New method for the devitalization of imported horsetail (Equisetum hyemale)

Despite being rated as one of the world’s worst weeds, Equisetum hyemale was until recently imported into New Zealand for use by the floristry industry, subject to devitalization. It was subsequently found that imported stems were not being successfully devitalized and importation was banned. This study, in two trials, used different dilutions of six herbicides, including Roundup, the one listed in the MAF Biosecurity NZ standard, to investigate if it were possible to render stems non-propagable without destroying their commercial use. This research found that a Sharpshooter (oryzalin) formulation at 1 and 1:2 dilutions of the field application strength was the only herbicide that completely devitalized the stem material with minimal impact on stem quality. Roundupat the concentration required by MAF Biosecurity NZ destroyed the stems, while 1:5 and 1:10 dilutions reduced the ability of the stems to be propagated, but still caused stem damage. AGPRO activated amitrole, Duplosan, Agritone and Kamba were not successful as devitalization agents

A new hoe share design for weed control: measurements of soil movement and draught forces during operation

This research introduces a new share design (L-share) that reduces the undesired random soil movement, providing a more controlled disturbance of the upper soil layer. Purpose: The aim of this study was to evaluate draught forces and soil movements when operating the new share. Materials and Methods: Experiments were conducted in a laboratory set-up using a soil bin with a fine loamy soil texture. The soil was compacted to a bulk density of 1500 kg m−3, with a penetration index of 486 kPa and a mean water content of 10%. The cultivation depths were 30, 50 and 70 mm and the operation speeds were 0.84, 1.67 and 2.31 m s−1. Cubes were used to measure soil movement by recording the displacement from their initial positions. The soil surface and furrow profile were measured by using a 2D laser range scanner. Results: The results showed that increasing operation speed and cultivation depths generally increased draught forces and soil movement. Changing the cultivation depth from 30 to 50 mm resulted in a 63% greater longitudinal force (Fx), and 71% greater Fx when increasing the cultivation depth from 50 to 70 mm. Conclusion: The study showed that the new L-share mounted on a modified spring tine only causes minor soil movement and thereby minimising the undesirable soil movement