia is May 5 to May 20. Planting early may have lower yields due to thrips damage, and cool and wet soils; later plantings may also drop yield due to poor germination and crop stand; and recommended increase of seeding rate to 5 or 6 seeds per foot when planting outside this time window. More information on this research is here.

effect-of-planting-time-on-disease-yield

Strip versus conventional till for peanut

Research at the North Carolina State University showed that peanut yields were lower when planted on fine-textured soiled in strip tillage in comparison with conventional tillage.  Yield reduction appeared to be associated with greater pod loss in the digging process for the strip versus conventional tillage. Use of stale seedbeds, by bedding rows without other tillage operations sometime after the harvest of previous crop and 4 to 6 weeks prior to planting peanut, was further proposed as a tillage practice that could alleviate yield reduction due to strip tillage. Research using corn, cotton and grain sorghum as rotation crops showed that, indeed, depending on year and location peanut yielded greater in stale seedbed and strip tilled land versus just strip-tilled soil. For example, in 2006 at Rocky Mount, NC, when soil was bedded and strip tilled, pod yield was 3620 pounds per acre, significantly more than 2570 pounds per acre when peanut was planted directly into stripped soil and crop stubble. However, similar responses were not observed in 2002 at either Lewiston or Rocky Mount; which probably denotes that more research is needed to document if stale beds in crop stubbles and in strip tillage peanut production work. According with these researchers, peanut yield in longer rotations was higher than yield of shorter rotation, but the rotation crop had no effect. The full article is here peanut-notes-2017-no-23-peanut-strip-tilled-into-grain-sorghum-stubble.

Information on the pesticides under European Union scrutiny

The European Union (EU) is reviewing the current maximum residue levels (MRLs) for pesticides, some being used in peanut production. The process started in 2016 and will continue in 2017. As expected, peanut imports in EU may be affected by these changes. I am providing here information on these products (credit David Jordan and American Peanut Council), and I will continue to do so when I have new information. Although under review, please note that not all pesticides may have their MRLs lowered. peanut-notes-2017-no-12-comments-on-pesticides-eu-peanut-imports peanut-notes-2017-no-11-wto-communication-on-pesticides-and-mrls

peanut-notes-2017-no-11-wto-communication-on-pesticides-and-mrls

 

Peanut Variety and Quality Evaluation 2016 Report

Growers in Virginia, North Carolina, and South Carolina are always in need for high yielding, disease resistant and early maturing peanut varieties with good grading and processing quality. The multi-state Peanut Variety and Quality Evaluation (PVQE) program evaluates advanced breeding lines from the North Carolina State University and University of Florida breeding programs that can further be released as Virginia-type cultivars suitable for the region. These lines are compared with the current commercial cultivars, ‘Bailey’, ‘Sugg’, ‘Sullivan’, ‘Wynne’, and ‘Emery’ for yield and quality throughout the production region in Virginia, North Carolina and South Carolina. The 2016 report with the agronomic and grade PVQE data is available here :http: //pubs.ext.vt.edu/AREC/AREC-198/AREC-198.html. A summary of the 2014-2016 agronomic and grade performance is presented in the table below. In average of 3 years and five locations each year, ‘Bailey’ produced 4,477 pounds per acre and the crop value was 776 dollars per acre. Some of the new lines, however, significantly exceeded ‘Bailey’ for both pod yield and crop value; lines N11028ol and N12008CLSmT in particular. Unlike ‘Bailey’, which has normal oil chemistry, all the breeding lines tested recently in the PVQE program are high oleic. This means they have over 75% of their oil content made of oleic fatty acid; and this characteristic extends the freshness and shelf life of the peanuts from 4 to 32 weeks.

