© The Authors, 2021, Published by the Universidad del Zulia*Corresponding author: acanales@unap.edu.pe
Angel Canales Gutiérrez
*
Guadalupe Sucari Turpo
Rev. Fac. Agron. (LUZ). 2022, 39(1): e223914
ISSN 2477-9407
DOI: https://doi.org/10.47280/RevFacAgron(LUZ).v39.n1.14
Crop Production
Associate editor: Professor Evelin Perez
Keywords:
Cereal
Growth
Organic matter
Effect of animal manure-based substrates on the emergence and vegetative growth of fodder
oats (Avena sativa L.)
Efecto de sustratos a base de estiércol de animales sobre la emergencia y el crecimiento vegetativo
de avena forrajera (Avena sativa L.)
Efeito dos substratos à base de esterco animal no aparecimento e crescimento vegetativo da aveia
forrageira (Avena sativa L.)
Universidad Nacional del Altiplano de Puno. Facultad de
Ciencias Biológicas. Programa de Ecología. Puno. Perú.
Received: 21-09-2021
Accepted: 15-01-2022
Published: 10-02-2022
Abstract
Oats (Avena sativa L.) are an annual forage grass of great current and
potential importance in agricultural development. The objective was to
determine the effect of animal manure-based substrates on the emergence
and vegetative growth (stem height and leaf length) of forage oats (Avena
sativa L.) in relation to organic amendments (chicken-cuy, cattle-sheep,
llama-alpaca) over time. Growth variables were measured every ten days up
to 60 days. A completely randomised experimental design was used; each
treatment consisted of ve replicates of ten seeds each. Analysis of variance
(ANDEVA), Tukey’s multiple comparison and regression and correlation
analysis were performed. Both stem height and leaf length were higher when
the seeds were established on a substrate based on a mixture of cattle and
sheep manure and were lower with the llama-alpaca manure mixture. In
general, growth expressed in stem height and leaf length increased over time.
The application of organic matter of animal origin improves the quality of
agricultural soils, which is reected in plant growth and development.
This scientic publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42, ISSN 0378-7818.
Rev. Fac. Agron. (LUZ). 2022, 39(1): e223914. January - March. ISSN 2477-9407.
2-5 |
Resumen
La avena (Avena sativa L.), es una gramínea forrajera anual de
gran importancia actual y potencial en el desarrollo de la agricultura.
El objetivo fue determinar el efecto de sustratos a base de estiércol
de animales sobre la emergencia y el crecimiento vegetativo (altura
del tallo y longitud de hojas) de la avena forrajera (Avena sativa L.)
en relación con las enmiendas orgánicas (gallina-cuy, vacuno-ovino,
llama-alpaca) en el tiempo, las variables de crecimiento se midieron
cada diez días hasta los 60 días. Se utilizó un diseño experimental
completamente aleatorizado; cada tratamiento constó de cinco
repeticiones de diez semillas cada uno. Se realizaron análisis de
varianza (ANDEVA), la comparación múltiple de Tukey y el análisis
de regresión y correlación. Tanto la altura de tallo como la longitud
de la hoja, fueron mayores cuando las semillas se establecieron en
un sustrato a base de la mezcla estiércol de vacuno-ovino y fueron
menores con la mezcla de estiércol llama-alpaca. En lineas generales,
el crecimiento expresado en la altura del tallo y la longitud de la hoja
se incrementó en el tiempo. La aplicación de materia orgánica de
origen animal mejora la calidad de los suelos agrícolas, lo cual se
reeja en el crecimiento y desarrollo de las plantas.
Palabras clave: cereal, crecimiento, materia orgánica.
Resumo
A aveia (Avena sativa L.) é uma erva forrageira anual de
grande importância atual e potencial no desenvolvimento agrícola.
