Green Manure Mulch and Cover Crop for Orchards

Note to readers, attached is the complete final report for FNE02-429.

We were hoping to see more obvious differences between the three plots based on apple production, apple size and tree vigor but we found little difference. The first two years of the project there were so few apples (weather conditions and bringing the trees back into production) that it was not a fair test. This year the crop was good but during the busy season the apples were picked before any comparisons could be made. However, there were two positive results.

The soil tests taken in 2002 and 2004 showed some differences. The organic matter in the test block was between 7.1 and 7.6 in 2002. In 2004 this level was between 9.2 and 12.0. According to the University of Maine's Testing Service recommends optimum range for organic matter is 5-8% so it would appear that there was too much organic matter. However for apple trees the slow breakdown of this organic matter over a year or two means no other nitrogen needs to be added. On the UMaine website under "interpreting soil test results for commercial crops", under nitrogen it says "because of ample rainfall in the Eastern U.S. there is not an acceptable year round soil text to predict the amount of nitrogen that will become available to plants over the course of a growing season. A soil's nitrogen supplying capacity depends on the microbial breakdown of organic matter to the ammonium and nitrate form". Increasing organic matter increases the likelihood that nitrogen will be available, given good microbial activity. We also noticed in the living mulch plot that in 2004 there were earthworms while none were found in any plot in 2002.

• FNE02-429 Final Report
• FNE02-429 Photos
• Compost Soil Test
• Living Mulch Soil Test
• Control Soil Test