Soil treatments and rootstocks for organic apple production.

Summary in the original language of the document

6 different soil treatments: Mechanical weeding to the middle of the alleyway, mechanical
weeding using 3 different equipments Clemens, Humus and a dish harrow, Soil covering
with wheat straw and natural vegetation were combined with 3 rootstocks: M9, J9 and M26
to find the best combination for the apple variety ‘Retina’. The trees were planted in the
winter 1997/1998, only sprayed at primary RIMpro warnings and drip irrigated. The tree
growth, nutrient content of the leaves in august, yield and fruit quality were determined.
The rootstock J9 had the highest yield and the biggest amount marketable fruit.
Mechanical cleaning to the middle of the alleyways, tree row weed control using Humus or
soil covering with straw gave the highest yield and marketable fruit. A one meter weeded
strip in the tree row did not remove the competition of the clover grass alleyway. Natural
vegetation (weed) in the tree row reduced the yield with more than 50 percent. There was
a break down of the Vf resistance of ‘Retina’