Ecological distribution of Spirillum lipoferum Beijerinck

1976 ◽  
Vol 22 (10) ◽  
pp. 1464-1473 ◽  
Author(s):  
J. Dobereiner ◽  
I. E. Marriel ◽  
M. Nery
Keyword(s):  
Acid Soils ◽  
Temperate Climate ◽  
Panicum Maximum ◽  
Forage Grasses ◽  
Ecological Distribution ◽  
African Countries ◽  
Grass Root ◽  
The Tropics ◽  
Hill Soils ◽  
Janeiro State

A survey in various countries revealed that the N2-fixing Spirillum lipoferum Beijerinck is a very common root and soil inhabitant in the tropics. More than half of the grass root and soil samples collected in tropical countries (four African countries and Brazil) contained abundant S. lipoferum populations, while less than 10% of the samples collected in temperate South Brazil, Kenya, and the U.S.A. contained the organism. There is a pronounced vegetation effect. Panicum maximum seems the most favorable among the forage grasses, while few positive samples were found under virgin tropical forest. Legume roots contained less S. lipoferum than adjacent soils. More than 80% of the samples from cereal roots (maize, sorghum, wheat, and rye) grown in fields fertilized with PK and Mo, in Rio de Janeiro State, were positive. Maize and sorghum grown under similar conditions in Wisconsin contained less than 10% of positive samples, but when maize fields were inoculated 90% of the root samples contained S. lipoferum. Alluvial soils were more favorable than eroded hill soils. Occurrence in soil was strongly pH-dependent with a pH around 7, being optimal (correlation coefficient r = 0.90). Sporadic occurrence was observed even in soils with pH 4.8. Surface-sterilized P. maximum roots collected from soils with pH ranging from 4.8 to 7.2 contained high S. lipoferum numbers which did not correlate with soil pH (r = 0.41). Amendment with malate of acid soils was not very effective in increasing nitrogenase (N2-ase) activity, but in two soils with pH above 6.4, high N2-ase activity was obtained after 16 to 48 h of incubation. In two soils from a temperate climate region, inoculation with S. lipoferum increased N2-ase activity produced through malate amendment.

scholarly journals SEMI-HYDROPONIC CULTIVATION AS A SELECTION TOOL FOR ALUMINUM TOLERANCE IN FORAGE GRASSES

2016 ◽  
Vol 24 (4) ◽  
pp. 350-356
Author(s):  
Gustavo André Colombo ◽  
Aurélio Vaz-de-Melo ◽  
Gilberto Coutinho Machado Filho ◽  
André Silva de Sousa
Keyword(s):  
Nutrient Solution ◽  
Aluminum Toxicity ◽  
Aluminum Tolerance ◽  
Dry Weight ◽  
Panicum Maximum ◽  
Forage Grasses ◽  
Breeding Programs ◽  
Brachiaria Humidicola ◽  
Hydroponic Cultivation ◽  
Constant Improvement

The constant improvement of selection methods is necessary in order to optimize efficiency of breeding programs for aluminum tolerance. Thus, the aim of this study was to establish a vase volume to the ideal semi-hydroponic cultivation of forage grasses subjected to stress by aluminum in nutrient solution. The experimental design completely randomized, with four replicates, each replicate consisting of one plant per vase. The treatments were arranged in a factorial design 4x5, being the first factor consists of four genotypes of forage grasses Brachiaria Humidicola; Brachiaria brizantha cv. Piatã; Panicum maximum cv. Massai and Panicum maximum cv. Mombaça) and the second consisting of five separate volumes plastics vases where seedlings were grown (0.2; 0.25; 0.3; 0.35 and 0.4 dm³). The grasses grown in a semi-hydroponics system irrigated with nutrient solution rich in aluminum (3 mg L-1). Was measured plant height, dry weight of aereal part and root length. The semi-hydroponic cultivation in aluminum increased nutrient solution is effective in differentiation of forage grasses genotypes in relation to aluminum tolerance. Pots volumes near 0.3 dm3 promote greater development for root and aerial part attributes in forage grasses grown in nutrient solution with aluminum toxicity.

