M. NANKOVA, K. KOSTOV and E. PENCHEV
Dobroudja Agricultural Institute, BG-9520 General Toshevo, Bulgaria
NANKOVA, M., K. KOSTOV and E. PENCHEV, 2004. Tolerance of Bulgarian wheat varieties to conditions of acid soil reaction. II. Effect of exchangeable aluminum on root mass and root-shoot relation. Bulg. J. Agric. Sci., 10: 117-124
The effect of the addition of increasing toxic aluminum rates (2.5 and 5.0 meq Al3+/100 g Orthic luvisols-FAO, containing 0.5 meq Al3+/100 g) on the development of root mass and its relation to the shoot of winter cereal crops was followed in a vegetation trial. The trial was performed against two backgrounds of soil fertilization - N0P0K0 and N200P200K200 (mg/1000 g soil). Under these conditions, 18 genotypes of T.aestivum L. and 1 genotype of T. durum Desf. were grown; Triticale variety Vihren was used as a control crop.
The increasing rates of toxic Al3+ (+ 2.5 and + 5.0 meq/100 g soil) reduced root mass yield with 55.0% and 17.2 %, respectively, according to the control variant. Balanced mineral fertilization had a positive effect on root mass according to the control variants for each Al3+ rates. Triticale variety Vihren, averaged for the trial variants, formed roots with the highest mass. Among all T. aestivum L. genotypes tested, the roots of varieties Svilena and Milena showed enhanced tolerance to high Al3+ concentrations in soil (a total of 5.5 meq/100 g soil) in combination with balanced mineral fertilization.
The constructed mathematical models give a qualitative expression of the investigated correlations between root mass and the shoot formed. The correlations between root and shoot biomass and the grain yield formed were positive, at a highest level of significance. Their values suggest linear relations between the investigated indices.