O objetivo era determinar o efeito dos substratos à base de esterco
animal no aparecimento e crescimento vegetativo (altura do caule
e comprimento das folhas) da aveia forrageira (Avena sativa L.)
em relação às emendas orgânicas (galinha-cuy, pecuária- ovelha,
llama-alpaca) ao longo do tempo. As variáveis de crescimento
foram medidas a cada dez dias até 60 dias. Foi utilizado um desenho
experimental completamente aleatório; cada tratamento consistia de
cinco réplicas de dez sementes cada. Análise de variância (ANDEVA),
a comparação múltipla de Tukey e a análise de regressão e correlação
foram realizadas. Tanto a altura do caule quanto o comprimento das
folhas eram maiores quando as sementes eram estabelecidas em um
substrato baseado em uma mistura de esterco bovino e ovino e eram
mais baixas com a mistura de esterco de llama-alpaca. Em geral, o
crescimento expresso na altura do caule e no comprimento da folha
aumentou com o tempo. A aplicação de matéria orgânica de origem
animal melhora a qualidade dos solos agrícolas, o que se reete no
crescimento e desenvolvimento das plantas.
Palavras-chave: cereais, crescimento, matéria orgânica.
Introduction
Oats (Avena sativa L.), is a monocotyledonous, annual herbaceous
plant belonging to the Poaceae family (Suasaca et al., 2020), has a
large number of varieties and are distributed in a wide diversity of
altitudinal oors ranging from 2,500 to 4,000 meters above sea level.
(Espinoza et al., 2018). It is undoubtedly a crop of wide climatic
adaptation (Servin et al., 2018) and important as forage (Espinoza et
al., 2018), as it has good nutritional and energy quality (Flores et al.,
2016); it can be used from its growth stage (Espitia et al., 2012), in
silage or hay (Condori et al., 2019) and for livestock feed (Rodríguez
et al., 2020).
Among the forage species, oats, is widely cultivated in Peru
(Mamani and Cotacallapa, 2018), despite the constant challenges it
confronts (droughts and frosts) (Benique, 2019); in turn these occur
with increasing intensity (Hijar et al., 2016) and therefore planting is
done in the rainy season (December, January and February), where
rainfall is recommended, being the harvest in March and April
(Huallpa et al., 2016).
The use of animal manure in agriculture is very important (Ávalos
de la Cruz et al., 2018), since it provides various nutrients that crops
need for their development (Huerta et al., 2019) and increased
production (Muñoz et al., 2016), and its use is of great social and
environmental importance (Huerta et al., 2019). In the high Andes,
there is evidence of loss of productive areas and an increase in degraded
soils from 35 to 120 ha (Loza and Taype, 2021). Soil degradation
has negative effects on plant yields; one of the factors is salinization,
which inuences the decrease in the biological fertility of the soil.
The application of organic amendments increases enzymatic activity
and soil respiration, reduces soil pH and electrical conductivity. The
addition of organic fertilizer inuences a higher rate of nitrogen
mineralization and higher urease activity (Mogollón et al., 2011).
Therefore, the incorporation of organic materials of animal or plant
origin to soils has been shown to improve their physical, chemical
and biological conditions, having effects on crop yield (Arrieche and
Ruiz, 2014).
The objective was to determine the effect of animal manure-based
substrates on the emergence and vegetative growth of forage oats
(Avena sativa L.) in relation to organic amendments over time.
Materials and Methods
The study was conducted in the District of Asillo, Peru at 3,913
m.a.s.l. (coordinates 14°47′34″S; 70°21′22″W), with mean annual
temperature of 16 °C and monthly precipitation of 153 mm (Huallpa
et al., 2016).
Two hundred seeds of Avena sativa L., selected on the basis of
size and color, were sown in perforated trays, with ten seeds per
replicate and ve replicates per treatment. Irrigation was carried out
every 2 days, with 250 mL of water for each treatment (table 1).
Table 1. Proportion of animal manure for each treatment.
Treatment Substrate Ratio
Control (T0) Tierra agrícola
T1 Agricultural land + chicken manure + guinea
pig manure
2:0.25:0.25.
T2 Agricultural land + cattle manure + sheep
manure
2:0.25:0.25.
T3 Agricultural soil + llama manure + alpaca
manure
2:0.25:0.25.
Manures from chicken (Gallus gallus domesticus), bovine (Bos
taurus), llama (Lama glama), sheep (Ovis orientalis), alpaca (Vicugna
pacos) and cuy (Cavia porcellus), which were collected from the eld
(corral), then crushed and applied to the trays for each treatment, were
evaluated.
The variables evaluated were:
Emergency percentage (E%): the number of emerged seeds was
determined by the following formula:
This scientic publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42, ISSN 0378-7818.