scholarly journals CARACTERÍSTICAS PRODUTIVAS DE TRÊS ESPÉCIES FORRAGEIRAS IRRIGADAS

Irriga ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 99
Author(s):  
Débora Pantojo de Souza ◽  
Arthur Carniato Sanches ◽  
Fernando Campos Mendonça ◽  
Rodolfo Guertas Maffei ◽  
Pedro José Catto
Keyword(s):  
Statistical Design ◽  
Sprinkler System ◽  
Forage Yield ◽  
Panicum Maximum ◽  
Forage Grasses ◽  
Brachiaria Brizantha ◽  
Significance Level ◽  
Tropical Forage ◽  
Dead Material ◽  
E Mail

CARACTERÍSTICAS PRODUTIVAS DE TRÊS ESPÉCIES FORRAGEIRAS IRRIGADAS  DÉBORA PANTOJO DE SOUZA1; ARTHUR CARNIATO SANCHES2; FERNANDO CAMPOS MENDONÇA3; RODOLFO GUERTAS MAFFEI4 E PEDRO JOSÉ CATTO4 1 Engenheira Agrônoma, Mestranda em Engenharia de Sistemas Agrícolas, ESALQ/USP, Piracicaba,SP. CEP:13418900, e-mail:[email protected] Engenheiro Agrônomo, Doutorando em Engenharia de Sistemas Agrícolas, ESALQ/USP, Piracicaba,SP. CEP:13418900, e-mail: [email protected] Prof. Dr. Dep. Engenharia de Biossistemas, ESALQ/USP, Piracicaba,SP. CEP:13418900, e-mail: [email protected] Acadêmicos de Engenharia Agronômica, ESALQ/USP, Piracicaba,SP. E-mail: [email protected]; [email protected].  1 RESUMO Este trabalho teve por objetivo a caracterização de parâmetros produtivos para três forrageiras tropicais irrigadas ao longo de três ciclos de cultivo. O experimento foi realizado na ESALQ/USP, em delineamento estatístico de blocos casualizados com parcelas subdivididas, com área total de 864 m². Foram estudadas as forrageiras Brachiaria brizantha cv. Marandu, Cynodon ssp. cv. Tifton 85 e Panicum maximum cv. Mombaça, no período compreendido entre 11 de fevereiro a maio de 2016. Consideraram-se os seguintes parâmetros produtivos de massa seca de forragem: produtividade total de forragem (PTF), produtividade de folhas (PF), produtividade de colmos (PC), produtividade de material morto (PMM), as porcentagens de massa de folhas (%MF), massa de colmos (%MC) e material morto (%MM) e a razão folha colmo-1 (RFC). A análise estatística de comparações múltiplas foi feita com o auxílio do software ASSISTAT 7.7, verificando-se que o capim Mombaça teve maior PTF (5.285,07 kg ha-1) em relação às demais espécies (nível α=0,01 de significância). Na média das três forrageiras, o 2º ciclo foi o mais produtivo (PTF = 3.883,69 kg ha-1). Também foi constatada a interação entre forrageiras e ciclos de crescimento para as variáveis PF e PC. O capim Mombaça apresentou a maior PF nos três ciclos, e PC maior em relação às demais forrageiras apenas no 1ociclo. A RFC não diferiu significativamente entre as forrageiras. Conclui-se que, dentre as três forrageiras estudadas, o capim Mombaça teve maior diminuição da produtividade ao longo dos três ciclos. Palavras-chave: Irrigação de pastagens, forrageiras tropicais, produtividade total de forragem.  SOUZA, D. P. de; SANCHES, A. C.; MENDONÇA, F. C.; MAFFEI, R. G.; CATTO, P. J.PRODUCTIVE CHARACTERISTICS OF THREE IRRIGATED SPECIES OF FORRAGEIRAS    2 ABSTRACT This work aimed to characterize the productive parameters for three tropical forage grasses during three cropping cycles. The experiment was carried out at the Luiz de Queiroz Agriculture College, under random blocks, in the split-plot statistical design, in a total area of 864 m². The forage grasses studied were Brachiaria brizantha cv. Marandu, Cynodon ssp. cv. Tifton 85,and Panicum maximum cv. Mombasa, from February 11th to May 6th, 2016 (3 growing cycles).The irrigation was made by a sprinkler system installed with a 12 x 12 m spacing, with sprinklers running at an average pressure of 300 kPa, whose distribution uniformity was previously checked (CUC = 87%). The following parameters were considered: total of forage yield (PTF), leaf yield(PF), culm yield (PC), dead material yield(PMM), leaf mass percentage (% MSF), stems percentage (% MSC), dead material percentage (% MSMM), and leaf culm-1 ratio (RFC). The multivariate statistical analysis was performed with the software ASSISTAT 7.7, and the results showed that the Mombaça grass had the highest forage yield (PTF = 5285.07 kg ha-1, significance level α = 0.01 ). Considering the culm yield and the average for the three forage grasses, the 2nd growing cycle presented the highest forage yield (3883.69 kg ha-1). The interaction between forage species and growing cycles was also verified, for the PF and PC parameters. The Mombasa grass had the highest PF values in the three growing cycles. For the PC parameter, the Mombasa grass was higher than the others only in the 1st cycle. Considering the RFC parameter, Tifton 85 had lower values than the others (1.24), but did not significantly differ from the other grasses. Among the three forage grasses studied, the Mombasa grass had the highest sensitivity to climate changes along the three growing cycles.         Keywords: Pasture irrigation, tropical forage grasses, total of forage yield.

