wAbstract
@Consumer demand for cleaned squid generates a substantial amount
of waste that must be properly disposed of, creating an economic
burden on processors. A potential solution to this problem involves
converting squid by-products into an organic fertilizer, for which
there is growing demand. Because fertilizer application to lawns
can increase the risk of nutrient contamination of groundwater,
we quantified leaching of NO3-N and PO4-P from perennial ryegrass turf (Loloum perenne
L.) amended with two types of fertilizer: squid-based (SQ) and
synthetic (SY). Field plots were established on an Enfield silt
loam, and liquid (L) and granular (G) fertilizer formulations
of squid and synthetic fertilizers were applied at 0, 48, 146,
and 292 kg N ha-1 year-1. Levels of NO3-N and PO4-P in soil pore
water from a depth of 60 cm were determined periodically during
the growing season in 2008 and 2009. Pore water NO3-N
levels were not significantly different among fertilizer type
or formulation within an application rate throughout the course
of the study. The concentration of NO3-N
remained below the maximum contaminant level (MCL) of 10 mg L-1
until mid September 2009, when values above the MCL were observed
for AQG at all application rates, and for SYL at the high application
rate. Annual mass losses of NO3-N were below
the estimated inputs (10 kg N ha-1 year-1)
from atmospheric deposition except for the SQG and SYL treatments
applied at 292 kg N ha-1 year-1, which had
losses of 13.2 and 14.9 kg N ha-1 year-1,
respectively. Pore water PO4-P levels ranged
from 0 to 1.5 mg P L-1 and were not significantly different
among fertilizer type or formulation within an application rate.
Our results indicate that N and P losses from turf amended with
squid-based fertilizer do not differ from those amended with synthetic
fertilizers or unfertilized turf. Although organic in nature,
squid-based fertilizer does not appear to be more -or less- environmentally
benign than synthetic fertilizers.
Keywords: Leaching; Turf; Perennial ryegrass; Nitrate; Phosphate;
Organic fertilizer; Synthetic fertilizerx
1. Introduction
2. Methods
@2.1. Study site
@2.2. Fertilizer sources
@2.3. Treatments
@2.4. Pore water sampling
@2.5. Analytical methods
@2.6. Estimates of NO3-N leaching
@2.7. Statistical analyses
3. Results and discussion
@3.1. Pore water NO3-N
@3.2. Mass of NO3-N leached
@3.3. Pore water PO4-P
4. Conclusions
Acknowledgements
References