Pub Date : 2020-01-01DOI: 10.46429/jaupr.v104i1.18280
J. Beaver, C. E. D. Jensen, P. Miklas, T. Porch
{"title":"Contributions in Puerto Rico to Bean, Phaseolus spp., Research","authors":"J. Beaver, C. E. D. Jensen, P. Miklas, T. Porch","doi":"10.46429/jaupr.v104i1.18280","DOIUrl":"https://doi.org/10.46429/jaupr.v104i1.18280","url":null,"abstract":"","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48546450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.46429/jaupr.v104i1.18283
M. Bertorelli, Barlin Orlando Olivares
Este estudio tuvo como objetivo evaluar la fluctuación poblacional de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) en etapa larval, en las diferentes etapas fenológicas del sorgo y su relación con el tipo de labranza, las condiciones climáticas, y distintos sistemas de uso del sorgo en el Fundo Las Tunas, municipio Simón Rodríguez, estado Anzoátegui, Venezuela. Para la evaluación se utilizaron cuatro sistemas de uso: S1 (Sorgo-Stylosanthes brasilianum-Brachiaria dictyoneura); S2 (Sorgo-Centrosema brasilianum-B. dyctioneura); S3 (Sorgo-B. dyctioneura); y S4 (Sorgo monocultivo) bajo dos tipos de labranza (liviana y profunda). La determinación de la fecha de ocurrencia de las etapas fenológicas del cultivo se realizó dos veces por semana durante todo el ciclo del cultivo. Los resultados del estudio revelaron que la fluctuación poblacional de S. frugiperda no se vio influenciada por el sistema de uso, pero sí por el tipo de labranza, se presentaron mayores valores de fluctuación población del insecto (>0.80 larvas por planta) con la labranza profunda. Se evidencia una estrecha relación entre estos factores de fluctuación poblacional del insecto, condiciones climáticas y los días después de la siembra; un mayor ataque de la plaga ocurrió en el periodo vegetativo cuando se presentaron bajos montos de precipitación diaria y altas temperaturas.
{"title":"Fluctuación poblacional de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) en el cultivo del sorgo del sur de Anzoátegui, Venezuela","authors":"M. Bertorelli, Barlin Orlando Olivares","doi":"10.46429/jaupr.v104i1.18283","DOIUrl":"https://doi.org/10.46429/jaupr.v104i1.18283","url":null,"abstract":"Este estudio tuvo como objetivo evaluar la fluctuación poblacional de Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) en etapa larval, en las diferentes etapas fenológicas del sorgo y su relación con el tipo de labranza, las condiciones climáticas, y distintos sistemas de uso del sorgo en el Fundo Las Tunas, municipio Simón Rodríguez, estado Anzoátegui, Venezuela. Para la evaluación se utilizaron cuatro sistemas de uso: S1 (Sorgo-Stylosanthes brasilianum-Brachiaria dictyoneura); S2 (Sorgo-Centrosema brasilianum-B. dyctioneura); S3 (Sorgo-B. dyctioneura); y S4 (Sorgo monocultivo) bajo dos tipos de labranza (liviana y profunda). La determinación de la fecha de ocurrencia de las etapas fenológicas del cultivo se realizó dos veces por semana durante todo el ciclo del cultivo. Los resultados del estudio revelaron que la fluctuación poblacional de S. frugiperda no se vio influenciada por el sistema de uso, pero sí por el tipo de labranza, se presentaron mayores valores de fluctuación población del insecto (>0.80 larvas por planta) con la labranza profunda. Se evidencia una estrecha relación entre estos factores de fluctuación poblacional del insecto, condiciones climáticas y los días después de la siembra; un mayor ataque de la plaga ocurrió en el periodo vegetativo cuando se presentaron bajos montos de precipitación diaria y altas temperaturas.","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47750486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.46429/jaupr.v103i2.18231
T. Ayala-Silva, H. Gubbuk, Y. Twumasi, N. Ledesma
Resumen en ingles
英文摘要
{"title":"MORPHOLOGICAL AND PHENOLOGICAL EVALUATION OF TEN AVOCADO CULTIVARS","authors":"T. Ayala-Silva, H. Gubbuk, Y. Twumasi, N. Ledesma","doi":"10.46429/jaupr.v103i2.18231","DOIUrl":"https://doi.org/10.46429/jaupr.v103i2.18231","url":null,"abstract":"Resumen en ingles","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47293479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.46429/jaupr.v103i1.17899
