Search

Fertility management has been a major concern for carrot growers because there has been little or no yield response to fertilizer application in various trials, even when fertilizer is based on soil test recommendations. Tissue testing may be an appropriate method to manage fertilizer applications to carrots. A greenhouse trial was conducted to identify critical tissue(s) at various growth stages that correlate with yield, establish relationships between nutrient concentrations of critical tissue(s) and nutrient concentrations in soil, and establish relationships among nutrient concentrations of critical tissue(s), nutrient concentrations in soil, and yield. Critical tissues varied for each nutrient studied at each growth stage. Correlations revealed significant relationships between nutrient concentrations of critical tissues and soil largely at active bulking but very few at initiation of bulking. Trend graphs revealed tissue zinc (Zn) concentration had the strongest relationship with yield. There was a significant difference in root fresh weight (RFW) with nitrogen (N) at 100 µg/g, significantly higher than at 0, 300, 350, and 400 µg/g. Greenhouse results suggest fertilizer with an N equivalent of 100 µg/g optimized yields. [ABSTRACT FROM AUTHOR]

Nitrogen (N) management in carrot ( Daucus carota L. var sativus ) production systems is critical for increasing efficiency of crop production, decreasing costs, and decreasing nitrate leaching losses to groundwater. Leaf tissue testing may be an appropriate method to monitor and meet carrot N requirements. A field trial was conducted in three locations to 1) determine if “critical tissues” identified in previous research are appropriate for leaf tissue testing in N management of carrots, 2) determine the effects of various N regimes on soil and tissue N concentrations, 3) describe the relationships among soil N concentrations, tissue N concentrations, and yield for several N regimes, and 4) study the effects of N regimes on growth, yield, and recovery of marketable grades of carrots. Nitrogen critical tissues for leaf tissue testing were not useful in N management. Overall, results showed no significant differences in soil and tissue N levels due to increasing N regimes. Correlations among soil, tissue, and yield differed at each harvest but most were not significant. N concentration was higher in soils at a depth of 0–15 cm compared to 15–30 cm. Total N concentrations in tissues decreased over sequential harvests. No clear relationships emerged comparing tissue NO 3 ‐N to soil N measurements over the entire growing season. There were no significant differences in growth and yield of carrots in response to N regimes. Interestingly, a N rate of 0 kg/ha had significantly more fancy‐grade carrots than a N rate of 200 kg/ha. There were no significant differences in culls due to increasing N application. [ABSTRACT FROM AUTHOR]