Washing and/or Cutting Petioles Reduces Nitrate Nitrogen and Potassium Sap Concentrations in Vegetables

• Published in: Journal of plant nutrition Vol. 29; no. 11; pp. 1975 - 1982
• Main Authors: Farneselli, Michela, Simonne, Eric H., Studstill, David W., Tei, Francesco
• Format: Journal Article
• Language: English
• Published: Philadelphia, NJ Taylor & Francis Group 01.11.2006; Taylor & Francis
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; BMP; Capsicum; crop nutritional status; Cucumis melo; Economic plant physiology; foliar fertilizer; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Analysis and diagnosis methods; Lycopersicon esculentum; Mineral nutrition; muskmelon; Nutrition. Photosynthesis. Respiration. Metabolism; pepper; Soil-plant relationships. Soil fertility. Fertilization. Amendments; tomato; pepper; Sap; Foliar fertilization; Nitrogen compounds; Washing; Nitrates; crop nutritional status; tomato; muskmelon; Inorganic element; Cutting; Dicotyledones; Angiospermae; Lycopersicon esculentum; Capsicum annuum; Chemical concentration; Solanaceae; Code of practice; Nutritional status; Non metal; Foliar analysis; BMP; Cucurbitaceae; Inorganic ion; Plant leaf; PLANT NUTRITION; Alkali metal; Nitrogen; Fertilizers; Group VA element; foliar fertilizer; Inorganic anion; Inorganic nitrogen; Vegetable crop; Fruit crop; Vegetative apparatus; Spermatophyta; Cucumis melo; Potassium; Petiole
• ISSN: 0190-4167; 1532-4087
• DOI: 10.1080/01904160600927955

Petiole sap testing using ion-specific electrodes is a simple method that can be used to guide in-season applications of nitrogen (N) and potassium (K) to vegetable crops. This method requires petiole sampling and sap extraction using a sap press. Because some vegetables are grown with foliar applications of N and/or K and because some crops have large petioles, petioles may need to be washed and/or cut before being pressed. Limited information is currently available on the effect of washing/cutting on sap-testing results. Hence, muskmelon (Cucumis melo L.), bell pepper (Capsicum annum L.) and tomato (Lycopersicon esculentum Mill) petioles were used to test whether washing/cutting reduced NO 3 (nitrate)-N and K concentrations and changed the subsequent interpretation of plant nutritional status. Washing for 30, 60, or 120 sec in distilled water and cutting petioles before or after washing significantly reduced sap concentrations (p = 0.01 and p = 0.04 for NO 3 -N and K, respectively) in seven of 12 tests when compared with the control method (petioles cut and not washed). The average concentration reductions between the control and the lowest value among all the washing/cutting treatments were 30% for NO 3 -N and 19% for K. These losses due to washing/cutting are likely often to change the diagnosis of nutritional status from "sufficient" to "less than sufficient" and, therefore, may suggest the need for unnecessary fertilizer applications.