INFLUENCE OF K/N RELATIONSHIP FERTILIZATION UPON SOME FOLIAR INDICATORS AND YIELDS OF SUGARCANE ABSTRACT

Transcription

1 Plant Physiology NFLUENCE OF K/N RELATONSHP FERTLZATON UPON SOME FOLAR NDCATORS AND YELDS 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 KN 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. n 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/V 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. NTRODUCTON 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 is 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 its action are still unknown. Potassium is very important for sugarcane plant and there are many re~orts of its effect upon yields (Aloma et ~ritz~, ~urnbeh", Samuels and Landraul3r '9. &mas4 has found that not only potassium but also N/K relationship is important to assure a proper plant development. n the present work the effect of different KN levels were studied on some sugarcane indicator tissues and their correlation with yield, 404

2 R. DE ARMAS AND N. MUSENKO MATER labs AND METHODS n 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). 2 Each replication covered an area of 192 m. 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 at sowing time. Potassium, as muriate (60% K20) was applied in two equal doses at 6 and 12 weeks after sowing. n order to keep the KN 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. n 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 index, nitrogen, phosphorus index and K~20 were determined in the samples according to Clements' Crop-logging techniques (~lements~'~) using Rapid Analytical Methods of HSPA described by clements6. i Ripening) stage was determined using the Factor Method (Armasand ~maral') and yields, by stalk-weighing and sugar laboratory analysis (Spencer and ~eade' ). RESULTS AND DSCUSSON The analysis of variance showed significant differences (P <O,Ol)for each KN level in green weight, moisture and KH20, either in plant or ratoon. The primary index also showed significant difference but only for plant cane data. 1! The two blanket applications of N and P showed significant difference (P<0.06) in <H20 only in plant cane. N and P values did not show significant difference even between levels. Significant differences (P<0.01) were obtained between cycles for all indicators except for phosphorus index, which showed a diminishing trend with age in the plant cycle but remained almost at constant level in ratoon. ; All interactions analyzed were not significant. Table 1 shows mean values for each indicator under study and Duncan Test

3 406 PLANT PHYSOLOGY results for every KN relation. 1 1 n general, increasing KN values increase green weight, moisture and potassium of leaf sheaths and decrease the primary index. As a general rule, there are no significant variations when </N levels are \ higher than unity, except for KH20, where significant increments were observed up to KN value of 2, TABLE 1. Foliar mean values obtained with different KN levels of fertilization.! Cane Plant K N Green Total Relation- Weight Moisture N Sugars KHz0 P ship (9) (% (% (% l ndex a 79.1 a 1.91 a a 0.27 a 0.10a ab 79.2 ab 1.91a 11.53ab 0.29a 0.10a 1.O 371 abc 79.7 abc 1.90 a bc 0.35 b 0.09 a bc 80.2 bc 1.88a 10.92bc 0.34b 0.10a c 80.2 bc 1.91 a bc 0.37 bc 0.09 a c 80.3 c 1.91 a c 0.40 c 0.09 a First Ratoon a 78.3 a 1.91 a 9.95 a 0.25 a 0.08 a ab 78.3 a 1.93 a 9.90 a 0.32 b 0.06 a 1.O 355 bc 78.8 ab 1.91 a 9.62 a 0.35 bc 0.08 a bc 79.4 b 1.91 a 9.67 a 0.37 c 0.08 a c 79.1 b 1.90 a 9.72 a 0.38 cd 0.08 a c 79.3 b 1.91 a 9.58 a 0.43 d 0.08 a 1 Different letters denote significant differqnce at least for P <0.05 ',, Ratoon results are very much alike those of plantcanedata. Agricultural and sugar yields at maturation showed significant difference only for different KN levels. Mean values are shown in Table 2. Table 2 shows no significant difference for yields K/N levels higher than 0.5, although for KN = 1 there was an increment of 3.8 t canelha. Significant increments were obtained in ratoon for KN levels up to 1.5. * Sugar yields showed significant increments for KN value up to unity in plant, and up to 1.5 in ratoon. 5 1 Several foliar indicators (green weight, primary index and potassium of leaf sheaths) showing significant differences among treatments in three different stages

4 of the plant development (beginning and end point of boom stage and maturation) were submitted to correlation analysis aim. TABLE 2, Mean yields obtained with different K/N levels in fertilization. L KN Relation- t Canelha t Sugar/ha ship Plant Ratoon Plant Katoon Different letters denote significant differences st least for P <0.05 n the case of green weight, low or medium positive correlations were obtained with sugar yields. The lowest correlation coefficient was at maturation stage. bow negative correlation coefficients were obtained in general for primary index till the end of the boom stage and turned positive at maturation. The explanation of such a behavior is found in the physiological role of carbohydrates in plants, where they are used as energy source during plant growthand kept as reserve at maturation. This fact can also explain the statement of some authors as Lunin and,4ughtry1 l, in the sense that sometimes positive or negative correlations can be found between primary index and nitrogen depending upon the stage of plant development considered. Potassium always showed high,er medium positive correlation coefficienfs indicating its direct influence upon yields. M/K relationships behaved in the same way, in some stages giving very high negative correlation coefficients. These facts emphasized the physiological importance of N/K equilibrium aqsure good yields. The experimental results obtained for the different foliar indicators used agreed with reports of other authors' for leaves 3, 4, 5 and 6 (Amaral, pampin2, ~rihas~ and Clements7). lnspite of the heavy application of potassium to some of the treatments, heavy concentration in leaf sheaths were not detected and as a rule values were /

