EFECT OF WEEDS IN SUGAR CANE PLANTATIONS IN THE WESTERN ZONE OF CUBA

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1 EFECT OF WEEDS IN SUGAR CANE PLANTATIONS IN THE WESTERN ZONE OF CUBA A. Leyva, J. R. Martin Oria and M. Bertoli Institute of Agricultural Science, Ciudad de la Habana, Cuba ABSTRACT A study was made in order to make an economic evaluation of the damage caused by the presence of weeds in sugar cane plantations in different western zones of Cuba. Four soils of the Ferralitic group, which are widely used in sugar cane plantations, were chosen. During the experiment four observations, were made of the frequency and coverage percent of the weed flora present in each zone studied; and a comparative evaluation was make of the yield and sugar production in association with weeds (Agrofitocenosis). The results obtained showed that for each zone studied there are different associations with more or less species, depending on the culture antecedents; there,,differences determined the intensity of the damage caused to the crop. This make it possible to determine also the species more widely spread in those zones. The species studied are common in other sugar cane-producing countries. INTRODUCTION The weed flora found in sugar cane plantations in Cuba groups over 130 species. Of these a smaller group of about 30 species is more frequently found and constitutes the more harmful species for the crop (Acufia I). These species are associated among them under specific soil climatic conditions in close relation with the crop. This is of high scientific and practical value for specialists who study these problems. In his research work done in Cuba to evaluate the economic importance of undesirable vegetation, Samek l2 points out the importance of cenogenetics studies of associations as a starting point tonwards the knowledge of the flora variation on the basiss of the culture antecedents and specific conditions of light and temperature. From the economical point of view, it is very important to know the differential behavior of weed associations in sugar cane plantations. Studies made in Cuba make it possible to find out the economic effects caused by the presence of weeds in different crops such as sugar cane and rice (Velasco and Rodriguez, l4 Rodriguez et a1 l1 Labrada and ~ufiiz,~ and Labrada and ~6mez~). This'research work is aimed at making an economic evaluation of the damage caused by weeds in sugar cane plantations, taking into account,the behavior of the weed associations under different conditions of moisture and soil in the western zone of Cuba. 266

2 MATERIALS AND METHODS To make this study, five soils were selected in different zones of the Province of La Habana (Table 1). Experiments 1, 2 and 4 were planted on soils in production, while Experiment 3 was carried out on a soil in fallow for more than six years. That cane was planted following the technical rules set by the Ministry of Agriculture. The date corresponding to the last six years were collected in order to know the culture antecedents of each experimental area. The rainfall in the different zones during that period of time was in accordance with the national average. This rainfall occurs between May and October, a period during which more than 80% of the total yearly rainfall takes place. The rainfall was of mm during the whole period. A randomized block design with four replications was used. The measurement area of each treatment was of 32 m2. The varieties used were B.4362, Ja and C. P A stafistical analysis was made. Observations of the frequency and coverage percent of the different species were made after 40 or 50 days of planting, following the "frequency-abundance" method, according to Rochecouste. lo Observations of the number of sugar cane stalks were made after ten months of planting. The Pol % in case (Spencer and Meade 13) yield in t canelha and t Pollha were measured at the moment of harversting. Table 1. Differents Types of Soils Experiments Soils 1 Ferral~t~c red compact 2 Ferral~t~c yellow 3 Ferral~t~c red 4 Ferral~t~c yellow-red RESULTS AND DISCUSSION The results obtained in the experiments are shown in Table 2. Experiment 1 In the study are a flora rich in less harmful1 species was established, such as the Richardia scabra in associations with Digitaria sarzguinalis-echinochloa colonurn, which constitute the principal association. The rest of the more harmful species, such as the Cynodon dactylon, Cyperus rotundus and Amaranthus spinosus had a low frequency (Table 3). According to Samek, l2 this association may be considered poor in number of species according to the conditions of the zone studied. The weed community established in this zone should respond to the effects of the culture antecedents, as the continued use of herbicides, the use of mechanical implements and the continued use of the soil without fallow.

