[USCC] Ron's question on paper sludge & biosolids

[Allison L H Jack]

Hi Ron,

I've read some great work by a team at Wisconsin and Oregon State who have 
documented positive changes in soil properties with composted waste paper 
sludge amendments. It is still not totally clear how different factors 
interact to reduce soil-borne diseases, but in at least one year of the 
three year study amendment with composted paper mill residuals were 
correlated suppression of disease.

I can send the pdf to you off list.

-Allison

Rotenberg, D., L. Cooperband, and A. Stone (2005) Dynamic relationships 
between soil properties and foliar disease as affected by annual additions 
of organic amendment to a sandy-soil vegetable production system. Soil 
Biology and Biochemistry, 37(7): p. 1343-1357.

Additions of organic amendments to agricultural soils can lead to improved 
soil quality and reduced severity of crop diseases. However, the 
relationship between disease severity and soil properties as affected by 
repeated additions of these amendments is poorly understood. The primary 
objectives of this study were to (i) resolve multivariate relationships 
between soil properties and foliar disease severity and (ii) identify soil 
properties that contribute to disease severity in an intensive irrigated 
vegetable production system receiving annual additions of fresh and 
composted paper mill residuals (PMR). Foliar diseases caused by Pseudomonas 
syringae pv. syringae on snap bean (bacterial brown spot) and P. s. pv. 
lachrymans on cucumber (angular leaf spot) are the focus of this report. 
The experiment consisted of a 3-year crop rotation of potato (1998 and 
2001), snap bean (1999 and 2002), and cucumber (2000). Treatments included 
a non-amended fertilizer control and two rates of fresh PMR, PMR composted 
alone (PMRC), and PMR composted with bark (PMRB). Soil measures included 
total soil carbon (TC) and nitrogen (TN), particulate organic matter carbon 
(POMC) and nitrogen (POMN), volumetric soil moisture (VM) and in situ 
NO3-N. Multiple regression (MR) and principal component analyses (PCA) were 
conducted to identify key soil properties that influenced the amount of 
disease. On average, the amount of TC in plots amended with PMR composts 
increased 77-178% from 1999 to 2002 compared to the non-amended soils. In 
1999, a year in which compost additions reduced the amount of bacterial 
brown spot of bean, TC explained 42% of the total variation in disease 
severity in the best MR model. Midseason TN alone was inversely related to 
angular leaf spot incidence in 2000, while POMN explained 51% of the 
variation in the best MR model for that year. In 2002, a year in which 
PMRC-amended soils exacerbated brown spot symptoms, midseason quantities of 
TN explained 80% of the variation in disease severity. Unique to 2002, 
NO3-N alone positively correlated with disease severity. Overall, the 
influence of soil carbon on disease severity was displaced by the 
increasing importance of TN and NO3-N, indicating a transition from a 
C-dependent to an N-dependent system.


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Allison L H Jack
Graduate Student
Department of Plant Pathology
Cornell University
335 Plant Science
Ithaca, NY 14850
607.273.5762
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