Effect of doses of lime and boron in the helianthus growth.

Abstract

There are few studies about the nutritional requirements and dry matter accumulation due to the mineral nutrition of Helianthus sp. Since this plant presents a high requirement of boron it is a good indicator of the boron deficiency in the soil. A study was curried out in pots in the greenhouse to evaluate the effect of different level of lime and of boron on growth and dry matter accumulation. The soil's pH improvement was done with lime in the folowing dosages: 15% (0 t/ha), 40% (1t/ha), 60% (2t/ha) and 80% (3t/ha) of bases saturation and the boron leveis (boric acid) were 0,1 and 2mg dm³ After 33 days of plantation the aerial part of the heilanthus plants was cut off and dried in greenhouse and, after that, evaluated in terms of dry substance yield. The increase of soil basis saturation to 40% resulted in a higher accumulation of dry substance which indicated that the 1 ton/ha dosage was considered sufficient to reach a satisfactory pH. The boron level at 1 pprn reached a higher value of dry substance which differs significantly from the helianthus yield with the absence of boron.