Summary of peanut 2014-2016 results

Summary of peanut 2014-2016 results

Peanut maturity progress in Suffolk, VA

The peanut maturity progress from Sep 2nd and until now seems to be optimal. Images taken on Sep 2nd and Sep 12 for ‘Bailey’ (Bailey peanut maturity progress in Suffolk), and ‘Sullivan’ and ‘Wynne’ (Sullivan and Wynne peanut maturity progress in Suffolk) peanut cultivars are presented here. Bailey, regardless when was planted May 2nd or June 4th, seems to be ready to dig in 10 to 15 more days. In the past 10 days, Sullivan shows a substantial increase of black and brown pod content, however the pod color spread is highest for this cultivar. This suggests that Sullivan may have two main crops this year, which is not surprising given the drought stress experienced for most part of August. This situation always makes digging decisions difficult, but we will continue to watch the maturity progress for this cultivar and extend the search to other locations than Suffolk. None the less, location and individual field conditions have significant effects on maturity. Under the conditions of 2016, Wynne is behind Bailey and Sullivan maturity wise. The images of podblasted pods suggest that digging for Wynne is expected in 20 to 25 days from Sep 12.  Again,  determining maturity in each field individually is the best method for farmers to determine the optimum digging time. Podblasting clinics, such as the one on Sep 19 planned by the new Extension Agent in Southampton County VA, Ms. Livvy Preisser <livvy16@vt.edu>, should be attended rigorously by peanut growing farmers.

Heat Units (HU) accumulation and predicted vs. observed optimum maturity in Suffolk, VA

September began and farmers may start planning for harvest. With peanut this is not an easy task. Days from planting and HU accumulation are usually used to determine a general harvest time; but fine tuning optimum maturity for individual cultivars, planting dates, and fields is absolutely necessary to minimize yield loss that may result from either rushed or delayed digging.  The table below shows the predicted digging dates based on HU from planting through end of August for Suffolk, VA, and comments on their suitability for estimating actual maturity (Digging Peanut in Virginia-Bailey) (Peanut maturity in VA), which was determined through pod blasting on Sep 2nd.

Based on observed maturity at this time, using solely HU accumulation may result in rushed digging this year.

Planting date HU accumulated through Aug. 31 Predicted days remaining Predicted date Predicted vs. observed maturity
15-May 2324 12 12-Sep Observed maturation through pod blasting shows later maturation than predicted by at least a week for all planting dates
25-May 2271 14 14-Sep
5-June 2058 24 24-Sep

Estimates are based on 2590 GDD required for Bailey to reach optimum maturity and a 22 daily average GDD from Sep 1 through Sep 24.

We will continue to update farmers on peanut maturity in SE Virginia, and encourage Extension Agents to organize pod blasting clinics by mid-Sep in every county.

Nodulation deficiency in peanut

Indeed, 2016 was not a good year for effective nodulation and early peanut root growth in the Virginia and Carolina region. The growing season started relatively cool and wet. Under this condition peanut developed only a few roots with a reduced number of nodules. These plants were smaller and less green than “normal” plants in particular when planted in crop residue because this maintained soil cooler and wetter. Figure 1 is an example and shows three peanut plants planted on May 9 and picture was taken on June 25. Two plants at the left are smaller, yellower, and with less root growth and number of nodules. These were planted in sorghum residue. The plant at the right is bigger, greener, and has more roots and nodules, but was planted in cultivated and sandier land.

Smaller and yellower two plants at the left are due to poorer nodulation than for plant at the right, even though planted at the same time.

Smaller and yellower two plants at the left are due to poorer nodulation than for plant at the right, even though planted at the same time.

What can be done to prevent poor nodulation, then? One very important thing is to inoculate at planting. But even then, in cool and wet soil roots grow slow for fast inoculation and Bradyrhizobium bacteria may die in absence of oxygen if the soil is too wet. Ammonium sulfate can be used up to 150 pounds of nitrogen per acre, which is about 714 pounds of ammonium sulfate per acre. Usually at beginning flowering poor nodulation will show up in yellow and smaller plants, and right then inorganic nitrogen needs to be applied. The sooner, the better.

It is, therefore, important to scout not just for disease and insects but also for the number and size of the nodules in the first 45 days after planting. To establish a threshold of nodules a farmer should look for during this time, my program has found that after two weeks after planting an average number of 5 big nodules on the main root is to be expected; at 30 days, 70 nodules of any size on the main and lateral roots; and about 130 at 45 days after planting.