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Abstract

Since 2010, AGGRAND has conducted a Vegetable Productivity Study as part of a long-term study to provide quantifiable crop growth, yield and soil-analysis comparisons. In its third year, soil nutrient levels and yield trends are becoming clearer as a result of following sustainable growing techniques in the AGGRAND plot. This year’s program featured yield comparisons of a plot using AGGRAND fertilizers and soil amendments and a plot using a fish/kelp based organic fertilizer. The organic fertilizer was applied according to the company’s application guidelines on the product label and the manufacturer’s website. A control plot that received only water was planted between the competitive and AGGRAND plots. This control plot was watered whenever the other plots received fertilizer. The plots were planted with three common garden vegetables — tomatoes, lettuce and snap peas — and were evaluated for total weight and number.

 

The AGGRAND fertilizer program produced greater yields of tomatoes, lettuce and snap peas when compared to the plots fertilized with the leading organic fertilizer.

 

Introduction

The report summarizing the results of the 2011 AGGRAND Growth Study (AGGRAND, 2012) provided an overview of the developments in organic agricultural research during the last 30 years. Factors such as weather, soil type, soil chemistry, soil biology, cultivation methods, pesticide and herbicide use are now being evaluated as part of the entire ecosystem. Researchers such as J.W Doran, Neal Kinsey, and Jeff Moyer have brought an eco-agriculture approach into the mainstream of agricultural thought.

 

Soil condition is one of the leading factors that influences crop production and can be modified to increase yields. A general knowledge of soils is important for any person involved at any level of agriculture.

 

Soil is defined as a thin layer of fractured and weathered minerals, organic matter, air, and water that physically and nutritionally supports plant life. An average soil is composed of approximately 45 percent mineral material, 5 percent organic matter, 20 percent to 30 percent air and 20 percent to 30 percent water. (Brady, 1974) The proportion of these constituents contributes significantly to the suitability of plant growth and development.

 

The mineral component of the soil contains fractions of sand, silt and clay. For example, a soil with an even balance of sand, silt and clay is considered a loam. A sandy loam has a higher proportion of sand compared to a clay or silt loam soil. (Brady, 1974) Organic soils, in contrast, found in marshes, swamps and bogs contain 80 percent to 95 percent organic matter and when drained are some of the most productive when raising specialty crops.

 

Soil water contains dissolved minerals in the form of charged ions and is the source of life-giving nutrients for the plant at the root hair. The water content and movement throughout the soil is dependent upon the physical characteristics of the soil. A soil consisting of a high proportion of sand will hold little water but will allow free growth of roots throughout the system if adequate moisture is available. (Taiz, 1991) On the other extreme, soils containing high amounts of clay can hold water in dry periods but do not facilitate good root development. There is a complex interaction of dissolved minerals, organic matter, soil water and air at the root surface.

 

Why do plants need fertilizer? Plants need food in the form of dissolved minerals, or ions in solution, to perform the complex process of photosynthesis. Being deficient in one or more nutrients, or water, will dramatically affect the plant’s ability to grow, bear fruit and reproduce in the most efficient manner. Direct application of minerals; fertilizers in the form of water-soluble salts; or natural fertilizers such as plant materials, animal manures and rendering byproducts; all are options for obtaining successful yields.

 

AGGRAND Natural Fertilizers and soil amendments are formulated with emulsified fish, kelp, lime, fulvic and humic acids, sulfate of potash, soft rock phosphate and other natural materials. These materials have been recognized as part of a sustainable cropping system designed to provide the necessary nutrients for plants to grow and thrive. They also build the soil by enhancing microbial growth. (Albrecht, 1996, Kinsey, 2009, National Stone Association, 1986, Senn, 1987). The competitive organic fertilizer used in this study is formulated to deliver similar benefits but appears to be less highly formulated than AGGRAND products.

Materials and Methods - Plot Plan

 

The following fertilizers and soil amendments were employed in this study:

 

• AGGRAND Natural Fertilizer (4-3-3), Product Code: NOF

 

• AGGRAND Natural Kelp and Sulfate of Potash (0-0-8), Product Code: NKP

 

• AGGRAND Natural Liquid Bonemeal (0-12-0), Product Code: NBM

 

• AGGRAND Natural Liquid Lime, Product Code: NLL

 

• AGGRAND Organic Fertilizer (4-3-3), Product Code: OSF

 

• ORGANIC COMPETITOR, (4-4-1) is primarily used by the consumer market. This product comes in a ready-to-spray quart bottle that covers approximately 3,000 square feet and is composed of hydrolyzed fish and seaweed with Chilean nitrate added to increase nitrogen levels.

 

The objective of this study was to compare yield by weight and number of vegetables. The study used the AGGRAND fertilization program — as outlined in the AGGRAND Gardening Guide (AGGRAND, 2010). The competitive organic fertilizer program included following the manufacturer’s mix ratios and application protocols. The soil was continually evaluated to determine nutrient shifts for each system and the impact of each fertilization system.

 

MATERIALS AND METHODS

Plot Plan A growth plot sowing plan was established to use the area most efficiently by providing ample room for the vegetables to grow and develop, while leaving enough room to water, fertilize and weed the plots. A 2-foot walking path was established between the vegetable types. See Figure 1.

