By Bill Cox and Eric Sandsted
Soil and Crop Sciences Section – School of Integrated Plant Science, Cornell University
High input wheat, which is characterized by high seeding rates, herbicide application in the fall, split-application of N in the spring resulting in higher total N rates, and a timely spring fungicide application(s) was introduced to New York in the 1980s. Known as intensive management of wheat in the 1980s, it was modeled after European wheat management systems, where yields were often twice that of NY wheat yields. As in the 2000s, consultants or farmers from other countries or regions came to NY to share with NY farmers and industry how they grew wheat. We conducted in-depth studies at the Aurora Farm in the 1980s and reported that yields were increased (10-15%) in 3 years but limited in response (2-5%) in 2 other years. More importantly, we found that intensive management of wheat did not pencil out unless prices exceeded ~$3.75/bushel, relatively high prices back in the 1980s. Wheat prices in NY plummeted to $2.80/bushel in 1985 and $2.25/bushel in 1986, which abruptly ended the push to adopt intensive management of wheat in NY until the 2000s.
Wheat prices in NY averaged ~$2.80/bushel in 2003 and 2004 and increased to $3.35 in 2005 and $4.00/bushel in 2006 so high input wheat management was hardly mentioned in NY. Once prices skyrocketed to $6.95/bushel in NY in 2007 and averaged $6.50/bushel from 2008-2013, high input wheat management became the mantra for wheat production in NY. In addition, wheat yields in NY also increased significantly averaging 64 bushels/acre from 2008-2013 compared with 55 bushels/acre from 2002-2007. Consequently, some growers believed that high input management was solely responsible for the high wheat yields, despite the introduction of newer high-yielding varieties and favorable weather conditions for high wheat yields. Wheat prices have plummeted over the last year with NY growers now receiving less than $4.00/bushel for their wheat. The question that once again arises, as it did in the mid-1980s, “does high input wheat pencil out, if wheat prices remain at $4.00/bushel or lower”?
We compared high input and recommended input management in conventional (and organic) wheat at the Aurora Research Farm in 2016, a year characterized by very dry conditions from March through June (6.52 inches total). This article will focus exclusively on comparing high and recommended input wheat in conventional management. Management inputs were detailed in another article in this issue (https://blogs.cornell.edu/whatscroppingup/2016/09/26/organic-wheat-looked-great-but-yielded-7-5-less-than-conventional-wheat-in-20152016/). Briefly, high input wheat was seeded at 1.6M seeds/acre, received an herbicide application (Harmony extra) in the fall, a split-application of N in the spring (~45 lbs. /acre of actual N at green-up and another ~45 lbs. /acre of actual N at the end of the tillering period in late April) and a timely fungicide application (Prosaro) at the end of May, just before anthesis. In contrast, recommended input wheat was seeded at 1.2M seeds/acre and received a single 60 lb. /acre application of actual N at green-up in late March.
We sub-sampled 1.52 m2 areas (8 rows by 1 meter) in two locations of all wheat plots to determine yield components of all treatments on July 5, the day before harvest. The sub-samples were first weighed, and then the spikes were counted. The spikes were then threshed so all the kernels (~20,000 kernels/sample) could be counted with a seed counter before being weighed. From the sub-sample data, we determined spikes/m2, kernels/spike, kernel weight, and harvest index (grain yield/total dry matter yield) of all the treatments.
Surprisingly, there was no response at all to high input wheat on the doughtiest soil at the Aurora Research Farm in the dry 2016 growing season (Table 1). Although we planted on September 24 and the warm fall and winter allowed the wheat to break dormancy in mid-March in excellent condition, yields were lower than expected. Apparently, the dry conditions from March through June and relatively droughty soils contributed to the somewhat disappointing yield.
Spike number at harvest, the typical ~500 spikes/m2 in NY wheat, did not differ between high and recommended input treatments (Table 1), despite the higher seeding rate and resultant higher plant density of the high input treatment (https://blogs.cornell.edu/whatscroppingup/2016/09/26/organic-wheat-looked-great-but-yielded-7-5-less-than-conventional-wheat-in-20152016/). Evidently, the 60 lb. /acre N rate at green-up stimulated tillering of the recommended input treatment, negating the potential lower spike density associated with the lower plant density. Likewise, kernel number/spike (~25/spike) and kernel weight (~320 mg) did not differ between the high and recommended input treatments (Tables 1 and 2). Kernels/spike and kernel weight were exceedingly low in this study compared with the typical 35-40 kernels/spike and 350-400 mg kernel weight for wheat produced in NY. Apparently, the lack of rainfall, especially in June (0.74 inches), coupled with the somewhat droughty soil, resulted in limited kernel set and/or retention as well as low kernel weight. The dry conditions also contributed to the low but similar harvest index values of ~0.40 for both treatments (Table 2).
In conclusion, wheat did not respond to high inputs on this somewhat droughty soil in Cayuga Co. If growers practiced high input instead of recommended input management with similar yield results, net returns would have much, much lower (higher seeding rate, three additional trips through the field for herbicide, a split-N, and fungicide applications, and the added cost of herbicide, additional N, and fungicide). Again, the dry conditions undoubtedly minimized leaching or denitrification of the single N application in late March and disease pressure throughout the spring cancelling out a response to those additional inputs. Also, yield responses to high input wheat seem to be more prevalent in western NY where growing conditions are more similar to SW Ontario and Michigan where growers have had excellent results with this management system. In central NY, I have found the responses to be more variable.
So, if you are a grower who is averse to having yields lowered because of potential stand loss due to harsh winter conditions, potential weed problems, potential loss of N from a single application at green-up, or potential yield losses from spring diseases, I would suggest using high input management at all times. On the other hand, if you are a grower who is risk averse to spending $ on inputs where there is not a guarantee of an economical return, I would recommend managing the crop according to the growing season and field conditions. If winter annuals or perennial weeds are present in the fall, herbicide application is warranted. But if weed pressure is low in November, the competitive nature of the wheat crop will probably keep weed densities relatively low in the spring. Likewise, if April conditions are wet, it would be prudent to apply additional N in late April, even with a single 60 lb. /acre application in March. But certainly in years with dry March and April conditions, such as in 2016, additional N would not be needed, especially on soils that are not excessively or somewhat poorly drained. Finally, if wet conditions persist before anthesis and are predicted to remain wet during and shortly after anthesis, a timely fungicide application is certainly the best management practice. But if dry conditions have prevailed and are forecasted to remain dry, a fungicide application may not be warranted. Wheat is currently selling for less than $4.00/bushel in NY so wheat growers should factor that into their management inputs.