Hohenheim Univeristy confirms the high effectiveness of steam against weeds at the 32nd horticulture day

On the 19.09.2009 (32nd horticulture day) Hohenheim University located close to Stuttgart presented the results of open field tests for weed control.

From June to September 2009 three methods of weed control were tested 4 times repeatedly on parcels of 16m x 1.2 m. On the parcels two Baby-Leaf salads “Batavia red” and “Batavia green” were planted.

The total testing area was divided into 18 plots, on which the three methods were compared with each other: weed control with pick, with herbicide and with soil steaming.

Steaming took place once before seeding after sufficient soil loosening, while herbicides were applied after seeding. Manual seed control with pick took place when weeds started to occur. Control plots were not subject to any weed control means.

Baby-Leaf cultures were harvested after 4 weeks. Then freshmass and drymass of salad and weed of all three test variations were measured and compared (steaming, herbicide, pick).

University Hohenheim yielded the result that after the application of 90°C hot steam, no weeds grew in the cultivation period. On sufficiently steamed areas weed control of Baby-Leaf-Cultures is not necessary.

Nitrate and Ammonium

As expected when examining the steamed soil, a relatively high but harmless concentration of ammonium and after harvest a high concentration of nitrate was measured due to the blocking of nitrifying bacteria through steaming. Ammonifying bacteria however were less affected through hot steam. Hence ammonia accumulates in steamed soil. More detailed results were yielded by S.N. Malowany and I.D. Newston in the middle of the last century already. Normally the ammonia / nitrate ratio normalizes within 6-8 weeks after steaming. This period can be significantly shortened if nitrifying and ammonifying bacteria are injected into the soil right after steaming(Integrated Steaming).

Comments are closed.