The uneven distribution of rainfall throughout the growing season means excellent crops for some, and poor crops for others.

The first week in September marked Penn State Extension’s third annual Crop Conditions Tour. The event, sponsored by the Pennsylvania Soybean Board, is an opportunity to take a snapshot of growing conditions across the state and offer some basic insights for the 2020 growing season. Extension educators surveyed over 120 corn and soybean fields for this year’s tour, covering 26 counties that account for over two-thirds of the state’s corn and soybean production. Last year, I noted that statewide crop conditions were somewhat consistent across the state. For 2020, things were everything but consistent, and in some cases, consistency was hard to find within a single field.

Warmer Than Average, Variable Precipitation

While 2020 started off with cool temps in April and May, the summer’s heat and sunshine helped most crops catch up. Nearly all fields accumulated growing degree days (GDDs) at or slightly above 10-year averages, when measuring from their respective planting dates. A notable exception are counties in the Northern Tier, such as Bradford, where sites accumulated GDDs well over their 10-year average, with some reporting the most GDDs on record, measured from mid-May planting dates. Much of this came later in the growing season but still likely pushed along crop maturity.

Rainfall was a clear case of those with and those without. The western half of the state was dry throughout the summer with some places receiving less than 10 inches of rain since the middle of May, which is less than half of the 10-year average. Meanwhile, areas southeast and east of Harrisburg received over 20 inches of rain, which is much closer to or above their 10-year averages. Additionally, areas along the Pennsylvania-Maryland line received some additional moisture.

In regions that had large amounts of rain, it was still an issue of timing and locality. Spotty showers persisted across many counties all summer, having an obvious effect on crop condition. Many areas that finally got rain got much of it at once at the end of the growing season, with over 4 inches of rain recorded in some areas over just a few days. Unfortunately, some of our later rains likely had little effect on declining summer crops.

Corn Conditions and Outlook

This year’s corn crop was off with a slow start, as cool weather from April through the early part of May slowed planting and emergence. The planting window across the state spanned nearly two months, with fields planted into the end of May (Figure 1). Due to the slow start, fields planted toward the latter half of the spring somewhat caught up with early planted ones. Most fields surveyed were between dough (R4) and dent (R5), with fields in the Northern Tier and on the Allegheny Plateau a little behind the warmer parts of the state. Unfortunately, with cooling temperatures in those regions come slower maturity and drydown; hopefully those areas will reach black layer before frost.

This year’s corn crop greatly reflects the disparity in rainfall. Fields in the southeastern part of the state fared the best in terms of condition and potential yield, and early estimates of yield are similar to those of last year. At the other end of the state were fair to poor crop conditions. Poor pollination was common across much of the western, central and northern parts of the state, reflecting moisture stress at those time. Late season drought stress was also shown in small kernel sizes, noted in Blair and Centre counties. Issues appeared earlier in the year too, resulting in short plants and stalks that did not set an ear. In some fields, ears were low on the plant or variable across the field due to short internode length from early season drought stress.

Soils played a big part in the success and failure of crop conditions in the western and central parts of the state. Essentially, those areas saw a reversal of 2019, with low lying and typically wet areas producing a good crop and dry areas resulting in poor crop conditions. Those two conditions could even be seen in the same field.

The dry weather across the western, northern and central parts of state combined with periods of dry between rain events in the southeast resulted in relatively low disease pressure for the 2020 corn crop. The late season diseases of gray leaf spot and northern corn leaf blight were present, as always. The other issue worth noting was lodged corn, with some attributed to stalk diseases and some likely due to localized weather conditions. Another common issue identified this year was red kernel streak, which may be a problem for those wanting to get certain premiums. Otherwise, it does not affect the nutritional value of corn. Corn earworms were spotty as usual, with few other major insect issues noted. Grassy weeds, such as foxtail, were one of the more frequently noted field issues.

