Archive for February, 2018

STRAWBERRY STEAMING TECHNOLOGY RIPENED FURTHER

Wednesday, February 21st, 2018

With the declared aim of getting a fully developed steaming solution for strawberry cultures on mounds (hills/ridges) ready for market this year, further technical solutions were successfully tested till February 2018 together with the Agricultural Department of the Office of the District Administrator, Karlsruhe (Landwirtschaftsamt des Landratsamts Karlsruhe). Making steaming the last mound (hill/ridge) preparation step before planting would be helpful for many strawberry cultivation firms. It has now been satisfactorily proven that this functions. Thanks to special cover technology, standard film that was laid on the finished ridge remains intact even after steaming. It was also proven that injecting superheated steam exclusively through the planting openings leads to heat penetrating the ridge well enough to achieve the positive effects especially regarding disease control.

Temperature flow in the mound shows that two injections points in a row are sufficient for steaming

Temperature flow in the mound shows that two injections points in a row are sufficient for steaming

The final experiment took place in Durbach in the Baden region. There, ridges were raised for the experiment using heterogeneous soil. The breadth of the ridge was 75 cm at the top and 90 cm at the base. The ridge was shaped 30 cm high. The steamer cups used were organised on a 30×30 cm planting grid. The steaming spikes or spines were arranged in a lattice. The ridge was covered using a standard film. The steamings took place on a double-row ridge of 3 rm hood length.

An MS 200 steam boiler made by MSD, Durbach was used to generate the steam with a maximum steam output of 250 kg/h at a working pressure of 0.5 bar and a steam emission temperature of 200°C.

Steaming hood weighed down on film-covered experimental mound (hill/ridge)

Steaming hood weighed down on film-covered experimental mound (hill/ridge)

In summary, the experimental arrangement was suited to the main questions raised. The spikes did not damage the film. No heat adhesion was observed – the same applies to contact points of the film with the steamer cup. In spite of observable hindrances like patches of too-wet soil, sufficient heat flow could be observed in the raised ridge. As expected, the highest temperatures of over 90°C were observed in the immediate surrounding of the steaming spike’s injection spot. Temperatures of at least ~75°C could still be measured on the ridge’s exterior. These temperatures are definitely sufficient to eliminate soil nematodes, soil-borne fungi, and weeds. It is assumed that soil fatigue could probably also be eliminated. Further experiments should confirm this assumption.

The official test report can be requested from Mr. Arno Fried at the Chamber of Agriculture, Office of the District Administrator, Karlsruhe (Landwirtschaftskammer des Landratsamts Karlsruhe).