Following last year’s dry and early harvest, I stated that our one crop of commercial soya beans was not yet field-ready. This season has provided a stiffer test but there is unquestionably more potential in the crops.

This year, Quinns of Baltinglass planted about 40 acres of soya beans for commercial production. This is two separate crops and the growers have different end uses planned. While combining of the seeds is the main objective, one of the crops this year is destined for whole-crop silage on a dairy farm.

David Shortall of Quinns showing the height of a soya plant earlier this week. The bottom of the lowest pods on these plants were five to six inches above soil level this year.

Whole crop soya

David Shortall of Quinns told me that research (not Irish) indicates that if the crop is harvested for silage before the oldest pods begin to turn yellow, there should be no major anti-nutritional factors evident in the silage to hit performance. But harvesting after this stage could result in inhibited animal performance. At this point the bulk of the foliage will still be green but there will be some leaves senescing at the base of the crop due to lack of light penetration.

Protein content in mature soya beans will tend to be 34-36% but in soya silage the protein content of the whole crop will be closer to 18-20% crude protein. This silage needs careful analysis post harvest and there also needs to be close examination of cow performance to check if the silage is delivering what it promises.

The pale colour of the new foliage indicates the appearance of a recent deficiency of either magnesium or manganese. The veins remain green but the interveinal areas are pale to yellow in colour. Some older lower leaves show a healthy dark green colour.

Mature soya beans

The crop destined for combining (with late September/early October the likely harvest date) was very interesting and different to last year.

Firstly it will be later maturing. In mid-August the lower pods are really only beginning to fill. The crop was slower for much of the year in the colder conditions and really only took off in the past few weeks. There are also numerous pods on the top of the canopy that can contribute to yield but these will need to do a lot of growing in the next two to three weeks. These did not exist on last year’s crop.

Perhaps the most interesting point is the location of the lowest pods. As the pods hang downwards it is very easy for a lot of the beans to be beneath the blade and lost. This year the majority of the lowest pods seem to be higher up on the stem, which should give the combine blade a better chance to get beneath them, so less losses. The second point is that there seem to be fewer pods on the lowest whorl, or bunch of pods, so there would be less left behind even where the combine blade is high. See harvest report last year.

This soya crop looked well this week and seems to have good potential if all the upper pods survive to fill seeds. There were two varieties in the field but there was little difference in their current state of development.

A big whorl of pods that went beneath the blade when harvesting the crop last year. There seem to be fewer pods lower down this year.

High density – taller crop

Three different seeding rates were used in the crop – 55, 60 and 65 plants/m2. The higher densities produced a taller and denser canopy, which was very obvious as we walked through it. So far there are no disease issues but higher density and taller foliage provide a humid canopy in this broken weather. And while the crop does have a wiry central stem, David tells me that bits of the second crop have lodged with the heavy recent showers.

One other interesting feature was the yellow appearance of the top of the crop. It would seem like the crop has just begun to show either magnesium or manganese deficiency, more likely the former, I think. With flowering just about finished and pod fill under way, it might still be useful and beneficial to treat the crop to boost chlorophyll levels to drive photosynthesis for pod fill.