|Stone, Kenneth - Ken|
|Foulk, Jonn - Fx - Fibers Llc|
|Dodd, Roy - Retired Non ARS Employee|
Submitted to: Crop, Forage & Turfgrass Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2015
Publication Date: 6/26/2015
Citation: Bauer, P.J., Stone, K.C., Foulk, J.A., Dodd, R.B. 2015. Nitrogen, phosphorus, potassium, calcium, magnesium, and zinc in southeastern USA harvested flax. Crop, Forage, & Turfgrass Management. doi: 10.2134/cftm2014.0082.
Interpretive Summary: Flax is a potential winter crop for the Southeast USA. Estimates of the fertilizer nutrients removed from the crop in the region are not available but will be useful for designing improved fertilizer management. We conducted this field experiment to determine how irrigation and cultivar affect nitrogen, phosphorus, potassium, calcium, magnesium, and zinc removal from a field when flax is harvested for straw (fiber), grain, or both. Our evaluation included a comparison of seed-type cultivar to fiber-type cultivars. We found irrigation has little effect on nutrient concentrations in the plant. Concentrations of nutrients in the straw were similar for the two cultivar types, but the two cultivar types differed for nutrient concentrations in the grain. Removal of nutrients from the field was primarily dependent on straw and grain yield. These results will be used by individuals in the flax fiber industry, extension personnel, and other agricultural advisors in developing production practices for farmers.
Technical Abstract: Flax (Linum usitatissimum L.) is a winter crop in the Southeast USA that has potential in double cropping systems. This research was conducted to provide estimates of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and zinc (Zn) removal in the harvested portions of the crop (straw and grain). Four fiber-type cultivars and one seed-type cultivar were grown with and without irrigation for two years. The four fiber-types were grown without irrigation in the third year. Nutrient concentrations were determined on the straw and grain in the first two years when the crop was harvested at seed maturity. In the third year, only nutrient concentrations in the straw were measured. Irrigation had a very limited impact on straw and grain nutrient concentrations. Differences among years were greatest for K concentration in the straw as K concentration in 2011/2012 was over 1.00% and almost five times greater than in the other two years. Differences occurred between the straw-type cultivars and the seed-type cultivars for both straw and seed nutrient concentration, but these were generally small. Nutrient removal in the flax straw and grain were primarily dependent on biomass. Our results indicate a flax straw crop of 5000 pounds (lbs) per acre will remove 48 lbs N, 8 lbs P, 13-56 lbs K, 17 lbs Ca, 9 lbs Mg, and 0.28 lbs Zn per acre.