Use of Shrimp Sludge as a Soil Amendment for Tomatoes

Chad King, Kevin Fitzsimmons, Dennis McIntosh

Environmental Research LabUniversity of Arizona

Purpose

• Determine feasibility of use of shrimp sludge from low salinity inland shrimp culture as a soil amendment.

• Apply sludge at disposal rates, not to meet plant requirements.

• Provide a use or disposal for a current waste product

• Reduce the potential for farm erosion, nutrient leaching/loss

Research Design• Collected and dried fresh sludge from a shrimp farm

in western Arizona, USA • Treatments of 5, 10 and 20% sludge application by

volume, 402, 805 and 1,610 g/plant• Mechanically mixed shrimp sludge and potting soil

mix (concrete sand, mulch, vermiculite)• Randomly transplanted and arranged 28 ‘Roma’

tomato starts in a greenhouse, one plant per pot• Each plant received 4 L of water daily, over four

applications by drip irrigation• Response measured in mass of tomatoes produced

Statistical Analysis

• One-way ANOVA of total mean mass of tomatoes per plant for each treatment

Shrimp Sludge Characteristics

Sample Total N 

% dry matter

Total PO4-P

% dry matter

Total K

% dry matter

NO3-N

 

g/g

Olsen P 

g/g

Soluble K 

g/g

EC 

dS/m

1 0.13 0.10 0.23 1497.4 22.60 27.3

2 0.48 0.21 0.20 4.36 73.50 53.6 8.5

Total N, PO4-P and K show total plant macronutrients

NO3-N, Olsen P and soluble K show plant available nutrients

EC provides a measurement of soil salinity

Results

Tomato Production

Treatment Tomato Mass (g/plant)

SEM

0% (Control) 39.2a 11.54

5%402 g/plant

65.1a 11.14

10%805 g/plant

141.1b 20.73

20%1,620 g/plant

113.6b 19.9

Different superscripts indicate a significant difference, p<0.05

Conclusions

• Applications of 10% and 20% increased plant production

• Suggests land application will benefit crop production while providing a disposal mechanism

• Large, field scale application experiment suggested to verify results

• Soil salinity must also be monitored, given high evaporation rates

• Sludge is highly variable, depending on pond management