Presentation by Prof. Silvino Vargas Hernández. PhD at the 5th All Africa conference on animal production, Addis Ababa, Ethiopia, 25-28 October 2010.

1. Prof. Silvino Vargas Hernández. PhD.
SCHOOL OF VETERINARY MEDICINE. DEBRE ZEIT. ADDIS ABABA
UNIVERSITY
25-28 OCTOBER, ADDIS ABABA, ETHIOPIA
REDESIGN AND MANAGEMENT OF NATIVE
GRASSLAND AGROECOSYSTEM AND ITS
IMPACT IN SOIL QUALITY AND HEALTH.

2. Overwhelming International Rejection of US
Blockade of Cuba at UN
Year In Favor Against Abstentions
1992 59 3 71
1993 88 4 57
1994 101 2 48
1995 117 3 38
1996 137 3 25
1997 143 3 17
1998 157 2 12
1999 155 2 8
2000 167 3 4
2001 167 3 3
2002 173 3 4
2003 179 3 2
2004 179 4 7
2005 182 4 1
2006 183 4 1
2007 184 4 1
2008 185 3 2
2009 187 3 2

3. Presentation outline
 Introduction
General objective
Methodology
Results
Conclusions
Recommendations

4. Introduction
 Better soil fertility is obtained in well managed and
permanent pastures but little is known about the
dynamics of nutrients and health through the time.
This paper is part of an integrated approach of
pastureland agroecological restauration in which was
studied the impacts of primary production and its
management upon biomass production, dairy cattle
yielding, soil fertility and economical indicators.

5. General objective
The objective of the present paper is to
evaluate the effect of a NGA (native grassland
agroecosystem) redesign and management
upon the soil quality and health in three years
time .

6. Methodology to redesign and management of NGA
 Thirty three paddocks were designed with a total area of 10.89 ha.
Five paddocks were chosen randomly for soil sampling. The soil was
classified as Brown Soil with Carbonates (BSC) (Hernández et al.,
2006).
 The NGA perimeter was fenced with four wires and live post of
Gliricidia sepium, Bursera simaruba and Ficus auriculata were
sowed at a distance of five meters one from the other and dry
wooden posts two meters apart.
 The area was divided into paddocks using an electric fence.
The stocking rate and grazing pressure were adjusted according
to the total biomass production every year.

7.  Planning of rotation periods were planned in accordance with the state
of growing and development of the vegetation.
Methodology to redesign and management (Cont.)
 The occupation period of each paddock was controlled in order to
protect the vegetative covering over de soil and the management of the
species according to phytotechnical needs of the species in each rotation
or grazing.
 The herd was organized in categories according to productive,
reproductive and growing stage with regard to their access to feeds and
management.

8. Management of grazing
In the LRP (low rainy period) the milking and foster mother
groups grazed from 6:00 - 9:30 h, in the NGA (native
grassland agroecosystem). These groups continued grazing in
PB (protein bank) paddocks from 10:00 - 12:00 h.
Then, the animals moved to shaded area in which they
consumed an average of 1.70, 1.37 and 1.48 kg DM cow-1
day-1
of milled sugar cane in 1, 2 and 3 years, respectively; 1 kg of
molasses and 0.05 kg of minerals salts.

9. Herd structure and management of growing-
development animals
The herd comprised a crossbred
animals of Holstein x Zebu, with 90
percent of its females inseminated with
Siboney of Cuba (5/8 Holstein x 3/8
Zebu).

10. Soil indicators
 A randomized design was applied to analyze the physical and
chemical indicators of soil, with 7 repetitions. Five paddocks
were used with an average area of 0.33 ha in the NGA.
 The sampling was carried out every semester, in two periods
of the year (PY), late November, at the end of rainy period
(FPLL), and late May, at the beginning of the rainy period
(IPLL). Seven samplings were carried out in a period of three
years time. The sampling method was using the diagonal and
zig-zag methods.

11. Soil indicators (Cont.)
 Ten sub-sampling were taken in each paddock and two
compound samples were used in each one to obtain 10
compound samples both in 1(0-10) and (10-20) cm soil depth
(SD).For the physical and chemical analysis 500 and 100 g of
soil were separated, respectively.
In the physical analyses the structure factor Vageler & Alten
(1931) and permeability Henin (1958) were determined In the
chemical ones there were carried out pH determinations (H2O)
and (KCl) using pH meter; assimilable phosphorous (P2 O5) and
potassium (K2O), according to the Oniani (1964) method; soil
organic matter (SOM) by means of Walkley and Black, method
cited by Jackson (1965).

