TITLE:
Effects of Soil Water Content in Four Soybean Genotypes in Different Environments in the Central Area of the Argentine Pampean Region
AUTHORS:
Martín M. Silva Rossi, Gabriel C. Caterina, Rodolfo L. Rossi
KEYWORDS:
Soybean, Water, Availability, Activity
JOURNAL NAME:
Open Access Library Journal,
Vol.2 No.11,
November
5,
2015
ABSTRACT:
In the Pampa Region there is limited information about the dynamics of
soil water and the consumption rate of different soybean genotypes. In the
Pampa Central Area, the first 15 cm of soil concentrates 80% of the soybean
plant’s root weight and over 40% of root absorbent surface. Despite the
importance of extracting the first centimeters of water, the water supply in
deeper zones could be very important as well. Because of this fact, the evaluation
of the evolution of soil moisture was proposed: in two soil types—Typic
Hapludoll and Entic Hapludoll; in different climatic years; in four soybean
genotypes—NA 3731RG, NA 4209RG, NA 4613RG and NA 5009RG; in their effect on
crop yield. In each of these environments, soil water content measurements were
made in the first 100 cm with a TDR (Total
Dormain Reflectometry) drill, over varietal performance tests with three
replications per genotype in each location. In all evaluated situations, a
significant effect on interaction genotype x soil depth, genotype x crop
emergence days and crop emergence days x soil depth was established. Also a
fast development of roots was observed, having found active roots for the
absorption of water within the first meter of depth 24 days after crop
emergence. A difference in difference of radical elongation rate among
varieties was also observed; because of the low water availability in
vegetative phases with similar soil humidity distribution, the genotype NA 5009
RG had reached 20 cm more of radical activity faster than NA 4613RG. The
highest crop yields were not associated to higher water content in soil during
the whole cycle. Highest crop yields were associated to a combination of
genotype, water availability between 50% of useful water during the whole
vegetative cycle and the beginning of the flowering period, and high water
availability in the first centimeters during reproductive phases. Under less
water availability, the genotype with higher speed of radical deepening reached
the highest yields.