M. L. Flores‐Mangual, A. González-Vélez
Plantains are produced in the mountainous region of Puerto Rico and are grown in highly weathered soils of low fertility and high degradation potential. Alternatives to mitigate soil degradation include the application of chicken manure and the placement of deleafed sigatoka-infected leaves on top of the soil (deleafing). The objective of this study was to determine the effect of chicken manure and deleafing on soil properties and plantain productivity. The experiment was conducted in a Dagüey soil series at the Agricultural Experiment Substation in Corozal, Puerto Rico. The treatments were: 1) 25 ton/ha chicken manure; 2) deleafing; 3) chicken manure + deleafing; and 4) control. Chicken manure was applied before planting, and leaves from deleafing were placed on the soil only in deleafing treatments. The application of chicken manure significantly increased soil aggregate stability, soil available phosphorous and nitrates. Also, plant growth and plantain yield increased with manure applications, and the days to flowering and harvest were reduced. There were no effects neither on soil bulk density, hydraulic conductivity nor on organic matter content. No significant difference in runoff volume was observed, but sediment load in runoff decreased. The deleafed leaves decreased soil penetration resistance.
{"title":"Effect of chicken manure application and plant deleafing on soil characteristics and dwarf plantain (Musa AAB) production","authors":"M. L. Flores‐Mangual, A. González-Vélez","doi":"10.46429/jaupr.v103i1.17899","DOIUrl":"https://doi.org/10.46429/jaupr.v103i1.17899","url":null,"abstract":"Plantains are produced in the mountainous region of Puerto Rico and are grown in highly weathered soils of low fertility and high degradation potential. Alternatives to mitigate soil degradation include the application of chicken manure and the placement of deleafed sigatoka-infected leaves on top of the soil (deleafing). The objective of this study was to determine the effect of chicken manure and deleafing on soil properties and plantain productivity. The experiment was conducted in a Dagüey soil series at the Agricultural Experiment Substation in Corozal, Puerto Rico. The treatments were: 1) 25 ton/ha chicken manure; 2) deleafing; 3) chicken manure + deleafing; and 4) control. Chicken manure was applied before planting, and leaves from deleafing were placed on the soil only in deleafing treatments. The application of chicken manure significantly increased soil aggregate stability, soil available phosphorous and nitrates. Also, plant growth and plantain yield increased with manure applications, and the days to flowering and harvest were reduced. There were no effects neither on soil bulk density, hydraulic conductivity nor on organic matter content. No significant difference in runoff volume was observed, but sediment load in runoff decreased. The deleafed leaves decreased soil penetration resistance.","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48831585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.46429/jaupr.v103i2.18232
W. I. Lugo, Américo Casas-Guérnica, L. Albanese
{"title":"PAUL F. RANDEL 1937 - 2018","authors":"W. I. Lugo, Américo Casas-Guérnica, L. Albanese","doi":"10.46429/jaupr.v103i2.18232","DOIUrl":"https://doi.org/10.46429/jaupr.v103i2.18232","url":null,"abstract":"","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41714214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.46429/jaupr.v103i1.17902
H. Sánchez-Rodríguez
