Introduction
The Andean tussock grasslands in the central Andes of Peru are located
in the headwaters of river basins from 3800 meters above sea level, covering
the topographically more rugged areas with steep slopes and unstable soils,
very prone to erosion; however, it is the most important natural plant
formation, for fulfilling ecological functions such as the regulation of carbon
sequestration, regulation of rainwater infiltration at that altitudinal level
(Sarmiento et al. 2014). These
grasslands are not considered important in the economy of local populations
because they are not very popular with domestic livestock such as sheep, cattle
and Andean camelids (alpacas and llamas), which reduces the opportunity to be
conserved or regenerated, but on the contrary, they are burned with the sole
intention of causing a green shoot that is temporarily consumed by livestock
(Yaranga et al. 2019).
The burning of grasslands has an adverse effect
not only on the sustainability of plant formation with degradation of surface
organic matter stored in the soil for millions of years but also on the loss of
Andean biodiversity (Grigulis and Lavorel 2020), decreased ability to protect
the soil against erosion and the protection of the most vulnerable grassland
species (Sarmiento et al. 2014) that
manage to produce seed and spread in the environment by not being consumed by
animals. In this situation, there is the alternative of using the plant fiber
of these grasslands in the elaboration of construction materials (Veláquez et al. 2016) that, the current
ecological industry is undertaking around the world. This study is part of
another project that studies this possibility, to give the tussock grasslands
the use with a local economic interest, which could change the attitude of
local ranchers in taking care of the tussock as a source of additional income
to Andean livestock. The interest in recovering degraded Andean grasslands by
transplanting seedlings in areas with low density requires the need to study
the viability of transplanting and its behavior in the face of fertilization
treatments with natural inputs and microclimatic factors.
There are many studies on the use of natural
fertilizers for crop growth and production; however, there are few studies on
the application of these inputs on natural grasslands, especially cattle feces
and rock phosphate. Andean soils are characterized by being acidic and potassium
deficient (Zapata and Roy 2007). However, phosphate rock has become an
effective alternative to highly soluble industrial phosphates (Jouany et al. 2021); meanwhile, the low
solubility of phosphate rock makes P remain available in the soil for a longer time
(Ojeda et al. 2019). In addition to
the fact that this input provides important secondary minerals such as calcium
and magnesium, from other microelements such as calcite and dolomite, this
increase the pH by reducing the saturation of aluminum in the soil (Zapata and
Roy 2007).
On the side of the use of cattle manure in
agriculture, studies have been conducted on the effect of the application of
cattle manure as a source of organic matter, to achieve long-term stable
yields, maintaining optimal soil properties (Menšík et al. 2018), in addition, they carry a large amount of germinal
seed (Wang and Hou 2021), which is
also beneficial in the case of application on natural pastures because it helps
the restocking of useful species in the animal diet. Livestock manure
application favors carbon sequestration in plants, and also increases soil
organic carbon content and total nitrogen (Ozlu and Kumar 2018), which induces
higher phytomass production even in soils contaminated by mining (Elouear et al. 2016). It has been reported that
the C:N ratio in manure depends on the animal species, the diet consumed by the
livestock (Wang et al. 2018) and the
geographical location (Aricha et al.
2021); however, N mineralization is higher in cattle manure than sheep manure
despite the higher N concentration in the latter (Wang et al. 2018). The availability of labile C and N is relatively
higher in cattle feces because of the cellulose/hemicellulose content, which
promotes microbial growth that accelerates the decomposition of feces, directly
influencing the higher
mineralization rate, with approximately twice as much N as sheep feces (Wang et al. 2018).
On the side of climatic effect on plant development, the link of plant
behavior with climate is important, to obtain a deeper understanding of the
function: stability and sustainability of grassland ecosystems (Gao et al. 2017), with precipitation and
temperature being the most important climatic factors in the ecosystemic
process of grasslands (Jiang et al.
