Seasonal Nitrate‐Nitrogen Content of Cotton Petioles as Affected by Nitrogen Application and Its Relationship to Yield¹

Abstract

Synopsis Nitrate‐nitrogen content of cotton petioles was found to be related to the rate of nitrogen applied and the total yield. Yield reductions were related to the length of time petiole nitrate‐nitrogen fell below minimum levels of 1000 and 2000 parts per million.

Changes in the Concentration of Leaf Nitrogen over the Season Affect the Diagnosis of Deficiency or Sufficiency in Strawberries in the Subtropics

“…Other workers have also reported linear declines in leaf N concentration in strawberry and other crops, as well as linear or exponential declines in NO3-N, depending on the type of leaf sampled [30][31][32][33]. For example, in strawberry, NO3-N decreased from about 400 to 50 mg/L in the sap of the young leaves (FW) from mid-May to early July, and from about 130 to 20 ppm in the sap of the youngest fully expanded leaves [30]. Changes in leaf NO3-N reflect changes in the uptake and use of N by the plant and the activity of nitrate reductase [34][35][36].…”

Monitoring nitrogen nutrition in cotton

“…Therefore, considering a 10-fold relationship between petiole sap and dry petiole NO 3 -, NO 3 -in dry petiole would range approximately from 200 to 950 mg kg -1 in our experiment. Petiole N-NO 3 -concentrations as high as 24-30 g kg -1 have been reported in upland cotton (Maples et al, 1977;Gardner & Tucker, 1967), but a critical minimum level of 1-2 g kg -1 during the first flower period was suggested to ensure growth and yield of upland cotton in California (MacKenzie et al, 1963). In Texas, this level was adequate for maximum production of Pima cotton, depending on the season (Tewolde et al, 1995).…”

Prediction of nitrogen fertilizer requirement in cotton using petiole and sap nitrate

“…Concentrations of nitrate in cotton petioles are affected by growth stage, moisture status, cultivar, plant density, soil type and N fertilizer rate, timing of application and N source (Mackenzie et al 1963;Amer and Abuamin 1969;Grimes et al 1973;Sunderman et al 1979;Lutrick et al 1986). Thus the use of petiole nitrate testing to indicate N status needs evaluation and calibration in each production region, particularly where soils are variable or when new cultivars are released.…”

“…Our aim was to detect N status of cotton at a stage when deficiency could be corrected by side dressing before crop yield was affected. Mackenzie et al (1963) recommended assessing the pattern of petiole nitrate decline through time, rather than at just one date; Baker et al (1972) also emphasised the importance of removing the effects of growth stage on petiole nitrate. These are key considerations because the rapid reduction in petiole nitrate with crop ages can significantly affect an assessment.…”