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Spring Survey to Focus on Plant Spacing Issue

Monday, April 1, 2013
filed under: Research and Development

Many production issues, like diseases and insects, can be examined under a microscope or studied in a research plot. But some simply cannot be solved in a lab. Nothing compares to “real life” data from the growers’ fields to get to the bottom of a problem — especially one that is reoccurring.

Every autumn for the last 12 years (with the exception of 2004), the National Sunflower Association has conducted in-depth surveys in producers’ fields throughout the main sunflower growing regions of the United States, as well as in Manitoba, Canada.

The data generated by the fall survey can be used by producers to make better management decisions. The information is also providing trends over time, which is used to help define research priorities in improving sunflower crop production and the bottom line for producers.

Examining Plant Spacing

Irregular plant spacing within a row has consistently ranked as either the top or second yield-limiting factor since the first survey was conducted in 2001. In an effort to capture this elusive piece to the sunflower puzzle, a spring survey will be conducted for the first time during the 2013 season. The main objective is to put this one aspect of plant stand into focus.

Why can’t this be accomplished by the fall survey? “The fall survey only shows the final stand at the end of the season,” explains Hans Kandel, extension agronomist with North Dakota State University. “We do not know exactly why there are gaps. Was it due to poor planting? Poor emergence? Disease or insects? Following the crop from start to finish hopefully will answer these questions at the end of the growing season.”

Why is plant stand such a critical aspect of sunflower production? The plant spacing difficulties consist of either a skip within the row or areas where plants grow too close together, causing one or more of the plants not to contribute to the sunflower yield. Equal distribution of plants is essential to obtaining the maximum yield.

It’s a difficult puzzle to solve because there are many factors that could be the cause. But it’s certainly worth a closer look, because it robs growers of yield every season. It is estimated that plants emerging at different stages for several weeks with multiple skips and doubles can decrease yields by more than 500 lbs/ac.

Irregular plant spacing in the row may have been caused by poor seeding conditions, failure to adjust the planter, driving too fast, poor germination, disease, insect damage or other factors. Based on the data collected and surveyor observations in 2012, Kandel estimates the average yield of 28 fields with plant distribution issues was 1,678 lbs/ac, compared to 21 fields with no stand problem or other problems yielding an average of 2,158 lbs/ac.

Producers know the need to pay special attention to their management and refine their technique while seeding sunflower. Planter calibration may be the first step to reducing skips and getting better plant spacing within the row. But some factors regarding plant stand go unaddressed or are simply beyond growers’ control. That’s where the survey data will come into play.

Survey Procedure

The spring survey will be different from that conducted in the fall — but yet similar in many ways in order to provide a starting point. Max Dietrich, oilseeds agronomist with Pioneer and organizer of the spring survey effort, says the idea came about during last fall’s research planning meeting.

“The NSA Research Committee meets in the fall to determine priorities for the next year’s project proposals based on the findings from the fall survey,” Dietrich explains. “The question on plant spacing keeps coming up year after year, and we simply don’t have the answer. The fall survey isn’t really geared toward finding a solution to problems that occur very early in the growing season.”

So Dietrich went to work on devising a plan to survey fields shortly after planting. The objectives and procedures put forth are much more detailed than the fall survey because of the goal of trying to pinpoint one particular aspect. The fall survey is designed to give a broader overview of possible yield-limiting factors.

Surveyors will be looking at 20 oil sunflower fields and 10 confection fields in North Dakota, South Dakota and Minnesota. Thirty separate growers will participate.

Dietrich will be conducting many of the oil sunflower field surveys himself and enlisting the help of confection company crop scouts for additional data. First, a surveyor will identify a sunflower grower who seeded his field with a planter. An interview will be conducted with the grower to get details on management, such as planting date, hybrid, seeding rate, previous crop, tillage practices, as well as fertilizer and herbicide application timing and rates.

The survey will also include estimation of plant stand, evaluation of plant spacing and seeding depth, evaluation of insect, rodent or bird damage, as well as disease presence and impact. Environmental factors will also be recorded, such as soil crusting and moisture conditions.

To obtain this information, the surveyor will venture into the field to evaluate the situation. “Surveyors will mark their entry point with flags in order to designate the same area to be evaluated in the fall,” Dietrich says. “We’re looking at conducting the survey from about June 24 through July 6. We want to time it just right in order to be able to see what might have happened in the cases of skips or poor stand.”

Surveyors will enter the field and go approximately 100 feet for the first evaluation; then go approximately 50 more feet and do the same evaluation a second time. Two rows of 25 feet will be sectioned off. In that area, surveyors are asked to record the total number of plants in both rows, keeping a close watch for doubles (plants four inches or closer) or skips (18 inches or more between plants). Skips will be evaluated for diseases, insects, birds or rodent activity. Surveyors will also dig up the furrow to attempt to diagnose the problem of the seed, such as seeding depth, germination, disease, insect, etc.

“After this is all said and done, we may actually come up with more questions than answers,” Dietrich points out. “But at least we will know what direction to turn by those questions. Growers know they can expect to lose 10% of their seeds to planting issues or environmental factors; but why are we seeing the fall survey report 20% or more being lost and not contributing to yield? These are things we need to address, clearly.”

Surveyors will also evaluate standing plants by taking a look at five consecutive plants. They will measure seed depth and count leaves on plants that are two inches or longer.

“If we look at five plants and one has two leaves and the one next to it has six, we have to ask what went wrong,” Dietrich notes. “As seed guys, we need to be looking back at our hybrids and make sure they are doing what they are set out to do.”

In a similar fashion as the fall survey, data collected will be sent to Kandel at NDSU. These same fields will be included in the fall survey to compare spring and fall observations. Results the first year will likely determine if the spring survey will be conducted for more than one year.

Dietrich set out to design the spring survey that will serve to provide answers to the reoccurring questions generated by the fall survey about poor plant stand. He suspects that will be accomplished to some degree — and hopefully serve as a catalyst for more research leading to real solutions.

— Sonia Mullally
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