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Project Leader(s):
Dale Moyer, Cornell Cooperative Extension, Suffolk County
Meg McGrath, Dept. of Plant Pathology, Cornell
Anu Rangarajan, Dept. of Fruit and Vegetable Science, Cornell
Type of grant:
Cultural methods; sanitation; physical controls
Project location:
throughout the Northeast
Abstract:
The primary goal of this long-term project is evaluating yearly soil
amendment of commercially-available composts plus 3-year rotation for
managing Phytophthora blight. This disease is a major concern
for many growers because an effective management program (including
fungicides) has not been identified and severe losses have resulted
in cucurbit crops, especially pumpkin, and pepper. Research is being
done where blight occurred in 1999 through 2001. Additionally, compost
is being examined as a soil-building amendment and fertilizer for rotation
crops. Yearly amendments of compost were demonstrated to be having a
long-term impact on nutrient availability and organic matter content
of soil. Soil samples collected in mid June before applying compost
or chemical fertilizer in 2003 revealed that plots receiving compost
in 2001 and 2002 had significantly higher organic matter content and
more available phosphorus, potassium, magnesium, manganese, and zinc
than non-compost-amended plots. A one-year-old compost made of leaves
and fruit waste was used. Its nitrogen content was 0.77%, thus applying
it at 40 ton/acre was expected to provide 30 lb/acre nitrogen assuming
10% availability of the nitrogen in the compost. More available nitrogen
was detected 22 days after applying fertilizer and compost in soil of
non-compost plots that received 50 lb/A nitrogen from a conventional
chemical fertilizer (15-15-15) than in plots receiving a combination
of compost and chemical fertilizer to achieve this same nitrogen rate.
The compost may not have provided the expected quantity of nitrogen
or it provided nitrogen more slowly than chemical fertilizer. However,
nitrogen content of leaves did not differ significantly. Compared to
non-compost plots, compost plots had a smaller plant canopy, numerically
more weeds (but not a significant difference), and yielded slightly
less based on data from the first harvest done 15-22 Sep (24.4 vs 20.7
marketable-sized pods/plant, respectively). In conclusion, amending
soil with compost yearly is having a long-term impact. Compost appears
to be a suitable source of nitrogen to at least partly replace chemical
fertilizer. Results may be improved by applying compost more than a
few days before planting or by using a lower estimate for the percent
available nitrogen in this compost. Availability of nitrogen is known
to vary substantially among composts.
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