Figure 1: 2012 Growth plot plan

test plot growth plan, lettuce, peas, tomatoes

On April 30, all plots were tilled, soil samples were acquired and soil temperature (Davis, Part # 6470) and moisture (Watermark®, Part # 6440) sensors were reset in the center of the AGGRAND, control and organic competitor plots. Sensors were placed at a depth of 12 inches (30.5 cm). These sensors were connected to a solar transmitter (Davis, Part # 6345), and transmitted data to the weather console and personal computer located in the AGGRAND laboratory. See Figure 2.

Figure 2: Preparations for Planting

preperations for tomato, pea and lettuce planting

To reduce wind, and maintain air and soil temperatures within the planting area, a 6-foot-wide windscreen was attached to the existing fence around the perimeter of the site. SunBlocker Premium, 60% Shade cloth was obtained from Farm-Tek Supplies, Dyersville, IA, (Part #103764).

 

The vegetables chosen in this study are popular hybrid and heirloom varieties, with seed established in cooler climates to produce good yields. The following seed were planted:

 

• Lettuce: Nancy (OG), (Lactuca sativa), Product ID: 438G, Lot: 40678, Vendor: Johnny’s Selected Seeds, Waterville, Maine

 

• Snap Peas: Snowbird — Edible podded, (Pisum sativum var. macrocarpon) Product ID: 52597A, Lot: For 2012, Lot 2, Vendor: Burpee Seeds, Warminster, Pennsylvania

 

• Tomatoes: German Johnson (OG), (Solanum lycopersicum), Product ID: 3815G, Lot: 40895, Vendor: Johnny’s Selected Seeds, Waterville, Maine

Soil Sampling

Each planter was tilled to a depth of about 8 inches. Using a soil sampling auger, soil samples were obtained from the top 6 inches of the planting bed at nine evenly spaced points in each quadrant. See Figure 3.

Figure 3: Soil sampling plan

The soil samples were shipped to Midwest Laboratories of Omaha, Neb. for analysis specifying the “S3C” package. The analysis included evaluation of percent organic matter; available phosphorus (weak and strong Bray); exchangeable potassium, hydrogen, magnesium and calcium; pH; buffer index; cation exchange capacity (CEC); percent base saturation of cation elements; and carry-over nitrogen as nitrate. Micronutrient analysis of sulfur, manganese, boron, zinc, iron and copper, evaluation of excess lime and soluble salts also were part of the detailed analysis. See Graphs 7-10 in the Results section for a summary of all soil analyses obtained during this study.

 

Soil Respiration

Carbon dioxide respiration is a measure of the bacterial action within the soil that leads to mineralization of key soil nutrients, such as nitrogen and phosphorus, and is an indicator of soil health. (Haney, 2008) This can be determined in a number of ways. Use of the Solvita Soil Respiration Kit, offered by Woods End Research of Mount Vernon, Maine, is one method that is accepted by the U.S. Department of Agriculture. (United States Department of Agriculture, 1999, Haney, 2008) The Solvita respiration system includes a Solvita Digital Color Reader, test jars and color-metric paddles (Part # DCR-soil).

 

On May 8, soil samples from each plot quadrant were evaluated for CO2 respiration by weighing 100 grams of soil from each plot quadrant and placing them into a Boekel Scientific convection oven (Model: 132000, Serial #: 022503749) set at 47.6° C (116° F) to dry overnight. The next day, 40.00 grams of soil for each plot were weighed using an AND FX3000i digital balance (Serial #: 15610355) and placed into small plastic beakers lined with filter material. The plastic beakers were placed in glass jars and 25.0 mL of distilled water was added. Test paddles were inserted into each jar and sealed. On May 10, the soil respiration paddles were measured (Serial # 047112S Exp: 02/16/2013) with the Solvita Digital Color Reader (model S100.)

 

On Oct. 2, CO2 respiration was tested again with soil samples collected as described above. In this instance,100 grams of soil from each plot were placed into the Boekel Scientific convection oven (Model: 132000, Serial #: 022503749) set at 50° C (122°F) to dry overnight. The next day, 40 grams of soil were placed into plastic beakers lined with filter material and placed into glass jars, 25.0 mL of distilled water was added by syringe. Test paddles were added as before and jars sealed. Results were measured on Oct. 4. See figures 4 through 7. Soil respiration data is summarized in Table 14, Graph 6 in the Results section.

Figure 4: Adding distilled water to soil

Figure 5: Sample jar, soil and paddle

soil sampling jar, soil and paddle

Figure 6: Solvita Test Paddles after 24 Hours

Figure 7: Color Reader

color tester

Weather Data

The documentation of weather data and comparison with historical data is essential to convey the conditions plants encounter throughout their growth and development. Weather data was collected, archived and reported throughout the 2012 growing season. Up to 31 parameters were evaluated by the weather station and associated software. Figure 8 shows the weather station data collection apparatus, and Figures 9 and 10 illustrate the data output at the host personal computer.

Figure 8: Weather station

Figure 9: Current weather data

weather data field testing

Figure 10: Display of temperature, precipitation and barometric pressure for one year

Display of temperature, precipitation and barometric pressure for one year

Tomato Starts and Transplants

Tomatoes were started in the AGGRAND laboratory instead of purchasing cultivars locally. On April 23, two tomato seeds were planted about 0.259 under the soil surface in four flats of 3.59x 3.59 pots (36). The seeds were potted in Pro-Mix (PGX) Professional potting soil Part # 0463 from Premier Horticulture, Inc., Quakertown, Penn. Filtered water was lightly sprayed on the flats to wet the seed and plant medium. The flats were placed in the growth area with heating mats under the flats and fluorescent growth lamps above, along with a plastic drape over each flat to maintain soil moisture. The most robust of the 72 plants after thinning were transplanted to the outdoor plots.