Canales and Sucari. Rev. Fac. Agron. (LUZ). 2022, 39(1): e223914
3-5 |
% E =
Stem height: measurements were made on three individuals at
random for each tray, using a tape measure.
Leaf length: measurements were made on three individuals at
random for each tray, using a tape measure.
Leaf and stem growth was recorded during 60 days (December
2020 - February 2021). Observations were made from day 25, every
ve days from 09:00 to 11:00 h, randomly selecting three individuals
per tray.
The experimental design used was a completely randomized
design. An analysis of variance (ANDEVA) was performed, and
Tukey’s test of measures was used to determine the differences
between treatments. Likewise, a regression analysis was performed
to determine the relationship of the growth variables with respect
to the evaluation time, and a correlation analysis was performed
to determine the association between the variables studied. The
statistical program INFOSTAT (2020), licensed for use, was used for
all analyses.
Results and discussion
The percentage of emergence at 10 days was 76, 0, 14 and 50 %,
for T0, T1, T2 and T3, respectively; while at 15 days the percentage
of emergence was 100 % for T0, T2 and T3; T1 registered 26 % and at
20 days it presented 100 % of emergence, being the latest treatment.
The time of seed emergence is reected by the environmental
conditions of the soil (Vargas, 1991) and the concentration of phytic
acid in the seeds, due to the effect of fertilizers, which generates their
vigor (Rivera et al., 2009).
Pino et al. (2008) indicated that in soils added with fresh poultry
manure, mineralized N correlates more closely with uric acid content,
which could be the cause of the lower percentage of emergence in
T1. In contrast, T0 caused emergence in less time, and T2 and T3
treatments showed similar behavior.
As for the variables measuring vegetative growth, highly
signicant differences between treatments were recorded for stem
height and leaf length (p < 0.01) (table 2).
Table 2. Analysis of Variance (ANDEVA) for oat stem and leaf
growth in different animal manure-based substrate
mixtures.
Stem
S.V.
SS DF MS F p-valor
Model 704.18 3 234.73 8.09 <0.0001
Treatment 704.18 3 234.73 8.09 <0.0001
Error 12,585.36 434 29
Total 13,289.54 437
Leaf
Model 1,420.21 3 473.4 11.6 <0.0001
Treatment 1,420.21 3 473.4 11.6 <0.0001
Error 17,718.5 434 40.83
Total 19,138.7 437
Stem height was greater in T2 and T0 with averages of 11.75
and 10.03 cm, respectively; while for T1 and T3 it was lower, with
averages of 9.67 and 8.35 cm, respectively (table 3).
Number of seedlingd emerged in the last count
Number of seeds sown
Table 3. Stem height and leaf length in Avena sativa in mixtures of
different organic substrates.
Treatment Stem height (cm) Leaf length (cm)
T0: control 10.03 ab 18.55 b
T1: Chicken-cuy 9.67 a 14.71 a
T2: Bovine-sheep 11.75 b 18.72 b
T3: Llama-alpaca 8.35 a 14.71 a
Means with a common letter are not signicantly different (p
>0.05).
It has been established that plant development is inuenced by the
composition and type of soil (Castro et al., 2015).
The development of stems and leaves, is related to the use of
various types of manure from domestic animals (Avalos de la Cruz
et al., 2018), which possess the necessary macroelements such as
N-P
2
O
5
-K
2
O that are applied during sowing and in tillering (INIA,
2006), being an important aspect for agriculture (Avalos de la Cruz
et al., 2018).
The effect of organic manure mixed with inorganic, inuences the
increase of nutrients for forage oats (Bar-Tal et al., 2004; Torres et al.,
2016), this increase of nutrients inuences the growth of all parts of
the plant. The use of compost, as organic fertilizer, also inuenced the
increase of organic matter in the soil for the production of forage oats
(Montaño et al., 2017), in the research conducted only animal manure
was applied. There was a positive trend of increase in stem height and
leaf length in all treatments in relation to time (10, 20, 30, 40, 50 and
60 days). Figure 1 shows the increase in stem height.
The regression coefcient for stem height at T0 was: r
2
= 0.88; Y
= - 6.87 + 0.40 X, while for leaf length (cm) it was: r
2
= 0.63; Y = 1.79
+ 0.39 X. For T1 in stem height it was: r
2
= 0.90; Y = - 15.21 + 0.60 X.
