References
- Anon . 1981 . Floriculture crops. Production area and sales, 1979 and 1980intentions for 1981 , Washington, DC 20250 : Crop Reporting Board, USDA .
- Eastin , E.F. 1976 . Use of ammonia electrode for total nitrogen determination in plants . Connu. Soil Sci. Plant Anal. , 7 : 477 – 481 .
- Hoagland , D.R. and Arnon , D.I. 1950 . The water‐culture method of growing plants without soil , Calif. Agr. Exp. Sta. . Circ. 347
- Kofranek , A.M. and Lunt , O.R. 1969 . A study of critical nutrient levels in Pelargonium hortorum, Cv. ‘Irene’ . J. Amer. Soc. Hort. Sci. , 94 : 204 – 207 .
- Mason , S.C. and Wilcox , G.E. 1982 . Nitrogen status evaluation of tomato plants . J. Amer. Soc. Hort. Sci. , 107 : 483 – 486 .
- Orion Research Incorporated . 1978 . Instruction manual (for) nitrate electrode Cambridge , Mass. 02139 Model 93–07
- Smith , F.F. 1962 . Mineral analysis of plant tissues . Ann. Rev. Plant Physiol. , 13 : 81 – 108 .
- Ulrich , A. 1942 . Nitrate content of grape leaf petioles as an indicator of the nitrogen status of the plant . Proc. Amer. Soc. Hort. Sci. , 41 : 213 – 219 .
- Ulrich , A. 1961 . Plant analysis in sugar beet nutrition . Plant Anal. Fert. Prob. , 8 : 190 – 211 .