 

Growth Table Details

• Heat Mats: (2) 20.759 wide x 489 long from Hydrofarm®, Petaluma, Calif.

 

• Growth Lamps configuration alternating, per side: – Four: Sylvania 40W GRO-LUX F40 GRO – Four: VitaLite® 40W duroLite® – Light Duration: 14 hours per day

 

• Soil Temperature was set at 80° F (26.7° C) with a Digital Heat Mat Thermostat from Hydrofarm®

 

• Lamp height above table: 12 inches (30.5 cm)

 

• Temperature and soil moisture checked every day

Figure 11: Newly seeded tomato flats

seeding tomatoes
planting tomato seeds
growing tomato seedlings

On April 25, each pot was moistened with a fine mist of filtered water. Tomato plants began germination on April 26. The next day, a small amount of water was sprayed on the top of each tomato pot to dampen the soil, then 1000 mL of filtered water was added to each tomato flat. The growing number and size of the plants required addition of 2000 mL of filtered water on April 30.The germination rate was 86 percent on April 30. The plants required 1000 mL of filtered water on May 3, 7 and 10.

 

The tomato plants were thinned to one plant per pot on May 11. The driest plants were segregated into one flat and watered with 1000 mL of filtered water and placed in a single flat. On May 15, plants were segregated into categories to reflect differing stages of development and fertilized in the following manner: (See Figure 12)

 

• AGGRAND: 25 mL of a 0.5 percent solution of AGGRAND natural fertilizer

  (Add 5 mL fertilizer measured with a syringe to graduated cylinder and add water to 1000 mL mark)

 

• Control: 25 mL of filtered water

 

• Organic competitor: 25 mL of a 0.8 percent solution

  (Add 8 mL fertilizer measured with a syringe to graduated cylinder and add water to 1000 mL mark)

 

Uneven water uptake necessitated watering individual plants with 50 mL of filtered water on May 21. The next day, the height of the growth table lamps was increased by 2 inches to facilitate tomato plant growth. On May 23, each flat received 1000 mL of distilled water. The next day, the growth-lamp height was increased again by 2 inches and dry plants were watered with 50 mL of filtered water. At this point there were seven organic competitor tomatoes and four AGGRAND tomatoes. All of the tomatoes received 55 mL of filtered water on May 25. The plants grew rapidly, and the growth lamps were raised an additional 3 inches on May 28. On May 29, six extra organic competitor plants received water and the organic competitor flat received 2000 mL of water. The control tomatoes received 1000 mL of water. The AGGRAND tomatoes received 2000 mL of water, while the AGGRAND spare plants received 100 mL each. Hardening to prepare the plants for transplanting outdoors began by placing them in the laboratory breezeway for two hours. (See Figure 14.) On May 30, the tomato plants were exposed to outdoor conditions for 2.5 hours. The plants were placed in the laboratory breezeway for three hours on May 31. June 1 the growth lamp height was increased 2 inches. All of the plants were exposed to morning sun for one hour and were outdoors for five hours during the afternoon. The plants received filtered water at the rates that follow:

• Organic competitor spares: 1000 mL entire flat

• Organic Competitor: 100 mL each plant

• Control flat tomatoes: 1000 mL

• Control flat spare tomatoes: 1000 mL

• AGGRAND spares: 1000 mL entire flat

• AGGRAND tomato flats: 1000 mL entire flat

Figure 12: Fertilizing tomato seedlings

Figure 13: Tomatoes before hardening

Planting Lettuce

On June 4, the final indoor watering took place with three organic competitor tomatoes receiving 100 mL and four control tomatoes receiving 100 mL each. Organic competitor spare tomatoes and control spare plants did not need watering.

 

On June 5 the tomatoes were transplanted (Figure 14) to the outdoor growth plots according to the Planting Detail (Table 1) and fertilized according to the Growth Plot Fertilization Plan (Table 3).

Figure 14: June 5 tomato planting and fertilizing

Planting Lettuce

On June 5, lettuce seeds were sown with 23 lettuce seeds in each row (Figures 15 and 16), with plans to thin to six plants in each row. Plants were fertilized according to the Fertilization Plan (Table 3). The small size and low density of the lettuce seed made it difficult to provide the desired spacing.

Figure 15: Lettuce Seed

 Figure 16: Planting Lettuce Seed

Snap Pea Sowing

On June 12, snap peas were sown. Three pea seeds were planted in each 29 x 1.58 mound, with the intent of thinning to one plant per location, and fertilized according to plans reflected in tables 1 and 3. Plants were trellised with a tomato cage after reaching about 49 (10 cm) in height.

Table 1 Planting detail

planting detail for lettuce, tomatoes and snap peas

Growth Plot Maintenance

Table 2 (below) summarizes plant weeding, cultivation and watering throughout the growing season.

Date                                                               Procedure/Observations

June 12                                  Sowed three snap pea seeds in the same area. Fertilized per fertilization plan.

 

June 18                                  Hoed, weeded and raked all plots.

