scholarly journals Forage Yield of Five Grasses Under Intensive Grazing Management in the Humid Region of Puerto Rico

1969 ◽  
Vol 64 (3) ◽  
pp. 259-263
Author(s):  
Edmundo Rivera ◽  
José Rodríguez
Keyword(s):  
Puerto Rico ◽  
Large Scale ◽  
Forage Yield ◽  
Grazing Management ◽  
Yield Potential ◽  
Experimental Plot ◽  
Forage Grasses ◽  
Humid Region ◽  
Second Year ◽  
Intensively Managed

Three grasses on intensively managed and grazed 10 x 10 m plots produced statistically similar yields of dry forage over a 3-year period expressed in kg/ha/yr as follows: Stargrass—12,445; Coast Cross #1—12,285; and Hemarthria PI 299995—13,685. Hemarthria PI 299994 produced significantly higher yields—15,370 kg/ha/yr. Cynodon plectostachyus, on the other hand, did not tolerate intensive grazing and produced only 4,695 kg/ha during the second year. Yields of Star and Hemarthria PI 299995 were comparable to yields obtained in a large scale grazing experiment nearby, which confirmed the validity of the small experimental plot technique in determining yield potential of grazed forage grasses.

scholarly journals Productivity of Four Intensively Managed Grasses under Grazing Management in the Humid Hill Region of Puerto Rico

1969 ◽  
Vol 64 (2) ◽  
pp. 236-240
Author(s):  
José Rodríguez ◽  
Edmundo Rivera ◽  
José Vicente-Chandler
Keyword(s):  
Puerto Rico ◽  
Large Scale ◽  
Grazing Management ◽  
Yield Potential ◽  
Experimental Plot ◽  
Forage Grasses ◽  
Grazing Experiment ◽  
Hill Region ◽  
Intensively Managed

Four grasses on intensively managed, grazed 10 x 10 m plots produced similar yields of dry forage expressed in kg/ha/yr as follows: Pangola—10,330; Signal—9,900; Tanner—11,030; and Transvala—10 ,620. Yields of Signal, Tanner and Congo grasses were comparable to yields obtained in a large scale grazing experiment nearby, a fact which confirmed the validity of the small experimental plot technique in determining yield potential of forage grasses under grazing management.

scholarly journals Effects of Phosphorus Fertilization on Productivity of Intensively Managed Grasses Under Humid Tropical Conditions in Puerto Rico

1969 ◽  
Vol 48 (3) ◽  
pp. 236-242
Author(s):  
Jacinto Figarella ◽  
José Vicente-Chandler ◽  
Servando Silva ◽  
Rubén Caro-Costas
Keyword(s):  
Puerto Rico ◽  
Phosphorus Content ◽  
Soil Phosphorus ◽  
The Other ◽  
Clay Soils ◽  
Phosphorus Fertilization ◽  
Humid Region ◽  
Tropical Conditions ◽  
Intensively Managed ◽  
Available Soil Phosphorus

The effects of phosphorus applications on yields and phosphorus content of otherwise well-fertilized tropical grasses growing on three typical soils of the Humid Region of Puerto Rico were determined. Napier grass responded strongly in yield to applications of 150 pounds of P2O5 per acre yearly on both Múcara and Catalina clay soils at Orocovis. The phosphorus content of the forage increased with applications of up to 300 pounds of P2O5 per acre yearly on both soils. On the other hand, Napier, Guinea, and Pangola grasses, growing on a Fajardo clay formerly in moderately fertilized sugarcane for many years, did not respond in yield or phosphorus content to applications of phosphorus over a 5-year period. Various methods of determining "available" soil phosphorus did not give satisfactory results with these soils.

scholarly journals Brachiaria decumbens intraspecific hybrids: characterization and selection for seed production

2016 ◽  
Vol 38 (1) ◽  
pp. 62-67 ◽  
Author(s):  
Lenise Castilho Monteiro ◽  
Jaqueline Rosemeire Verzignassi ◽  
Sanzio Carvalho Lima Barrios ◽  
Cacilda Borges Valle ◽  
Celso Dornelas Fernandes ◽  
...  
Keyword(s):  
Seed Production ◽  
Acid Soils ◽  
Forage Yield ◽  
Low Fertility ◽  
Yield Potential ◽  
Phenotypic Correlation ◽  
Brachiaria Decumbens ◽  
Second Year ◽  
High Forage ◽  
Intraspecific Hybrids