3 ' Table 2. Thousands Stalkslha, t canelha, % Pol in Cane and t Pollha Thousands Stalkslha t Canelha % Pol in Cane t Pollha Experiment 1 Treatments Free of weeds With weed - X Es Experiment 2. Treatments Free of weed With weed - X Es Experiment 3 Treatments Free of weed With weed - X Es Experiment 4 Treatments Free of weed With weed - X Es Table 3. Weed Flora in Experiment 1 Species Frequency Coverage Rlchardia scabra, L. 25 Digitaria sanguinalrs (L.) Scop Echinochloa colonum (L.) Link. 12 Eleusine indica (L.) Gaertn. Amaranthus spinosus, L Cyperus rotundus, L. 5 Cynodon dactylon (L.) Pers. 2 8

4 Martin Oria 7' pointed out the importance of the associations and the establishment of a specific flora as a result of the continuous applications of herbicides. The economic effects on the crop are shown in Table 2. In Experiment 1 there was a decrease in yield which in turn affected the sugar production although there was no decrease in the Pol % in case. Similar results have been obtained in other scientific works (Leyva and Suarez, Leyva and Borrego 6). Experiment 2 The more harmful species were grouped in this association: Cynodon dactylon- Pharthenium hysterophorus-eleusine indica which represented the main coverage of the area studied. The rest of the species was insignificant. Table 4. Weed Flora IS in Experiment 2 S pec~es Frequency Coverage Cynodum daclylon (L) Pers. 21 Parthenrum hysterophorus, L Eleuslne rndrca (L) Gaertn. 11 Rlchardla scabra, L. 7 Segbania sp 3 Cyperus rorundus, L 3 Dlgrrarra sangulnalrs (L.) Scop 3 23 Ipomea sp. 2 Echrnochloa colunum (L) L~nk 2 Mrmosa pudrca, L. 2 Euphorbla hrrta, L 1 The establishment of this flora responded to a high degree to the soil per climatic conditions together with the cultural antedecents, principally to the use of herbicides, derivates of triazines and ureas mixed with 2-4-D. The establishment of this flora caused considerable decrease in yield and sugar production. There was no decrease in the Pol % in case. The species Cynodon dactylon in this weed association could be the main cause for greater damage, due to its tolerance to usual herbicides, and its different forms of reproduction. Casamayor and Garcia ' evaluated the economic importance of this weed on studying several biotypes, and they recommended Bromacil for its control. Experiment 3 In this experiment there was a high number of especies rich in dicotyledons, especially the species Amaranthus spinosus, Parthenium hysterophorus. This association was established by different subsequent associations, as proposed by Sama. These subsequent association start with the association Portulaca oleracea Kallestroemietum maximal followed by Portulaca oleracea Parthenium 269

5 I hysterophorus reaching its peak in six months if the field is left unattended. Cornparing this association with that found in Experiment 1, important changes were observed in the flora due tu culture management. Because of this there should be a modification of this flora towars one having less harmful species. Table 5 Weed Flora in Exper~ment 3 Spec~es Frequency Coverage Parihenrum hysierophorus. L 35 Amaranihus sprnosus, L 23 Argemone mexrcarla, L 12 Poriulaca cleracela, L 11 Cyperus roiundus, L 11 Echrr7ochloa col~tnum (L ) Link 9 Drgriarra sar~gurnalrs (L ) Scop 2 Rotloboellra exaliata. L 1 Cenchrus echrnatus, L 1 Srda rhombrfolra. L 1 Eleus~ne indrca (L) Gratn 1 Vrgurera helranihordes, H B K 1 Experiment 4 A flora with a high number of species was established in this zone. This association was rich in Brachiaria ~lantiginea, Phyllantus swarzlzii (Table 6). This association could be established as a result of the specific ecological conditions of the zone; with a deficient crop management and insufficient applications of herbi- ' cides. Table 6 Weed Flora In Exper~ment 4 Species Frequency Coverage Brachrarra plantrg~nea, Llnk Phyllanihus swarzlzr~, Kostel 22 Urerta Lobaia, L - Cyperus sp - Cyrzodon daciylon (L ) Pers 3 7 % Eleusine ind~ca, (L) Gaertn - Mimosa pudlca, L - Chamaesyce brasll~ensrs, Lam - S~da rhomb~fol~a, L. - The association of weeds in relation with the crop (Agrofitocenosis) showed significant differences in relation with the treatment free of weeds. There was a decrease in yield and sugar production and as in the other cases, it did not affect the Pol % in cane. Velasco and Rodriguez found similar damage in the conditions of Matanzas Province where the species Brachiaria predominated.