                                               Documented cutworm damage on tomato plants and picked worms off of plants.

 

June 21                                  Fertilized all plants in the organic competitor plot according to the fertilization plan.

                                               Fertilization of the lettuce was delayed because of a lengthy rainstorm.

                                               Discovered plants were infested with foliar cutworms.

 

June 28                                 Fertilized organic competitor plot per fertilization plan.

                                              Replanted a number of peas that failed to germinate because of extremely wet soil.

                                              Hoed, weeded and cultivated all plots.

 

June 29                                  Fertilized AGGRAND and competitor lettuce plots.

                                               Watered control lettuce plants. Watered and replanted pea seeds in the AGGRAND and control plots.

 

July 2                                      AGGRAND tomatoes starting to bloom.

 

July 3                                      Fertilized AGGRAND tomatoes per fertilization plan.

                                               Control plot received water through precipitation. Placed support cages around all tomato plants.

                                               Noted three small tomatoes in organic competitor plot;

                                               one dollar size, one the size of a quarter and one the size of a dime.

 

July 5                                     Fertilized all of the plants in the organic competitor plots according to the fertilizer plan.

                                              The control plots received adequate water through precipitation.

 

July 10                                   Fertilized AGGRAND lettuce plants according to the fertilization plan.

                                              Applied 6000 mL water per row of lettuce in control plots.

 

July 12                                  Fertilized all plants in the organic competitor plots. Replanted and watered peas in the AGGRAND plot.

                                             Applied 6000 mL of water per row to all plants in the control plot.

 

July 17                                  Fertilized AGGRAND plots. Tomatoes at full bloom. Many of the peas are at or near bloom.

                                             Applied 6000 mL water per row to all plants in the control and organic fertilizer plots.

                                             Applied 6000 mL of water per row to lettuce in AGGRAND plot.

 

July 19                                 Fertilized all plants in the organic competitor plots.

 

July 20                                 Thinned pea plants to one plant per cage. Some peas are producing pods.

 

July 23                                 Of the 23 lettuce seeds sown in each row, 25 were harvested in the AGGRAND plot.

                                            Because of extreme rainfall in June, some seeds moved next to each other or slightly out of the row.

                                            Some plants were coupled with a larger plant when harvested.

                                            At harvest, plants were pulled root and all from the soil. Root sections were cut off and each plant weighed.

                                            Results were recorded in the 2012 harvest spreadsheet. Applied 6000 mL of water in each row to all plots.

                                            Cultivated and weeded each plot. Obtained chlorophyll readings of lettuce plants.

 

July 25                                 Harvested peas in all plots. Harvested lettuce in AGGRAND and organic competitor plots.

 

July 26                                 Harvested peas in control plot.

 

July 27                                 Performed the final fertilizer application on all plots.

                                            Watered the control plot with 6000 mL of water per row.

 

July 30                                 Harvested peas and lettuce in the competitor plots, weighed and logged the results.

 

July 31                                Obtained chlorophyll readings of competitive plot tomato plants.

 

Aug. 1                                 Harvested peas in all of the plots and entered the data into the growth plot harvest database.

 

Aug. 2                                 Harvested lettuce in all of the plots and entered weights into the growth plot harvest database.

 

Aug. 6                                 Harvested lettuce and peas in all plots. Harvested one tomato in the organic competitor plot.

                                           Recorded weight of produce in the growth plot harvest database.

                                           Monitored soil moisture, and found the rain on Aug. 4 and 5 adequately watered the tomatoes.

 

Aug. 10                              Harvested peas in all plots. Harvested one tomato in the organic competitor plot.

                                          Watered all tomato plants in plots with 3.3 gallons of water.

                                          Also applied 3.3 gallons of water around the moisture sensor to determine the soil moisture change.

                                          Recorded all harvest data in the growth plot harvest database.

 

Aug. 13                             Harvested peas in all plots and recorded data in the growth plot harvest database.

                                         Harvested one tomato in the organic competitor plot.

                                         Watered tomato plants in all plots with 3.3 gallons of water,

                                         and applied another 3.3 gallons of water around the moisture sensor to determine the soil moisture change.

 

Aug. 17                             Harvested peas in all plots and entered information into the database.

 

Aug. 20                             Harvested tomatoes in the AGGRAND plot. Weighed and recorded each tomato in the database.

 

Aug. 22                              Harvested tomatoes in the AGGRAND and organic competitor plots. Harvested peas in all plots.

                                          Watered tomato plants in all plots with 3.3 gallons of water and applied 3.3 gallons of water

                                          around the moisture sensor to determine the soil moisture change.

 

Aug. 23                              Harvested tomatoes in the organic competitor plot. Three tomatoes were damaged by birds.

 

Aug. 27                              Harvested tomatoes and peas in all plots.

                                          Watered tomatoes in all plots and applied water to the moisture sensor area.

 

Aug. 29                              Harvested tomatoes in all plots.

 

Aug. 31                              Harvested peas and tomatoes in all plots.

 

Sept. 4                               Harvested tomatoes in all plots. Weeded all plots.

 

Sept. 7                               Harvested tomatoes in all plots.

 

Sept. 11                             Harvested tomatoes in all plots.

 

Sept. 14                             Harvested tomatoes in control plot.

 

Sept. 17                             Harvested tomatoes in all plots.

 

Sept. 21                             Harvested tomatoes in all plots because of potential hard freeze.

