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RUSSET NORKOTAH: MANAGEMENT PROFILE
Seed and Planting
Due to its tendency to oversize, Russet Norkotah should be planted 9 to 11 inches apart within rows. Plant six inches deep due to a high set. Cut seed pieces are preferred over single drops in order for the plant to have more stem. Avoid physiologically ageing seed. Don't warm seed at 60 F for more than two weeks before planting. Don't hold pre-cut seed for more than a month. Don't plant in cold soil, less than 50 F, or stem cankers, Rhizoctonia, develop resulting in poor roots and poor nutrient uptake. Early planting does not increase yields but will allow early harvest with full yield potential. This makes Russet Norkotah a good summer crop. Also, this variety grows better in acidic soils over alkaline soils.
Toxic Seedpiece-Decay Syndrom
This is an unusual disorder that is observed in very few varieties. However, it is often seen in Russet Norkotah. A noticable wilting of the vine occurs just before tuberization about 3 weeks after emergence and is associated with the plant switching its nutrient flow from the seedpiece to the root system. The root system about this time has reached its maximum growth (12 inches root length) and the canopy is about midway (10 inches stem height) in its growth (Pavlista, 1995, UNL Cooperative Extension Circular 95-1249 "Potato Production Stages: Scheduling Key Practices"). Leaf margins in the upper canopy, the new leaves, dehydrate and turn brownish as if windburned. Brown streaks may be visible along the lower part of the stems. The seedpiece rots leaving a light-brown, jelly-like residue. The cause is not known but the syndrom occurs when early season weather conditions were wet and warm. Plants normally recover in two weeks from this. I have not found any data relating this to yield or quality loss in the crop and I have only seen this syndrom occur occasionally in the summer crop in south of the North Platte River.
Fertilization
Russet Norkotah requires 20-30% less nitrogen than recommended for Russet Burbank. Colorado recommendations are 200-230 lb N/acre, 120-200 lb P/acre and 0-40 lb K/acre. Apply most nitrogen before tuber set (first flowering). Early pre-plant nitrogen should be above 100 lb N/acre to get maximum rapid growth, 110-140 lb N/acre is usually recommended. The remaining 75-100 lb may be applied through the sprinkler in 10-25 lb increments. High early-season application of nitrogen does not delay tuberization, but mid-season application can slow tuber bulking which normally is rapid. Russet Norkotah grows well after alfalfa and clover.
In most Nebraska soils, adding potassium is usually not recommended.
Petiole Nitrate-Nitrogen
Unlike most potato varieties, Russet Norkotah shows little, if any, yield response to split nitrogen application. When all nitrogen is added pre-plant, nitrate-N levels were 16-18,000 ppm at 55 days after planting (DAP) and dropped to about 6-8,000 ppm at tuber maturation (Figure 1). Higher nitrate-N levels were associated with yield decreases in Idaho. Russet Norkotah matures earlier than Shepody and requires less nitrogen uptake for best yield, grade and quality compared to Shepody (see NPE, April, 1996).
Irrigation
Since the rooting system is very shallow, about 12 inches deep, Russet Norkotah is sensitive to drought stress. The recommended irrigation interval at maximum ET early in the season is 2½ days. Early season drought stress must be avoided. On the other hand, because of its rapid tuber bulking and early senescence, over-watering during the later part of the season must be avoided. Late-season over-watering may result in leak, blackleg/soft rot and pink rot especially during warm day-time temperatures.
Insect Note
Aphids are notably attracted to Russet Norkotah.
Senescence/Desiccation
Due to its early maturity, Russet Norkotah usually undergoes natural senescence about mid-August. As a fall crop, it should be allowed to die naturally unless field sampling shows a large number of tubers are oversizing. This variety is easily desiccated and desiccants may be applied 95-110 days from planting or 70-80 days after emergence depending on planting date. Skin set can occur as early as 12 days after desiccation but needs to be checked before harvest.
Harvest/Disease Notes
Harvesting of Russet Norkotah needs to be done under cool temperatures and dry soil conditions, usually in the morning. This is because of this variety propensity for Pythium leak and Erwinia soft rot/blackleg. Metalaxyl with a blight protectant treatments, applied when tubers are about "marble sized" and when they are about "golf ball sized" are highly recommended to assist controlling soft rot and pink rot. After harvest, tubers need to be kept cool, dry and well ventilated. Neither Pythium nor Erwinia like air. If lenticels are swollen due to excess soil moisture, these diseases readily enter the tuber and a wet barrier over lenticels inhibiting air passage into tubers promotes growth of these diseases inside.
Storage/Disease Notes
Storage of fall crop Russet Norkotah is not recommended past March. About 3-4 months storage is maximum for best results. It's lack of storability is due to its disease susceptibility, tendency to dehydrate and bruising in storage. Besides leak, soft rot and pink rot, this variety is prone to silver scurf, tuber early blight, dry rot, and moderately to black scurf. During long storage, it dehydrates and develops pressure bruising and internal blackspot.
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