PASTURE SCIENCE

Yield components and bromatological composition of three Megathyrsus maximus cultivars in Guayas area, Ecuador

Y. Méndez-Martínez¹  , J. J. Reyes-Pérez^{1  2}  , R. A. Luna-Murillo²  , D.M. Verdecia^{3  *}  , Marisol Rivero-Herrada¹  , L.B. Montenegro-Vivas¹  , R.S. Herrera⁴ 

¹Facultad Ciencias Pecuarias, Universidad Técnica Estatal de Quevedo (UTEQ), Quevedo, Los Ríos, Ecuador

²Universidad Técnica de Cotopaxi (UTC), Extención La Maná, La Maná, Los Ríos, Ecuador

³Facultad de Ciencias Agropecuarias, Universidad de Granma, Apartado Postal 21, Bayamo, C.P. 85 100, Granma, Cuba

⁴Instituto de Ciencia Animal, Apartado Postal 24, San José de las Lajas, Mayabeque, Cuba

ABSTRACT

With the objective of evaluating the yield components and bromatological composition of three Megathyrsus maximus cultivars in Guayas area, Ecuador at different regrowth ages, the research was carried out, following a random block design with factorial arrangement (3x3) with five replications. The productivity (yields of total dry matter, leaves, stem and biomass), morphological components (plant height, length and width of leaves, number of leaves and stems) were studied; as well as the contents of DM, CP, NDF, ADF, ADL, cellulose (Cel), hemicellulose (Hcel), cellular content (CC), P, Ca, ash, OM, DMD, OMD, ME, LNE and the relations NDF-N and ADF-N at the ages of 21, 42 and 63 days. Analysis of variance was performed according to experimental design. The highest yields of DM and biomass were obtained in Tanzania at 63 days of regrowth (2.74 and 8.25 t/ha, respectively). The highest DM and biomass yields were obtained in Tanzania at 63 days of regrowth (4.18 and 12 t/ha, respectively). The CP and CC decreased with the maturity of the plant and the best values were obtained in Tanzania at 21 days of regrowth (15.67 and 62.16 %, respectively), while the components of the cell wall increased with age and Tanzania showed the best values. There was significant interaction between varieties and maturity (P <0.0001) for all indicators. It is concluded that the studied varieties show adequate productive performance under conditions of low rainfalls. The Tanzania and Tobiata cultivars are a good option to replace the food deficit during the dry period due to its higher proportion of leaves, better relations NDF-N and ADF-N that give it higher quality.

Key words: yield; regrowth age; Megathyrsus maximus; chemical composition; digestibility; energy

INTRODUCTION

Grasses are an appropriate source of nutrients, mainly in tropical countries; due to the number of species that can be used for this purpose, possibility of growing them all year, the ruminant ability to use forages; as well as non-competition as food for human. However, its low quality affects the obtaining of adequate productive results and its adaptability to prevailing environmental conditions in the various ecosystems, are some of the causes that limit the development of livestock (^{Abril et al. 2017}).

To mitigate this situation, great efforts have been made in the introduction of new species and varieties with better performances. However, its growth, productivity and quality are unknown as the age of the plant increases in the current climatic conditions of Ecuador (^{Méndez-Martínez et al. 2018}).

Megathyrsus maximus is a plant perfectly adapted to tropical conditions, although its production potential is affected by the prevailing environmental factors, when it is subjected to repeated cuts and nutrients that are extracted based on biomass production are not restored (^{Brant et al. 2017}).

The study of the agro-productive and nutritive potentials of three Megathyrsus maximus cultivars (v. Common, Tanzania and Tobiata) introduced in Guayas area, Ecuador, in various edaphoclimatic conditions is of great importance, especially because of the great expectations that have been created by its greater agro- productivity and wide range of adaptation to different climatic regions, drought tolerance and its adaptability to a wide range of soils. These elements are very useful for the different specialists of the livestock branch of the region where these species are extended for its use in forage balances. Hence the objective of this study was to evaluate the yield components and bromatological composition of three Megathyrsus maximus cultivars in Guayas area, Ecuador at different regrowth ages.

MATERIALS AND METHODS

Location. This research was carried out at the El Mamey farm, located in El Ají sector, Guayas Parish, Guayas province. Ecuador. It is located between the geographical coordinates 01 ° 00´ of south latitude and 79° 30 of west longitude at 75 m o.s.l. The study was developed in the period between July-September (dry season) of 2015.