 

Sept. 24                             Obtained soil samples of all plots at nine evenly located points and shipped to

                                          Midwest Laboratories for analysis. Removed tomato plants from all planters.

                                          Removed moisture and temperature sensors in preparation of planting bed maintenance.

 

Sept. 25-27                        Tilled and raked growth plots, reintroduced soil temperature and moisture sensors and removed windbreak.

Tables 3, 4 and 5 summarize fertilizer applications and mix ratios for each plot; 6000 mL of fertilizer mix or water was applied with a watering can per row on all plants after initial planting and fertilizer applications (Figure 18). The application date is shown in red. Control applications containing only tap water followed the same timing and volume as the organic competitor product in the competitive plots. Generally, the competitive fertilizer was applied at regular one-week intervals after the initial planting and establishment of the plants.

Figure 18: AGGRAND fertilizer application preparation

preperation for applying aggrand natural liquid fertilizer
fertilizer can, water can,

Table 3: Fertilizer application timing, rate and mix ratio

Fertilizer application timing, rate and mix ratio

Table 4: Fertilizer application timing, rate and mix ratio

Table 5: Fertilizer application timing, rate and mix ratio

Post Harvest

On Sept. 26, soil samples were obtained at the end of the harvest and before tilling all of the planters. Soil samples, 6 inches deep from nine evenly spaced points, were obtained, mixed and forwarded to Midwest Laboratories for analysis for percent organic matter; available phosphorus (weak and strong Bray); exchangeable potassium, hydrogen, magnesium and calcium; pH; buffer index; cation exchange capacity (CEC); percent base saturation of cation elements; carryover nitrogen as nitrate; micronutrient analysis of sulfur, manganese, boron, zinc, iron and copper; evaluation of excess lime; and soluble salts. (See sampling plan, Figure 19) Three post-harvest samples were tested. All soil samples are summarized in Graphs 7 - 10.

Figure 19: Post Harvest Soil Sampling & Plan

post harvest soil sampling

After the harvest was complete the growth plots were tilled and the soil temperature and moisture probes were reset (Figure 20).

Figure 20: Fall Tilling & Raking Growth Plots

fall tilling and raking, seasonal garden maintenace

Plant Vigor

Chlorophyll levels are an indicator of the amount of nitrogen in the plants, which is related to the plant’s vigor. A Field Scout CM1000 Chlorophyll Meter from Spectrum Laboratories of Plainfield, Ill. (Part # 2950, Serial # 539) was used for accurate measurement and to determine the amount of nitrogen needed for optimal growth. (Murdock, et.al. 2004) The CM1000 was generated from technology developed by NASA in the 1990s. The ratio of the percentage of reflectance at the differing wavelengths of light provides a relative number that correlates to the amount of chlorophyll in the plant’s leaves. (NASA, 2011) Data variability is the result of a number of factors such as chlorophyll levels, leaf texture and the amount of pubescence of each leaf species.

 

On July 23, the lettuce crop was measured for relative chlorophyll levels. Tomatoes were measured on two occasions, July 19 and 31. The readings were taken in full sun, between 10 a.m. and 2 p.m., for optimal intensity. See Figures 21 and 22.

Figure 21: CM1000 measuring a lettuce plant

Figure 22: Red absorbing and reflected beam

CM1000 measuring a lettuce plant
red absorbing and reflected beam from the cm1000

RESULTS AND DISCUSSION  - Tomatoes

As in previous years, the focus of this study was to determine total yield by weight and number of tomatoes from each plot, but other parameters such as plant vigor and appearance are helpful in developing the history of why plants under certain fertilization programs yield more fruit than others.

 

Tomato plants were started from seed, with a germination rate of 86 percent. The tomato plants encountered slow initial growth because of extremely warm temperatures just after transplanting and cold, wet conditions during the last half of June. Leaf cut worms also were a problem. Damage by this pest made it necessary to replace 16 plants from all plots. The intense rainstorm on June 19 and 20 flattened many plants to the ground.

Figure 23: Leaf Cut Worm

leaf cut worm

Tomato growth rate rapidly increased during July due to consistently warmer temperatures and the population reduction of the cut worms. Tomato plants started to bloom on July 2 and on July 3 cages were placed around each plant. Comparison pictures were taken late June through the month of August. Figure 24 shows the comparison between fertilizer programs on July 30.

Figure 24: Tomato Plants, July 30

tomato plants in test plot,

To determine plant vigor, chlorophyll readings were taken of the tomato plants in each plot on July 19 and July 31. Five plants on the south and west sides of each plot were evaluated with the aim of obtaining the best sun angle for maximum light intensity. Eighteen data points were taken at random for the AGGRAND and Leading Organic plants with 17 readings being obtained for the Control plot for the July 19 testing, and nine points were obtained for each plot on July 31. See Table 7.

Table 7: Relative Chlorophyll Readings - Tomato Plants

Relative Chlorophyll Readings, Tomato Plants

The data shows that the AGGRAND - fertilized plants had more measurable chlorophyll as the growing season progressed, which means more nitrogen in the leaves correlating to increased vigor. This also substantiates the observations that the plants subjected to the AGGRAND fertilization program yielded more fruit weight per plant and per plot when compared to the other growth plots. Images of tomato plants obtained on Aug. 14 documented exceptional growth in the AGGRAND plot and the more pronounced bottom leaf die-back on the organic competitor and control plants. See Figure 25.