The regression coefcient for T2 in stem height was: r
2
= 0.87; Y
= - 7.55 + 0.45 X, while for leaf length it was: r
2
= 0.61; Y = 1.34 +
0.41 X. For T3 in stem height it was: r
2
= 0.78; Y = - 3.23 + 0.27 X.
As can be evidenced by the results of the regression analysis in all
treatments, there was a signicant response in terms of stem height
and leaf length with respect to time.
Organic manures are important sources of organic carbon (Ren
et al., 2014) together with the application of fertilizers substantially
improve plant growth and yields (Mahmood et al., 2017; Torres et al.,
2016), due to the increase of organic matter in the soil (Montaño et
al., 2017), which plants require for their development (Huerta et al.,
2019).
The values of Pearson’s correlation coefcients (r), between
stem height and leaf length, showed a positive trend, which were
determined by the effect of the different animal fertilizers (T0 = 0.71,
T1 = 0.91, T2 = 0.78 and T3 = 0.63) (gure 2).
As can be seen in gure 2, there is a high correlation between
stem height and leaf length which registered a high coefcient
(r = 0.91) for T1, while for T3 (r = 0.63) it was lower. With the
application of organic matter (animal manure) in soils, biological and
physicochemical properties are improved (Cairo and Alvarez, 2017),
allowing higher yield and plant productivity (Torres et al., 2016).
Therefore, it has been determined that there is a leaf/stem ratio of
38/62 until maturity in oats (INIA, 2008), and as it advances in its
development the leaf area decreases (Pereira and Grabowski, 2015).
In the Peruvian altiplano, soils show evidence of increasing
loss of productive areas (Muñoz et al., 2016). This soil degradation
process has negative effects on crop yield. Therefore, by applying soil
amendments, enzymatic activity increases, pH improves and there is
a greater mineralization of nitrogen (Muñoz et al., 2016).
This scientic publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42, ISSN 0378-7818.
Rev. Fac. Agron. (LUZ). 2022, 39(1): e223914. January - March. ISSN 2477-9407.
4-5 |
Figure 1. Stem growth (cm) in different manure-based substrate mixtures (T0= control, T1=chicken-cuy, T2=bovine-sheep and T3=plain-
alpaca) over time.
Figure2. Correlation between stem height (cm) and leaf length (cm) of Avena sativa, established in different manure-based substrate
mixtures (T0= control, T1= chicken-cuy, T2= bovine-sheep and T3= llama-alpaca).
This scientic publication in digital format is a continuation of the Printed Review: Legal Deposit pp 196802ZU42, ISSN 0378-7818.
Canales and Sucari. Rev. Fac. Agron. (LUZ). 2022, 39(1): e223914
5-5 |
Conclusions
The bovine-sheep manure, llama-alpaca and the control reached
a percentage of oat seed emergence of 100% in the shortest time
(15 days), while with the chicken-cuy mixture it was 20 days. The
shorter emergence time is important for obtaining and availability
of oat plants, reducing the time of activities associated with
propagation, optimizing the family economy.
Stem height and leaf length were greater when the seeds were
established in a substrate based on a mixture of cattle and sheep
manure, with the consequent increase in fresh and dry matter of the
plants, and were lower with the llama-alpaca manure mixture.
In general terms, growth expressed in stem height and leaf
length increased over time due to the effect of the different organic
substrates used for oat germination, being an alternative to the use
of inorganic fertilizers that favor soil degradation.
Cited literature
Arrieche, I. y Ruiz. M. (2014). Efecto de la fertilización orgánica con NPK sobre
la materia orgánica, y el rendimiento del maíz en suelos degradados.
Observador del Conocimiento, 2(1). https://bit.ly/3r7ViCQ
Ávalos de la Cruz, M., Figueroa,U., García,J., Vázquez,C., Gallegos,M. y
Orona,I. (2018). Bioinoculantes y abonos orgánicos en la producción de
maíz forrajero. Nova Scientia, 10(20): 170–189.https://bit.ly/3HSnsZy
Bar-Tal, A., Yermiyahu, U., Beraud, J., Keinan, M., Rosenberg, R., Zohar, D.,
Rosen, V. & Fine, P. (2004). Nitrogen, phosphorus and potassium uptake
by wheat and their distribution in soil following successive, annual
compost applications. Journal of Environmental Quality, 33:1855-
1865. https://bit.ly/3tet63T
Benique, E. (2019). Impacto del cambio climático en el rendimiento de la
producción de cañihua (Chenopodium pallidicaule) en la Región -
Puno. Revista de Investigaciones Altoandinas, 21(2): 100–110. https://
bit.ly/3r1P0oh
Cairo, P. y Álvarez,U. (2017). Efecto del estiércol en el suelo y en el cultivo
de la soya Glycine max (L.) Merr. Pastos y Forrajes, 40(1): 37-42.