Agrometeorological conditions. The climate of the territory is classified as humid subtropical (^{García 2004}), with rainfalls of 117.2mm during the experimental period. The average, maximum and minimum temperature was: 23.87; 29.17 and 21.03°C; relative humidity 79 %, indicators that are within the range of the historical average until 2014 (116.32 mm; 22.4; 29.52; 21.1°C for the average, maximum and minimum temperature, respectively and 75.6 % relative humidity) the soil in the area is Inceptisol (^{Soil Survey Staff 2003}) and its chemical composition is in table 1.

Table 1 Characteristics of the soil 

Indicator	Value	SD±
pH	5.47	0.03
N, cmolc kg^-1	1.50	0.05
P, cmolc kg^-1	5.1	0.2
K, cmolc kg^-1	0.54	0.01
Ca, cmolc kg^-1	1.50	0.05
Mg, cmolc kg^-1	0.80	0.046
Sand, %	24.00	2.646
Loam, %	56.00	2.65
Clay,%	20.00	3.46

Treatment and experimental design. A randomized block design with factorial arrangement (3x3) was used: three Megathyrsus maximus cultivars (Common, Tanzania and Tobiata) and three regrowth ages (21, 42 and 63 days) and five replications.

Procedure. The experimental plots (5x5 = 25m²) were sowing in February 2015 of Megathyrsus maximus cultivars Common, Tanzania and Tobiata at a distance of 50 cm between rows and 20 cm between plants. The plants had a period of establishment until July, where the uniformity cut was made. From there, samplings at 21, 42 and 63 days of regrowth were made, eliminating 50 cm of border effect and cutting all the material from the harvestable area at 10 cm above soil level. The biomass production, yield in total dry matter, leaves and stems, number of leaves and stems (by bunch), as well as the length and width of leaves were evaluated (^{Herrera 2006}). Then two kilograms (two samples) were taken for each of the treatments and for replication for further analysis in the laboratory.

Only irrigation was used to facilitate germination and establishment, and no fertilization or chemical treatment was used to eliminate weeds. At the beginning of the experiment, the population of the varieties in the plots was 97 %.

Determination of chemical composition. The DM, CP, ash, OM, P, Ca were determined according to ^{AOAC (2016)}; NDF, ADF, ADL, cellulose (Cel), hemicellulose (Hcel) and cellular content (CC) according to ^{Goering and Van Soest (1970)}; the digestibility of dry matter was quantified by ^{Aumont et al. (1995}) and the metabolizable energy and net lactation energy were established according to ^{Cáceres and González (2000)}. All analyzes were performed in duplicate and by replication.

Statistical analyais and calculations. Analysis of variance was performed according to the experimental design and mean values were compared using ^{Duncan (1955)} multiple range test. For the normal distribution of the data the Kolmogorov-Smirnov (^{Massey 1951}) test was used and for the variances the ^{Bartlett (1937)} test.

RESULTS

The best results of the productive indicators (table 2) were for Tanzania cultivar at 63 days with 2.74; 1.51; 1.23 and 8.25 t/ha for the total yield of leaves, stems and biomass, respectively. With interaction variety x regrowth age (P <0.0001) in all the studied indicators.

Table 2 Yield indicators of three Megathyrsus maximus varieties 

Age, days	Varieties			SE^1 ±	P
	Common	Tanzania	Tobiata
Dry matter , t/ha
21	0.16^g	0.24^f	0.15^g	0.008	0.0001
42	0.50^e	1.25^c	0.61^e
63	1.05^d	2.74^a	1.48^b
Biomass, t/ha
21	0.95^g	1.06^f	0.96^g	0.011	0.0001
42	2.07^e	4.26^c	3.68^d
63	3.67^d	8.25^a	5.25^b
Leaves, t/ha
21	0.12^h	0.19^g	0.11^h	0.005	0.0001
	0.30^f	0.83^b	0.37^e
63	0.50^d	1.51^a	0.77^c
Stems, t/ha
21	0.04^f	0.05^f	0.04^f	0.004	0.0001
42	0.20^e	0.42^d	0.24^e
63	0.55^c	1.23^a	0.71^b

^abcdefgValues with different letters differ at P<0.05 (^{Duncan 1955})

¹SE, standard error of the interaction variety x age

There were variety x regrowth age interactions for all morphological indicators (table 3). Where with 1.17m; 125.50; 75.50; 0.99 and 0.042m, Tanzania at 63 days showed the highest results for height, number of leaves, number of stems, leaf length and leaf width, respectively.

