EFFECTS OF SOIL TEXTURE AND SOIL SALINITY ON THE PLANT WATER RELATIONSHIP, GROWTH, YIELD AND WATER USE EFFICIENCY OF THE SOYBEAN CROP - Soybean and Wheat Crops: Growth, Fertilization, and Yield - page 23

Chapter 2
E FFECTS OF S OIL T EXTURE AND S OIL S ALINITY ON
THE P LANT W ATER R ELATIONSHIP , G ROWTH , Y IELD
AND W ATER U SE E FFICIENCY OF THE S OYBEAN
C ROP
N. Katerji a , M. Mastrorilli b , F. Lahmer c , A. Hamdy c
a INRA, Unité de Recherche Environnement et Grandes Cultures,
78850 Thivernal-Grignon, France
b CRA, Research Unit for Cropping Systems in Dry Environments, 70125 Bari, Italy
c CIHEAM, , Mediterranean Agronomic Institute, 70010 Valenzano, Italy
A BSTRACT
Soybean was grown in a lysimeters filled with loam and clay soils and was irrigated
with water having three different levels of salinity (fresh water, and saline waters with 15
and 30 meq Cl/l).
During the soybean crop cycle, soil salinity was determined from the salt balance.
Leaf-water potential, stomatal conductance and actual evapotranspiration were used as
the water-stress indicators. Growth was measured through leaf area and dry matter and,
finally, the yield and its components were determined. The water use efficiency was also
calculated.
Without salt stress (treatments irrigated with fresh water), the effect of soil texture on
the water relationship, productivity and water use efficiency of the soybean was not
demonstrated.
With salt stress, all the parameters, in both types of soil, were coherent, indicating
systematic differences between the saline treatments and the control treatments
(treatments irrigated with fresh water).
Soil texture affects the soybean response to soil salinity. The saline treatments in the
loam soil caused the values of the water stress indicators, of growth, of yield and of water
use efficiency to be higher than the highest values observed for the same treatments on
the clay soil.