The University of Arizona
M.A.C. Aquaculture Division

Integrative Research Combines Aquaculture & Agriculture:

Fish & Field Crops

Project Proposal

Kalb Stevenson

Question:

What will be the costs and benefits to growing fish in ponds that will be emptied to irrigate field crops? Will there be sufficient nitrogen and phosphorus release through fish waste and algae biomass to create significant differences in barley and cotton growth?

Background:

Integrative studies in Arizona are gaining popularity with the growing concerns of drought and water conservation.  Millions of gallons of water are used each year in production agriculture that could be used for aquaculture first.  “Farming the water” before using it to irrigate land has the potential to create additional income for Arizona growers, increase organic nutrient content of soils, decrease chemical fertilizer use, create an additional crop in the form of food or ornamental fish, and conserve water.

 Introduction:

The purpose of this experiment is to examine the effects of fish effluent on western cotton and poco barley growth.  The study is designed to look at the effects of chemical fertilizers, natural, organic fertilizers (effluent), and the combination of both.  We will measure the costs and benefits of combining aquaculture and agriculture in the field.  Significant attention is paid to the vegetative growth and yield of each crop, as well as nutrient content of the water and soils.  Another large part of this experiment is determining whether or not healthy, aquatic life can be sustained in such an integrative system.  Catfish and tilapia are raised seasonally in cages throughout the experiment, and koi are free-swimming in the pond year round.

Methods:

In this integrative study at the Maricopa Agricultural Center in Maricopa, AZ, the effects of fish effluent irrigation on field crops were observed. A long, perforated PVC pipe was constructed, secured, and attached to a pump at the bottom of an elevated fish pond to collect a full distribution of fish waste and algal biomass.  Koi were stocked into the pond free swimming during the winter, while tilapia and catfish were interchangeably placed into floating cages depending on the season (see attached map). The purpose of cages in aquaculture is to alleviate mid-season harvesting difficulty. The weight and number of each fish was tracked closely throughout the year to determine if normal growth and health persisted. Dry, floating feed was given twice per day, 5 days per week, at a rate equal to 2-3% of the estimated total pond biomass. A total of 669 lbs. of feed was given from May through September. The nutrient-rich fish effluent was pumped onto the field to act as an organic fertilizer by supplementing plant growth.

The field portion of this experiment was conducted on 0.955 acres of sandy loam soil on field 102, borders 5-6 from December 2001 to present. The experimental design used in this study was a randomized complete block (RCB) design. The randomization of treatments within each rep helped to decrease type II error by eliminating any chance for researchers’ bias in the field, therefore decreasing the probability that a true null hypothesis would be rejected.  It consisted of four treatments, each with four repetitions, and would be considered a 4x2 factorial design (4 treatments x 2 kinds of field crops).

The treatments differed according to their source of irrigation and applications of fertilizer. The treatments were 1.) well water irrigation only (w.w.), 2.) well water irrigation + standard chemical fertilizer applications (w.w.+s.f.),  3.) fish effluent irrigation (f.e.), 4.) fish effluent irrigation + standard chemical fertilizer applications (f.e.+s.f.).  Each of the 16 plots was approximately 130ft x 20ft, or approximately 0.06 acres. Standard farm practices were used for planting, harvesting, pesticide/herbicide application, and irrigation/fertilization when needed.  For the crop varieties, short-season barley was planted in the winter, and late-season cotton was planted in the summer. This rotational crop system simulates continual irrigation on a field throughout a season.

During barley season, measurements were taken throughout the year for plant height, and a final yield per acre was calculated at the end of the season. Throughout the summer, cotton plants were measured for height and total nodes, while petiole samples of were analyzed to determine plant tissue concentrations of nitrates and phosphates. Height-node ratio was calculated twice during the year to determine treatment influence on vegetative growth, and a final yield per acre was recorded as well. Water sampling was also done during this study, but an accurate total amount of nitrogen and phosphorous applied to the field cannot be calculated until more data becomes available.

