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Previous crops were durum in 2003, potatoes in 2002, and safflower in 2001. Residual soil N to 4 feet was 28 lb/ac. Residual soil P to 6 inches was 27 ppm and residual soil K to 6 inches was 483 ppm. Five rates of liquid 28-0-0 were applied September 17, 2003. A check treatment with no applied N was included.

Table 1. Residual soil N and applied soil N on sugarbeets grown under sprinkler and flood irrigation.

Plots were planted to stand with the variety AC927 on Apr 22 with a commercial six-row planter. Ro-Neet 6E (3.5 lb AI/ac) and Counter (1 lb AI/ac) were applied in 7” bands at planting. Betamix (0.75 pt/ac) was applied on June 2. Headline (9.2 oz/ac) was applied by ground rig on July 20. Sprinkler plots were irrigated on Apr 29, May 4, May 22, Jun 29, Jul 15, Jul 21, Jul 28, Aug 5, Aug 12, Aug 23, and Sep 7. Flood irrigated plots were irrigated on Jun 22, Jul 7, Aug 4, Aug 17, and Aug 30. Precipitation for April 1 – September 30 in 2004 was 7.62 inches. Average precipitation for April - September period (56-year average) is 10.72 inches. Plots were harvested on Oct 1.

Table 2. Stand, yield, and quality of sugarbeets grown under flood and sprinkler irrigation with six rates of available N.

N to 4 ft and applied N, lb/ac	Irrigation	Harvest Stand, plants/ac	% sucrose	Root Yield T/acre	Sucrose Yield, Lb/acre	Na ppm	K ppm	Amino-N ppm	% extrac-tion	Extract-able Sucrose, Lb/acre
28	flood	37990	19.87	26.6	10910	159	1497	97	96.1	10460
100	flood	37630	19.94	28.1	11210	175	1575	110	95.8	10740
125	flood	40050	20.27	28.4	11530	169	1507	103	96.1	11080
150	flood	38720	20.09	27.6	11110	186	1479	104	96.0	10670
175	flood	39080	19.64	28.6	11210	218	1515	119	95.7	10730
200	flood	39930	19.43	30.5	11710	240	1664	130	95.1	11130
LSD_0.05		NS	0.54	2.2	NS	39	96	NS	0.4	NS
28	sprinkler	40540	20.01	28.1	11230	174	1512	118	95.9	10760
100	sprinkler	41020	19.61	30.9	12090	225	1741	160	94.9	11480
125	sprinkler	41990	19.26	30.3	11680	223	1688	185	94.7	11060
150	sprinkler	41500	19.29	30.4	11740	208	1599	168	95.1	11160
175	sprinkler	38720	19.38	29.4	11390	218	1635	165	95.1	10830
200	sprinkler	42110	19.32	29.8	11520	216	1575	147	95.3	10970
LSD_0.05		NS	0.53	NS	NS	NS	155	47	0.7	NS

Greatest root yield and sucrose yield under flood irrigation were achieved with 200 lb of available N. This treatment had the highest amount of applied N (172 lb/ac). Greatest root yield and sucrose yield under sprinkler irrigation were achieved with 100 lb of available N. This was the lowest amount of applied N (72 lb/ac). Sugarbeets under sprinkler irrigation had higher average impurity contents than sugarbeets under flood irrigation, with greater loss to molasses and lower percent extraction. These data indicate that sprinkler irrigated sugarbeets need less applied N than flood irrigation sugarbeets.

Treatment	Soil N to 4 feet	Applied N	Available N
No applied N	28	0	28
Recommended – 50 lb/ac	28	72	100
Recommended – 25 lb/ac	28	97	125
Recommended	28	122	150
Recommended + 25 lb/ac	28	147	175
Recommended + 50 lb/ac	28	172	200