2017). It is well known that rainfall favors plant growth, but excess rainfall
mainly in autumn can impair growth, thus an increase of 10 mm can cause a delay
of 0.2 to 4 days in the mean senescence date of grasslands (An et al. 2020). On the other hand,
temperature elevation affects soil N and C reserve, thus also growth, flowering
duration of plants in combination with altitude (Arroyo et al. 2021) and other phenological characteristics, through
disturbance in respiration, assimilation, photosynthesis, and plant metabolism
(Getabalew and Alemneh 2019); However, an irregular topography in the Andes
also maintains a diversity of local microclimates that differ in soil
temperatures, to which various plant species have adapted, which would buffer
the abrupt effect of general climate change (Ohler et al. 2020).
A similar experience was carried out in the
Cordillera Blanca of Huaraz – Peru, revegetating a degraded area by
transplanting Festuca dolichophylla
and Calamagrostis macrophylla,
obtaining good results with 28% of revegetation, through the application of
sheep manure (Tacuna et al. 2015).
Taking into account these considerations, the general objective was to evaluate
the viability and level of growth of Andean grassland species related to
altitudinal gradient, the application of natural fertilizers (cattle manure and
rock phosphate) to the soil, and the behavior of temperature and local
precipitation (Tacuna et al. 2015).
Materials and Methods
Study area
The study was conducted in the territory of the Acopalca community in
the province of Huancayo and Junín region, in the central Andes of Peru,
located between UTM coordinates L18 S: 481880, E 8672695 at 3498 m altitude and
4941157, E 8683594 at 5510 m altitude. The local population is mainly dedicated
to livestock raising, consisting of cattle, sheep and alpacas, on grazing areas
ceded to each registered family as active community members. The specific study
areas are located between 4012 and 4333 meters above sea level, so the average
seasonal temperature varies from -8°C at dawn to 16.2°C during the day during
the dry season (May to September) and from 4°C to 12°C during the rainy season
(October to April), with an average daily seasonal rainfall of 0.56 mm and 2.88
mm respectively, accumulating an annual average of 1170 mm.
Data collection
The study areas were selected for the convenience of the research, considering
the dominance of grassland species (Fig. 1a), in them were fenced five plots of
900 m2 according to the method suggested by Otzen and Manterola
(2017), with wooden posts and barbed wire, each plot was separated between 0.8
and 3 km away. Within each plot, five subplots of 64 m2 were located
and each of them was divided into two halves, to apply two natural fertilizers:
cattle manure and phosphoric rock; in each fertilized plot 25 seedlings were
transplanted, of different species taking into account the species present in
them, such as C. intermedia, F. rigidifolia, C. antoniana, Festuca spp
and C. tarmensis.
After having marked the subplots, the natural
fertilizer was applied in each area of fertilization, on the left side was
applied the cattle manure, previously dried and crumbled, spreading over the
area, broadcast and uniformly at the rate of 4000 kg/ha (Zapata and Roy 2007).
In the same way, but on the right side was spread ground phosphate rock (P2O5:
18–22%, CaO: 28–30%, SO4: 3–5%) at a rate of 1500 kg/ha (Elouear et al. 2016). The transplanting
procedure was carried out in stages as follows: (a) plot fencing followed by
subplot marking and division of composting areas, (b) estimation of the average
density of the grassland species present, using the "nearest
neighbor" method (Pieper 1973), measuring the distance to the nearest
plant of the same species in cm, in the form of a cross starting from the
epicenter of a plant, (c) identification and marking of transplanting points in
those empty spaces between 3 or 4 plants, with space greater than the average
distance between neighboring plants, (d) from the contour of the plot were
selected the plants of good development, enough to be divided into more than 5
cuttings, (e) the leaves and stems were cut leaving between 3 to 5 cm in
height, then they were extracted taking care that the root biomass is covered
soil, (f) division of the extracted plant in rectangular sections with
approximately 10 to 15 cm of side, as far as possible maintaining the soil
covering the root system, using a metal machete and (g) digging of holes in the
transplanting points and transplanting of the cuttings.
Data collection began 30 days after the
transplants were installed (October 2020), in the case of non-viable cuttings,
these were exchanged for new ones; 10 transplants were also marked in each
specific area of fertilization. The height of the shoot was measured in cm,
using a pleximeter graduated in mm (two measurements per plant to record the
resulting average), recording 100 data for each plot. The foliage cover of the
shoot was evaluated by double measurement of the projection to the ground in a
cross from the flag leaves. The total data collected amounted to 200 monthly
records per plot, accumulating 18000 data in 9 months of monitoring. From the
last 5 months (February 2021) the beginning of inflorescence formation of some
plants was observed, whose height was also measured, as additional data.
