Oakes Irrigation Research Site
Carrington Research Extension Center * North Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Phone: (701) 742-2744, FAX: (701) 742-2700, E-mail:												Blaine.Schatz@ndsu.edu
												Leonard.Besemann@ndsu.edu

2013 Irrigated Potato Starter Fertilizer Trial
H. Hatterman-Valenti and C. Auwarter

This study was conducted at the Oakes Irrigation Research Site to evaluate various rates of in‑furrow starter fertilizer on Russet Burbank potato. Plots were 4 rows by 17 feet arranged in a randomized complete block design with four replicates. Starter fertilizer, fert-A and fert-B, was tank-mixed and applied at different rates (shown below). There was also a grower standard application with 10-34-0 at 25 gal/ac and an untreated that didn’t receive any starter fertilizer. Soil tests taken prior to trial showed 22 lbs N, 15 ppm P, and 140 ppm K. Pre-plant applications of 50 lbs N as 46-0-0 and 200 lbs K (grower standard application, treatment 2) and 140 lbs K (treatments 3-6) as 0-0-60 were applied and incorporated on May 15, 2013. Closing disks were removed from the planter as we planted potatoes to expose seed piece in-furrow and applied starter fertilizer. In addition to fert-A and fert-B, 28-0-0 was tank mixed to bring the total N to 100 lbs in each treatment. At this point, 100 lbs N, various lbs P and 200 lbs K were applied in treatment 2, and 140 lbs K were applied in treatments 3-6. Fifty lbs N/ac was stream-bar applied on June 6 and July 11 as 28-0-0. Thirty-four lbs N/ac was stream-bar applied on July 20 as 28-0-0. The stream-bar applied N treatments were immediately irrigated with 0.30” water. Potatoes were harvested October 29 with a single-row digger and graded in Fargo.

Fertilizer applications:			A = 5/15/13 – Treatments 1-6 @ Pre-plant
			B = 5/15/13 – Treatments 2-6 @ Planting
			C = 6/6/13 – Treatments 1-6 @ Tuber hooking
			D = 7/11/13 – Treatments 1-6 @ Early tuber bulking
			E = 7/20/13 – Treatments 1-6 @ Tuber bulking

All treatments had total yields over 400 CWT/ac. The highest yielding treatment had the highest amount of fert-A at 20 gal/ac (trt 5) with a total yield of 484 CWT/ac. The lowest yielding treatment was the grower’s standard practice (trt 2) with 413 CWT/ac. Treatments 4 and 5 were the only treatments with over 400 CWT/ac of marketable tubers. These two treatments also had the most harvested tubers with 133 and 137 in 20 ft of row, respectively.

Table 1. Treatments and yield data in the 2013 Irrigated Starter Fertilizer Trial.
Trt	Form	Rate/		App		ounces						ounces
Name	Conc	Unit		Code	Total	0-4	4-6	6-10	>10	>4	Total	0-4	4-6	6-10	>10
					----------------CWT/ac------------------						--Tuber Count in 20 feet--

1 N	28%	50 lb ai/a		A	431	36	41	139	216	395	120	39	18	35	28
N	28%	50 lb ai/a		C
N	28%	50 lb ai/a		D
N	28%	34 lb ai/a		E
2 N	46%	50 lb ai/a		A	413	37	44	131	200	375	120	41	19	33	27
K	60%	200 lb ai/a		A
10-34-0	10,34%	25 gal/a		B
N	28%	50 lb ai/a		C
N	28%	50 lb ai/a		D
N	28%	34 lb ai/a		E
3 N	46%	50 lb ai/a		A	418	31	39	146	202	386	118	37	17	37	27
K	60%	140 lb ai/a		A
Fert-A¹	na	15 gal/a		B
Fert-B¹	na	3 gal/a		B
N	28%	50 lb ai/a		C
N	28%	50 lb ai/a		D
N	28/%	34 lb ai/a		E
4 N	46%	50 lb ai/a		A	469	39	54	155	222	431	133	42	24	39	28
N	60%	140 lb ai/a		A
Fert-A¹	na	10 gal/a		B
Fert-B¹	na	2 gal/a		B
N	28%	50 lb ai/a		C
N	28%	50 lb ai/a		D
N	28%	34 lb ai/a		E
5 N	46%	50 lb ai/a		A	484	37	40	175	232	446	137	42	18	45	32
K	60%	140 lb ai/a		A
Fert-A¹	na	20 gal/a		B
Fert-B¹	na	3 gal/a		B
N	28%	50 lb ai/a		C
N	28%	50 lb ai/a		D
N	28%	34 lb ai/a		E
6 N	46%	50 lb ai/a		A	428	39	39	130	221	390	120	41	17	33	29
K	60%	140 lb ai/a		A
Fert-A¹	na	10 gal/a		B
Fert-B¹	na	5 gal/a		B
N	28%	50 lb ai/a		C
N	28%	50 lb ai/a		D
N	28%	34 lb ai/a		E

LSD (P = 0.05)					222	20	23	89	131	214	57	21	10	23	19

¹ Fert –A & B – Confidential data.

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