In Vitro gas production assessement of Panicum maximum incubated with Leucaena leucocephala at varying proportions to predict the nutritional value for ruminants

2021 ◽  
Vol 44 (3) ◽  
pp. 371-377
Author(s):  
O. O. Falola ◽  
O. O. Olufayo
Keyword(s):  
Leucaena Leucocephala ◽  
Crude Protein ◽  
Small Ruminants ◽  
Short Chain Fatty Acids ◽  
Gas Production ◽  
Panicum Maximum ◽  
In Vitro Gas Production ◽  
Metabolisable Energy ◽  
The Tropics

The inclusion of multipurpose trees with grass such as Panicum maximum in the diet of ruminants may enhance productivity. Thus, the study was carried out to determine the proximate composition, in vitro gas production characteristics and parameters of Leucaena leucocephala and Panicum maximum at varying proportions. Five diets were formulated such that Panicum maximum was substituted with Leucaena leucocephala at different ratio: T1 (100% Panicum maximum), T2 (100% Leuceana leucocephala), T3 (50% P. maximum + 50% L. leucocephala), T4 (75% P. maximum + 25% L .leucocephala) and T5 (25% P. maximum + 75% L. leucocephala). Data were subjected to analysis of variance. Values obtained for dry matter (34.43 –35.95g/100g) decreased with the increased inclusion of Leuceana leucocephala in the diets. The crude fiber values (14.33 – 30.75g/100g) also followed the same trend while crude protein (CP) content (10.70 – 26.78g/100g) increased the inclusion of Leucaena leucocephala in the diets. There were significant (P < 0.05) differences in the treatment means of organic matter digestibility (OMD 31.93 – 37.07%), Metabolisable energy (ME 3.62 – 4.33 MJ/kgDM), short chain fatty acids (SCFA 0.04 – 0.16mL) and methane (ME 1.00 – 2.50 mL).The values (2.00 – 4.67 ml/200mgDM) obtained for immediate soluble 'a' was significantly (P < 0.05) different among the treatments. The extent of gas production (a+b) ranged from 2.00 – 4.67 mL/200mgDM, T1 (100% Panicum maximum) recorded the lowest while highest was observed in T2 (100% Leucaena leucocephala). The insoluble but degradable fraction 'b'ranged from 2.67 – 5.67ml/200mgDM, while the rate of gas production 'c' ranged from 0.04 – 0.14ml/hr. In conclusion, the enhanced values of crude protein, OMD, SCFA, and ME in the Panicum maximum and Leucaena leucocephala mixture indicate that the diets is able to meet the nutrients requirements of small ruminants in the tropics especially during the dry season.

