of its effect upon yields (Aloma et. ~ r i t z ~ , ~urnbeh", Samuels and .... Proyecto de fertilization rnediante analisis foliar en 10s l~aboratorios azucareros. ATAC ...
Plant Physiology
INFLUENCE OF K/N RELATIONSHIP FERTILIZATION UPON SOME FOLIAR INDICATORS AND YIELDS OF SUGARCANE R. de Armas and N. Musienko Plant Physiology Laboratory, Faculty of Biology University of Havana, Cuba
ABSTRACT Potassium was applied to sugarcane using six KIN levels (from 0 to 2.5) with two back application of N and P to study the behavior of green weight, moisture, nitrogen, phosphorus index, total sugars and KH20 using leaves 3,4, 5 and 6 as indicator tissue.
In general, increasing N/K level up to unity significantly increased green weight and moisture grant and significantly decreased total sugars. KHz0 showed significant increments up to K/IV value of 2, but nitrogen and phosphoms did not show significant change. Sugar yields showed significant differences in cane plant crop up to K/N value of unity and in the first ratoon crop, up to 1.5. High or medium correlations between potassium and yields were obtained in the different stages of plant development. K/N relationship behaved very much alike in some stages showing very high correlation coefficients. INTRODUCTION Potassium was one of the first mineral elements identified as essential for plant growth by Buner and Lucamus in 1866 (Morard12). Since then a great deal of papers has been written showing potassium as the only univalent cation essential in higher plants nutrition where it i s also the most abundant. Many of those papers have shown the intimate relationship of potassium with almost every aspect of plant physiology. A multiplicity of functions has been attributed to potassium but the mechanisms of i t s action are still unknown. Potassium is very important for sugarcane plant and there are many re~orts ~ r i t z ~~urnbeh", , Samuels and of its effect upon yields (Aloma et Landraul3r &mas4 has found that not only potassium but also N/K relationship i s important t o assure a proper plant development.
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In the present work the effect of different KIN levels were studied on some sugarcane indicator tissues and their correlation with yield,
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R. DE ARMAS AND N. MUSIENKO
MATER lAbS AND METHODS In June, 1975, a randomized complete block design experiment with 12 treatments and four replications was conducted on red ferraiitic soil using t h ~ sugarcane variety Ja60-5. The treatments were arranged in factorial. d
Six K/N levels were used, 0; 5; 1.0; 1.5; 2.0 and 2.5 with two different blanket applications of N and P (100 kglha of N and P205and 200 kglha of N and P205). Each replication covered an area of 192 m2. Nitrogen using urea (46% N) was applied in 3 doses with 115 of the amount at sowing time; 215 six weeks later, and the rest of it 12 weeks after sowing. Phosphorus as triple superphosphate (46% P205) was applied a t sowing time. Potassium, as muriate (60% K20) was applied in two equal doses at 6 and 12 weeks after sowing. In order to keep the KIN levels under study under ratoon condition, the same amounts of fertilizers were applied after harvesting in April, 1976 with one half at two weeks and the rest, six weeks later. In both cycles studied, samples were taken periodically (6 in plant and 4 in first ratoon) using leaves no. 3.4, 5 and 6. Green weight, moisture content, primary 0 determined in the samples index, nitrogen, phosphorus index and K ~ 2 were ' ~ ) Rapid Analyaccording to Clements' Crop-logging techniques ( ~ l e m e n t s ~using tical Methods of HSPA described by clements6. Ripening)stage was determined using the Factor Method (Armasand ~maral') and yields, by stalk-weighing and sugar laboratory analysis (Spencer and ~ e a d e ' ).
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RESULTS AND DISCUSSION The analysis of variance showed significant differences (P