Figure 25: Tomato Plants, Aug. 14

full grown tomato plants

Tomato harvest commenced on Aug. 10 with the following criteria:

 

• Tomatoes to be orange to red on vine for harvest

 

• Fruit on the ground is counted and measured, even when green

 

• Measure weight and maximum diameter for each tomato in each plot

Figure 26: Tomatoes at various ripening stages

tomato ripening

Tomatoes were harvested on Aug. 13, 15, 20, 22, 23, 27, 28, 29, 31, Sept. 4, 7, 11, 14, 17 and finally on Sept. 21 in the competitive plots. Each tomato was weighed using an AND FX3000i digital balance, serial # 15610355. (Figure 27) Table 8 summarize the harvest results.

Figure 27: Tomato weighing

tomato weighing digital scale

Table 8: Tomato harvest of competitive plots

The AGGRAND fertilization system tomatoes, as shown in the competitive plots, produced heavier fruit with slightly fewer numbers, but resulted in more total weight per plot and plant when compared to plants that were fertilized with the organic competitor.

 

Lettuce

Lettuce is considered a cool season vegetable and was expected to grow well in the Superior area. The germination rate of the lettuce seeds was very low with 167 plants emerging out of the 552 seeds sown, which is 30.3 percent. This low success rate was most likely because of high temperatures at initial planting and the heavy rainfall experienced in June. Many of the seeds did not germinate or were simply washed away by the flood waters.

 

On July 23, plant vigor was determined by measuring chlorophyll levels of the lettuce plants. Each plant was scanned and the data recorded. The data was averaged and the standard deviation was determined to arrive at the final, relative chlorophyll reading.

See Table 9.

Table 9: Relative chlorophyll readings for lettuce

Relative chlorophyll readings for lettuce

The data above shows that the AGGRAND-fertilized plants had slightly less chlorophyll than the organic competitor plants, but more than the control, which means more nitrogen in the leaves, or increased vigor. This is somewhat counter to the observations that the plants subjected to the AGGRAND fertilization program yielded larger plants and earlier development when compared to the other growth plots. See Figure 28.

Figure 28: Harvesting AGGRAND lettuce

Lettuce harvest of the AGGRAND plot began on July 23, and showed superior development over the organic competitor and control plots. The lettuce root stem was cut off at the node where the bottom leaves of the plant meet. Each lettuce head was weighed using an AND FX3000i digital balance, serial # 15610355. See Figure 29.

Figure 29 Trimming root to node and weighing

trimming root to node and weighing

The lettuce harvest spanned several weeks, including the following days: July 23, 25, 30, Aug. 2, 6, and 10. Table 10 summarizes the lettuce harvest.

Table 10: Lettuce Harvest Competitive Plots

The AGGRAND - fertilized lettuce plot produced heavier heads and higher per-plant quantities than the produce grown with the organic competitor. As expected, the control plants fared the worst as far as quantity, total weight and number of plants.

Snap Peas Snap

Peas are a gardener’s favorite because they are relatively easy to grow and achieve high yields. This vegetable is easy to prepare and process because the entire pod can be consumed without the time-consuming pea-shelling process. The seed took approximately one month to germinate. Cold temperatures and excessive rain in June caused the delayed germination process. On June 28, a number of snap peas were replanted because of the flooding. Thinning to one plant per mound occurred throughout the summer because of increasing temperatures. Three snap-pea plants were replanted in the AGGRAND plot on July 12 because of the germination difficulty. Snap peas were picked when the pod was beginning to bulge but not enlarged. The pea pods were weighed per plant using an AND FX3000i digital balance, serial # 1561035. See Figures 30 and 31.

Figure 30: Picking Snap Peas

Figure 31: Weighing Snap Peas

digital weighing snap peas

Table 11: Summary of pea harvest in competitive plots

Summary of pea harvest in competitive plots

Yield Summary / Weather Observations

The AGGRAND-fertilized plot produced more pea pods than the organic competitor or the control plot. An unexpected development was that the control plants produced more pods than the organic competitor plot.

Yield Summary

Table 12: Total Yield (by number) in the competitive plots

yeild by number

Table 13: Total Yield (by weight in pounds) in the competitive plots

yield by weight lettuce, tomatoes, snap peas

Weather Observations

Historical weather data for the period 1909 to 2010 was acquired from Dr. Edward J. Hopkins, Assistant Wisconsin State Climatologist for observations in Superior, Wis., at position 46.70°N, 92.02°W, approximately 4.25 miles (6.84 km) southeast of the AGGRAND growth plots located at 46.73°N, 92.11°W. Temperature and precipitation comparisons covered a period from May through September where these parameters have the most influence on plant growth.

 

For the period of May through July 2012, and in September, the average maximum temperatures were higher than the 100-year average. This resulted in accelerated growth of tomatoes, but may have limited lettuce and pea germination. Average minimum temperatures were higher than the long-term average. The overall temperature during the period from May through September was slightly higher, which enabled the crops to be harvested about two weeks earlier than in 2011. See Graphs 1, 2 and 3.