Data analysis
The collected data were arranged in double-entry matrices, the factors
and variables (canopy cover, canopy height and inflorescence height) and
physical and (climatic, etc.) factors in rows and monthly data in columns, in
an Excel sheet. Foliage cover was calculated by the ellipsoidal area formula,
using the equation A= r1*r2*л, where: A is the area covered by foliage,
r1 is the radius of axis 1 in cm, r2 is the radius of axis 2 and л is the
ratio between the length of a circumference and its diameter as a constant
element with a value of 3.1416 (Martínez-Encino et al. 2013; Yaranga et al.
2021). To contrast the study hypotheses on foliage cover, foliage height
considering the average leaf flag and, inflorescence height. The data generated
were analyzed using the "Generalized linear mixed model" method
recommended for biological studies by Dicovskiy
Riobóo and Pacheco (2018), using the
Rstudio vs 4.1.2, using the following equation:
Yijkl = μ + Ω i + βj + λk +
εijkl
Where Yijkl: Plant characteristic evaluated;
Ωi: The effect of the plot on the evaluated plant characteristic; βj:
The effect of the species; λk: The random effect of the evaluated plant
characteristic and εijkl: the random effect of variation.
A canonical correlation analysis was also
performed between the biological variables under study and the environmental
variables: minimum temperature and maximum temperature in °C, rainfall in
liters per m2 in each plot, using PAS vs 3.14 software, under the multiple
linear correlation model: $X=(X_1, X_2, X_p) and Y=(Y1, Y2,..., Yq)Y=(Y1, Y2,...,
Yq) recommended by Trendafilov and Gallo (2021).
Results
Foliage cover, leaf height and
inflorescence height
Foliage cover and growth height were considered important morphological
characteristics for monitoring transplanted plants, according to plant species,
plot location, and fertilizer applied. Regarding foliage cover, it was observed
that the species C. intermedia showed
the fastest response in the second month of control from 226.91 to 271.8 cm2
to experience a gradual reduction in the following months up to 195.57 cm2
in the last month of control (Fig. 2a); F.
rigidifolia showed a continuous increase until the fourth month from 232.71
to 281.71 cm2 and ended with 231.62 cm2 (Fig. 2b). Third
species C. tarmensis showed maximum
development in the second month from182. 64 to 276.3 cm2 and was
reduced to 120.16 cm2 in the 9th month of control (Fig.
2c); while, in Festuca spp the increase was observed in the
third month from 320.63 to 390.4 cm2 being reduced at the end with
195. 5 cm2 (Fig. 2d); finally, the species C. antoniana showed the greatest increase in the third month from
250.3 to 326.05 cm2 then decreased in the eighth month to 122 cm2
and recovered in the ninth month with 269.67 cm2 (Fig. 2e).
In the statistical analysis of foliage cover,
significant differences were observed for P ≤ 0.001, resulting in
the species C. antoniana with the
highest cover of 873 ± 165.7 cm2, followed by Festuca spp. with 620±143.3 cm2, then
F. rigidifolia with 301±63.3 cm2 and C. intermedia
with 278±83.2 cm2 and finally C.
tarmensis with 227±42.6 cm2 (Fig. 3a). At the plot level,
differences were also observed for p≤0.001,
resulting in the plot located in Gerbacio (P5) with 747±231.2 cm2,
followed by the plot in Sillapata Baja (P3) with 714±113. 9 cm2,
then in Sillapata Alta (P2) with 388±69.1 cm2, then in Aylli (P1)
with 205±67.9 cm2 and finally in Otushpalla (P4) with 197±82.3 cm2
(Fig. 3b).
