Malvern Westcott

Direct measurement of petiole sap nitrate in potato to determine crop nitrogen status.

Abstract Rapid determination of crop nitrogen (N) status in the field would facilitate the use of plant tissue testing as a tool for ? management in potato (Solarium tuberosum L.). The Cardy portable nitrate (NO3) meter may provide the means for on‐site determination of petiole sap NO3 (PSN) concentration. Our objective was to establish the relationship between Cardy meter readings of PSN and laboratory measures of petiole dry matter NO3 (PDMN). In a two‐year replicated field study in western Montana, ‘Russet Burbank1 potatoes were grown under a line‐source sprinkler irrigation system with ? fertilization treatments of 0 ? or a rate of 270 kg N/ha applied in four different timing schemes. This created a wide range in crop ? and water status. Petiole samples were collected at five or six dates each year. Subsamples were analyzed for PSN in expressed sap using the Cardy NO3‐specific electrode or for PDMN with a benchtop NO3‐specific electrode after extraction with a solution of aluminum sulfate [A12(SO4)3]....

Drip irrigation for application of potassium to tart cherry 1

Abstract Fertilization of fruit crops through drip irrigation is an efficient method of meeting the crops nutritional needs, though cumulative effects or interactions with native minerals may be pronounced in the restricted zone of application. Sources of potassium (K) for tart cherries have not been previously compared for their effects on tree performance and possible interaction with other nutrients under conditions of drip application in an orchard. Our objective was to evaluate these factors by drip application of four rates (0, 0.35, 0.7, and 1.4 kg K2O per tree) of three sources (KCl, KNO3, and K2SO4) of K to tart cherry trees during three consecutive growing seasons. Application of non‐Cl sources of K by this method maintained foliar K within the sufficiency range and increased fruit yield in one year of the study, but had no effect on fruit size or quality. Maximum fruit yield was obtained at 1.5–2.0% foliar K. Application of non‐Cl sources suppressed uptake of calcium (Ca) and magnesium (Mg) in...

Seasonal Trends and Plant Density Effects on Cichoric Acid in Echinacea purpurea (L.) Moench

ABSTRACT Field studies were used to identify the effects of plant density and seasonal trends on cichoric acid in Echinacea purpurea roots, foliage, and flowers. A spoke-wheel planting design was used to determine optimum plant density. Very dense plant populations (over 15 plants per m2) resulted in high biomass production, but cichoric acid concentration in the plant tissue was reduced. A density of 9 to 10 plants/ m2 maintained cichoric acid in the root near 12 mg/g with root dry matter yields of approximately 2500 kg/ha in the second year. Biweekly sampling of roots, foliage, and flowers from late June through mid-October showed that cichoric acid declined in all tissues during the growing season, but most rapidly in over-mature flowers. The highest concentration of cichoric acid was detected in immature flowers, but the greatest amount of cichoric acid per flower was in fully developed flowers before petal senescence. The total amount of cichoric acid per root was highest before flowering, but peaked in the plant top in early to mid-August in western Montana. Removal of 50 percent of the foliage in mid-August of the second year of growth resulted in a small but significant reduction in the yield of roots harvested that fall, but removal of only the flowers had no effect. The root crown was higher in cichoric acid than the thick (> 1 mm diameter) or fine roots. Drying of foliage rapidly in a forced-air dryer at 32°C or slowly in a shaded greenhouse did not differ in cichoric acid concentration in the tissue.

Double Cutting Meristem Black Mitcham Peppermint

Abstract Propagating ‘Black Mitcham’ peppermint (Mentha piperita L.) using in vitro meristem culture has produced a more vigorous plant biotype that produces more dry matter, but less essential oil than biotypes propagated with stem cut culture. Management systems need to be developed that will take advantage of the increased vigor of the meristem peppermint. The objectives of this research were to develop double cutting systems for meristem peppermint by determining the effects of double cutting on essential oil yield, oil quality, and stand longevity. Experiment 1 (1994/1995) compared single cutting (1 Aug 1994) to double cutting with first harvests on 21 June, 28 June, 5 July, 12 July and 19 July and second harvests on 1 Sep or 27 Sep Experiment 2 (1995/1996) compared a single cutting (7 Aug 1995) to double cutting with first harvest on 11 July and second harvests on 1,8,15 and 22 Sep. In the second year of each experiment, all plots were harvested on the same date to determine effects of the previous ...