scholarly journals Performance of paraquat and sethoxydim in arracacha

1969 ◽  
Vol 85 (1-2) ◽  
pp. 63-68
Author(s):  
María de L. Lugo ◽  
Alvaro Acosta
Keyword(s):  
Puerto Rico ◽  
Weed Control ◽  
Field Experiments ◽  
University Of Puerto Rico ◽  
Agricultural Experiment Station ◽  
Herbicide Application ◽  
Agricultural Experiment ◽  
Late Application ◽  
Hand Weeding ◽  
The University

Field experiments were conducted at the Adjuntas Agricultural Experiment Station of the University of Puerto Rico during 1996 and 1998 to evaluate the efficacy of the herbicides paraquat and sethoxydim on arracacha. In 1996, no differences were found among the treatments for weed control four weeks after the first and second herbicide applications. Weed control ranged from 72% (two applications of sethoxydim) to 87% (hand weeding) at four weeks after herbicide application, and from 43% (one application of paraquat) to 97% (two applications of paraquat) at four weeks after the second herbicide application. There were no significant differences in yield between treatments with two applications of paraquat and that of hand weeding.The lowest yield (7,632 kg/ha) was obtained when sethoxydim was applied once. In the 1998 experiment, no differences in weed control were found among treatments at four weeks after the first herbicide application; weed control ranged from 81% (two applications of sethoxydim) to 98% (hand weeding). When rated at four weeks after the second herbicide application, the lowest weed control (84%) was obtained with one late application of paraquat. There were no significant differences in yield and number of corms per hectare among treatments.

scholarly journals Evaluation of a Swine Line Developed at the Agricultural Experiment Station of the University of Puerto Rico

1969 ◽  
Vol 51 (1) ◽  
pp. 4-21
Author(s):  
Ismael Carlo ◽  
C. L. Arcelay
Keyword(s):  
Puerto Rico ◽  
Feed Efficiency ◽  
University Of Puerto Rico ◽  
Agricultural Experiment Station ◽  
Multiple Test ◽  
Weaning Age ◽  
Overall Evaluation ◽  
Agricultural Experiment ◽  
Fat Thickness ◽  
The University

The performance of the pigs of the 3/4 Duroc X 1/4 English Large Black Landrace line developed by the Station was compared with the performance of some imported animals. These imported pigs were from the Duroc, the Yorkshire, and the Hampshire breeds. The comparison and the evaluation of the animals was based on preweaning and postweaning characters. The preweaning characters considered were the number of pigs at farrowing, the number at 21 days, and at weaning age. The rate of gain, the feed efficiency, the back-fat thickness corrected to 200 pounds, and carcass evaluation were considered as postweaning characters. All the data obtained were submitted to analysis of variance and where the F values were significant, they were subjected to a Duncan Multiple Test to determine significance among the means. The overall evaluation of both preweaning and postweaning characters showed that the animals of the 3/4 Duroc X 1/4 English Large Black Landrace line of pigs were as good as any of the animals of the imported breeds with which they were compared, with the possible exception of the carcass evaluation, where the imported breeds gave somewhat better results. They were especially good in the number of pigs weaned, as well as in the weight at weaning time and in rate of gain.

scholarly journals Establishment of rhizoma perennial peanut (Arachis glabrata) under irrigation at two semiarid sites in the Caribbean.

1969 ◽  
Vol 85 (3-4) ◽  
pp. 105-114
Author(s):  
Teodoro M. Ruiz ◽  
Rafael Ramos-Santana ◽  
Antonio Sotomayor-Ríos
Keyword(s):  
Weed Control ◽  
Management Strategies ◽  
Lateral Spread ◽  
University Of Puerto Rico ◽  
Agricultural Experiment Station ◽  
Arachis Glabrata ◽  
Agricultural Experiment ◽  
The Caribbean ◽  
Planting Distance ◽  
The University