Anecdotally, wild type (WT) Puerto Rican Holstein cows perform poorly in hot weather compared with their short-haired (SLICK) counterparts, but scientific evidence supporting this claim is limited. Thus, comparisons of their vaginal temperature (VT), sweat gland size (SGS) and milk production (MP) values were made. Data were analyzed by Proc GLIMMIX and REG (SAS). During the cool season (March 2014) VT was similar in WT and SLICK cows (38.71±0.09 and 38.71±0.08 °C, respectively; P=0.9634). However, in the intermediate air temperatures (AT) season (April 2014), WT cows presented VT values 0.25° C higher than their SLICK counterparts from 1900-2100h (P=0.0213). Moreover, in the hot season (August 2015) VT was greater in WT than in SLICK cows by 0.31° C from 1800-0700h and 0900-1600h (P=0.0032), and by 0.20° C at 0800h (P=0.0584) and 1700h (P=0.0619). The VT increased linearly until AT reached 30.5° C in both WT (0.10° C per 1° C of AT; P<0.0001) and SLICK cows (0.08° C per 1° C of AT; P<0.0001). After 30.5° C, no further VT-AT relationship was observed. The WT had smaller SGS (232±12 vs. 315±9 μm perimeter; P=0.0024) and smaller MP (17.11±0.63 vs. 20.26±1.28 kg/d; P=0.0288) than the SLICK cows. The SLICK cows demonstrated superior thermoregulatory capacity, which seems to depend directly on the severity of the AT.
{"title":"Thermoregulatory and productive-related comparisons between wild type and slickhaired Puerto Rican Holstein cows","authors":"H. Sánchez-Rodríguez","doi":"10.46429/jaupr.v103i1.17902","DOIUrl":"https://doi.org/10.46429/jaupr.v103i1.17902","url":null,"abstract":"Anecdotally, wild type (WT) Puerto Rican Holstein cows perform poorly in hot weather compared with their short-haired (SLICK) counterparts, but scientific evidence supporting this claim is limited. Thus, comparisons of their vaginal temperature (VT), sweat gland size (SGS) and milk production (MP) values were made. Data were analyzed by Proc GLIMMIX and REG (SAS). During the cool season (March 2014) VT was similar in WT and SLICK cows (38.71±0.09 and 38.71±0.08 °C, respectively; P=0.9634). However, in the intermediate air temperatures (AT) season (April 2014), WT cows presented VT values 0.25° C higher than their SLICK counterparts from 1900-2100h (P=0.0213). Moreover, in the hot season (August 2015) VT was greater in WT than in SLICK cows by 0.31° C from 1800-0700h and 0900-1600h (P=0.0032), and by 0.20° C at 0800h (P=0.0584) and 1700h (P=0.0619). The VT increased linearly until AT reached 30.5° C in both WT (0.10° C per 1° C of AT; P<0.0001) and SLICK cows (0.08° C per 1° C of AT; P<0.0001). After 30.5° C, no further VT-AT relationship was observed. The WT had smaller SGS (232±12 vs. 315±9 μm perimeter; P=0.0024) and smaller MP (17.11±0.63 vs. 20.26±1.28 kg/d; P=0.0288) than the SLICK cows. The SLICK cows demonstrated superior thermoregulatory capacity, which seems to depend directly on the severity of the AT.","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47835584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.46429/jaupr.v103i2.18229
H. Sánchez-Rodríguez
Resumen en ingles
英文摘要
{"title":"HAIR DIAMETER COMPARISON BETWEEN SLICK- AND WILD TYPE-HAIRED PUERTO RICAN HOLSTEIN COWS","authors":"H. Sánchez-Rodríguez","doi":"10.46429/jaupr.v103i2.18229","DOIUrl":"https://doi.org/10.46429/jaupr.v103i2.18229","url":null,"abstract":"Resumen en ingles","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42802600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.46429/jaupr.v103i2.18228
C. V. Rua-Bustamante, Maximiliano Ambrosio, Abner A. Rodríguez-Carías
Se evaluó la ganancia diaria de peso (GDP) de ovinos de pelo tipo Sudán en crecimiento utilizando 1,090 registros tomados durante dos años en tres granjas localizadas en el trópico seco en la región del Caribe de Colombia. En cada una de las granjas se registró el tipo de parto de la oveja y el sexo de los corderos. Para determinar la GDP, los corderos se pesaron semanalmente desde el nacimiento hasta los 240 días de edad. Los datos se analizaron según un diseño estadístico completamente aleatorizado con arreglo factorial 3 (granjas) x 2 (sexo del cordero) x 3 (tipo de parto, sencillo, doble o triple). Se utilizó la prueba de Tukey para la separación de medias. La GDP fue similar entre las tres granjas evaluadas con un promedio general de 112 g. Se observó en promedio una mayor (P<0.05) GDP en hembras que