Garlic- Fertilization and Foliar Feeding

2005

 

During the garlic growing season of 2004-2005, we compared the application of different top-dressed and foliar fertilizers to stiff neck garlic and examined the effects on garlic bulb yield. Many small growers use foliar feeding in their fertility management program. We studied whether it would be worthwhile for a grower to apply foliar fertilizers to the garlic plants or top-dress their garlic beds with fertilizers such as alfalfa meal or compost.

Null Hypotheses

  1. There will be no difference in yields between a high potassium foliar fertilizer and a high nitrogen foliar fertilizer compared to the untreated control.
  2. There will be no difference in yields between the alfalfa meal and poultry compost top-dressing treatments and the untreated control.

Methods

On November 12, 2004, the garlic variety Music was hand-planted on 30 inch beds in double rows at 6″ spacing. ¬†Forty cloves were planted for each replication and there were four replications of each treatment for both experiments. We used a randomized complete block design with four blocks per experiment. Pre-planting soil fertility was adequate for average production.

Top-dressing Fertilization Experiment
Foliar Fertilization Experiment
alfalfa
alfalfa
poultry
control
maxicrop
maxicrop
control
mermaids
control
poultry
alfalfa
poultry
mermaids
control
maxicrop

maxicrop

poultry
control
control
alfalfa
control
mermaids
mermaids
control
I
II
III
IV
I
II
III
IV
The garlic was covered with two layers of floating row cover for the winter and secured with pots filled with soil. The covers were removed on April 20, 2005. The garlic was hand cultivated in early May and again in early June. No flame weeding was done this year due to low weed pressure.

Two different types of foliar fertilizers were used. One is a high nitrogen fertilizer (Mermaids Fish Powder) which is made up of hydrolyzed fish powder containing 12% N, 0.25% P, and 1.0% K. This foliar fertilizer had high solubility. We applied it at a rate of 1 Tbsp./gallon of water. The other type of foliar fertilizer is high in potassium (Maxicrop Kelp Extract). This foliar fertilizer is extracted from Norwegian sea kelp and is reported to contain 70+ growth hormones, cytokinins, auxins, vitamins, and enzymes. It is also rich in trace elements. It contains 1% N, 0% P, and 4% K. We applied it at the rate of 1/2 tsp./gallon of water.

The plants were sprayed with the foliar feed to the point of run-off early in the morning or in the late evening when the sun was not as intense and there was no wind. We sprayed the foliar fertilizers four different times during the time of major bulb development (May 19th, June 2nd, June 16th, and June 23rd).

For the top-dressing fertilization experiment, we applied either poultry compost or alfalfa pellets on May 5, 2005. Each 15 square foot treatment replicate received either 5.5 lbs. of alfalfa pellets or 3.4 lbs of poultry compost.

The garlic plots received 9.6 inches of precipitation. In addition, 3.9 acre inches of water was supplied by a single line of drip tape for a total of 13.5 inches over the entire growing season. Our previous research has indicated that garlic needs at least 12 inches of water for optimal production.

The garlic was hand harvested on July 5, 2005. For data collection, 20 randomly chosen bulbs were measured from each replication. Diameter of the bulb and individual bulb weight were recorded. Data analysis was performed on Systat (version 10.0, SPSS, Inc.), using ANOVAs and an alpha value of 0.05.

Results

Some interesting trends were found in the foliar fertilizer study, however there were no statistically significant differences in the treatments.

For the top-dressing experiment, some of our results were confounding and indicated the possibility of error in our methodology. We will be repeating the study in the future and will report the results on our website when they are available.

Conclusions

Initial results show no appreciable difference in the use of foliar fertilizers compared to the control plants when the field baseline fertility is adequate. The practice of foliar feeding requires additional time and energy on the part of the grower. According to our study, it is questionable as to whether it is worth the time and cost involved.
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