Data Analysis:

The majority of the statistics used in this study were ANOVAs.  Descriptives and Post Hoc tests (LSD, Bonferroni, and Duncan) were also computed to determine significance of the data. The comparisons within the test that were of highest interest were between treatments 3&1, 4&2, and 3&2.  It was easy to predict that plots with chemical fertilizer would be more significantly different than plots without, so the narrower focus was on the fish effluent plots, and the differences between those and the plots irrigated with well water.  Chemical fertilizer applications were applied only a few times per year, so adding nutrients naturally within each irrigation may have produced significant effects.

The last comparison (3&2) is the only one that is of interest which will compare a fertilized to non-fertilized treatments. As mentioned previously, it is difficult to accurately estimate the total amount of N & P extracted from the soil by an effluent irrigated plant.  Assuming leeching is slow and uptake of N & P is equal throughout treatments, data for petiole sampling (NO3 & PO4), height, nodes, height-node ratio, and yield may all be factors expressing the effects of effluent irrigations on cotton.

Although LSD and Duncan tests were performed, data from the Bonferonni Post Hoc will be reported because of its decrease in type I error.  If it can be shown through this study that the treatments give a “rate” effect in regard to plant growth (low, med low, med high, high), future tests using multiple regression and orthogonal comparisons would occur. For this initial study, however, we will try to assess the significance of the treatment comparisons listed above using one-way ANOVAs.  If the data are normally distributed, most of the data points will lie within the standard deviations of the mean, and will therefore account for 95% of the data.  P-values of significant data will be reported, but all analyses can be found in the back of this report along with its original data.

Results & Discussion

*Pending

Summary

*Pending

Shrimp & Olive Trees

 Project Proposal

Chad King

Questions:

What will be the impact on olive tree growth among treatments receiving as a water source the following treatments:  well water, effluent water from low salinity shrimp ponds, and urea fertilizer applied with well water at rates consistent with regular farm management?

 What is the effect of the land application of aged shrimp sludge from low salinity culture on olive tree growth?

 Background:

As aquaculture grows in amount of production, variety of culture crops, and geographic range, the environmental impacts of these concentrated animal feeding operations must be addressed.  One of the main environmental concerns is nutrient management.  Nutrient-rich effluent waters and solid sludge remaining in ponds after harvest have the potential to cause eutrophication of natural surface waters, groundwater contamination, or increased rates of greenhouse gas release if treatment and disposal of these wastes is not carefully controlled.  One method of safe disposal of these nutrients is application on agricultural lands.  This practice will not only serve as aquacultural waste disposal, but also improve agriculture production through the addition of nutrients.  In arid lands, environmental impacts due to the groundwater pumping may also be decreased through this practice of reusing water, a resource more valuable than the nutrient inputs.  Research must continue to focus on quantifying the benefits of land application in order to provide the impetus for more sustainable and environmentally sound waste management practices.

Experimental Design:

120 olive trees (one gallon size, one year old from cuttings) were randomly planted into ten rows of twelve trees.  Trees were randomly assigned to each row (treatment) according to water source, three each of well water and well water and fertilizer, and four effluent water treatments.  Trees were planted in the bottom of a single furrow – through which irrigation was applied to the trees - in sandy soil, in an isolated field where the top layer of soil had previously been removed during shrimp pond building.  Irrigation is performed at a frequency of one to three weeks (every week in the summer and less in the winter, in accordance to plant needs).  Irrigation rates were 1000 gallons/row in year one from March to May and October to December, and 2000 gallons/row in year one from May through October.  In year two, treatment rows will receive 2000 gallon/row each time, to accommodate larger trees and larger water needs.  Duplicate water samples are taken from the water from each treatment, and tested for nutrient content and salinity.  The effluent treatment receives water during periods of shrimp production, when the ponds are full and discharging effluent.  Other times of the year, the effluent treatment receives well water.  Likewise, the well water + fertilization treatment groups receive fertilizer applications with the scheduled fertilizer application for the rest of the farm.  This treatment group receives well water only when the rest of the farm is not being fertilized.  Tree height and diameter are measured monthly.  At planting, 7.1 kg of sludge was applied around each of the last six trees in each row (60 trees total).  This extrapolates to an application rate of 5461.5 kg/ha if only applied to the planting furrows, or 32,769 kg/ha if applied at this rate to the whole field.  The experimental plot measures 0.133 ha (0.329 acres), and irrigation for the first year (March to December) was 5,122.6 m3/ha/yr (1.67 AF/acre/yr).  Fertilizer was applied at the rate of 17.05 g of N/tree/application.  This experiment will preferably carried out for two full years, to account for all of the growth cycle and to take advantage of a complete year of treatments.

