|Larkin, Robert - Bob|
Submitted to: Northeast Potato Technology Forum Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 3/10/2008
Publication Date: 3/13/2008
Citation: Erich, S., Tavantzis, S., Larkin, R.P., Alyokhin, A., Gross, S. 2008. Compost and Biological Amendments in Potato Systems: Effects on Soil Properties and Fertility. Northeast Potato Technology Forum Abstracts. CD-ROM. Interpretive Summary:
Technical Abstract: An interdisciplinary field experiment was conducted at two field sites in Maine to assess the effect of compost and biocontrol agents on potato diseases, insect populations, soil quality, and yield. The two sites were Aroostook Farm (AF, a conventionally managed research site) and Wood Prairie Farm (WP, an organically managed commercial farm). Biocontrol agents used included hypovirulent Rhizoctonia, Bacillus subtilis, and Trichoderma virens, each of which was added to four replicate plots both with and without a wood-based compost amendment. Soil quality was very different between the two sites: soil organic matter was about 3.4% at AF and about 9% at WP. The WP farm included potato only one year in four and grew green manure crops to build soil organic matter levels. In contrast the AF site included potato in alternate years and no green manure crops. Biocontrol agents had little effect on soil properties so sampling contrasted compost amended to compost unamended plots at each site. WP had higher levels of water stable aggregates (WSA) at each of the three sampling times than AF. There was a small decrease in the level of WSA from June (pre-plant) to August for the WP site but no further decline from August to October (post-harvest). The AF site showed little change in WSA over time. Compost amendment did not affect aggregation at either site. Although soil moisture was always significantly higher at WP than AF, compost amendment did not affect soil moisture at either site. Soluble inorganic N levels were higher at AF than WP in late June due to the use of inorganic N fertilizer at AF. At all other sampling dates, N levels were similar at the two sites and unaffected by compost use.