6 I hysterophorus reaching its peak in six months if the field is left unattended. Comparing this association with that found in Experiment 1, important changes were observed in the flora due tu culture management. Because of this there should be a modification of this flora towars one having less harmful species. Table 5. Weed Flora in Experiment 3 ~ Species Frequency Coverage 1 Parrhenium hysterophorus. L. 35 Argemotle mexicarla. L. Porrulaca cleracela, L. Cyperus rorurldus. L. Echinochloa colunu?n (L.) Link. Digiraria sanguinalis (L.) Scop. Rorloboellia esalrara, L. Cenchrus echinarus, L. Sida rhombifolia, L. Eleusine indica (L.) Gratn. Viguiera helianrhoides, H. B. K. Experiment 4 A flora with a high number of species was established in this zone. This association was rich in Brachiaria plantiginea, Phyllantus swarzlzii (Table 6). This association could be established as a result of the specific ecological conditions of the zone; with a deficient crop management and insufficient applications of herbicides. Table 6. Weed Flora in Experiment 4 Species Frequency Coverage Brach~aria plant~g~nea, Link Phyllanthus swarzlz~~, Kostel Urena Lobata, L Cyperus sp Cynodon dactylon (L ) Pers Eleuslne lnd~ca, (L.) Gaertn Mrmosa pudrca, L Chamaesyce braslllensrs, Lam Srda rhomb~folra, L i The association of weeds in relation with the crop (Agrofitocenosis) showed significant differences in relation with the treatment free of weeds. There was a decrease in yield and sugar production and as in the other cases, it did not affect the Pol % in cane. Velasco and Rodriguez found similar damage in the conditions of Matanzas Province where the species Brachiaria predominated.

7 CONCLUSIONS A point analysis of all these associations showed differences in the decrease in yields in the crop. It was observed that these differences were in direct relation to the richness of the flora and to the species found. The most common species in the different associations were Cynodon dactylon, Cyperus sp., Eleusine indica and Echinochloa colonum which are the most resistant to the control methods used. The associations Brachiaria plantiginea - Phyllanthus swarzlzii, Amaranthus spinosus - Parthenium hysterophorus and Cynodon dactylon-parthenium hysterophorus - Eleusine indica showed the greatest decrease in t Pollha 642%, 35,2% and 34,2% respectivily), while the association Richardia scabra, Digitaria sanguinalis, Echinochloa colonum proved to be the least harmful, since it shower only a 25% decrease in sugar production. There was no decrease in Pol % in case in any of the associations, while the population of stalks and the t canelha were affected. REFERENCES Acuda, J. (1974): plantas indeseables en 10s cultivos cubanos. Instituto Investigaciones Tropicales. Academia de Ciencias de Cuba. Casamayor, R. y Garcia, R. (1977): Cynodon dactylon: Una mala hierba para el cultivo de 10s citricos en Cuba. Centro Agricola. Revista cientifica de la Facultad de Ciencias Agricolas. Ado IV (2). Universidad Central de Las Villas, pp Labrada, R, y Muiiiz, R. (1979): Valoracidn preliminar de lucha quimica contra las malezas en el cultivo del pepino. Cycumis sativus, L. Tiabajo de Diploma. ISCAH. Facultad de Agronomia. Labrada, R. y Gdmez R. (1980): Valoracidn preliminar de medidas quimicas de lucha contra las malezas en meldn de agua. Trabajo de Diploma, ISCAH. Facultad de Agronomia. Leyva, A. G. y Suirez J. C. (1980): Control de,adventicias en caiia de azlicar (Saccharum sp., hibrido) variedad Ja con aplicaciones de mezclas de herbicidas en post-emergencia avanzada. 111 Conferencia de Ciencias Agropecuarias. Universidad Central de las Villas, Cuba. Leyva, A. G. y Borrego, M. (1981): Estudio de la mezcla DCMU + Bromacil en el control de la vegetacidn extrada en caiia de azlicar (Saccharum sp., hibrido) variedad Ja en aplicaciones post-emergentes. 111 Seminario Cientifico del Inst, de Ciencia Agricola (INCA) ISCAH, Cuba. Martin Oria, J. R. (1975): Control de malas hierbas en aplicaciones pre-emergentes con combinaciones de herbicidas. Seminario de Investigaciones. Universidad Central de Las Villas. Martin Oria, J. R. (1978): El uso de herbicidas en canas de azhcar, efectos fitotdxicos, modo de aplicacidn y control de malezas en las variedades Ba. 4362, Ja y C (Tesis). Instituto de Ciencia Agricola ISCAH, La Habana, Cuba. Minist. Agricultura (1975): Normas TCcnicas para el cultivo de la,cafia de azlicar. Minist. Agric. La Habana. Cuba. Rochecouste, E. (1967): Weed Control in Sugar Cane Research and Application Mauritius Sugar Industry. Resear'ch Institute. Rodriguez, J., Farias, I. M. y, Ldpez A. (1977): Agrofitocenosis del arroz (Oriza sativa, L.) Centro Agricola. Revista Cientifica de la Universidad Central de Las Villas, Ado IV, No. 3, Las Villas, Cuba. Shmek, V. (1971): Acerca de las comunidades de hierbas malas en 10s alrededores de La Habana. Revista Agricultura, Aiio IV No. 2, pp , Academia de Ciencias de Cuba. Spencer, L. S, and Meade, G. P. (1945): Cane Sugar Handbook ed. New York, John Wiley and Sons. Velasco, A, y Rodriguez, E: (1968): Ptrdidas econdmicas por malas hierbas en la cafia de az6car. Serie Caria de azdcar No. 14. Instituto de Investigaciones de la Cada de azlicar. Academia de Ciencias' de Cuba.