Table 3 Morphological components of three Megathyrsus maximus varieties 

Age, days	Varieties			SE^1 ±	P
	Common	Tanzania	Tobiata
Height, m
21	0.74^d	0.78^d	0.75^d	0.010	0.0001
42	0.83^c	0.96^b	0.86^c
63	0.94^b	1.17^a	0.98^b
Number of leaves
21	27.25^g	26.50^h	25.50^h	0.057	0.0001
42	52.75^f	58.25^d	56.00^e
63	77.00^c	125.50^a	106.00^b
Number of stems
21	12.50^f	17.50e	16.50e	0.692	0.0001
42	27.25^d	39.00c	29.50d
63	35.50^c	75.50a	66.50b
Leaf lenght , m
21	0.37^f	0.43^e	0.39^f	0.007	0.0001
42	0.43^e	0.58^d	0.53^d
63	0.86^c	0.99^a	0.93^b
Leaf width , m
21	0.021^d	0.027^c	0.027^c	0.001	0.044
42	0.028^c	0.035^b	0.034^b
63	0.033^b	0.042^a	0.038^a

^abcdefghValues with different letters differ at P<0.05 (^{Duncan 1955})

¹SE, standard error of the interaction variety x age

The crude protein and cell content at 21 days with 15.67 and 62.16 % showed the best results for Tanzanian and Common cultivars. While for the latter variety the cell wall components (NDF, ADF, ADL and Cel) were increased with the regrowth age with 69.35; 35.74; 5.63 and 30.10 %, respectively. The highest hemicellulose content (33.96 %) was recorded at 63 days in Tobiata (table 4)

Table 4 Protein content and fibrous fractionation of three Megathyrsus maximus varieties  

Age, days	Varieties			SE^1 ±	P
	Common	Tanzania	Tobiata
Dry matter, %
21	19.66^g	21.54^f	23.76^e	0.012	0.0001
42	27.24^d	28.35^cd	29.16^c
63	31.87^b	30.46^b	33.64^a
Crude protein , %
21	11.87^c	15.67^a	11.48^c	0.008	0.0001
42	10.33^e	12.52^b	10.83^d
63	9.13^g	9.37^f	9.23^g
Neutral detergent fiber , %
21	37.84^h	43.48^f	39.66^g	0.014	0.0001
42	55.16^d	53.54^e	55.77^d
63	69.35^a	65.25^b	67.33^c
Acid detergent fiber , %
21	19.27^h	22.66^g	25.53^f	0.009	0.0001
42	30.56^d	29.36^e	30.83^d
63	35.74^a	32.74^c	33.37^b
Acid detergent lignin, %
21	2.43^g	2.14^h	2.33^g	0.011	0.0001
42	4.13^e	3.78^f	4.55^d
63	5.63^a	4.67^c	5.26^b
Cellulose, %
21	16.85^g	20.53^f	23.19^e	0.014	0.0001
42	26.43^c	25.58^d	26.28^c
63	30.10^a	28.07^b	28.12^b
Hemicellulose, %
21	18.57^f	20.81^e	14.14^g	0.016	0.0001
42	24.60^c	24.18^d	24.94^c
63	33.61^a	32.52^b	33.96^a
Cell content , %
21	62.16^a	56.62^c	60.34^b	0.014	0.0001
42	44.84^e	46.46^d	44.23^e
63	30.65^h	34.75^f	32.67^g

^abcdefghValues with different letters differ at P<0.05 (^{Duncan 1955})

¹SE, standard error of the interaction variety x age

For the content of ash, minerals and organic matter (table 5) there was interaction (P <0.0001) variety x regrowth age. With the highest percentages of ashes at 63 days (16.84) and 42 d P (0.37%) for Tobiata variety; while Ca (0.78 %) corresponded to Tanzania with 63 d and for Common with 21 days of regrowth OM (89.67 %).

