Cooperative Extension Service
College of Agricultural and Environmental Sciences
The University of Georgia
George
Boyhan, Extension Horticulturist-Vegetables
East Georgia Extension Center
Rosenwald Building, Third Floor
PO Box 8112
Georgia Southern University
Statesboro, GA 30460
912-681-5639 | 912-681-0376, Fax | 912-682-3481,
mobile
I've updated my mailing list for my newsletter, so this may be the first time you've received this; or you may know someone who received it in the past who is not receiving it now. Instead of sending my newsletter to everyone in the extension listserv, I try to target those who would be most interested in my areas of specialization.
The newsletter primarily serves those agriculture agents in onion counties, counties with organic growers and counties with significant cucurbit production. I also try to target counties in the Southeast. Also on the list are those who have requested they receive the newsletter as well as outside clientele such as seed companies and fertilizer companies.
Please remember this is a work in progress, and the mailing list will be fine-tuned over time. If you know anyone who you think should be receiving this newsletter, let me know.
We have completed the third year of onion fertility experiments. The results of the third year (2001-2002) are in the table below. The soil test recommended 150 pounds of nitrogen, 40 pounds phosphorus, 180 pounds potassium and 60 pounds sulfur. These levels were used for all treatments, varying the element under consideration. All phosphorus was applied at planting unless it was a phosphorus treatment, in which case the treatment was put out in three applications. The fertilizer applications dates were December 6, 2001; January 29, 2002; and February 25, 2002. Onions were harvested on May 8, 2002, which was late for this year. Notice the dramatic loss in yield from field weights to graded yields. This was due to severe bacterial disease, particularly sour skin on the late-harvested onions at the Vidalia Farm.
The top five treatments were 150 pounds of nitrogen/acre applied as diammonium phosphate (DAP), the Meister program 1 (125 pounds nitrogen/acre), ammonium nitrate (150 pounds nitrogen/acre), DAP at 100 pounds nitrogen/acre, and Meister program 2 (150 pounds of nitrogen/acre). It should be remembered that these results are preliminary and for one year only. A more detailed analysis of data with other years is required to get a true picture.
| Onion Fertility Experiment, 2001-2002 | ||||||||||
| Treatments | Field
Weight 50-lb bags/A |
Cured 50-lb bags/A |
Jumbo 50-lb bags/A |
Medium 50-lb bags/A |
Nitrogen (%) |
Phosphorus (%) |
Potassium (%) |
Calcium (%) |
Sulfur (%) |
Magnesium (%) |
| DAP 150 units nitrogen, 180 units potassium | 1038 | 926 | 173 | 9 | 3.3 | 0.68 | 3.9 | 0.71 | 1.04 | 0.21 |
| Meister Program 1 | 1034 | 954 | 217 | 27 | 2.8 | 0.49 | 3.5 | 0.66 | 0.52 | 0.21 |
| NH4NO3 150 units nitrogen, 180 units potassium | 1010 | 924 | 187 | 7 | 4.2 | 0.47 | 4.3 | 0.75 | 0.99 | 0.20 |
| DAP 100 units nitrogen, 130 units potassium | 1004 | 896 | 122 | 7 | 4.6 | 0.64 | 3.8 | 0.77 | 0.99 | 0.19 |
| Meister Program 2 | 962 | 911 | 231 | 9 | 2.8 | 0.42 | 3.3 | 0.72 | 0.52 | 0.23 |
| KCl 160 units potassium, 150 units nitrogen | 957 | 777 | 244 | 21 | 3.9 | 0.50 | 4.2 | 0.99 | 0.86 | 0.19 |
| 150 units nitrogen, 180 units potassium, 40 units phosphorus | 937 | 874 | 317 | 22 | 3.5 | 0.37 | 4.0 | 0.98 | 0.85 | 0.17 |
| 0 units potassium, 150 units nitrogen | 928 | 868 | 315 | 20 | 4.0 | 0.52 | 3.1 | 1.03 | 0.83 | 0.22 |
| 150 units nitrogen, 180 units potassium, 300 units phosphorus | 911 | 847 | 304 | 17 | 3.6 | 0.56 | 4.0 | 0.90 | 1.15 | 0.19 |
| 150 units nitrogen, 180 units potassium, 235 units phosphorus | 903 | 827 | 210 | 21 | 3.7 | 0.51 | 3.5 | 0.95 | 0.92 | 0.17 |
| KCl 100 units potassium, 150 units nitrogen | 897 | 848 | 338 | 39 | 3.5 | 0.44 | 3.3 | 0.88 | 0.84 | 0.18 |
| CaNO3 150 units nitrogen, 180 units potassium | 882 | 748 | 244 | 12 | 3.7 | 0.47 | 4.1 | 0.84 | 0.97 | 0.18 |
