The benefits of a pre-harvest field walk
A pre-harvest field walk can help identify a number of factors, which can be used to boost future crop management standards.
This is according to Teagasc tillage specialist, Ciaran Collins.
He explained: “Many people say that the combine is the ultimate judge of crop performance, and it is difficult to argue with that.
“Once the grain passes over the weighbridge, the season’s successes and disappointments are measured in tonnes.
“However, by the time the combine enters the field, many of the opportunities to understand why a crop performed as it did have already been missed.”
The period between now and the start of harvest is one of the most valuable times of the year for assessing crops.
It is an opportunity to evaluate everything from establishment and variety choice to nutrition, disease control and weed management.
The aim is simple, identify what worked, what did not, and use that knowledge to improve crop performance and profitability next season.
Assessing crops
Crop production is an expensive business, with little room for unnecessary costs or lost yield. Small improvements in agronomy often add up to significant gains in profit.
While winter barley is now approaching harvest and there is relatively little that can be taken from it, most other crops still have much to teach us before the combines arrive.
“One of the first things to assess is crop establishment," Collins said.
“Simply asking whether a crop is thin or thick, or carrying out a few shoot counts, can provide valuable information.
“Were target plant populations achieved? Did establishment suffer because of seedbed conditions, drilling date or pest damage?
“These observations are easily forgotten once harvest begins but can influence drilling decisions for years to come.”
This season, Barley Yellow Dwarf Virus (BYDV) has been one of the major talking points, particularly in winter wheat and spring barley.
Pre-harvest is an ideal time to assess its true impact. Factors to look out for include patches of stunted or uneven crop.
The appearance of impacted grain in affected patches is also important. But most importantly, once the combine passes through these areas, what is the yield penalty?
“These are the observations that help refine future BYDV management strategies,” said Collins.
Crop varieties
Variety choice is another area where there is always something new to learn.
New varieties continue to enter the market, while the strengths and weaknesses of existing varieties become clearer each season.
Visiting cereal variety trials is an excellent way to compare performance, but there is no substitute for evaluating varieties under the conditions on your own farm.
This year has highlighted some clear varietal differences.
The warm, humid conditions during flowering have increased the risk of fusarium infection in winter wheat, particularly in the south. Yellow rust has also been a significant challenge in many crops.
Comparing how different varieties have performed against these diseases, or against septoria where that is the greater threat, can provide invaluable guidance when selecting varieties for next season.
Disease control
Disease control programmes also deserve scrutiny.
Rhynchosporium and net blotch were more prevalent than many expected in spring barley this year. These issues give rise to a number of important questions.
Which fields remained greener for longer? Did fungicide programmes provide the expected level of protection? If disease broke through, was it due to product choice, application timing, rate or simply disease pressure exceeding expectations?
Standing in a crop, pre-harvest, often provides answers that are impossible to see once the field has been cut.
Nutrition is another area where a short walk can uncover valuable information, according to Collins.
"Weak patches are often easy to spot at this stage. The important question is why they occurred.
“Is the problem nutritional, or is it related to soil structure, drainage or compaction? A quick inspection with a spade can reveal restricted rooting, poor soil structure or other underlying issues.
“Similarly, where trace element deficiencies occurred earlier in the season, now is the time to ask whether corrective measures were successful or whether a different approach is needed next year," Collins said.
