Desire for Greener Land

Crop rotation with legumes
Chile – Rotación de cultivos con leguminosas (Spanish)
Biological Nitrogen Fixation (BNF) of legumes as a source of N in crop rotations
with cereals in Mediterranean Chile
In the past, legumes were commonly used as a biological and economic source of N
for farming systems. Nowadays, N-fixing legumes have been recovering as viable
crops because of the increased cost of N fertilizer and the need to develop more
sustainable farming systems. These systems combine phases of legumes of different
duration, in which N is fixed and accumulates in the soil, followed by phases of cereal
growing during which accumulated N is extracted. In this new rotation for rainfed
agricultural systems in Central Chile, four legume-wheat rotations were compared to a
monoculture crop rotation (wheat followed by oat). The legume species are: the
narrow-leaf lupin (Lupinus angustifolium); Wonga (early-flowering and high-yielding
narrow-leafed lupin variety), yellow lupin (Lupinus luteus); Motiv, Peas (Pisum
sativum); Rocket and a fodder mixture of vetch (Vicia atropurpurea) with oats. Legume
seeds were inoculated with a specific Rhizobium. In the year following the legume
crop, wheat was seeded without N fertilisation on the incorporated residues of grain
legumes and green manure (vetch with oats). The BNF in the grain legumes varies
from 124 to 178 kg N ha -1, depending on the type of legume. Peas are the most
efficient fixing legume crop. In the lupins - wheat (L. angustifolius) rotation without
application of N to the wheat after lupins, production of wheat was between 79 and
110% of that when fertilised with N. In the peas - wheat rotation, a yield equivalent to
72 and 105% of the wheat fully fertilised with N was obtained. While peas (Pisum
sativum) can be eaten as a green vegetable, lupins and Vicia are used as fodder
supplements for animals.
The new rotations were developed and evaluated experimentally. Then, through a
technology transfer programme, the technology was transferred to real conditions with
farmers in a programme covering 250 ha in the municipality of Yumbel.
The area has a subhumid Mediterranean climate with an average annual precipitation
of 695 mm (80% concentrated in winter), with five months of drought. Soils are Alfisols
of the Cauquenes type, classified as Ultic Palexeralfs. The soil is formed from
weathered granite with moderately acidic conditions and low organic carbon. Clay
content in the soil is 15% at depths of 0-18 cm depth. Below this depth, it is above
44%. The topography comprises a hillslope with a gradient of 10-20 % and the main
traditional crop rotation is oat-wheat or wheat-natural pasture. The farmers are
smallholders working on their own land. The sizes of the holdings on the dryland soils
vary from 5 to 20 ha.
SLM Technology: Crop rotation with legumes, Chile DESIRE – WOCAT 2012
Above left: Wheat in the crop rotation after
peas (Photo: Soledad Espinoza)
Above right: Peas in the crop rotation (Photo:
Carlos Ovalle)
Location: Secano interior, Mediterranean Chile
Region: Cauquenes and Bíobio
Technology area: 250 km 2
Conservation measure: agronomic
Stage of intervention: prevention of land
degradation
Origin: through experiments / research, < 10
years ago
Land use: annual cropping
Climate: subhumid, temperate
WOCAT database reference: QT CHL02 on
cdewocat.unibe.ch/wocatQT
DESIRE site information: www.desirehis.eu/en/secano-interior-chile
Related approach: not documented
Compiled by: Carlos Ovalle and Soledad
Espinoza, Instituto de Investigaciones
Agropecuarias (INIA La Cruz)
Date: 10th Nov 2011
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