Leaf height in the 5 species showed a certain
homogeneity even with small seasonal variations, thus in C. intermedia
increased from 8.425 cm in the first month of control to 16.23 in the final
control; in F. rigidifolia from 9.121
to 20.11 cm, in C. tarmensis from
8.035 to 14.19 cm, in Festuca spp. from 8.938 to 22.23 cm and finally
in C. antoniana from 10.748 to 19.55
cm. In a statistical analysis, no significant difference was observed for p ≤ 0.05, with averages of Festuca spp. with
22.2±1.15 cm; F. rigidifolia with
20.1±0.77 cm, C. antoniana with
19.50±1.07 cm; C. intermedia with
16.2±0.815 and C. tarmensis with
14.2±0.865 cm (Fig. 3c). In the comparison by plot location effect, a
significant difference was observed for p
≤ 0.05, being the highest in P3 with 21.9±0.843 cm, followed by P5,
P2, and P1 with 18.9±084 cm, 18.5±0.84 cm and 17.8±.83 cm, finally the lowest
for P4 with 14.4±084 cm.
%2025-32_files/image002.png)
Fig. 1: a) Andean tussock grasslands, b) location of the study area in the
central Andes of Peru
%2025-32_files/image004.png)
Fig. 2: The behavior of aerial coverage, leaf flag height, of five Andean
grassland species: a) Calamagrostis
intermedia, b) Festuca rigidifolia,
c) C. tarmensis, d) Festuca sp., e) C. antoniana, f) monthly average leaf and
inflorescence height
In addition, the height to the apex of the
inflorescence of the plants was evaluated (Fig. 2f), which on average started
at 33.41 cm and reached 42.92 cm in May and was reduced to 42.66 cm in June,
due to the effect of the night frosts on the first inflorescences. The same
data shows the evolution of the monthly average height including the five
species, which at the first control started with 9.28 cm, reached 18.46 cm in
May and by June was reduced to 18.3 cm due to the effect of the low temperature
during the period. In the statistical analysis between species, no difference
was observed for p ≤ 0.05,
whose averages were, for C. antoniana
50.0±14.29 cm, F. rigidifolia
54.4±5.91 cm; for Festuca spp. 54.3±12.31 cm; for C. intermedia 46.3±7.48 cm (Fig. 3c). In
the statistical analysis by the effect of plot location, no difference was
observed for p ≤ 0.05, whose
averages were for P3 57.7±9.99 cm, for P2 55.8±6.55 cm, for P1 45.9±6.42 cm,
for P5 34.5±19.49 cm and finally P4 52.3±7.34 cm (Fig. 3d).
%2025-32_files/image006.png)
Fig. 3: Least significant difference (LSD) of canopy cover: a) between species and b) at plot
level; LSD of leaf height: c) between species and d) at plot level
%2025-32_files/image008.png)
Fig. 4: Monthly growth trend of species: a) canopy cover, b)
leaf height and inflorescence height, by the effect of fertilization with
cattle manure and phosphate rock
Effect of natural fertilization
on canopy cover, leaf height and inflorescence height
Foliage cover due to the effect of the application of cattle manure was
better than in those applied with rock phosphate, In the first case, after 30
days it reached 227.06 cm2 and at the end of the evaluation period,
it reached 290.42 cm2 (Fig. 4a), while in the second case, it
started with 191.71 cm2 and at the end, it reached 263.60 cm2
(Fig. 4b). Statistical analysis showed differences for p ≤ 0.05 in favor of cattle manure with 413±38.2 cm2
and rock phosphate with 258±100.8 cm2 (Fig. 5b).
The evolution of the average height of the leaf
tray was different between natural fertilizers applied at the study site (Fig.
4a) it was observed that the transplants fertilized with cattle manure
developed from 10.27–20.43 cm, while those fertilized with rock phosphate
developed from 7.95–16.17 cm. In both cases, it was observed that the greatest
development occurred between the third and fifth months coincided with the
beginning of the rainy season, and then slowed its growth until the last month
of control. In the statistical analysis, no difference was found for p ≤ 0.05, whose averages were
54.5±4.59 cm for the transplants fertilized with cattle manure and 45.4±6.76 cm
for those fertilized with rock phosphate (Fig. 5a).