Two experiments were conducted to determine time for full establishment of rhizoma perennial peanut (RPP) under irrigation. Experiment one (E1) and experiment two (E2) were conducted, respectively, at the Lajas and Fortuna Substations of the Agricultural Experiment Station of the University of Puerto Rico. At Lajas, rhizomes of accessions USDA-ARS no. 17033, 17050, 17052, 17097 (PI no. 276233, 262826, 262833, 262839, respectively) and cultivars Florigraze and Arbrook, planted at 0.76 and 1.5 m apart in rows, were compared for rate of establishment at 60,120, 180 and 240 days postplanting. At Fortuna, rhizomes of accessions 17033 and 17097, and cv. Florigraze were compared at 80,160, and 240 days postplanting. In E2, plots were subjected to the following weed control methods: (1) manual, (2) mowing, and (3) chemical. Time to full establishment in E1 increased from about six months to eight with an increase in planting distance from 0.76 to 1.5 m. Accessions 17033 and 17097 and cv. Florigraze showed a tendency for faster lateral spread prior to 120 days postplanting than the other RPPs. However, peanut genotypes achieved fufl cover at about the same time. The use of herbicide in E2 was the most effective method for promoting faster cover of RPP plants. Establishment of the stand was achieved prior to 240 days in plots receiving weed control treatments 1 and 3, whereas those receiving treatment 2 achieved only 62.5% cover. Compared to a tropical grass, RPP exhibits a slower pattern of lateral spread and requires a longer time for full establishment when planted under similar conditions. However, reducing planting distance and using herbicides to control weeds are management strategies that can reduce time for full establishment of the RPP stand.

scholarly journals Sugarcane Variety Trials in Puerto Rico, 1952-57

1969 ◽  
Vol 43 (1) ◽  
pp. 1-18
Author(s):  
F. Méndez-Roig ◽  
G. Samuels ◽  
A. Colón
Keyword(s):  
Puerto Rico ◽  
Sugarcane Variety ◽  
University Of Puerto Rico ◽  
Agricultural Experiment Station ◽  
North Central ◽  
Eastern Area ◽  
Variety Trials ◽  
The North ◽  
Agricultural Experiment ◽  
The University

The sugarcane variety trials performed by the Agricultural Experiment Station of the University of Puerto Rico, Río Piedras, P.R., during the period 1952-57, involved 24 separate experiments and 51 crops. The following results are significant: 1. In the production of available 96° sugar per acre P.R. 980 was the outstanding variety of the Southern, Western, Northwestern, and Interior Areas of the Island. B. 37161 was first in the Eastern Area and in Caguas Valley, and it tied P.R. 980 in the North Central and B. 41227 in the Northeastern Areas of Puerto Rico. 2. P.R. 980 was first in 10 and B. 37161 in 6 of the 24 experimental sites in terms of tons of cane produced per acre. 3. The check varieties, M. 336, P.O.J. 2878, and P.R. 902 and 905, produced low yields in both tons of cane and of sugar per acre as compared with the leading varieties. 4. M. 336, P.R. 1016, M. 975, and P.P.Q.K. were the leading varieties in sucrose-percent-cane. 5. P.R. 980 and P.R. 1013 ranked first in tons of sugar produced per acre per month. 6. For agronomic evaluation, the leading varieties were ranked in a table in which consideration was given to such factors as germination, stooling, ratooning habit, girth, erectness, flowering, trashiness, and disease resistance.

scholarly journals Sugarcane Variety Trials in Puerto Rico, 1951-55

1969 ◽  
Vol 41 (3) ◽  
pp. 147-160
Author(s):  
Ferdinand Méndez-Roig ◽  
George Samuels
Keyword(s):  
Puerto Rico ◽  
Puerto Rican ◽  
Sugarcane Variety ◽  
Commercial Variety ◽  
University Of Puerto Rico ◽  
Agricultural Experiment Station ◽  
North Central ◽  
Variety Trials ◽  
Agricultural Experiment ◽  
Entire Island

Sugarcane variety trials performed by the Agricultural Experiment Station, University of Puerto Rico, Río Piedras, P. R., During the period 1951-55, involved 19 separate experiments and 33 crops. The following results are significant: 1. In the production of available 96° sugar per acre B. 37161 was the outstanding variety of East and North Central cane areas of the Island. P.R. 980 was the leading variety in the Northwest, West, South, and Interior of Puerto Rico. 2. B. 40105, B. 37172, B. 41227, H. 328560, and P.R. 975 all were among the leading producers in tons of sugar per acre. 3. The check varieties M. 336, P.O.J. 2878, and P.R. 902, ranked poorly in the trials as compared with the leading varieties in tons of sugar produced per acre. 4. In terms of tons of cane per acre B. 37161 and P.R. 980 were the two leading varieties for the entire Island, with H. 328560, B. 41227, and B. 37172 also showing favorable cane-tonnage figures. All check varieties did poorly in tons of cane per acre as compared to the leading variety. 5. The varieties were also ranked according to their production of sucrose-percent- cane. P.R. 975 and B. 4362 were first and second, respectively. These two varieties also produced higher cane tonnage than the favored commercial variety M. 336, which ranked third. 6. Finally, the varieties were ranked according to the tons of sugar per acre produced per month, and P.R. 980 ranked first. The first eight experimental varieties produced over 0.60 ton of sugar per acre per month as compared with all commercial varieties, except B. 37161, which produced below 0.50 ton of sugar per acre per month. 7. The reluctance of Puerto Rican farmers to adopt the new cane varieties tested and proven superior to the old commercial varieties is very unprofitable to them. Yields are cited which show that if the land now used to grow the older cane varieties were planted to the new leading experimentally tested varieties discussed in this article, the present sugar crop in Puerto Rico could be produced on about two-thirds of the present acreage. This would release over 100,000 acres for other agricultural uses.