Abstract: Brachiaria decumbens has great importance in the national beef cattle scenario due to its high forage yield potential and high adaptability to acid soils and low fertility. In order to obtain new cultivars, intraspecific hybrids, previously selected by the Brachiaria breeding program, were evaluated in 2013 and 2014 for phenological characteristics and seed production potential through their production components, aiming to obtain cultivars with satisfactory production agronomic characteristics and forage yield, resistant to 'cigarrinhas-das-pastagens'(Tomaspia sp.) and good seed production. Estimates of phenotypic correlation and analysis of variance were performed using the SAS 9.3 software. From the results obtained in both consecutive years, it was observed that there was a correlation between the reproductive tiller number (RT) and the pure seeds (PS) weight in the seedbeds of the second year of production around 70% (p < 0.01), which can be considered as a parameter to estimate the production of pure seeds before the start of flowering.

scholarly journals Effects of Three Harvest Intervals and Two Fertilizer Rates on the Yield and HCN Content of Ten Cynodon Cultivars

1969 ◽  
Vol 63 (1) ◽  
pp. 35-44
Author(s):  
J. Vélez-Santiago ◽  
A. Sotomayor-Ríos ◽  
S. Torres-Rivera
Keyword(s):  
Puerto Rico ◽  
Acid Content ◽  
Crude Protein ◽  
Cynodon Dactylon ◽  
Forage Yield ◽  
Protein Yield ◽  
Hydrocyanic Acid ◽  
Forage Grasses ◽  
Harvest Intervals ◽  
Fertilizer Rates

Ten forage grasses (Cynodon spp.), including recent introductions, and Stargrass (C. nlemfuensis var. nlemfuensis) were grown in the central mountains of Puerto Rico to measure the effect of two fertilizer rates and three harvest intervals on the forage yield, crude protein yield and hydrocyanic acid content (HCN) for a 2-year period. Fertilizer treatments applied after each harvest consisted of 2.24 and 4.48 metric tons/ha/year of a 15-5-10 fertilizer. Significant differences occurred between fertilizer rates as to dry forage and crude protein yields. Number of harvests per year were 6, 8 and 12 for 30-, 45- and 60-day intervals, respectively. Significant differences occurred among cultivars and harvest intervals. Cynodon dactylon (PRPI 11504), C. plectostachyus (PRPI 11487) and C. nlemfuensis var. nlemfuensis (PRPI 2341) occupied most of the top yield positions at the three harvest intervals. HCN within the cultivars ranged from 0 to 333 p/m.

scholarly journals Effect of Three Harvest Intervals on Yield and Composition of Nineteen Forage Grasses in the Humid Mountain Region of Puerto Rico

1969 ◽  
Vol 60 ◽  
pp. 294-309
Author(s):  
A. Sotomayor-Ríos ◽  
J. Vélez-Santiago ◽  
S. Torres-Rivera ◽  
S. Silva
Keyword(s):  
Puerto Rico ◽  
Crude Protein ◽  
Sharp Decrease ◽  
Significant Negative Correlation ◽  
Forage Yield ◽  
Mountain Region ◽  
Forage Grasses ◽  
Average Temperature ◽  
Harvest Intervals ◽  
Positive Correlations

The response of 19 forage grasses to three cutting intervals in the humid mountain region of Puerto Rico was evaluated. Nine Brachiarias, nine Digitarias, and one Cynodon species were evaluated during a 2-year period under cutting management at the Corozal Substation for green forage (GF), dry forage (DF), and crude protein (CP) yields and for dry matter (DM), crude protein (CP), Ca, P, K, and Mg contents. In terms of green forage yield (GFY), the most productive species at the 30-day harvest interval was D. setivalva (PRPI 6402) with 86,794 kg/ ha/year. At the 45- and 60-day harvest intervals, Brachiaria sp. (PRPI 9626) produced 102,116 and 109,213 kg/ha/year, respectively. This species also produced the highest DFY at the 30-day harvest interval with 18,430 kg/ha/year. C. nlemfuensis, var. nlemfuensis (PRPI 2341), stargrass, and B. decumbens (PRPI 5365) produced the highest DFY at the 45- and 60-day intervals with 21,758 and 27,238 kg/ha/year, respectively. The highest CP content at the 30-, 45-, and 60-day intervals was observed on the three Digitaria hybrids, D. pentzii x D. smutzii (PRPI 9621), D. pentzii x D. milanjiana (PRPI 9619), and D. pentzii x D. pentzii (PRPI 9620) with 14.3, 12.0, and 11.1 %, respectively. D. decumbens (PRPI 6439), 'Transvala' Digitgrass, produced the highest CP yield at the 30-day harvest interval with 2, 179 kg/ha/year. Stargrass had the highest CP yield at the 45- and 60-day harvest intervals with 2,141 and 2,030 kg/ha/year, respectively. The P, Ca, Mg, and K contents of the 19 grasses on the average decreased as the harvest interval increased. A sharp decrease (from 1.81 to 1.47 to 1.42%) of the K content of the grasses was observed at the 30-, 45-, and 60-day intervals, respectively. The GFY, DFY, and DM of the 19 grasses increased on the average with the length of the harvest interval. On the other hand, the CP content and yield of the 19 grasses decreased as the harvest interval increased. No significant correlation was obtained between total rainfall, CP, and DFY of the 19 grasses. Significant positive correlations were obtained between DFY of the 19 grasses and average temperature. A significant negative correlation was obtained between average temperature and CP content.