Graph 1

Graph 2

Graph 3

Precipitation during the 2012 growing season was marked by extremes. May and June provided excessive precipitation, especially on June 19 and 20 when 8.36 inches (21.23 cm) of rain fell. The storm moved seeds out of the seedbeds and plots and caused physical stress on the tomato plants. Overall precipitation was above average for the 2012 growing season. However, July through September showed much lower than normal rainfall amounts, which required regular irrigation of the garden plots. See Graphs 4 and 5.

Graph 4

Soil Analysis and Respiration

Graph 5

Soil Analysis and Respiration

Soil respiration is an indicator of microbial activity and soil health. This was measured to determine if one fertilizing regime was more effective in obtaining a response from the soil microbial community. Table 14 and Graph 6 summarize the respiration of soil samples collected during the spring and fall of 2012. As the data reveals, the respiration in the AGGRAND plot is greater than the control and competitive plots, and also varies depending on the season. The soil samples collected in the autumn had a longer period of reduced moisture, thus reducing the microbial activity within the samples.

Table 14

colormetric reading and carbon dioxide levels

Graph 6

As with any cropping system there is removal of vegetation in the form of fruit, roots and stems. At the end of this growing season, most of the vegetative materials were removed from the plot after harvest. Soil analyses are conducted at the beginning and end of every growing season to determine the relative health of the soil, the impact of the crops growing on the plot and to determine if the fertilizing programs are maintaining or enhancing nutrient levels.

 

Soil samples were taken in April 2010, when no inputs or growth activity had taken place in the growth plots. Since then, soil samples have been obtained prior to planting and after harvest. The samples obtained in April and September 2012 reflect the composted manure input of October 2011 (AGGRAND, 2012).

 

 

Comparing the initial soil samples taken during April 2010 and the latest samples from September 2012, nitrate nitrogen is the only nutrient that appreciably increased since the 2011 growing season. This could be attributed to the microbial processing of the composted manure (AGGRAND, 2012). Because of the mechanisms of plant growth and natural weathering processes, a number of soil nutrients decreased in all plots. Sulfur levels were reduced in all plots, along with iron in the AGGRAND and control plots. Copper and boron levels are comparable in all plots, with manganese showing higher levels in the AGGRAND plot. Sodium, a highly leachable species, continues to be reduced in the AGGRAND and control plots, most likely from precipitation and water movement through the soil. The competitive plot sodium levels increased after the 2012 growing season, indicating a possible influence of the organic competitor fertilizer. When compared to the soils in the control and competitive plots, phosphorus, potassium, magnesium and nitrate levels are higher in the AGGRAND plots. See Graphs 7 - 10.

Graph 7

Graph 8

Graph 9

Graph 10

CONCLUSIONS

Overall, the 2012 Vegetable Productivity Study revealed that the AGGRAND fertilization program, as outlined in The Gardening Guide (AGGRAND, 2010), increased vegetable yield in terms of number and total weight over the competitive organic and control plots. The average weight and size of some of the AGGRAND vegetables were slightly smaller than the control or organic-fertilized produce, but not significantly.

 

The organic competitor fertilizer is comprised of a blend of liquid hydrolyzed fish, Chilean nitrate and seaweed that readily mixes with water and is easily applied. Application is frequent, with addition of the product every week during the growing season. The AGGRAND system enhances the soil environment and provides necessary nutrients, but requires the grower to monitor plant growth, flower bloom and fruit development for timely fertilizer applications. Timely additions of fertilizers and soil amendments are important when the plant is expending energy when developing flowers and fruit.

 

Nitrogen, phosphorus and potassium ratios (N, P, K) of the fertilizers employed in this study were 4-3-3, 0-12-0 and 0-0-8 for the AGGRAND program, and (4-4-1) for the organic competitor fertilizer. Both fertilizer systems tout that the products are natural or organic, and influence the soil in similar ways. Organic competitor products recommend a dilution rate significantly lower than the AGGRAND products, which is apparent when the products are mixed with water. The organic competitor produces a translucent liquid; while the AGGRAND product yields an opaque mixture that provides more nutrients to the plants and soil. Mix ratios for the competitive product were obtained from the manufacturer’s product label or website. The organic competitor offers similar products that recommend application every other week and once per week during the growing season. Per previous work with competitive products, it was decided to apply the highest recommended rate to determine the performance comparison with the AGGRAND system.

 

In 2011 there was difficulty establishing plants from seed due to the high temperature of the heated mats. As a result of installing thermostats set at 80°F (26.7°C) on the heated growth mats, the tomato starts had excellent germination rate ranging from 86% to 95%. Due to cut worm problems in 2011, additional starts were grown in 2012 for potential replacement in case of pests, hail or other environmental impacts. The transplant process went fairly well for the Competitive Plot tomatoes and produced satisfying yields. Over 580 pounds of tomatoes were produced in these plots. The AGGRAND tomato plants received four fertilizer applications in the field, while the organic competitor plants received a total of seven field applications. Nevertheless, the AGGRAND program produced, 6 percent by weight, more tomatoes than the organic competitor. This shows that the correct product mixture and application timing can increase yields with less labor. For future tomato work, more time will be taken to harden these plants prior to outdoor planting; protection will be provided with “Kozy Coats” Insulating Plant Protectors.

 

Snap peas were a convenient crop to evaluate because they have large seeds, are easy to grow, and, in this case, had ample room to trellis. As mentioned previously, elevated temperatures produced some difficulty in germination, plus the rain event in June caused flooding throughout the plots, and moved some of the seeds out of the planting area. The AGGRAND plot had considerable yield improvement over the organic competitor for both numbers and weight of snap peas. Planting in late May would provide a better yield.