scholarly journals Yield Performance of Six Lychee Cultivars Grown at Two Locations in Puerto Rico

2016 ◽  
Vol 26 (6) ◽  
pp. 748-753
Author(s):  
Ricardo Goenaga ◽  
David Jenkins ◽  
Angel Marrero
Keyword(s):  
Puerto Rico ◽  
Ethnic Diversity ◽  
Fruit Production ◽  
Fruit Weight ◽  
University Of Puerto Rico ◽  
Yield Performance ◽  
Agricultural Experiment ◽  
Marketable Fruit ◽  
The University ◽  
Lower Production

The globalization of the economy, increased ethnic diversity, and a greater demand for healthy and more diverse food production has increased the demand for tropical fruits. There is a lack of formal experimentation to determine yield performance and fruit quality traits of lychee (Litchi chinensis) cultivars. Six lychee cultivars (Bosworth-3, Brewster, Groff, Mauritius, Kaimana, Salathiel) grown on Mollisol and Inceptisol soils were evaluated for 8 years at the Adjuntas Agricultural Experiment Station of the University of Puerto Rico (UPR-Adjuntas) and La Balear farm, Adjuntas, Puerto Rico, respectively. At UPR-Adjuntas and La Balear, cultivar Groff had a significantly higher production (257,296 fruit/ha) of total fruit than other cultivars, whereas Salathiel had the lowest. However, total fruit production of ‘Groff’ was not significantly different from ‘Kaimana’ and ‘Bosworth-3’at La Balear. At UPR-Adjuntas, cultivars Groff and Bosworth-3 had significantly higher number of marketable fruit than the rest of the cultivars averaging 171,760 fruit/ha. At La Balear, ‘Kaimana’ had a higher number of marketable fruit, but it was not significantly different from ‘Groff’, ‘Bosworth-3’, and ‘Mauritius’, averaging 291,360 fruit/ha. At both sites, individual fruit weight of marketable fruit was higher in ‘Kaimana’ than the rest of the cultivars. However, at La Balear, there were no significant differences between ‘Kaimana’ and ‘Mauritius’. At both locations, cultivars exhibited erratic production patterns, which were characterized by lower production during 1 or 2 successive years following heavy cropping. At current farm gate prices and fruit yield reported in this study, cultivars Groff, Bosworth-3, and Kaimana can generate a good income for growers, and allow them to diversify crops as part of their farm operations.

scholarly journals Evaluation of diquat for postemergence weed control in pumpkin (Cucurbita moschata)

1969 ◽  
Vol 72 (2) ◽  
pp. 285-290
Author(s):  
Luis Almodóvar-Vega ◽  
Manuel Díaz-Rivera ◽  
Nelson Semidey-Laracuente
Keyword(s):  
Toxic Effect ◽  
Weed Control ◽  
Clay Soil ◽  
Cucurbita Moschata ◽  
Agricultural Experiment Station ◽  
Herbicide Application ◽  
Promising Candidate ◽  
Plot Yield ◽  
Broad Leaf ◽  
Agricultural Experiment