Crop condition varied greatly based on where you were this year. In northern Pennsylvania, yield estimates of fields ranged from 83 to over 200 bushels per acre. with an average of 124 (Table 1). In the central and southcentral parts of the state, yield estimates ranged from 52 in the extremely droughty Centre County, to over 225 bushels per acre in the eastern portion of the region. An average for the area is 140 bushels per acre. In the west, yield estimates of surveyed fields fell into the 89 to 207 bushels per acre range, with an average of around 145. In the southeast, estimates of yields ranged from 133 to 255 bushels per acre, with an average of 182 bushels. Based on all surveyed fields, the average yield was approximately 153 bushels per acre, down approximately 20 bushels from last year’s Crop Conditions Tour estimate, and close to the 2019 USDA end-of-year estimate. Our estimates have tracked slightly higher than USDA, and I expect this year’s numbers to be an overestimate as well. However, a decent statewide average corn yield is still possible, as our corn production is so heavily weighted to the southeast.

Resilient Soybeans

The challenging weather across the state highlighted the adaptability of soybeans to less than ideal conditions. In most cases where corn was a near failure, a respectable soybean crop was still possible. For most of the fields surveyed, planting dates were in late April and into May. Maturity was spaced a little wider than this time last year, with fields between beginning seed (R5) and beginning maturity (R7). Like with corn, the condition of the soybean crop was best in the southeastern portion of the state. Elsewhere, plants were shorter than usual, and some fields did not achieve canopy closure on 30 inch rows. Pod abortion was noted, and some fields had some localized premature leaf drop due to dry conditions. However, plants still produced an adequate number of pods in many cases.

Soybean diseases were not much of a problem throughout the growing season, due in part to dry conditions. Frogeye leaf spot began to appear later in the season, and its presence varied by location. Septoria brown spot also varied by location, with some fields having very little of the pathogen late into the year. Steam diseases began to appear late in the season and were noted on the tour, including stem canker and charcoal rot, a rarely seen disease in Pennsylvania. White mold was mostly absent across surveyed fields. However, with dry weather came insect pests, and this year saw damage from spider mites, grasshoppers, stink bugs and beetles. Even the rarely damaging silver spotted skipper was abundant in some fields. Deer damage was more apparent in fields this year as well, as under the dry conditions, fields were much slower to recover.

While soybean yields can be estimated, such as with the 1/10,000 acre method, we found mixed results with the method. For 2020, we have moved to a simpler estimate of pods per acre (Table 2). While this does not provide an estimate in bushels, it does offer relative comparisons between regions and from year to year. Pod counts mostly reflect our weather this year, with areas in the southeast faring better than the western, northern and central areas of the state. Our overall assessment of stand conditions reflects those counts, with most fields rated as average. The exception lies in the southeast where they were rated slightly higher, as above average. For 2019, USDA estimated a statewide average of 49 bushels per acre. With this year’s less than ideal conditions across the state, we expect 2020’s average yield to be less.

A Hard Year to Assess

The year 2020 will be remembered for lots of challenging issues, and for some a difficult growing season will be added to that list. How this season will ultimately look in terms of statewide yields is quite hard to tell due to the inconsistency of this year’s weather and the swings in crop condition between, and even within, counties. This is likely the year where individual fields or areas within a county could look quite different than what we saw during the tour. As farmers across the state begin to harvest corn and soybeans, we will be quite interested in what some of those numbers really are. We hope for everybody that they are a least a bit better than expected.

The 2020 Pennsylvania Crop Conditions Tour was a great success that provided everyone involved with some interesting insights on our corn and soybean crop. I would like to thank the Pennsylvania Soybean Board for their support and all the educators who bore the burden of collecting data without (unfortunately) the help of our industry, government and nonprofit partners. We hope that next year is one where we can all come together as a group again.

Those who helped with this year’s tour include Adrianna Murillo-Williams, Andrew Frankenfield, Anna Busch, Brittany Clark, Casey Guindon, Del Voight, Dwane Miller, Heidi Reed, Jeff Graybill, Justin Brackenrich, Leanna Duppstadt, Leon Ressler, Liz Bosak and Nicole Santangelo.

Zach Larson is a field and forage crops educator with Penn State Extension.