Canonical correlation between
the biological and environmental variables
Among the environmental variables, the monthly accumulated rainfall
(recorded in each plot), showed that in November 2020 there was no rainfall,
which marked an irregular event during the rainy season; likewise, February
2021 did not correspond to the peak of rainfall. On the other hand,
precipitation was also not uniform for the five plots during the observation
period (Fig. 6). Otherwise, the monthly precipitation averages varied from 1.59
to 154.67 L/m2 and during the evaluation period from 457.57 to
533.96 L/m2 in 9 months of record (Table 1).
The CCA with the environmental
variables (monthly average of minimum temperature, the maximum temperature and
rainfall analyzed at 95% probability, showed that the biological variables
(foliage cover, foliage height, and inflorescence height) maintained the highest
correlation in %2025-32_files/image010.png)
Fig. 6: Canonical correlation of canopy cover, canopy height, and inflorescence
height, with climatic variables: minimum temperature, maximum temperature and
rainfall
Table 1: Monthly rainfall recorded on each plot (P)
|
Months |
Aylli (P1) |
Sillapata alta (P2) |
Sillapata baja (P3) |
Otush palla (P4) |
Gerbacio (P5) |
Monthly average |
|
Oct-20 |
47.75 |
35.81 |
3.98 |
35.81 |
35.81 |
31.83 |
|
Nov-20 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
0.00 |
|
Dec-20 |
109.42 |
89.13 |
99.47 |
92.51 |
92.51 |
96.61 |
|
Jan-21 |
158.76 |
157.96 |
171.89 |
167.11 |
167.11 |
164.57 |
|
Feb-21 |
67.84 |
39.39 |
48.94 |
25.86 |
25.86 |
41.58 |
|
Mar-21 |
79.58 |
71.62 |
79.58 |
79.58 |
79.58 |
77.99 |
|
Apr-21 |
64.66 |
59.68 |
67.64 |
85.55 |
85.55 |
72.61 |
|
May-21 |
3.98 |
1.99 |
15.92 |
5.97 |
5.97 |
6.76 |
|
Jun-21 |
1.99 |
1.99 |
3.98 |
0.00 |
0.00 |
1.59 |
|
Total plots |
533.96 |
457.57 |
491.39 |
492.38 |
492.38 |
493.54 |
%2025-32_files/image012.jpg)
Fig. 5: LSD of: a) aerial cover of Andean grassland species
and b) height of flag leaves, both due to the effect of fertilization with
cattle manure and rock phosphate
the second quadrant, with the months from
October to March (rainy period) and the maximum temperature; on the contrary,
the months of April, May and June (dry period) were not correlated with the
biological variables (Fig. 6). The description of occurrences was in 90.65% of
the data.
Discussion
Rapid response observed in the initial growth of the shoot of the
transplanted cuttings was due to the solidity of the root architecture that was
protected by the soil loaf that accompanied and provided nutrients necessary
for the growth of the grassland plants, avoiding water stress (Fry et al. 2018); even though the
transplanting was done at the end of the dry seasonal period (September 2021),
allowing to continue the good development in some until the third month and in
others as in F. rigidifolia until the
sixth month of transplanting, to then move to a period of slowing growth
despite the rainy period that should influence the greater development. This
aspect indicated that the nutritional reserve of the soil loaf was depleted,
therefore, the plants had to consolidate the fixation of their roots to the
surrounding soil to assimilate the nutrients of the new edaphic layer (Lepik et al. 2021), which was achieved in the
ninth month of transplanting to show new growth acceleration in June, except
for F. rigidifolia. This biological
behavior indicates that the transplanting of grassland species including the
soil bread surrounding the roots was necessary and reduced the effects that
should be negative by the extraction of the plant from the soil and segmentation
into cuttings; on the other hand, it was revealed the indication that root
fixation under the form as the cuttings have been obtained is consolidated from
the ninth month of transplanting, which coincides with results obtained in the
asexual propagation of native grasses evaluated in Brazil by Figueiredo et al. (2018).
The variation of response based on the location
of the plots is due to differences in soil physical-chemical characteristics
such as structure, compaction, erosion susceptibility, mineral contents,
moisture content and other properties; according to these criteria the study
plots varied in altitude (4012 and 4333 masl), precipitation received by plots
(491 and 533 L/m2) and soils that varied in pH (4. 6 to 5.9), in OM
(7.3 to (15.2%), in P (3.8 to 24.2 ppm); this was also found by Andueza et al. (2021) when evaluating growth and
maturity stage and chemical composition in 6 perennial types of grass, about
altitudinal gradient and climatic variables during 2 years in 3 different
locations; also topography influences plant development, through a regulatory
phenomenon of respiration, being higher in flat areas than in sloping ones
(Zhang et al. 2021).
