Wonders of Wheat: Tidbits About Spring Wheat Yields

By Ed Vasey, “Spring Wheat Doctor”
Professor Emeritus, NDSU Department of Soil Science

In 2003, a winter wheat management system very much like the “more efficient yield” of spring wheat management concept was introduced into the region’s spring wheat area. It was advertised as Intensive Spring Wheat Management, but data presented was for winter wheat. Interest by spring wheat producers in using a refined management system was evident based on numbers attending seminars and acreage sign-up. Interest was influenced by advertising that lead one to believe the approach could produce 100-bushels-per-acre or better yields of spring wheat, which it did in 2003.

It is my opinion that 2003 in spring wheat country fit conventional more-efficient-yield, intensive, profitable or just about any good management system very well. The season started out bleak because surface soils were dry. Stored soil water from fall and over-winter precipitation was fair to good in some areas of the state.

Timely, above-average rainfall and cool temperatures in April and May (5 - 6 inches based on data from the North Dakota Agricultural Weather Network (NDAWN)) improved yield expectations in much of the spring wheat region. This meant more nitrogen was likely going to be needed.

Rainfall in late May and in June (6-7 inches) was above average and assured top-dressed nitrogen was moved into the soil so it could be taken up by the plants. July rainfall was mainly below normal, thus scab was not a major problem. I recall two other seasons where similar climatic patterns occurred. The were 1985 and 1992, years where 80-bushel-per-acre yields or higher of spring wheat were common. My interest in more efficient yield began in 1982.

In 2003, I looked at conventionally grown spring wheat as early as the sixth leaf stage (about 30 days after planting) with potential yield of 80 bushels or more per acre. Based on spikelet (head) exams, I calculated potential yields of up to 100 bushels per acre. Some heads filled eight rows rather than the more common six rows, thus yield went up.

Producers need to remember we are in a semi-arid climate with 12 to 15 inches of rainfall in our 90- to 100-day growing season for wheat, not 30 to 35 inches of rainfall during an eight-month growing period. Spring wheat here goes through 20 stages of growth in 90 to 100 days. This results in a new segment of development taking place every four and a half days. Many years we will not receive the timely rainfall needed to improve yield outlooks or give efficient utilization of post-applied nitrogen as occurred in 2003.

Under our conditions, reduction of nitrogen application rates before or at seeding would be very harmful to potential spring wheat yields when this occurs. Producers and agribusiness firms need to carefully evaluate yield data reported in 2003 spring wheat trials. It is one-year data obtained under very good growing conditions – the best I have seen in 50 years. Keep in mind the season allowed early planting with very timely rainfall in much of the state. NDAWN data showed temperatures during early stages of wheat growth were cooler than normal by 5 to 10 degrees. This resulted in the production of more kernels per head and increased yields by 20 to 25 bushels per acre.

One-year comparisons of conventional to intensive management where five to six additional inputs are used do not tell what input produced the response. Economics of these inputs must be considered. In some cases, 15 to 20 bushels per acre at $3 per bushel would be needed to cover additional input costs. NDSU Research Extension Centers collected data in 2003 to help ascertain the influence of different inputs. Inputs alone and in combinations are being researched.

My feedback system says in 2003 method of nitrogen application did not have significant effect on yield in these trials. Similar results were reported by Minnesota researchers at the recent Minnesota Association of Wheat Growers meeting in Grand Forks.

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Ed Vasey was NDSU Extension Service soils specialist from 1967 to 1992. He specialized in refined input management strategies for spring wheat from 1983 to 1992. In 1992 he published a manual on more efficient yield of spring wheat. Since retiring in 1992 he has worked as a private consultant known as the “Spring Wheat Doctor.” He feels major yield limiting factors during the 1990's were the after-effects of the drought of 1988-1991, emphasis on LISA (low-input sustainable agriculture), and excess water contributing to scab from 1992 to 2002.

Source: Ed Vasey, (701) 232-8439
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu