Beans: March is still a good time to sow

The time of sowing beans is always a hot topic of conversation.

Many farmers think twice about planting in April, while others drill away. The decision is often dependent on the area of the country you’re in or the type of soil on your farm.

Data from seed crops

Seedtech has compiled some data from seed crops which were grown for the company across the country over the past four years – 2016 to 2019.

Data was available from 51 crops. In the graph below the date of sowing is shown as well as the yield shown as a percentage of the average yield for each season (relative yield).

It should be noted that these crops were not planted in a trial situation and were all grown on different soil types and were managed differently.

What did the data show?

A large number of the crops were planted in the middle to the end of March and many of these yielded close to the average yield.

An important observation is that beans drilled in February did not always yield highest and April drilled beans did not always yield lowest.

The graph below shows that there is a wide window available to drill beans. However, beans drilled in from mid-April on are less likely to yield as well as those planted earlier.

The mix in results also shows what farmers know too well – that there are other factors, apart from drilling date, which will affect crop yield.

Data source: Seedtech

The wide window available to sow beans means that farmers who have seed still have plenty of time to plant. This will also add value to a following cereal crop – adding to potential yield and giving the possibility of planting a seed crop for example. The protein payment will also add to income at the end of the season.

Planting and seed rate

Beans planted in March can expect an establishment rate of 85% – the target plant population at this time of year should be 30 plants/m².

Crops which are planted in April can expect a higher establishment percentage at 95% and a target plant population of 35 plants/m².

Calculating seed rate is carried out as it is for a cereal crop. Farmers must have the target plant population; the estimated establishment percentage and the thousand seed weight (TSW).

For example, a TSW of 500 with a target plant population of 30 plants/m² and an establishment rate of 85% will give a seed rate of 176kg/ha.