Table 5 Minerals and organic matter of three Megathyrsus maximus varieties 

Age, days	Varieties			SE^1 ±	P
	Common	Tanzania	Tobiata
Ashes, %
21	10.33^f	12.50^e	12.63^e	0.01	0.0001
42	13.14^d	13.55^d	14.39^c
63	15.45^b	15.75^b	16.84^a
Calcium, %
21	0.47^f	0.57^e	0.56^e	0.01	0.0001
42	0.73^b	0.63^d	0.72^b
63	0.67^c	0.78^a	0.69^c
Phosphorus, %
21	0.023^e	0.027^cd	0.026^d	0.001	0.0001
42	0.033^b	0.028^c	0.037^a
63	0.036^a	0.033^b	0.034^b
Organic matter , %
21	89.67^a	87.50^b	87.37^b	0.01	0.0001
42	86.86^c	86.46^c	85.61^d
63	84.55^e	84.24^e	83.16^f

^abcdefValues with different letters differ at P<0.05 (^{Duncan 1955})

¹SE, standard error of the interaction variety x age

For the quality indicators (table 6) there was variability between cultivars as forage maturity advanced for NDF/N, ADF/N advanced, DMD, OMD, ME and FNE relations. The best results were for Tanzania variety of 17.35 and 9.04 % at 21 days in NDF/N and ADF/N relations, the DMD and OMD (53.83; 54.32 %) at 21 days for Common and Tobiata cultivars, the energy contribution 7.97 and 4.55 MJ/kg (ME, FNE) at 21 days was better for the Common.

Table 6 Quality indicators of three Megathyrsus maximus varieties  

Age, days	Varieties			SE^1 ±	P
	Common	Tanzania	Tobiata
NDF/N relation
21	19.52^b	17.35^a	21.60^c	0.029	0.0001
42	33.36^f	26.72^d	32.19^e
63	47.50^i	43.52^g	45.60^h
ADF/N relation
21	10.15^b	9.04^a	13.90^c	0.015	0.0001
42	18.48^f	14.65^d	17.79^e
63	24.46^i	21.84^g	22.60^h
DM digestibility, %
21	53.83^a	51.35^b	53.03^a	0.006	0.0001
42	46.22^c	46.93^c	45.95^d
63	39.97^g	41.78^e	40.86^f
OM digestibility , %
21	55.11^b	52.93^c	54.32^a	0.005	0.0001
42	47.63^e	48.48^d	47.40^e
63	41.43^h	43.21^f	42.31^g
Metabolizable energy, MJ/kg
21	7.97^a	7.63^b	7.84^a	0.001	0.0001
42	6.80^d	6.93^c	6.76^e
63	5.83^g	6.11^f	5.97^g
Net lactation energy, MJ/kg
21	4.55^a	4.31^b	4.47^a	0.001	0.0001
42	3.73^d	3.83^c	3.71^d
63	3.05^f	3.25^e	3.15^ef

^abcdefghValues with different letters differ at P<0.05 (^{Duncan 1955})

¹SE, standard error of the interaction variety x age

DISCUSSION

The productivity (table 2) had a marked effect of the regrowth age. ^{Brant et al. (2017)} when evaluating the Tanzania cultivar found biomass and dry matter yields of 23 and 8t/ha, respectively, results superior to those obtained in this study. According to ^{Reis et al. (2013)} and ^{Bosi et al. (2014)} the dry matter production is important to determine the adaptability of the species to the edaphoclimatic conditions. As stated by these authors, the plants depending on their characteristics have different levels of tolerance to these scenarios. However, in other studies where the species were subjected to shade levels up to 50 % show the drastic reduction in forage yield (^{Fernández et al. 2016}).

^{Velasco et al. (2018)}, in Chiapas region, Mexico, reported when evaluating the effect of the regrowth age and the seasonal climatic effect on the yield of Mombasa cultivar higher productions in spring-summer than in autumn-winter (10; 12; 6 and 2 t/ha at 80 days of regrowth), stating that this seasonal performance had a direct relation with the accumulated rainfalls (59.6 mm) and the variations of maximum (32.8°C) and minimum (21.6°C) temperatures. ^{Lemos et al. (2014)}, found in Tanzania cultivar 4.83; 2.33 and 1.52 tDM/ha for total yield, leaves and stems.

Seasonal and annual growth of morphological components in grass (table 3) is directly related to climatic conditions, soil fertility and management practices. The proportion of leaves, stems and roots that are generated by the genotype-environment interaction; these indicators result in forage yield. The knowledge of the influence of seasonality on the growth of species of interest, allows to identify the availability and, consequently, to adopt management strategies (^{Ojeda-Quintana et al. 2016} and ^{Velasco et al. 2018}).

