Tropical Grasslands (2001) Volume 35, 241245
The response of Stylosanthes hamata cv. Verano to applications of sodium and chloride
K. BETTERIDGE1,2 and R.J. JONES
1CSIRO Division of Tropical Agriculture, Townsville, Queensland, Australia
Stylosanthes hamata cv.Verano was grown for 116 days in pots with factorial combinations of sodium levels and chloride (equivalent to 0–356 kg/ha Na, and 0–548 kg/ha Cl) using a yellow earth soil. Treatments were applied from day 42 in 2 applications 6 weeks apart. Plant height was unaffected by treatment, but plant top yield declined linearly with Cl rate and was reduced by 9% at the highest Cl level. Sodium, except at the highest level, had little effect on top growth. Leaf number and inflorescence number were both depressed by increasing NaCl rates. Effects were greater on the yield of roots than of tops, with the highest NaCl treatment reducing root yield by 31%.
The Cl content in tops increased linearly with Cl rate (P < 0.001), the highest level recorded being 1.48% of dry matter. Na had only a small effect (P > 0.05). A significant Na × Cl interaction resulted in Cl rate increasing the N and P concentration of plant tops at zero Na rate, whereas Cl rate depressed N concentration at the highest Na rates.