The incorporation of organic matter and
minerals to the soil, enrich the availability of nutritional elements for
plants (Elouear et al. 2016);
however, the effect on natural fertilizers could not be perceived immediately
because the mineralization process is slow due to several factors: the
decomposition time of cattle manure, the climatic characteristics and the
altitude of the location of the plots; on the other hand, the poor solubility
of rock phosphate in water and the acid condition of Andean soils (Rolando et al. 2017); in this context,
transplants fertilized with cattle manure had greater response in the expansion
of canopy cover versus those fertilized with phosphate rock, because cattle
manure carries with it parts of the urine that is a source of nitrogen plus the
labile carbon that is released in the decomposition period of cellulose and
hemicellulose, plus those released by the microorganisms in the rumen of cattle
(Wang et al. 2018) and these when
washed by rain is integrated into the soil in less time, therefore assimilated
by the plant and by soil microorganisms; meanwhile, the phosphate rock did not
contribute N or C which, are the main promoters of growth and leaf elongation
in plants in the first instance.
The regret is shared that inter-annual changes
in precipitation are not visualized in their real dimension, because the data
available in the long term are statistically managed for large areas, which
hides the real changes that occur and vary over small areas where there is no
recording equipment (Djebou et al.
2021). These irregularities of precipitation create space of scarcity or lack
of rainfall that affects the maintenance of soil moisture; however, the lack of
water in the soil can be mitigated if the vegetation protects the soil against
rapid evaporation through the shade formed by the abundance of its leaves (De
Jesus et al. 2021). These criteria
are very important, to note that the Andean grasslands, being populated by tall
grass species with many tillers, maintain soil moisture, which allows
maintaining a continuous growth of the transplanted cuttings, at least until
completing their vegetative development (Muñoz 2017; Padilla et al. 2019).
The correlation of canopy cover, canopy height,
and high inflorescence height from October 2020 to March 2021 was due to the
higher rainfall that occurred in these months by which the soils were
maintained with higher humidity, in addition to the less abrupt temperature,
mainly in the maximum temperature. These variables, being the main climatic factors
influenced the production of leaves, stems, and the development of the
different phenological phases of production and reproduction of the plants
(Muñoz 2017). Meanwhile, the dry months: April, May and June did not maintain
the level of correlation observed for that period, which contrarily reduced the
expansion of canopy cover and the growth of leaves, stems, and inflorescence,
because of the scarcity of water in the soil, the reduction of soil
microorganisms and their association with minimum temperatures (Li et al. 2021); however, the continued
growth even at the lower level was due to the change of the structure with
increased vertical development of roots to fulfill the function of searching
for water in the subsoil (Padilla et al.
2019). Since longer-lasting rainfall has allowed the greater accumulation of
water deep in the subsoil and was not strongly affected by the phenomenon of
evapotranspiration (Muñoz 2017; Chen et
al. 2021).
Conclusion
The transplantation of cuttings in Andean pasture proved to be feasible
despite having started the research in the dry season (April to August). The
development of the cover and height of foliage was different due to effect of
the application of natural fertilizers, as well as according to altitude,
average temperature, and monthly rainfall, measured for nine months in each
control site.
Acknowledgments
In this article, we would like to express our gratitude to the community
of Acopalca in the person of its president Dario Palomino Cunyas, and to the
families who donated and fenced the study plots, as well as guarded the control
plots during the evaluation period; also to the Belgian association VLIR-UOS
that supported the inter-university relationship and provided funding for this
and other studies, to Katholieke Universiteit Leuven (KUL) and to the
Asociación Civil de Desarrollo Sostenible that played the role of bridge
between the financier and the project in coordination with KUL.
Author Contributions
RMY planned the research, performed the data analysis, and directed the
writing of the article. KM, MYR, and DHC participated in research planning, and
control area installation and was responsible for data collection.
Conflict of Interest
All authors declare no conflict of interest.
Data Availability
The original data can be seen in the attached file.
Ethical Approval
Not applicable in this paper.
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