5 408 PLANT PHYSOLOGY TABLE 3. Correlation coefficients between some foliar values in three stages of plant development arid yields. Sugarcane plant and first ratoon. Ton Canelha Beginning of End of Boom stage Boom stage Maturation Plant Ratoon Plant Ratoon Plant Green weight t ** M.55 4O.65"" 0.55 t0.48 Total Sugars -0.57" "" t0.24 % K t0.82" * t0.67" * t0.84" * +0.73* * +0.64" -- Ton sugarlha Green Weight ** t0.64" Total Sugars " * M % K +0.75"* +0.70** t0.63" 40.83"" t0.69" +0.65" * Significant at P <0.05 * * Significant at P <0.01 below normal. First ratoon crop yields were somewhat better than sugar. As a rule, the higher the KN relationship the higher the yields obtained, between 0 to 2. Only for sugarlha, K/N=2.5 showed a new increase for regular crop. These increases were not always statistically significant specifically for KN values higher than 1.5 (see table 2). The influence of different levels of potassium and the N/K relationship in the plant upon yields must be emphasized. These facts were evidenced by the correlation coefficient found. CONCLUSONS Significant variations in green weight, moisture and total sugars were obtained with increasing KN up to unity. For KH20, significant increments were obtained with KN relationships up to 2, but sugar yields increased significantly with KN

6 'r, %. DE ARMAS AND N. MUSENKO relationships up to 1 for cane plant and 1.5 for first ratoon. Potassium levels and N/K relationship within the plant influenced yield. KN in the ratio between 1 and 1.5 is recommended. REFERENCES C 1. Aloma, J., H. Perez, and J. Cuellar (1974). Advances in sugarcane fertilization in Cuba. SSCV 15: Amaral, A. y B.R. Pampin (1970). Proyecto de fertilization rnediante analisis foliar en 10s l~aboratorios azucareros. ATAC, 39 Conferencia, Seccion Laboratorio. 3. Armas, R. (1974). Estudio de la influencia de altas concentraciones de Potasio en el estado metabolic0 de la cana de azucar. Ciencias Serie 3 No.: 20, UH. 4., (1974). Efectos de la fertilization n~trogenada en la cana de ',aizucar, en suelos con grandes reserves de pstasio asimilable. Ciencias Serie 3, No. 31, UH. 5. Armas, R. y A. Amaral (1974). Metodo para determiner el momento de la maduracion de un campo de cana de azucar. - Uso del Pol % en Cana. Ciencias, seri'e 3, No. 33 UH. 6. Clements, H.F. (1943). Soil and plant material analysis by rapid chernical methods. V HSPA. 7., (1953). Crop logging of sugarcane. Principles and Practice. SSCT 8: 79-97: 8., (1971). The Crop logging system for sugarcane production. SSCT 14: Fritz, J. (1974). Effect of tertilizer application upon sucrose % cane. SSCT 15: Humbert, H.P. (1962). Potash and, sugarcane quality. SSCT 11: Lunin and J.D. Aughtry (1953). The effect of soil type and fertilization on the growth and the yield of a ratoon cane crop as indicated by crop logging. SSCT,8: Morard, P. (1974). Papeles fisiologicos que desempena el potasio en 10s vegetales. Reviste de la Potasa. Seccion 3, No. 10: Samuels, G. and P. Landrau, Jr. (1955). The nfluence of potassium on the

7 440 PLANT PHYSOLOGY yield and sucrose content of sugarcane. :Soil Sci. 19: , (1956). The sucrose content of sugarcane as influenced by fertilizers. lssct9: Spencer, L.S..and G.P. Meade (1963). Cane sugar handbook (9th Ed.). John Wiley and Sons, lnc. NY, 845 p. NFLUENCA DE LA RELACON K/N EN LA FERTLPZACON SOBRE ALGUNOS NDCADORES FOLARES Y COSECHA DE CANA DE AZUCAR R. de Armas and N. Musienko. RESUMEN El potasio fue aplicado a la cafia de azbcar usando 6 niveles d$ KN (desde 0 a 2.5) con dos aplicaciones posteriores de N y P para estudiar el comportamiento peso en verde, bunledad, nitrogeno, indice de fosforo, azucares totales y KH20, usando las hojas 3,4,5, y 6 como tejidos indicadores. En general, aumentando el nivel de KM hasta uno, fue responsable de aumentos significativos en el peso en verde y la humedad y disminucion importante en azucares totales mostro aumentos significativos hasta valores de 2K/N, per0 el N y el P no mostraron diferencias significativas. La produeion de azucares mostro diferencias significativas en las caiias plantas hasta valores de 1 KN en el cultivo de caiia soca de 1 basta 1.5. Fueron obtenidas correlaciones elevadas o medianas entre potasio y cosecha en 10s diferentes estados de desarrollo de la planta. La relacion KN se comport6 de forma rnuy parecida en varias etapas mostrando coeficientes de correlacion muy altas.