Effect of liming on dry matter yield of wheat in pots of low humic gley soil

Abstract

This experiment was carried out with the aim of verifying the effect of liming on three wheat cultivars, IAC-5, Alondra and Anahuac, in lowland hydromorphic soils (Low Humic Gley) rich in organic matter. The treatments consisted of five levels of liming using two recommended methods. These treatments were: control without liming; liming by the aluminium method and 1/3, 2/3 and 4/3 of the liming recommended by the buffer method of Shoemaker, McLean and Pratt (SMP buffer method). Adequate levels of calcium and magnesium in the plants were obtained with higher doses of calcium than those indicated by the aluminium method. With the aid of curves adjusted to the experimental data it was verified that the maximum yields of dry matter of 15.86, 15.88 and 12.53 g/pot for the cultivars IAC-5, Alondra and Anahuac, respectively, occurred with higher quantities of calcium at 2/3 of liming indicated by the SMP method at pH 6.0 At this rate of liming aluminium levels in the soil were not totally neutralized and the levels of calcium and magnesium adequate for maximum yield were estimated in 4.6, 4.08 and 4.7 meq/100 g of soil. The results indicate that for Low Humic Gley soils with a high level of organic matter, the level exchangeable aluminium does not constitute an adequate criterion for indicating liming requirements for wheat.