 

AGGRAND - fertilized lettuce yields were substantially higher than the organic competitor. This directly correlated to the number of seeds that germinated in each plot. It appears the AGGRAND - fertilized plot retained moisture better, provided a higher concentration of growth hormones, keeping the seed cooler and facilitating better germination. The organic competitor plants were slightly heavier, but with the increased number of AGGRAND plants, the yields were in favor of AGGRAND.

 

The AGGRAND plot continues to show overall better nutrient levels than the competitive plot with higher phosphorus, potassium and magnesium. Nitrate - nitrogen increased in all plots as a result of adding the same amount of composted manure, but the AGGRAND plot tested higher for the nutrient, indicating that the mineralization process via microbial activity is higher in this soil. This is supported by higher CO2 respiration values for this plot.

REFERENCES

 

Albrecht, W.A. (1996). The Albrecht papers. (Vol. 1). Metairie, LA: Acres U.S.A.

 

AGGRAND (2011). 2010 Vegetable Productivity Study. G-2851. Superior, WI: AMSOIL, INC.

 

AGGRAND. (2012). 2011 Vegetable Productivity Study. G-2957. Superior, WI: AMSOIL, INC.

 

AGGRAND (2010). The gardening guide. G-1292. Superior, WI: AMSOIL, INC.

 

Brady, N.C., (1974). The Nature and Properties of Soils. New York, NY: MacMillan Publishing Co., Inc.

 

Carson, T., (2004). Golf Course Management. 72: 28.

 

Havlin, J.L., J.D. Beaton, S.L. Tisdale, and W.L. Nelson. (2005). Soil fertility and fertilizers, an introduction to nutrient management. Upper Saddle River, NJ: Pearson Education.

 

Haney, R. L., W. F. Brinton, and E. Evans. (2008). Soil CO2 respiration: comparison of chemical titration, CO2 IRGA analysis, and the Solvita gel system. Renewable Agriculture and Food Systems. 23:1–6.

 

Haney, R. L., W. F. Brinton, and E. Evans. 2008. Estimating soil carbon, nitrogen, and phosphorous mineralization from short-term carbon dioxide respiration. Communications in Soil Science and Plant Analysis. 39: 2706-2720.

 

Kinsey, N. and C. Walters. (2009). Hands on agronomy. Austin, TX: Acres U.S.A.

 

Murdock, L., D. Call, and J. James. (2004). Comparison and use of chlorophyll meters on wheat (reflectance vs. transmittance/absorbance). Lexington, KY: University of Kentucky Extension.

 

NASA. (2011). Chlorophyll Meters Aid Plant Nutrient Management. Available at: http://www.sti.nasa.gov/tto/Spinoff2009/er_10.html

 

National Stone Association. (1986). Aglime fact book. Washington, D.C.: National Stone Association.

 

Senn, T.L. (1987). Seaweed and plant growth. Clemson, SC: Senn.

 

Taiz, L. and E. Zeiger. (1991). Plant Physiology. Redwood City, CA: The Benjamin/Cummings Publishing Company, Inc.

AGGRAND Natural Liquid Kelp and Sulfate of Potash 0-0-8

• Provides increased heat, cold and drought tolerance

• Decreases susceptibility to insect attack and infection by disease-causing organisms

• Aids in early plant growth and development

• Promotes early ripening, improves quality and extends shelf-life of fruits and vegetables

• Effective as a foliar feed or soil application

• Washington State Department of Agriculture (WSDA) Listed for use in organic crop production

 

 

 

AGGRAND Fertilizer Organic Series 4-3-3

• Multi-purpose – produces excellent results on flowers, fruits, vegetables, lawns, trees and crops

• Contains menhaden fish emulsion, North Atlantic Kelp, sulfate of potash and rock phosphate

• Rock phosphate provides a natural source of phosphorus and calcium

• Effective as a foliar feed or soil application

• OMRI Listed product meets the USDA National Organic Plan (NOP) grower requirements

• Registered with the California Department of Agriculture Organic Input Materials program

 

 

 

AGGRAND Natural Fertilizer 4-3-3

• Multi-purpose – excellent for flowers, fruits, vegetables, lawns, trees and crops

• Contains menhaden fish emulsion, North Atlantic Kelp, sulfate of potash and blood meal

• Effective as a foliar feed or soil application

• Stimulates soil microbial activity

• Promotes plant vigor which contributes to disease and stress tolerance

• USDA Bio-Preferred Product – 100 percent bio-based

 

 

 

AGGRAND Natural Liquid Lime

• Very fine calcitic limestone in suspension

• Effective as a foliar or soil application – improves plants’ cellular structure

• For lawns, pastures and hay fields to supply calcium (additional soil liming may be required on highly acidic soils)

• Improves soil structure and the environment for soil organisms AGGRAND Natural Liquid Bone Meal 0-12-0

• Provides a readily available source of phosphorus and calcium

• Releases slowly over the growing season

• Perfect for all flowering bulbs and transplants

• Ideal for root and fruit crops

 

 

AGGRAND Natural Liquid Bone Meal 0-12-0

• Provides a readily available source of phosphorus and calcium

• Releases slowly over the growing season

• Perfect for all flowering bulbs and transplants

 • Ideal for root and fruit crops