Direct Drilling Demo Day sowing areas in the spring: emergence, growth stages and NDVI

The aim of eAgronom’s Direct Drilling Demo Day held on 6th of September was to introduce and compare different seeders that can be used for direct drilling. In total, 15 different drills and an agridrone participated in our first ever demo day.

Direct drilling is one of the main principles of regenerative agriculture. It is also an economically sustainable practice that allows farmers to reduce production costs. Direct drilling contributes to many benefits like soil aggregation, water retention, earthworm abundance and also reduces risk of soil erosion, nutrient leaching, CO2 emissions and fuel consumption per hectare.

eAgronom’s comparison of different direct drills is taking place in Tartu county near town of Elva on a land owned by Rannu Seeme OÜ. The pre-crop on that field was winter oilseed rape with a yield of 3.4 t/ha and soil type there is light sandy loam.

Previous tasks conducted on the field

Before sowing, the whole area was sprayed with glyphosate and harrowed with a Horsch Cultro straw harrow. We also left a part - a stripe across the field - where the harrow wasn’t used. NPK 10-26-26 fertilizer was also applied at a rate of 150 kg/ha. 

On the Direct Drilling Demo Day, winter wheat 'Julie' was sown at the rate of 140 kg/ha. Participating drills also added an extra 50 kg/ha of NPK 10-26-26 fertiliser to the seedbed. Seedbed fertiliser was not used with John Deere as it is not a combi drill.

In the autumn, the field was further treated with the herbicides Legacy Pro (2 l/ha) and Trimmer 500 WG (20 g/ha). In spring, the field was fertilised with ammonium nitrate (33.5%) with a rate of 250 kg/ha and treated with the herbicides Calibre (22,5 g/ha) and Primus (0,08 g/ha) and growth regulator Stabilan (0,8 l/ha) at the growth stage 28.

eAgronom’s Direct Drilling Demo Day in 2023.

Tillering and growth stages

Tillering and growth stages were determined on 24th of April. At that time, all of the plants had reached the growth stage of 30 in all areas. The variety that was sown is generally good at tillering - this is confirmed by the number of tillers counted in the field. 

Amazone and Horizon had the highest number of tillers per plant and agridrone the lowest. In the case of Agridrone, the lower number of tillers was somewhat expected as the area was cultivated after the sowing in order to establish better seed to soil contact. This, in turn, led to deeper seed insertion which resulted in lower tillering.

Determination of growth stages on 24th of April.

NDVI i.e. normalised difference vegetation index

In addition to the counting of the tillers and determination of the growth stages, we also obtained NDVI (Normalized Difference Vegetation Index) images that help us to better distinguish the differences between sowing areas. Images were taken with the help of Agro Droon OÜ on 17th of April.

NDVI image (click here for a larger one and here for a video playing through the areas one by one).

The images show that the Horsch Sprinter, Weaving GD300M, Kverneland U-drill and the Horsch Serto have the greenest, most uniform vegetation. This indicates that these seeders can handle well varying soil conditions and maintain the correct seed depth. Amazone Primera has the reddest result, but this is partly due to unsown strips in the field. In addition, the lowest spot of the field was on its sowing area and thus some of the vegetation died there due to water accumulation in the autumn.

NDVI image together with an aerial photo.

If you compare the NDVI image with the aerial photo from which a peat strip can be seen on the field, we can assume that in some cases the quality of the drilling is connected with the change in soil type on the field, or the presence of a compacted area such as an old tramline or something similar. It can also be seen that unevenness of ground has affected the crops - the vegetation is sparse at higher spots. The NDVI image is also partly influenced by the different row widths of the drills and this gives some areas a greener colour.

Planned tasks on the field

This season, some fertilisation and plant protection tasks will be carried out and when these tasks are completed, the only thing left is to wait for the harvest. The planned yield is 8 t/ha and the total rate of nitrogen application is 170 kg N/ha of active ingredient. In addition, it is planned to treat the plants with the fungicide Balaya and the growth regulators Moddus 250 EC and Stabilan during the 31st growth stage. At the 37th growth stage, an additional treatment with Revytrex fungicide and Medax Top growth regulator are also planned. 

More pictures of the sowing areas, including the ones taken from the ground, can be found here.

See the autumn results (number of plants per square metre and growth stage) of the sowing areas here.