12. Soil indicators
 The density of worms was determined with the manual
extraction of soil monoliths (20x20x20 cm) with the aid of a
trident and direct count of organisms (Martínez, 2002) with
same amount of paddocks and repetitions that the previous
indicators.
The samplings to determine the microbiology of the soil
were taken from 0-10 cm, using the same paddocks, with an
annual sampling consisting of 10 compound samples taken
every year in late May. For the isolation and determination of
total microorganisms in solid stage, bacteria, fungi and
actinomycetes, the cultivation media were, Agar Glycerine
Pectone; Agar Rosa Bengala and Amoniacal Starch,
respectively (Mayea et al., 2004).

13. Soil structure factor
Results
Fig. 1. Soil structure factor (SSF) .Interaction year – periods in each soil depth . EE1 =0.69, EE2 =0.45 (0-
10cm); EE1 =0.66, EE2 =0.69 (10-20cm). abcd
Means with different letters in the superscripts differ
significantly P<0.05 (Duncan, 1955).

14. Results
Permeability of the soil
Fig. 2. Soil permeabiliity (PER) . Interaction year – periods in (0-10 cm) soil depth. EE1
=1.11, EE2 =0.07 (0-10cm). abMeans with different letters in the superscripts differ
significantly P<0.05 (Duncan, 1955).

15. Oponencia I

16. Results
Soil pH
Fig. 3. pH (H2O) of soil interaction year –period of year in each SD. abcd
Means with different letters in
the superscripts differ significantly P<0.05 (Duncan, 1955). EE1 =0.01, EE2 =0.08 (0-10cm); EE1 =0.10,
EE2 =0.08 (10-20cm).

17. Results
Soil organic matter
Fig. 4. Soil Organic Matter (MOS). Interaction year – periods in (0-10 cm)soil depth. abc
Means with different letters in the superscripts differ significantly P<0.05 (Duncan,
1955). EE1 =0.28, EE2 =0.20 (0-10cm).

19. Results
Assimilable P2O5
Fig. 5. P2O5 content. Interaction year – periods in each soil depth. abcd
Means with different
letters in the superscripts differ significantly P<0.05 (Duncan, 1955). EE1 =0.28, EE2 =0.22
(0-10cm); EE1 =0.38, EE2 =0.45 (10-20cm)

21. Results
Assimilable K2 O
Fig. 6. K2O content. Interaction year – periods in each soil depth.abcd
Means with different
letters in the superscripts differ significantly P<0.05 (Duncan, 1955)

22. Results
Dynamics of the
earthworms m -2
Fig. 7. Dynamics of earthworms. Year main effect. ab Means with different letters in the
superscripts differ significantly P < 0.05. Original data were transformed according to √ x +
0.375

23. Results
Dynamics of the microbial communities
Fig. 8. Dynamics of bacteria * 10 7
, fungi * 10 4
& actinomycetes * 10 6
in the AES. abc
Means with different letters in the superscripts differ significantly P < 0.05 (Duncan,
1955).*** P < 0.001 Data were transformed to ln.

24. Attributes of livestock agroecosystem
 Use of soil cover.
 Grazing all year round.
 Redesign while production is taking place.
 Positive annual forage balance.
 Higher productive performance.
 Self - sufficency in feed balance.
 Higher milk production (endougenous feed) with less cows.
 Increased body reserves.
 Economic profitability.
 Minimum input and highly optimized resources.
 Improving of biodiversity.
 A superior management culture of natural resources.

25. Conclusions
The contents of SOM and their assimilable nutrients,
described a dynamics corresponding with the
mineralization processes which are encouraged and
regulated by the edafoclimatic and management
conditions.
The dynamics of the earthworms, the microbial
populations increment and both, the improvement
or stability of the physical properties in the native
grassland agroecosystem were a demonstration of
good management practices applied to the plant-
animal – soil system during the studied years .

26. Recommendations
 To redesign and apply a rational grass management in no
less than 40 % of the available native grassland
agroecosystem.
 To regulate the stocking rate, grazing pressure, resting and
occupation periods in the paddocks in every period of the
year, to maintain and improve soil quality and health and
consequently to develop a sustainable dairy cattle
agroecosystem.

27. 6.7 L of milk was achieved in this project !

28. Thank you for your attention!
Amesgnalehu!
7 L of milk was achieved in this project !

29. Oponencia I Cont. R/11
El pH puede modificarse en base a múltiples factores:
 La MOS (complejo órgano-minerales, capacidad buffer).
 Cationes en la solución del suelo.
 Cationes cambiables.
 Composición de los cationes en el complejo.
 Cationes, bases cambiables (Ca 2 +
, Mg 2+
, K+
, Na+
).
 Cationes acidificantes (H+
, Al3+
).
 La época del año (Mayor pH en PLL ,lavado de electrólitos. En el
PPLL (acumulación de electrólitos H+
) y por tanto disminuye el
valor del pH.
 Cantidad y tipos de sales solubles (ciclo etilénico).
 Al disminuir el pH dentro de ciertos límites hay aumento de la
biodisponibilidad de microelementos, excepto el molibdeno (Cairo
y Fundora 2005).