Nonparallel Geographic Patterns for Tolerance to Cold and Desiccation in Drosophila-Melanogaster and Drosophila-Simulans

1990 ◽  
Vol 38 (2) ◽  
pp. 155 ◽  
Author(s):  
JK Davidson
Keyword(s):  
Cold Tolerance ◽  
Desiccation Tolerance ◽  
A Priori ◽  
Strong Association ◽  
Temperate Climate ◽  
Physiological Mechanisms ◽  
Parallel Patterns ◽  
Climatic Extremes ◽  
Geographic Patterns ◽  
The Tropics

D. melanogaster populations from the fluctuating temperate climate of Melbourne (38�S) and in the tropics at Townsville (19�S) were investigated for differentiation in cold tolerance and desiccation tolerance, and were found to differ as predicted a priori from climatic considerations. Flies from the former locality were more tolerant to both of these environmental stresses. In comparable D. simulans populations, there was no significant differentiation between populations for cold tolerance or desiccation tolerance. In both species, there was genetic variation within each population. It is hypothesised that the non-parallel patterns in these sibling species may be due to different genetic strategies in temporal variation for tolerance to the stresses associated with climatic extremes. For D. melanogaster and D. simulans, there was no strong association between cold tolerance and desiccation tolerance in either the Melbourne and Townsville populations. Correlations between the stresses over the 15 strains were calculated for the sexes, generations, localities and species separately and were all non-significant. Cold tolerance and desiccation tolerance thus involve different physiological mechanisms.

scholarly journals Effect of exercise and humid heat upon pulse rate, blood pressure, body temperature, and blood concentration

1920 ◽  
Vol 91 (636) ◽  
pp. 111-126 ◽  
Keyword(s):  
Blood Pressure ◽  
High Temperature ◽  
Body Temperature ◽  
Human Body ◽  
Temperate Climate ◽  
Human Organism ◽  
Atmospheric Conditions ◽  
Hot Climate ◽  
The Tropics ◽  
Short Time

The effect of exercise on the human body has been made the subject of much study at different times. Researches have been carried out under atmospheric conditions such as prevail in different parts of Northern Europe, and they have been extended in a few instances to the effects of high temperature and humidity upon the human body. In the latter observations the conditions such as high temperature and varying humidity were produced by artificial means only, and general deductions as to the influence of an actual tropical climate upon the human organism cannot be safely drawn from them. In these experiments the subjects were living in a temperate climate, were exposed to heat and humidity for a short time only, and left the hot chamber at the end of the experiment for an atmosphere of coolness and comfort; in the tropics, on the other hand, the inhabitants are continuously exposed to heat and humidity without respite. Conclusions of real value can thus be drawn only from observations actually carried out in a hot climate, and systematic work in this direction is still lacking. Although observations have been made in the tropics on body temperature, blood pressure, pulse and respiration rate, and metabolism, yet their object has only been to obtain normal standards for the tropics for comparison with those of Europe.

scholarly journals Accessing the nutritional composition and phytochemical screening of Panicum maximum and Newbouldia laevis leaves

