Prof. Silvino Vargas Hernández. PhD.SCHOOL OF VETERINARY MEDICINE. DEBRE ZEIT. ADDIS ABABA

UNIVERSITY25-28 OCTOBER, ADDIS ABABA, ETHIOPIA

REDESIGN AND MANAGEMENT OF NATIVE

GRASSLAND AGROECOSYSTEM AND ITS

IMPACT IN SOIL QUALITY AND HEALTH.

Overwhelming International Rejection of US

Blockade of Cuba at UN

Year In Favor Against Abstentions1992 59 3 711993 88 4 571994 101 2 481995 117 3 381996 137 3 251997 143 3 171998 157 2 121999 155 2 82000 167 3 42001 167 3 32002 173 3 42003 179 3 22004 179 4 72005 182 4 12006 183 4 12007 184 4 12008 185 3 22009 187 3 2

Presentation outline

Introduction

General objective

Methodology

Results

Conclusions

Recommendations

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.

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 .

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.

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.

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-1day-1

of milled sugar cane in 1, 2 and 3 years, respectively; 1 kg of

molasses and 0.05 kg of minerals salts.

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).

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.

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).

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).

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). abcdMeans with different letters in the superscripts differ

significantly P<0.05 (Duncan, 1955).

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).

Oponencia I

Results

Soil pH

Fig. 3. pH (H2O) of soil interaction year –period of year in each SD. abcdMeans 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).

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).

Results

Assimilable P2O5

Fig. 5. P2O5 content. Interaction year – periods in each soil depth. abcdMeans 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)

Results

Assimilable K2 O

Fig. 6. K2O content. Interaction year – periods in each soil depth.abcdMeans with different

letters in the superscripts differ significantly P<0.05 (Duncan, 1955)

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

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.

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.

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 .

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.

6.7 L of milk was achieved in this project !

Thank you for your attention!

Amesgnalehu!

7 L of milk was achieved in this project !

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).