^{Murillo et al. (2014)}, notified for cv. Mombasa increases in height at ages higher than 50 days of regrowth in all seasons of the year, which is related to the restriction of light that occurs in the canopy, when it is higher than 95 % of light interception, shading and basal leaves senescence causes an increase in the proportion of stems and dead material in the meadow. Aspects that coincide with the results obtained by ^{Patiño et al. (2018)} in Sucre, Colombia. ^{Pereira et al. (2017)}, found heights for Tanzania and Aries cultivars of 2.66 and 2.62 m and the differences found between this study and the present research are due to the characteristics inherent to each hybrid.

The chemical composition (table 4) decreased with maturity, with variability among the evaluated varieties. ^{Fernandes et al. (2016)} reported for Megathyrsus maximus cv Tanzania fibrous component values (NDF, ADF, ADL) of 73; 37 and 6 % with the increase in the regrowth age, which associated this performance with the increase in the proportion of supportive tissue (stems). While, ^{Fernandes et al. (2014)} and ^{Antonio et al. (2018)} in Tanzania and Mombasa found concentrations of DM (15.5-18.8 %); CP (13.9-17.1 %); NDF (71.1-73.6 %); ADF (31.4-34.2 %); Lignin (3.5-5.2 %); Ash (7.9-8.1 %) and OM (85.6-88.4 %), which were influenced by increases on the physiological age of the plant and the levels of structural components of the cell wall.

On the other hand, ^{Montalvão et al. (2018)} reported contents of CP, NDF, ADF, ADL, HCEL and CEL of 10.2; 70.8; 46.6; 5.8; 24.2 and 40.7 %, respectively. ^{Mojica-Rodríguez et al. (2017)} when evaluating the effect of the regrowth age on the quality of Mombasa and Tanzania cultivars found from 21 to 63 days decrease of the CP from 5.5 to 5.9 percentage units, while for the cell wall there were increases for the NDF and ADF from 9 to 10.5 and 8.2 to 6.4 percentage units.

Although there was interaction variety x regrowth age for minerals and organic matter (table 5), the low values found in this study may be the product of the effect of low rainfalls during the study period (117.2mm) that allow minerals be unavailable to be absorbed by the roots of the plants (^{De Barros et al. 2017}). ^{Méndez-Martínez et al. (2018)} and ^{Montalvão et al. (2018)} reported similar results with ash percentages (9-14) and OM (85-90) for this species. Concluding that the variability of these indicators depends on the characteristics of each species and the effect of edaphoclimatic conditions.

The quality (table 6) was affected by the increase in the maturity of forages, with decrease in DMD, OMD, ME and LNE; with increases in the relation NDF-N and ADF-N. ^{Montalvão et al. (2018)}, obtained similar results in the relation between the fibrous fraction and nitrogen, stating that at a higher regrowth age there is a decrease in the percentage of leaves and increase in stems, and therefore low CP levels and high components of the cell wall affects the degradation of organic matter and energy contribution due to the lower efficiency of rumen microorganisms. In studies by ^{Fernandes et al. (2016)} there was a decrease in the dry matter digestibility, influenced by the increase in the fibrous faction and decrease in foliage and, consequently, the quality of biomass. On the other hand, ^{Fernandes et al. (2014)}, reported for cv Tanzania digestibility of the dry matter and crude protein from 63.66 to 58.04 % and 54.1 to 56.31 %, respectively.

^{Antonio et al. (2018)} reported increases in digestibility of DM, NDF, ADF, ADL, hemicellulose and cellulose of 1.7; 3.1; 4.7; 2.1; 2.3 and 4.6 % when using fibrolytic enzymes in Megathyrsus maximus vc Mombasa, stating that cellulose and hemicellulose are fermented by rumen microorganisms easily. However, as the lignin content increases, it joins to carbohydrates and the fermentation degree decreases, which can reach zero, depending on the intensity of lignification. Each type of lignocellulosic complex has a maximum degree of fermentation by microorganisms, and this maximum can be altered when the material is processed. The highest degradation of the fraction when enzymes are used in foods confirms that lignin is a degradation limiting factor.

CONCLUSIONS

It is concluded that the studied varieties have an adequate productive performance under conditions of low rainfalls. The Tanzania and Tobiata cultivars are a good option to replace the food deficit during the dry period due to its higher proportion of leaves, better NDF-N and FAD-N relations that give it a higher quality.

