Apple-pomace Compost and Pre-plant 

 Monoammonium Phosphate for 

 Improving the Growth of Newly Planted 

 Apple Trees 



Renae E. Moran 



Department of Animal and Horticultural Sciences, University of Maine 



James R. Schupp 



Hudson Valley Laboratory, Cornell University 



In many orchards in the Northeast, early yield is 

 limited by tree growth, and trees are typically not 

 cropped until the third or fourth season because growth 

 IS not vigorous. Management practices that encourage 

 rapid early tree growth and early fruit production result 

 in economic advantages to growers by hastening a 

 return on investment. Decreasing the time required for 

 trees to fill their space would allow growers to increase 

 early yields. 



Increasing early tree growth can be accomplished 

 by adding organic matter or phosphorus fertilizer to 

 the planting hole. Adding compost as a source of 

 organic matter to planting holes affected young apple 

 tree growth in experiments in Massachusetts and 

 Maine. Organic matter is often low in many existing 

 orchard soils. Increasing soil organic matter improves 

 its water and nutrient holding capacities, which 

 enhances root regeneration and promotes overall tree 

 vigor, but the effects of planting-hole treatments are 

 most visible during the year of planting. As root 

 growth extends beyond the volume of the planting 

 hole, the effects of planting-hole treatments diminish. 

 If organic matter amendments were broadcast 

 throughout the orchard soil, perhaps the beneficial 

 growth response could be sustained for a longer 

 period. For pre-plant compost to be a feasible 

 management practice, an economical, local source of 

 compost must be available. University of Maine 

 Cooperative Extension developed an apple-pomace 

 composting project in cooperation with Chick 

 Orchards in Monmouth, Maine. Apple pomace from 

 the cider operation was mixed with leaf waste from the 



local waste transfer station, and chicken manure from 

 a local egg farm at a 2:6: 1 ratio by volume. Wood ash 

 was used to adjust the pH to 5.8 prior to composting. 

 Composting reduced the volume of apple-pomace 

 waste by 50% and converted it into a soil amendment 

 with highly desirable characteristics. 



Newly transplanted trees have impaired root 

 systems, so P fertilizer is often recommended for new 

 plantings. Since P is very immobile in soil, this 

 nutrient is more beneficial when it can be incorporated 

 prior to planting. Research in British Columbia has 

 shown that monoammonium phosphate (MAP 1 1-55- 

 0) fertilizer, incorporated into the soil used to fill the 

 planting hole, increased tree growth in the first 2years 

 after planting and increased flower production and 

 fruit set in the early years of the planting. The addition 

 of MAP to the planting hole has become a common 

 practice in B.C. orchards, especially when replant 

 problems are anticipated. It has been suggested that 

 root uptake or utilization of P may be more efficient in 

 the presence of ammonium. Moreover, MAP could be 

 influencing tree growth by providing N. This study 

 was performed to determine if pre -plant-incorporated 

 apple-pomace compost and MAP, either alone or in 

 combination, would improve early apple tree growth 

 and precocity. 



Methods 



This experiment was conducted at Highmoor 

 Farm in Monmouth, Maine, on land which had been 

 fallow for 6 years, but in continuous apple production 



Fruit Notes, Volume 67, Winter, 2002 