2020 ◽  
Vol 40 (1) ◽  
pp. 161-167
Author(s):  
A. O. Yusuf ◽  
O. S. Sowande ◽  
O. M. Sogunle ◽  
V. A. Akinbami ◽  
O. O. Oyebanji ◽  
...  
Keyword(s):  
Veterinary Medicine ◽  
Crude Protein ◽  
Nutritional Composition ◽  
Animal Production ◽  
Panicum Maximum ◽  
Ether Extract ◽  
Phytochemical Screening ◽  
Crude Fibre ◽  
Dry Seasons ◽  
The Tropics

Ruminant livestock in most parts of the tropics graze extensively on naturally growing forages which are poor in quality. These tropical forages compared to those in the temperate, support lower levels of ruminant animal production mainly because they contain less nitrogen and are less digestible. The quality and quantity of these grasses become more critical in the dry seasons and thereby imposing more serious constraint to the development and productivity of these animals. Therefore, a study was conducted to access nutritional composition of Panicum maximum and Newbouldia laevis. Phytochemical screening of Newbouldia laevis was also carried out. Newbouldia laevis had higher crude fibre, ether extract and crude protein compared to Panicim maximum. The phytochemical screening revealed the presence of Tannin, Alkaloids, Flavonoids and Saponnin in Newbouldia laevis. The percentages of tannin, alkaloids, flavonoids and saponin in the Newbouldia laevis were 11.5, 52.07, 3.1 and 0.64, respectively while none was recorded for Panicum maximum. The relatively high crude fibre, ether extract and crude protein values for both plants s appeared satisfactory for animal production. Also, the presence of the phytochemicals in the plant showed it importance in ethno veterinary medicine and pharmacology.

scholarly journals Fibrous Carbohydrate Fractions and in Vitro True and Apparent Digestibility of 10 Tropical Forage Grasses

1969 ◽  
Vol 58 (3) ◽  
pp. 293-304
Author(s):  
J. Coward-Lord ◽  
J. A. Arroyo-Aguilú ◽  
O. García-Molinari
Keyword(s):  
Nutritive Value ◽  
Panicum Maximum ◽  
Apparent Digestibility ◽  
Forage Grasses ◽  
Mean Values ◽  
Brachiaria Ruziziensis ◽  
Tropical Forage ◽  
The Difference ◽  
Tropical Climates

Ten tropical forage grasses (Pangola, Digitaria decumbens; Congo, Brachiaria ruziziensis; Signal, Brachiaria brizantha; Buffel, Cenchrus ciliaris; Guinea, Panicum maximum; Jaragua, Hyparrhenia rufa; Giant Pangola, Digitaria valida; African Crab, Digitaria swazilandensis; Venezuelan Elephant, Pennisetum setosum; and Limpo, Hemarthria altissima) lightly fertilized with NH4NO3 at the rate of 350 kg/ha, were harvested by hand (machete) every 30 days up to 180 days of age, beginning August 20, 1970, at the College of Agricultural Sciences grass collection, University of Puerto Rico at Mayagüez. They were evaluated chemically for cell-wall constituents or neutraldetergent fiber (NDF), acid-detergent fiber (ADF), permanganate lignin (L), cellulose (C) and silica (Si), as outlined by Goering and Van Soest and for in vitro true digestibility (IVTD), utilizing the Goering and Van Soest modification of the Tilley and Terry procedure. Hemicellulose (H) was determined as the difference between NDF and ADF. Statistical analyses of variance were conducted. Highly significant differences in NDF, ADF, H, L, L/ADF, C, and Si contents were observed between species. IVTD and in vitro apparent digestibility (IVAD) also revealed highly significant differences between species. Guinea and Buffel grasses exhibited the highest mean values in NDF and ADF contents but the lowest in IVTD and IVAD, suggesting that, as total fiber and lignocellulose contents increase, digestibility decreases. Similar trends were observed in other species. Highest mean values were obtained in Guinea grass for C, in Jaragua grass for Si and in Limpo grass for L and H. As the grasses advanced in maturity from 30 to 180 days, NDF, ADF, L, L/ADF, C and Si revealed highly significant increases while IVTD and IVAD revealed highly significant decreases with HC remaining almost constant throughout. The largest increase in NDF, ADF, L and C contents and the largest decrease in IVTD and IVAD evaluations occurred between the 30- and 60-day intervals, probably due to the high environmental temperature and high transpiration causing early onset of lignification and silicification in tropical climates. Pangola grass underwent little change in nutritive value as compared to other species. Evidence is presented that fibrous fractions and IVTD evaluations of all species compared favorably among themselves and that all fibrous fractions (except H) and IVTD differed significantly with plant age.