Recuperado en 02 de diciembre de 2021. https://bit.ly/339UAwS
Castro, L., Murillo, M., Uribe, L. y Mata, R. (2015). Inoculación al suelo con
Pseudomonas uorescens, Azospirillum oryzae, Bacillus subtilis y
microorganismos de montaña (mm) y su efecto sobre un sistema de
rotación soya-tomate bajo condiciones de invernadero. Agronomía
Costarricense, 39(3): 21–36. https://bit.ly/3GgxK55
Condori, R., Loza, G., Achu,C. y Alberto, H. (2019). Calidad del ensilaje de
avena forrajera (Avena sativa L.) conservado en tres diferentes tipos de
silos artesanales. JSAAS, 6(2): 57–65. https://bit.ly/3ndKkuu
Espinoza, F., Nuñez,W., Ortiz, I. y Choque, D. (2018). Producción de forraje
y competencia interespecíca del cultivo asociado de avena (Avena
sativa) con vicia (Vicia sativa) en condiciones de secano y gran altitud.
Revista de Investigaciones Veterinarias del Perú, 29(4): 1237–1248.
https://bit.ly/3qd0u9u
Espitia, E., Villaseñor, H., Tovar, R., Olan, M. y Limon, A. (2012). Momento
óptimo de corte para rendimiento y calidad de variedades de avena
forrajera. Revista Mexicana de Ciencias Agrícolas. Revista Mexicana
de Ciencias Agrícolas, 3(4): 771–783. https://bit.ly/3f7aHO7
Flores, M., Sánchez, R., Echavarría, F., Gutiérrez, R., Rosales,C. y Salinas, H.
(2016). Producción y calidad de forraje en mezclas de veza común con
cebada, avena y triticale en cuatro etapas fenológicas. Revista Mexicana
de Ciencias Pecuarias, 7(3): 275–291. https://bit.ly/3zLF9qx
Hijar, G., Bonilla, C., Munayco, C., Gutierrez, E. y Ramos,W. (2016). Fenómeno
el niño y desastres naturales: intervenciones en salud pública para la
preparación y respuesta. Revista Peruana de Medicina Experimental y
Salud Pública, 33(2): 300–310. https://bit.ly/3FectHO
Huallpa, R., Céspedes, R. y Esprella, B. (2016). Evaluación del efecto de biol
bovino en la producción y calidad de la avena forrajera (Avena sativa
L.), en época de invierno en la estación experimental Choquenaira,
Viacha – La Paz. Revista de Investigación e Innovación Agropecuaria y
de Recursos Naturales, 3(3): 103–113. https://bit.ly/3JTrClL
Huerta, E., Cruz, J. y Aguirre, L. (2019). La apreciación de abonos orgánicos
para la gestión local comunitaria de estiércoles en los traspatios. Revista
de Alimentación Contemporánea y Desarrollo Regional, 29(53): 1–24.
https://bit.ly/3Gqoco4
INFOSTAT. (2020). Sofware estadistico. Versión 2020 con licencia de uso.
Instituto Nacional de Innovación Agraria (INIA). (2006). Avena INIA 902 –
Africana. Instituto Nacional de Innovación Agraria (INIA). Programa
Nacional de Investigación en pastos forrajes estación experimental
agraria Illpa. Puno. 4 pp.
Instituto Nacional de Innovación Agraria (INIA). (2008). Avena Forrajera Inia
905 - La Cajamarquina. Plegable Nº 7, Instituto Nacional de Innovación
Agraria (INIA). Hecho el Depósito Legal en la Biblioteca Nacional del
Perú Nº: 2008-14042. Distrito Baños del Inca. Cajarmarca. 4 pp.
Loza, A. y Taype, I. (2021). Análisis multitemporal de asociaciones vegetales
y cambios de uso del suelo en una localidad altoandina, Puno-Perú.