REFERENCES

Abril, J.L., Roncallo, B. & Bonilla, R. 2017. Efecto de la inoculación con bacterias del género Bacillus sobre el crecimiento de Megathyrsus maximus Jacq, en condiciones de estrés hídrico. Rev. Agron. Noroeste Argent. 37 (1): 25-37. ISSN:0080-2069 (impresa). 2314-369X (en línea)

Antonio, G., Gaio, M., Del Valle, T.A., Campana, M. & Gomes, J.P. 2018. Efeitos de enzimas fibrolíticas sobre a degradação in situ da matéria seca e da fibra de forrageiras. Revista Agrarian. 11(42): 363-370. DOI: 10.30612/agrarian.v11i42.7488.

AOAC. 2016. Official methods of analysis of AOAC International. 20th ed., Rockville, MD: AOAC International, ISBN: 978-0-935584-87-5, Available: Available: http://www.directtextbook.com/isbn/9780935584875&gt , [Consulted: October 10, 2019].

Aumont, G., Caudron, I., Saminadin, G. & Xandé, A. 1995. Sources of variation in nutritive values of tropical forages from the Caribbean. Animal Feed Sci. Tech. 51(1):1-13. http://doi.org/10.1016/0377-8401(94)00688-6.

Bartlett, M. 1937. Properties of sufficiency and statistical tests. In: Proceedings of the Royal Society of London. Ser. A; 160(2): 268-282. Available: http://doi.org/10.1098/rspa.1937.0109. [Consulted: October 05, 2019].

Bosi, C., Pezzopane, J.R.M., Sentelhas, O.S., Santos, P.M. & Nicodemo, M.L.F. 2014. Produtividade e características biométricas do capim-braquiária em sistema silvipastoril. Pesq. Agropec. Bras. 49(4):449-456. ISSN: 1678-3921

Brant, M.C., Tuffi-Santos, L.D., Freitas, I.C., Frazão, L.A., Silva, M.S.N., Machado, V.D. & Santos, M.V. 2017. Productivity, control, and decomposition of irrigated forage species under glyphosate doses and shading. Planta Daninha. 36:e018175761. Doi: 10.1590/S0100-83582018360100130.

Cáceres, O. & González, E. 2000. Metodología para la determinación del valor nutritivo de los forrajes tropicales. Pastos y Forrajes. 23(1): 87-92. ISSN:0864-0394.

De Barros, E., Pereira, F.V., Henrique, P., Ferracciú, L.R., Olinda, B. & Alves, E. 2017. Growth of tropical grasses in Oxisol contaminated by nickel. Chilean Journal of Agricultural Research. 77(3):273-280. doi:10.4067/S0718-58392017000300273.

Duncan, D. B. 1955. Multiple Range and Multiple F Tests. Biometrics. 11 (1): 1-42, ISSN: 0006-341X, DOI:10.2307/3001478.

Fernandes, A.M., Deresz, F., Sampaio, D., Ferraz, F.C. & Siqueira, L. 2014. Nutritive value of Tanzania grass for dairy cows under rotational grazing. Revista Brasileira de Zootecnia. 43(8): 410-418. http://dx.doi.org/10.1590/S1516-35982014000800003.

Fernandes, M.H.M.R., Fernandes, J.S., De Resende, K.T., Bonfa, H.C., Reis, R.A., Ruggieri, A.C., Fernandes, J.J.R. & Santos, P.M. 2016. Grazing behavior and intake of goats rotationally grazing Tanzania-grass pasture with different post-grazing residues. Tropical Grasslands. 4(2):91-100. DOI: 10.17138/TGFT(4)91-100.

García, E. 2004. Modificaciones al sistema de clasificación climática de Köppen. V Edición. Ed: Instituto de Geografía Universidad Nacional Autónoma de México, México. 98 pp. ISBN: 970-32-1010-4.

Goering, H. K. & Soest, P. J. V. 1970. Forage Fiber Analyses (apparatus, Reagents, Procedures, and Some Applications). (ser. Agriculture handbook, no. ser. 379), U.S. Agricultural Research Service, 24 p., Available: Available: https://books.google.com.cu/books/about/Forage_Fiber_Analyses_apparatus_Reagents.html?id=yn8wAAAAYAAJ&redir_esc=y , [Consulted: February 12, 2019].

Herrera, R.S. 2006. Fisiología, calidad y muestreos. In: Fisiología producción de biomasa y sistemas silvopastoriles en pastos tropicales. Abono orgánico y biogás. EDICA. Mayabeque, Cuba. p.1-108.