 

 

 

Results:

Results will be based around the following analysis:

Question 1:

Question 2:

For more detailed information on this topic, please visit:

http://ag.arizona.edu/azaqua/aquaculture_images/shrimp/Olive/Olive%20Web.htm

Shrimp & Tomatoes

Project Proposal

Chad King

Question: 

What application rate of dried shrimp sludge will produce greatest rates of above ground plant biomass growth and fruit production?

Background:

Aquaculture sludge accumulates at 11-38% of feed input to growout ponds.  This produces significant accumulation over the course of a 90+ day growing season.  While much of this material is consumed by bacteria or suspended in the water column and lost with harvest water, many cubic meters are left on the bottom of inland shrimp ponds after harvest.  This material is typically removed in preparation for the next growing season.  Rather than dispose of this nutrient rich matter, this study examines the use of sludge as a garden or field amendment.  Were these applications to prove to be beneficial, sludge could be used in field application to improve agricultural crop yields, or sold to gardeners as a high quality soil amendment alternative to mined fertilizers.

Experimental Design:

Dried shrimp sludge is mixed with an organic but nutrient-poor potting soil mix across a ranges of percentages of shrimp sludge to soil by volume (0%, 5%, !0%, 25%).  These 4 soil mixes are placed into 6 liter pots (n=7 for each treatment).  The pots are placed randomly into 4 rows of 7, evenly spaced at .5 meters apart in a greenhouse.  One tomato seedling is added to each pot.  Watering is uniformly applied by drip irrigation, three times per day for 30 minutes each time, at a rate of one gallon per hour.  As the tomatoes grow they are pruned according to standard greenhouse procedure, with trimmings from each plant weighed and recorded.  Support is provided by string each plant up.  Fruit is weighed and measured as it is produced, and at the end of the season each plant is weighed and measured.  Samples of plant and fruit biomass will be weighed fresh then oven dried to determine dry weight randomly throughout the experiment, to determine a standard ratio of fresh weight to dry weight from which dry weight of plants and fruit can be calculated without drying all samples.  This experiment will continue for the length of one growing season, terminating between one and two months after fruiting begins.  Total time of the experiment will therefore be between four and five months total.  Upon termination, all plants and remaining fruit will be harvested and weighed.

Conclusions:

The treatment which produces the most above ground plant biomass and fruit will be identified as the best application rate for tomatoes.  Extrapolations will be drawn to determine the amount of sludge needed for field application, the area of shrimp ponds needed to provide ample sludge to treat one hectare, and the amount of N, P, and K initially applied to each tomato plant.

Alligators & Chickens          

Project proposal

Kalb Stevenson

Question:

Can alligators be raised as a sustainable aquaculture crop in arid environments using mortalities from chicken farms as a high-protein dietary supplement?

Background:

Alligator farming is a thriving industry in the Southeast, and has increased tremendously in the past decade.  The expensive hides and tasty meat are the main output crops from gator farming.  In large farms, however, gator feed can get quite expensive, as these ferocious reptiles take years to grow to mature size. 

Chicken farms, such as Hickman’s Egg Ranch in Arizona, house millions of chickens in their facilities.  Each week, hundreds of chickens die and must be buried, wasting a valuable crop. These dead chickens could be gathered together, frozen, sanitized, and transported to alligator farms to use as a high-protein supplement in gator food to produce shiny hides and strong, healthy reptiles!

This integration of aquaculture (alligator farming) and agriculture (chicken farming) would decrease the cost of burial for chicken farmers and decrease the cost of feed for alligator farmers.  Alligators also produce waste that is full of concentrated and pungent ammonia.  This waste could be harnessed in aquaculture facilities to use as fertilizer on agricultural fields that would grow grain to once again feed chickens.  Much of integrative aquaculture and agriculture is nutrient cycling, which allows growers to save money and resources to be conserved.