8 EFFET DES MAUVAISES HERBES SUR LES CANNAIES DE LA REGION OCCIDENTALE DE CUBA A. Leyva, J. R. Martin Oria et M. Bertoli Institut de sciences agricoles, Ciudad de la Habana, Cuba Afin d'kvaluer sur le plan economique les dommages provoquks par les mauvaises herbes dans la culture de la canne a sucre, les auteurs ont effectue une ktudes dans les regions occidentales du pays. Le test a kt6 realis6 sur quatre sols du groupe ferralitique cultivks extensivement de canne a sucre. L'incidence des espkces et le pourcentage de couverture ont ete observes. Les rendements agricole et sucrier de la canne (agrophytocenose) ont kt6 comparks. Les rksultats obtenus montrent, dans chacune des regions ktudikes, des associations diffkrentes selon les procedes culturaux antkrieurs. Ces differences sont a I'origine de I'importance des dommages subis par la plantation. Les auteurs ont dktermine les espkces les plus communes dans ces rkgions, qui le sont aussi dans d'autres pays producteurs de canne. EFECTO DE LAS ADVENTICIAS EN LAS PLANTACIONES DE CANA DE AZUCAR EN LA ZONA OCCIDENTAL DE CUBA A. Leyva, J. R. Martin Oria y M. Bertoli Instituto de Ciencia Agricola, Ciudad de La Habana, Cuba RESUMEN Con el objetivo de hacer una valoracion economics de 10s dafios que producen las adventicias en el cultivo de la cafia de azucar, se realizo un estudio en las zonas occidentales del pais. Se escogieron cuatro suelos del grupo Ferralitico de amplia utilizacion en cana de azucar. Se realizaron observaciones en la incidencia de especies y % de cobertura. Se evaluaron en forma comparativa 10s rendimientos agricolas y azucareros de la cana (Agro-fitocenosis). Los resultados obtenidos demostraron que para cada zona estudiada existen asociaciones diferentes en dependencia de 10s antecedentes culturales. Estas diferencias determinaron la intensidad del dano del cultivo. Se determinaron las especies mas comunes en estas zonas. Las especies estudiadas son comunes en otros paises caneros.