en machos (115 versus 103 g) y tal como esperado, la GDP individual de corderos producto de partos sencillos (117 g) fue mayor (P<0.05) que la de corderos nacidos de partos dobles (106 g) o triples (23 g). La mayor GDP de corderas se observó en dos de las tres granjas. La GDP fue similar en machos o hembras nacidos de partos sencillos, sin embargo, en corderas nacidas de partos dobles la GDP fue mayor (P<0.05) que en corderos, y lo contrario se observó en partos triples donde la GDP fue 32 g mayor (P<0.05) en machos que en hembras. En resumen, la GDP de ovinos de pelo tipo Sudán en la región del Caribe de Colombia es buena dado su sistema de crianza extensivo. La GDP fue similar entre fincas pero difirió entre el sexo de la cría y el tipo de parto.
{"title":"Ganancia de peso en ovinos de pelo tipo Sudán: Efecto de la granja, sexo y tipo de parto","authors":"C. V. Rua-Bustamante, Maximiliano Ambrosio, Abner A. Rodríguez-Carías","doi":"10.46429/jaupr.v103i2.18228","DOIUrl":"https://doi.org/10.46429/jaupr.v103i2.18228","url":null,"abstract":"Se evaluó la ganancia diaria de peso (GDP) de ovinos de pelo tipo Sudán en crecimiento utilizando 1,090 registros tomados durante dos años en tres granjas localizadas en el trópico seco en la región del Caribe de Colombia. En cada una de las granjas se registró el tipo de parto de la oveja y el sexo de los corderos. Para determinar la GDP, los corderos se pesaron semanalmente desde el nacimiento hasta los 240 días de edad. Los datos se analizaron según un diseño estadístico completamente aleatorizado con arreglo factorial 3 (granjas) x 2 (sexo del cordero) x 3 (tipo de parto, sencillo, doble o triple). Se utilizó la prueba de Tukey para la separación de medias. La GDP fue similar entre las tres granjas evaluadas con un promedio general de 112 g. Se observó en promedio una mayor (P<0.05) GDP en hembras que en machos (115 versus 103 g) y tal como esperado, la GDP individual de corderos producto de partos sencillos (117 g) fue mayor (P<0.05) que la de corderos nacidos de partos dobles (106 g) o triples (23 g). La mayor GDP de corderas se observó en dos de las tres granjas. La GDP fue similar en machos o hembras nacidos de partos sencillos, sin embargo, en corderas nacidas de partos dobles la GDP fue mayor (P<0.05) que en corderos, y lo contrario se observó en partos triples donde la GDP fue 32 g mayor (P<0.05) en machos que en hembras. En resumen, la GDP de ovinos de pelo tipo Sudán en la región del Caribe de Colombia es buena dado su sistema de crianza extensivo. La GDP fue similar entre fincas pero difirió entre el sexo de la cría y el tipo de parto.","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47102171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.46429/jaupr.v103i2.18226
S. Mathanker, C. Estévez de Jensen, Andrés M. Pagán-López, L. Pérez-Alegría
Unmanned aerial vehicles (UAVs) or drones are being studied for many agricultural applications. One application is plant phenotyping to reduce the time and effort required in collecting field data. This study aims to explore the use of a UAV, 4K-color camera and a commercial image analysis service to measure citrus plant parameters that are important to a crop scientist or grower with limited technical background and resources. Citrus spp. are important crops in Puerto Rico and the United States. Currently, the citrus industry is struggling to contain the devastating effects of citrus greening or Huanglongbing disease. The disease is associated with a phloem-limited bacteria, Candidatus Liberibacter asiaticus (CLAs), vectored by the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. The use of insecticides for vector control is the primary strategy used in nurseries and orchards. However, once the citrus plant is infected, there is no effective control available for the disease. In Puerto Rico this disease has reduced Citrus spp. yields by more than 50%; studies are underway to find effective control measures such as supplemental nutrients, vector management practices, planting disease-free