Lemos, N.LS., Ruggieri, A.C., Costa E Silva, V., Campos, A.F., Malheiros, E.B. & Teixeira, I.A.M. 2014. Tanzania grass structure grazed by goats managed with different residual leaf area index under intermittent stocking. Biosci. J. Uberlândia. 30(6):1811-1818. ISNN: 1981-3163.

Massey, F. J. 1951. The Kolmogorov-Smirnov test for goodness of fit. Journal of the American Statistical Association. 4(543):68-78. Available: http://dx.doi.org/10.2307/2280095. [Consulted: October 04, 2019].

Méndez-Martínez, Y., Verdecia, D.M., Reyes-Pérez, J.J., Luna-Murillo, R.A., Rivero-Herrada, M., Montenegro-Vivas, L.B. &. Herrera, R.S. 2018. Quality of three Megathyrsus maximus cultivars in the Empalme area, Ecuador. Cuban Journal of Agricultural Science. 52(4): 423-433. ISSN: 2079-3480.

Mojica-Rodríguez, J.E., Castro-Rincón, E., Carulla-Fornaguera, J. & Lascano-Aguilar, C.E. 2017. Efecto de la edad de rebrote sobre el perfil de ácidos grasos en gramíneas tropicales. Corpoica Cienc. Tecnol. Agropecuaria, Mosquera (Colombia). 18(2): 217-232. http://dx.doi.org/10.21930/rcta.vol18_num2_art:623.

Montalvão, D., Abdalla, A.L., Tavares, P., Zanuto, G., Dias, T.P., McManus, C., Abdalla, A.L. & Louvandini, H. 2018. Morphological characteristics, nutritive quality, and methane production of tropical grasses in Brazil. Pesq. Agropec. Bras. Brasília. 53(3):323-331. DOI: 10.1590/S0100-204X2018000300007.

Murillo, S.J., Barros, H.J.A., Rocallo, F.B. & Arrieta, P.G. 2014. Requerimientos hídricos de cuatro gramíneas de corte para uso eficiente del agua en el Caribe seco colombiano. Corpoica Cienc. Tecnol. Agropecu. 15(1):83-99. ISNN: 0122-8706.

Ojeda-Quintana, L.J., Toledo-Vazquez, L., Hernández-Rodríguez, C., Machado-Díaz, Y. & Furrazola-Gómez, E. 2016. Influencia de la aplicación de Azospirillum lipoferum en Megathyrsus maximus vc. Guinea tobiatá en un suelo Pardo Grisáceo. Pastos y Forrajes. 39(1): 27-32. ISSN:0864-0394.

Patiño, R.M., Gómez, R. & Navarro, O.A. 2018. Calidad nutricional de Mombasa y Tanzania (Megathyrsus maximus, Jacq.) manejados a diferentes frecuencias y alturas de corte en Sucre, Colombia. Revista CES Medicina Veterinaria y Zootecnia. 13 (1) : 17-30. DOI: http://dx.doi.org/10.21615/cesmvz.13.1.2

Pereira, F.C.B., De Mello, L.M.M., Pariz, C.M., De Mendoça, V.Z., Yano, E.H., De Miranda, E.E.V., Cusciol, C.A.C. & Martello, J.M. 2017. Morphological assessment of fall irrigated maize intercropped with tropical forages. Irriga, Botucatu. 22 (3):512-529. DOI: http://dx.doi.org/10.15809/irriga.2017v22n3p512-529.

Reis, G.L., Lana, Â.M.Q., Emerenciano-Neto, J.V., Lemos-Filho, J.P., Borges, I. & Longo, R.M. 2013. Produção e composição bromatológica do capim-marandu, sob diferentes percentuais de sombreamento e doses de nitrogênio. Biosci J. 28:(5):1606-1615. ISSN:1525-3244

Soil Survey Staff. 2003. Keys to Soil Taxonomy. USDA, Ninth Edition, Washington D. C, p. 332.

Velasco, M., Hernández, A., Vaquera, H., Martínez, J., Hernández, P. & Aguirre, J. 2018. Growth analysis of (Panicum maximum Jacq.) Cv. Mombasa. Rev.MVZ Córdoba 23(Supl):6951-6963. DOI: 10.21897/rmvz.1415.

Received: June 06, 2019; Accepted: June 20, 2019

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