scholarly journals The Postcoloniality of Poor African Leadership in Achebe’s Fiction: A Close Reading of Arrow of God and A Man of the People

2018 ◽  
Vol 6 (2) ◽  
pp. 84
Author(s):  
Confidence Gbolo Sanka ◽  
Patricia Gustafson-Asamoah ◽  
Charity Azumi Issaka
Keyword(s):  
Close Reading ◽  
African Countries ◽  
Modern Democracy ◽  
Abuse Of Power ◽  
The People ◽  
Grass Root ◽  
African Leadership ◽  
Post Colonialism

The paper aims at tracing the genesis of abuse of power and the irresponsibility that goes with it to its full blossoming in Achebe’s fiction through a close reading of Arrow of God and A Man of the People. Disenchantment with leadership in Africa, especially after independence, is not new on the African literary scene. But to Achebe, the problems associated with poor leadership in Africa did not start after independence. Failure in leadership only worsened in most African countries after independence due to the perpetuation of colonial vestiges. By doing a close reading of the two novels and by using the theory of postcoloniality, the researchers compare the traditional world of Ezeulu in Arrow of God to the post-independence setting of Chief Nanga in A Man of the People. The paper concludes that Africa has gone beyond the politics of post-colonialism and is now at the postcoloniality stage. In order for Africans to truly overcome the perennial problem of poor leadership, there is the need for us to first accept our role as a continent in contributing towards the failure of leadership in Africa. There is also the urgency to encourage grass root participation and understanding of modern democracy, to build stronger institutions and to put in place heavier punishments for those who abuse power.

scholarly journals RAINFALL CHANGE DETECTION IN AFRICA USING REMOTE SENSING AND GIS BETWEEN 1999 – 2018

2020 ◽  
Vol 1 (2) ◽  
pp. 52-54
Author(s):  
Abdullahi Muktar ◽  
Wali Elekwachi ◽  
Nwankwoala Hycienth ◽  
Stephen Hemba
Keyword(s):  
Remote Sensing ◽  
Rain Gauge ◽  
Accurate Estimate ◽  
Remote Sensing And Gis ◽  
Easy Access ◽  
African Countries ◽  
Image Differencing ◽  
Weather Stations ◽  
The Tropics ◽  
Rain Gauge Network

Many researchers used gauge data from weather stations for rainfall estimate across Africa. Since Africa lies within the tropics, there is possibility for variations in rain received from place to place. Therefore, there is need for excessive density of the gauges for accurate estimate of Africa’s rainfall. Due to numerous challenges, these cannot be achieved. This necessitates the application of remote sensing and GIS to detect changes in rainfall amount in Africa between 1999 and 2018. The data used was obtained from remote sensing satellite (TRMM) and analyzed using GIS application (IDRISI Taiga). The Simple Image Differencing was performed on the two annual mean images covering January to December, 1999 and January to December, 2018. This provides reliable information on rainfall estimate that can complement sparsely and unevenly distributed rain gauge network in Africa. The analysis shows that latitudinal locations, to some extent, determine spatial distribution of rainfall in Africa. It is also observed that significant changes in rainfall rate are mainly found around coastal regions. It was recommended that adequate ground data it needed to confirm these findings. African countries should provide adequate and justly distributed weather stations with on-net database for easy access to the data.

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