vegetative material and protective screen structures. An experiment at the Fortuna Agricultural Experiment Substation, in Juana Díaz, Puerto Rico, was conducted to address the challenges posed by citrus greening. The experiment was established in a four-year-old grove of Tahiti lime (Citrus latifolia Tan.) on Cleopatra mandarin (Citrus reshni hort. ex Tanaka), naturally infected with Candidatus Liberibacter asiaticus. The experiment was arranged in a randomized complete block design with four replicates and three treatments: supplemental nutrients, supplemental nutrients + salicylic acid, and granular fertilization. Tree growth parameters were measured, and laboratory analyses were carried out to determine nutrient levels and disease severity levels from the leaf samples. The color camera, on board the UAV, was employed to acquire images of the experimental plot. Drone Deploy application was used for planning the UAV flights and image analysis. Field-measured plant height and canopy diameter compared well with the parameters determined from the color images. The average errors in measuring canopy diameter (14.5%) and plant height (22.4%) could be considered within an acceptable range, especially for comparing different treatments or crop varieties. However, the average errors in measuring canopy volume (47.5%) were high and can be considered unacceptable. It appears that the assumed conical shape of the trees could be one of the main reasons, besides the algorithms used in calculating plant volume, and built-in inaccuracies of the single frequency GPS (global positioning system) used in estimating altitude. Further studies could help in reducing errors and exploring other applications. The method used can be of importance in evaluating fruit trees.
{"title":"UAV color images for determination of citrus plant parameters","authors":"S. Mathanker, C. Estévez de Jensen, Andrés M. Pagán-López, L. Pérez-Alegría","doi":"10.46429/jaupr.v103i2.18226","DOIUrl":"https://doi.org/10.46429/jaupr.v103i2.18226","url":null,"abstract":"Unmanned aerial vehicles (UAVs) or drones are being studied for many agricultural applications. One application is plant phenotyping to reduce the time and effort required in collecting field data. This study aims to explore the use of a UAV, 4K-color camera and a commercial image analysis service to measure citrus plant parameters that are important to a crop scientist or grower with limited technical background and resources. Citrus spp. are important crops in Puerto Rico and the United States. Currently, the citrus industry is struggling to contain the devastating effects of citrus greening or Huanglongbing disease. The disease is associated with a phloem-limited bacteria, Candidatus Liberibacter asiaticus (CLAs), vectored by the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. The use of insecticides for vector control is the primary strategy used in nurseries and orchards. However, once the citrus plant is infected, there is no effective control available for the disease. In Puerto Rico this disease has reduced Citrus spp. yields by more than 50%; studies are underway to find effective control measures such as supplemental nutrients, vector management practices, planting disease-free vegetative material and protective screen structures. An experiment at the Fortuna Agricultural Experiment Substation, in Juana Díaz, Puerto Rico, was conducted to address the challenges posed by citrus greening. The experiment was established in a four-year-old grove of Tahiti lime (Citrus latifolia Tan.) on Cleopatra mandarin (Citrus reshni hort. ex Tanaka), naturally infected with Candidatus Liberibacter asiaticus. The experiment was arranged in a randomized complete block design with four replicates and three treatments: supplemental nutrients, supplemental nutrients + salicylic acid, and granular fertilization. Tree growth parameters were measured, and laboratory analyses were carried out to determine nutrient levels and disease severity levels from the leaf samples. The color