In 1982, the bipyridilium herbicides diquat [6,7-dihydrodipyrido (1,2- :2;i-c) pyrazinediium ion] at 0.56, 1.12 and 2.24 kg ai/ha, and paraquat [1, 1-dimethyl-4,4' -bipyridinium ion] at 2.24 kg ai/ha were evaluated for postemergence control of weeds in pumpkin cv. Borinquen (Cucurbita moschata (Duchesne) Poir). The experiment was established in Fraternidad clay soil, a Vertisol at the Lajas Substation, Agricultural Experiment Station. No statistical differences (P=0.05) in yield were detected among the hand-weeded plots (25,580 kg/ha), diquat treated plots (23,296 kg/ha), and paraquat treated plots (27,341 kg/ha). Significant differences in plot yield were observed among paraquat 2.24 kg rate treatment, diquat at the lower rates, and the non-weeded plots. Yields were 0.56 kg diquat (17,172 kg/ha), 1.12 kg diquat (19,551 kg), and non weeded check (10,243 kg/ha). All rates of herbicides provided 100% control of Ipomoea tillacea L.; the higher rates also controlled over 85% Euphorbia heterophylla. Control of grass weeds was inefficient (10% or less) with diquat sprays 1 month after the second herbicide application. Nevertheless, diquat seems to be a promising candidate herbicide for postemergence weed control in pumpkin since it efficiently controlled broad leaf weeds with less toxic effect on applicators than paraquat.

scholarly journals Application timing of oxyfluorfen and halosufuron-methyl in onion (Allium cepa L.).

1969 ◽  
Vol 91 (3-4) ◽  
pp. 149-160
Author(s):  
Carlos J. Ruiz-Vargas ◽  
Elvin Román-Paoli ◽  
María de L. Lugo ◽  
Nelson Semidey
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Severe Damage ◽  
Agricultural Experiment Station ◽  
Application Timing ◽  
Weed Density ◽  
Allium Cepa L ◽  
Previously Treated ◽  
Agricultural Experiment ◽  
Better Than

During 2002 and 2003, two field experiments were conducted at the Agricultural Experiment Station of Lajas to evaluate phytotoxicity and efficacy of weed control of oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl) benzene] and halosulfuron-methyl [methyl 5- [[(4,6-dimethoxy-2- pyrimidinyl)amino]carbonylaminosulfonyl]-3-chloro-1-methyl-1-H-pyrazole-4- carboxylate] applied on three different dates and at three rates after onion (Allium cepaL.) planting. In the first experiment, early applications of oxyfluorfen at 0.13 and 0.27 kg ai/ha at 5,10 and 15 days after onion emergence (DAE) were less phytotoxic (≤ 30%) than simultaneous applications of halosulfuron-methyl, which resulted 100% phytotoxic at 0.027 and 0.054 kg ai/ha. Ten days after each application the lowest weed density (seven plants per 0.5 m2) was obtained with the oxyfluorfen treatment at 15 DAE; however, twenty days later the lowest weed density (five plants per 0.5 m2) resulted from the application at 5 DAE. Greater weed densities were obtained with both rates of halosulfuron-methyl (≥52 plants per 0.5 m2), regardless of application timing. In the second experiment, the applications of halosulfuronmethyl at 35 DAE to plots previously treated with oxyfluorfen at 5, 10 and 15 DAE, caused severe damage (≥80%) to onion. In relation to weed control, the best combination of both herbicides was the application of oxyfluorfen at 10 DAE followed by halosulfuron-methyl at 35 DAE; however, this treatment was not significantly better than the application of oxyfluorfen alone at 10 DAE. The use of oxyfluorfen alone at 10 DAE resulted in higher onion yield and bulb number than any of the other herbicide treatments. Halosulfuronmethyl application reduced onion yield by more than 97%; therefore, the use of this herbicide in this crop should be avoided. Key words: weed density, phytotoxicity, herbicides in this crop should be avoided.

scholarly journals Sugarbeet Production in Puerto Rico

1969 ◽  
Vol 55 (1) ◽  
pp. 114-129
Author(s):  
Peter C. Sweere
Keyword(s):  
Puerto Rico ◽  
Intensive Care ◽  
South Coast ◽  
Sugar Production ◽  
University Of Puerto Rico ◽  
Agricultural Experiment Station ◽  
The South ◽  
Experiment Station ◽  
Highly Sensitive ◽  
Agricultural Experiment

Observational and replicated tests with a number of U.S. and European sugarbeet varieties were conducted from 1963 through 1967 at four substations of the Agricultural Experiment Station, University of Puerto Rico. The purpose of the tests was to determine the adaptability of this crop to Puerto Rico as a possible alternative or supplement to sugarcane for sugar production. Best results were obtained with irrigation on the south coast where yields of 3 to 3.5 tons of sugar per acre were recorded. Such yields were considered insufficiently attractive to offset the disadvantages of sugarbeet cultivation with the advantages of sugarcane cultivation. Beets require intensive care, need close daily attention, and are highly sensitive to correct management.

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