Uniciencia, 35(2): 1-19. https://bit.ly/3faKpuA
Mamani, J. y Cotacallapa, F. (2018). Rendimiento y calidad nutricional de avena
forrajera en la región de Puno. Revista de Investigaciones Altoandinas,
20(4): 385–400. https://bit.ly/3qbUgGM
Mahmood, F., Khan, I., Ashraf, U., Shahzad, T., Hussain, S., Shahid, M., Abid,
M. y Ullah, S. (2017). Effects of organic and inorganic manures on
maize and their residual impact on soil physico-chemical properties.
Journal of Soil Science and Plant Nutrition, 17(1): 22-32. https://bit.
ly/3GK0ovy
Mogollón, J., Tremont, O. y Rodríguez, N. (2011). Efecto del uso de un
vermicompost sobre las propiedades biológicas y químicas de suelos
degradados por sales. Venesuelos, 9(1 y 2):48-57.https://bit.ly/3f9AWnh
Montaño, M., Hernández, A., Martínez, A., Ojeda, D., Núñez, A. y Guerrero,
V. (2017). Producción y contenido nutrimental en avena forrajera
fertilizada con fuentes químicas y orgánicas. Revista Fitotecnia
Mexicana, 40(3): 317 – 32.https://bit.ly/3qbVr9a
Muñoz, J., Huerta, M., Lara, A., Rangel, R., y De la Rosa, J. (2016). Producción
y calidad nutrimental de forrajes en condiciones del trópico húmedo
de México. Revista Mexicana de Ciencias Agrícolas, 16: 3329–3341.
https://bit.ly/3fboqUq
Pereira, K. y Grabowski, C. (2015). Potencial de la escoria siderúrgica en la
inducción de resistencia a enfermedades foliares del trigo (Triticum
aestivum L.). Investigación Agraria. 17(2): 98-107. https://bit.
ly/3A2BtB2
Pino, A., Repetto, C. y Mori, C. (2008). Patrones de descomposición de
estiércoles en el suelo. Revista Terra Latinoamericana, 26(1): 43–52.
https://bit.ly/3tiQhKr
Ren, T., Wang, J., Chen, Q., Zhang, F. & Lu, S. (2014). The effects of manure
and nitrogen fertilizer applications on soil organic carbon and nitrogen
in a high input cropping systems. PLoS ONE. 9(5): e97732. https://bit.
ly/3HQtCcC
Rivera, J., Peraza, F., Serratos, J., Posos, P., Guzmán, S., Cortez, E., Castañón,
G. y Mendoza, M. (2009). Efecto de la fertilización nitrogenada y
fosforada en el contenido de ácido fítico y vigor de la semilla de avena
de la variedad Saia en México. Revista Internacional de Botánica
Experimental,78: 37-42. https://bit.ly/3JV7Xlb
Rodríguez, S., Salgado, O., García, G., Cervantes, F., Figueroa, M. & Mendoza,
M. (2020). Chemical and organic fertilization in oats: seed yield and
quality. Agronomía Mesoamericana, 31(3): 567–579. https://bit.
ly/3f73ldA
Servin, M., Sánchez, R., Ramírez, O., Galindo, M. y Gutiérrez, H. (2018).
Modelos para programación y optimización de agua de riego en avena
forrajera. Revista Mexicana de Ciencias Pecuarias, 9(4): 668–684.
https://bit.ly/3qarpCL
Suasaca, L., Apaza, A., Flores, J., Perca, O. y Quinto,W. (2020). Inuencia de
las pacas de avena en la temperatura y humedad en las viviendas en
zonas altoandinas. Investigación & Desarrollo, 20(1): 215–227. https://
bit.ly/3zJOBe3
Torres, E., Ariza, D., Baena, C., Cortés, S., Becerra, L. y Riaño. C. (2016).
Efecto de la fertilización en el crecimiento y desarrollo del cultivo de
la avena (Avena sativa). Pastos y Forrajes, 39(2): 102-110. Recuperado
en 02 de diciembre de 2021, de https://bit.ly/3r7EEmO
Vargas, M. (1991). Factores que afectan la germinación de semillas. Boletín
Técnico, 24(1): 26-31. https://bit.ly/3JXF8V9