scholarly journals The Effect of Different Fertility Levels on Yields of Intensively Managed Coffee in Puerto Rico

1969 ◽  
Vol 43 (3) ◽  
pp. 141-146
Author(s):  
Fernando Abruña ◽  
José Vicente-Chandler ◽  
Servando Silva
Keyword(s):  
Puerto Rico ◽  
Phosphoric Acid ◽  
Significant Response ◽  
First Year ◽  
Strong Indication ◽  
Strong Response ◽  
The Third ◽  
Second Year ◽  
Intensively Managed ◽  
Normal Rainfall

The effect of three levels each of nitrogen, phosphoric acid, and potash, on yields of intensively managed coffee grown in Alonso clay at Castañer were determined. Yields averaging in excess of 15 hundredweights of market coffee per acre were obtained over 3 successive years, compared to an Islandwide average of about 150 pounds. A marked response to the application of 150 pounds of nitrogen per acre occurred during all 3 years, with a strong indication of a response to an additional 150 pounds of nitrogen during the 2 years of normal rainfall. A strong response to the application of 150 pounds of potash per acre occurred during the first year, a response to the 300-pound application the second year, and to the 150- and 300-pound levels the third year. There was no significant response to phosphorus in any year.

scholarly journals Comparative value of various methods of approximating the permanent wilting percentage

1969 ◽  
Vol 36 (2) ◽  
pp. 122-133
Author(s):  
M. A. Lugo López
Keyword(s):  
Puerto Rico ◽  
Organic Matter Content ◽  
Clay Content ◽  
Matter Content ◽  
Regression Equations ◽  
Accurate Approximation ◽  
Time Saving ◽  
Laboratory Equipment ◽  
Pressure Plate ◽  
Humid Region

Very accurate estimations of the permanent wilting percentage can be obtained for soils of all regions of Puerto Rico by use of regression equations based on the hygroscopic coefficient. Reliable estimates can also be obtained for humid-region soils by using the clay content as a basis. Attempts to correlate permanent wilting-percentage values with moisture equivalents and organic-matter content did not give such satisfactory results. The 15-atmosphere percentage as determined by using pressure plates gives an accurate approximation of permanent wilting-percentage values. It is time-saving, but initial expense in laboratory equipment is rather high. This approach is to be preferred whenever feasible. A regression equation is given relating pressure-plate values to the permanent wilting percentage. Whenever less precise estimates are acceptable and time is not a factor, advantage should be taken of the established correlation between the hygroscopic coefficient and the permanent wilting percentage.

scholarly journals Production of grazed tropical grasses in different agroecosystems in Puerto Rico. III. Semiarid

1969 ◽  
Vol 72 (2) ◽  
pp. 211-219
Author(s):  
Luis E. Tergas ◽  
Jaime Vélez-Santiago ◽  
Angel V. Méndez-cruz
Keyword(s):  
Puerto Rico ◽  
Rainy Season ◽  
Semiarid Region ◽  
First Year ◽  
Panicum Maximum ◽  
Forage Production ◽  
Tropical Grasses ◽  
Significant Difference ◽  
Second Year ◽  
Cynodon Nlemfuensis

A field experiment was conducted at the Lajas Experiment Substation in the semiarid region of Puerto Rico to evaluate the production and persistence of 8 tropical grasses, Cynodon nlemfuensis Star, C. dactylon Coastcross-1, C. plectostachyus Star, Panicum maximum USDA Pl291047, Makueni, Guinea and P. maximum USDA PI 259553, and the naturalized pasture Dichanthium annulatus pajon. Small plots were grazed at 3- to 5-week intervals for 2 years. P. maximum USDA PI 259553 and Makueni were highly productive in the semiarid,.region, as well as in previous experiments in humid regions in Puerto Rico. They are highly recommended for grazing trials. P. maximum Makueni and USDA PI 291047 were the most productive during the first year, although they were not significantly different (P=0.05) from P. maximum USDA PI 259553 and Common Guinea, and Cynodon plectyostachyus Star. The production of C. nlemluensis Star was similar to that of Dichanthium annulatus but higher than that of C. dactylon Coastcross-1 (P=0.05). The average production for all grasses declined at the beginning of the year, during the cool short days in February and March, 1983, without any significant difference (P=0.05) among species and cultivars. Production increased at the beginning of the rainy season, but it was low at the peak of the rainy season because of trampling in poorly aerated and compact soils. C. plectostachyus Star was the most productive grass during the second year of experiment, although it was not significantly different (P=0.05) from P. maximum USDA PI 291017 and 259553 and cultivar Makueni. The production of Common Guinea and that of D. annulatus were. similar and higher than that of C. nlemfuensis Star and C. dactylon Coastcross-1 (P=0.05), which did not persist at the end of the experiment. Forage production during the second year was lower than in the first year because of less rainfall in 1983. The mean CP content of all grasses varied from 11.29 to 14.05, except that of D. annulatus, which was only 9.73%. CP content was lower during the periods of maximum forage production.