| 150 units nitrogen, 180 units potassium, 170 units phosphorus | 877 | 811 | 194 | 33 | 3.5 | 0.54 | 3.7 | 0.86 | 0.85 | 0.17 |
| Regal Chemical program 2 (Liquigreen) | 866 | 801 | 160 | 13 | 3.6 | 0.44 | 4.2 | 0.68 | 0.92 | 0.24 |
| CaNO3 175 units nitrogen, 180 units potassium | 866 | 796 | 191 | 21 | 3.5 | 0.54 | 4.7 | 0.97 | 0.84 | 0.18 |
| 150 units nitrogen, 180 units potassium, 0 units phosphorus | 844 | 783 | 287 | 39 | 3.4 | 0.38 | 4.1 | 0.90 | 0.79 | 0.17 |
| Regal Chemical program 1 (Liquigreen) | 838 | 884 | 258 | 21 | 4.1 | 0.38 | 3.3 | 0.99 | 0.44 | 0.32 |
| KCl 70 units potassium, 150 units nitrogen | 818 | 772 | 248 | 21 | 3.8 | 0.55 | 4.0 | 0.94 | 0.89 | 0.20 |
| 150 units nitrogen, 180 units potassium, 105 units phosphorus | 800 | 747 | 241 | 30 | 3.7 | 0.40 | 3.8 | 0.86 | 0.89 | 0.17 |
| KCl 190 units potassium, 150 units nitrogen | 760 | 744 | 305 | 25 | 3.3 | 0.50 | 4.8 | 0.92 | 0.91 | 0.18 |
| CaNO3 75 units nitrogen, 180 units potassium | 692 | 643 | 244 | 44 | 2.8 | 0.45 | 3.6 | 0.79 | 0.59 | 0.16 |
| CaNO3 100 units nitrogen, 180 units potassium | 664 | 629 | 191 | 20 | 2.9 | 0.51 | 4.2 | 0.85 | 0.80 | 0.18 |
| CaNO3 125 units nitrogen, 180 units potassium | 639 | 593 | 188 | 23 | 3.1 | 0.51 | 3.8 | 0.75 | 0.72 | 0.16 |
| 0 units nitrogen, 180 units potassium | 182 | 162 | 11 | 96 | 2.0 | 0.50 | 3.6 | 0.95 | 0.50 | 0.20 |
| R2 | 0.619 | 0.611 | 0.481 | 0.760 | 0.347 | 0.298 | 0.288 | 0.507 | 0.733 | 0.585 |
| CV | 25% | 38% | 56% | 117% | 26% | 28% | 21% | 18% | 26% | 22% |
Adjusted
LSD (p 0.05) |
277 | 249 | 138 | 22 | 1.53 | NS | NS | 0.23 | 0.21 | 0.06 |
| 1 | DAP 150 units nitrogen, 180 units potassium |
| 2 | 0 units nitrogen, 180 units potassium |
| 3 | CaNO3 75 units nitrogen, 180 units potassium |
| 4 | CaNO3 100 units nitrogen, 180 units potassium |
| 5 | CaNO3 125 units nitrogen, 180 units potassium |
| 6 | CaNO3 150 units nitrogen, 180 units potassium |
| 7 | CaNO3 175 units nitrogen, 180 units potassium |
| 8 | NH4NO3 150 units nitrogen, 180 units potassium |
| 9 | DAP 100 units nitrogen, 130 units potassium |
| 10 | 0 units potassium, 150 units nitrogen |
| 11 | KCl 70 units potassium, 150 units nitrogen |
| 12 | KCl 100 units potassium, 150 units nitrogen |
| 13 | KCl 160 units potassium, 150 units nitrogen |
| 14 | KCl 190 units potassium, 150 units nitrogen |
| 15 | Regal Chemical program 1 (Liquigreen) |
| 16 | Regal Chemical program 2 (Liquigreen) |
| 17 | Meister Program 1 |
| 18 | Meister Program 2 |
| 19 | 150 units nitrogen, 180 units potassium, 0 units phosphorus |
| 20 | 150 units nitrogen, 180 units potassium, 40 units phosphorus |
| 21 | 150 units nitrogen, 180 units potassium, 105 units phosphorus |
| 22 | 150 units nitrogen, 180 units potassium, 170 units phosphorus |
| 23 | 150 units nitrogen, 180 units potassium, 235 units phosphorus |
| 24 | 150 units nitrogen, 180 units potassium, 300 units phosphorus |
| Soil Test Recommendations: | |
| - | 150N-40P-180K and 60S |
| - | Variety: Sweet Melissa |
| - | All phosphorus 1st application except P treatments |
| - | Sulfur source: CaSO4 (14% S) |
| - | Sulfur application split 1/2 at planting, 1/2 end of January |
| - | DAP: 18-46-0 |
| - | CaNO3: 15.5-0-0 |
| - | Phosphorus: 0-20-0 |
| - | Potassium: 0-0-60 |
| - | December 6, 2001 - 1st application |
| - | January 29, 2002 - 2nd application |
| - | February 25, 2002 - 3rd application |
| - | Harvested 5/8/02 |
| - | Meister 19-8-19 |
| 15 | Regal: 18-6-8 |
| 16 | Regal: 14-0-12 8% sulfur |
From My Desk
This is a very short newsletter and it's a month late. I was on vacation in July and attended the NACAA meeting in Savannah right after my vacation; I've been trying to catch up ever since. I also just got my new computer and have been transferring my files over as well as changing some software I use. I switched e-mail software and had some trouble converting my mail list. I hope everyone who is supposed to get this does.
I plan on getting my August newsletter out ASAP. Thank you for your patience.