Agriculture Reference
In-Depth Information
rotations were combined factorially and studied over a 4-year period on
land left uncultivated for 25 years.
Materials and methods
Research was carried out at the University of Reggio Calabria, in Southern
Italy, at a hilly site (6-8% slope, 250 m a.s.l., 485 mm mean annual rainfall,
of which 86% occurs between October and May, 16 and 23°C average min-
imum and maximum temperatures). The main soil physical and chemical
characteristics as measured at the beginning of the experiment are shown in
Table 3.8.1. A field that had been abandoned for 25 years, where a mixture
of native prairie species was the dominant vegetation, was brought back to
cultivation according to two different crop management systems: a conven-
tional system (CS), based on the standard agricultural practices in the study
area (i.e. ploughing to a 30-35 cm depth, fertilization to reintegrate total
crop nutrient uptake, and chemical weed control) and a low-input system
(LIS), based on sustainable agricultural practices (i.e. no-tillage, fertiliza-
tion to reintegrate only nutrients taken up by crop-marketable product, and
mechanical weed control, except for glyphosate spraying prior to sowing).
Crop residues were removed in CS and left on the soil surface in LIS. Three
crop rotations, specifically durum wheat (
Triticum durum
Desf.) continuous
cropping (typical of the study area) (Rotation 1), a horse bean (
Vicia faba
L. var.
equina
Persoon)-durum wheat 2-year rotation (Rotation 2) and a
Table 3.8.1.
Soil characteristics measured at the beginning of the experiment (1993).
Depth (cm)
Characteristic
Analytical method
0-7
7-30
pH (H
2
O)
Mc Lean, 1982
7.2
7.2
Clay (%)
USDA (Gee and Bauder, 1982)
41.0
44.2
Silt (%)
USDA (Gee and Bauder, 1982)
22.6
19.8
Sand (%)
USDA (Gee and Bauder, 1982)
36.4
36.0
Organic matter (%)
Walkley-Black (Nelson and Sommers, 1982)
2.8
2.0
Total nitrogen (‰)
Kjeldahl (Bremmer and Mulvaney, 1982)
1.1
0.9
P
2
O
5
(mg kg
−
1
)
Olsen (Olsen and Sommers, 1982)
12.3
11.6
K
2
O (mg kg
−
1
)
Knudsen et al., 1982
373
.3
216
.3
Aggregate stability (%)
Malquori (Lotti and Galoppini, 1980)
57.7
56.0
Field capacity (0.3 bar)
a
Richard chamber
28.5
30.1
Wilting point (15 bar)
a
Richard chamber
17.8
18.5
a
As a percentage of dry weight.
Search WWH ::
Custom Search