camera, on board the UAV, was employed to acquire images of the experimental plot. Drone Deploy application was used for planning the UAV flights and image analysis. Field-measured plant height and canopy diameter compared well with the parameters determined from the color images. The average errors in measuring canopy diameter (14.5%) and plant height (22.4%) could be considered within an acceptable range, especially for comparing different treatments or crop varieties. However, the average errors in measuring canopy volume (47.5%) were high and can be considered unacceptable. It appears that the assumed conical shape of the trees could be one of the main reasons, besides the algorithms used in calculating plant volume, and built-in inaccuracies of the single frequency GPS (global positioning system) used in estimating altitude. Further studies could help in reducing errors and exploring other applications. The method used can be of importance in evaluating fruit trees.","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45741460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.46429/jaupr.v103i1.17900
H. Sánchez-Rodríguez
The present study compared the monthly body weight (BW) of 14 wild type (WT) and 11 slick-haired (SLICK) Puerto Rican Holstein heifers from four to 34 months of age at the Agricultural Experiment Station in Lajas, Puerto Rico. Data were analyzed by the GLIMMIX, GLM and REG Procedures in SAS. Hair coat type and age interacted to affect BW (P=0.0005). However, no differences in BW were observed between WT and SLICK heifers (overall mean BW of 279.33±5.78 and 275.06±6.91 kg, respectively; P=0.3182). From four to 34 months, BW increased in both the WT (93.52±11.42 to 446.35±28.27 kg; P<0.0001) and the SLICK heifers (85.69±9.97 to 381.37±35.81 kg; P<0.0001). The interaction observed between hair coat type and age could be the result of different growth trends, as WT heifers presented a linear curve (BW = 12.28 age + 54.41; R2=0.88; P<0.0001); while their SLICK counterparts showed a quadratic regression (BW = −0.32 age2 + 22.75 age + 6.24; R2=0.74; P<0.0001) between BW and age. These results suggest that SLICK heifers may reach maturity at an earlier age and with less BW. Future studies should evaluate if such differences affect the efficiency and productivity of these animals at maturity.
{"title":"Growth comparison between wild type and slick-haired Puerto Rican Holstein heifers","authors":"H. Sánchez-Rodríguez","doi":"10.46429/jaupr.v103i1.17900","DOIUrl":"https://doi.org/10.46429/jaupr.v103i1.17900","url":null,"abstract":"The present study compared the monthly body weight (BW) of 14 wild type (WT) and 11 slick-haired (SLICK) Puerto Rican Holstein heifers from four to 34 months of age at the Agricultural Experiment Station in Lajas, Puerto Rico. Data were analyzed by the GLIMMIX, GLM and REG Procedures in SAS. Hair coat type and age interacted to affect BW (P=0.0005). However, no differences in BW were observed between WT and SLICK heifers (overall mean BW of 279.33±5.78 and 275.06±6.91 kg, respectively; P=0.3182). From four to 34 months, BW increased in both the WT (93.52±11.42 to 446.35±28.27 kg; P<0.0001) and the SLICK heifers (85.69±9.97 to 381.37±35.81 kg; P<0.0001). The interaction observed between hair coat type and age could be the result of different growth trends, as WT heifers presented a linear curve (BW = 12.28 age + 54.41; R2=0.88; P<0.0001); while their SLICK counterparts showed a quadratic regression (BW = −0.32 age2 + 22.75 age + 6.24; R2=0.74; P<0.0001) between BW and age. These results suggest that SLICK heifers may reach maturity at an earlier age and with less BW. Future studies should evaluate if such differences affect the efficiency and productivity of these animals at maturity.","PeriodicalId":14937,"journal":{"name":"Journal of Agriculture of The University of Puerto Rico","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42227820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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