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Shoot and Root Biomass Allocation of Sunflower Varying with Soil Salinity and Nitrogen Applications
Author(s) -
Ma Tao,
Zeng Wenzhi,
Li Qi,
Yang Xu,
Wu Jingwei,
Huang Jiesheng
Publication year - 2017
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2017.04.0194
Subject(s) - sunflower , shoot , seedling , agronomy , salinity , helianthus annuus , soil salinity , fertilizer , irrigation , biomass (ecology) , horticulture , biology , ecology
Core Ideas Soil salinity could be alleviated by proper use of N fertilizer. No alleviation effect of additional N fertilizer is seen under saline conditions in sunflower's seedling stage. A pot experiment might not be an acceptable substitute for field trail.Soil salinity (S) is one of the most important abiotic stresses limiting crop production in arid and semiarid regions. This study was conducted to investigate the interactive effects of S and nitrogen (N) fertilizer on shoot and root biomass allocation of sunflower ( Helianthus annuus L.) at different growth stages. Outdoor field and pot experiments were performed in the Hetao Irrigation District, China. The field study consisted of a 3 × 2 factorial design with three salinity levels (S 0 : electrical conductivity of a saturated‐paste extract [EC e ] = 1.9 dS m −1 ; S 1 : EC e = 7.4 dS m −1 ; S 2 : EC e = 12.7 dS m −1 ) and two N application rates (low: 45 kg N ha −1 ; moderate: 135 kg N ha −1 ); the S 2 treatment was not included in pot study. The results indicated that sunflower allocated more biomass to root under saline conditions in the seedling stage. However, a detrimental effect of moderate N application rate on seedling growth could be found at the S 1 level. Moreover, after bud initiation, a moderate N application rate accelerated shoot and root biomass accumulation at the S 0 and S 1 levels, but it still aggravated salt stress and inhibited sunflower growth at the flowering and mature stages at the S 2 level. In addition, our study indicated that the sunflowers planted in pots showed enhanced salt tolerance and decreased the root/shoot ratio earlier than sunflowers planted in fields. We suggest applying less N fertilizer before sowing at both the S 1 and S 2 levels and using proper additional N fertilizer in the bud stage at the S 1 level to promote sunflower growth after salt tolerance has been enhanced.