scholarly journals Production of grazed tropical grasses in different agroecosystems in Puerto Rico. II. humid northern coastal plains

1969 ◽  
Vol 72 (2) ◽  
pp. 201-210
Author(s):  
Luis E. Tergas ◽  
Jaime Vélez-Santiago ◽  
Doralissa Vera de Saldaña
Keyword(s):  
Puerto Rico ◽  
Crude Protein ◽  
Relative Difference ◽  
Panicum Maximum ◽  
Coastal Plains ◽  
Crude Protein Content ◽  
Rainfall Distribution ◽  
Tropical Grasses ◽  
Average Production ◽  
Humid Region

A field experiment was conducted near Barceloneta in the humid northern coastal plains of Puerto Rico to evaluate the production and persistence of 10 tropical grasses: Cynodon sp. local, Digitaria pentzii Slenderstem, C. nlemfuensis Star, C. plectostachyus Star, C. dactylon Coastcross-1, D. milanjiana Pangola Soto, Panicum maximum Guinea, P. maximum Guinea USDA PI 259553, P. maximum Makueni and D. decumbens Transvala grazed at 3- to 5-week intervals for one and a half year. P. maximum USDA PI 259553 was the most productive grass, but during the 13 grazings in 1981-1982, it was not significantly different (P=0.05) from C. plectostachyus Star; Cynodon sp. Local, D. pentzii Slenderstem, C. nlemfuensis Star, P. maximum Makueni, and D. decumbens Transvala. Guinea and D. milanjiana Pangola Soto were the least productive (P=0.05). Results for 7 grazings from January to June 1983 again showed P. maximum USDA PI 259553 to be the most productive grass, although not significantly different (P=0.05) from D. decumbens Transvala, C. dactylon Coastcross-1 and D. pentzii. The production of P. maximum Makueni and C. plectostachyus Star was intermediate; C. nlemfuensis Star and Guinea were the least productive, and D. milanjiana Pangola Soto did not persist under intensive grazing (P=0.05). The total mean production of all grasses of 0.92 and 1.00 ton/ha/grazing, respectively, were related to rainfall distribution. The general mean in crude protein content of forage was higher during the drier months. Average production of all grasses in this experiment was lower than in a similar experiment at Corozal in the humid region of Puerto Rico, the relative difference varied among cultivars.

scholarly journals Gefährlich und nützlich zugleich: Strategien zum Management der invasiven Robinie

2018 ◽  
Vol 169 (2) ◽  
pp. 77-85 ◽  
Author(s):  
Michaela Vítková ◽  
Marco Conedera ◽  
Jiří Sádlo ◽  
Jan Pergl ◽  
Petr Pyšek
Keyword(s):  
Time Management ◽  
Large Scale ◽  
Agricultural Landscape ◽  
Black Locust ◽  
Robinia Pseudoacacia ◽  
Management Strategies ◽  
Habitat Type ◽  
Agricultural Landscapes ◽  
Wide Range ◽  
Intensively Managed

Dangerous and useful at the same time: management strategies for the invasive black locust The North American black locust (Robinia pseudoacacia) is considered controversial as many other introduced tree species because of its both positive and negative properties. Based on a literature review and own data we analyze the occurrence of black locust in Czechia and Switzerland and present the management approaches in place. In both countries, black locust is on the blacklist of invasive introduced species. It can grow in a wide range of habitats from urban and agricultural landscape to dry grassland and forest. Meanwhile, the species became in many places part of the environment and human culture, so that neither unrestricted cultivation nor large-scale eradication is feasible. We suggest a context-dependent management which respects the different needs and takes into account the local environmental conditions, land-use, habitat type, risk of spread as well as economic, cultural and biodiversity aspects. To this purpose we propose three management strategies: 1) control respectively gradual suppression of black locust in forests where the species is not welcome, 2) its eradication in sensitive ecosystems as dry grasslands or clear and dry forests and 3) its tolerance in intensively managed agricultural landscapes and in urban environment.

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