Effects of different Mg fertilizer sources on the magnesium availability in soils

摘要: Pot experiments with different soils were conducted to determine the effect of Mg fertilizer sources on magnesium availability. The studied included Kieserite (MgSO4 H2O), a synthetic sulphate (SMS) variable content crystal water and calcined magnesite (Mg-oxide). three fertilizers vary greatly in their solubility water, affecting availability plants once applied soil. Whereas dissolved gradually SMS immediately, Mg-oxide released only insignificant amounts cool (20 °C) after intensive stirring. Due fact that these dissolution properties may distinctly affect soils, as standard source was tested against slow release fine coarse form. Soil extraction samples taken from 0–10 10–20 cm depths at 4, 8 12 weeks applying soil surface revealed rate which appeared available pool (CaCl2 extracts) varied significantly between sources. much greater than Mg-oxide. Nutrient depended fineness material, i.e. coarser less available. Maize grown test plant pots 10.6% larger yield 19.6% uptake treated pots. High under high rainfall conditions, however, also through large losses occurring by leaching. Therefore, second experiment, behaviour fertilizers, versus quickly dissolving studied, using an Ultisol (Serdang Series Malaysia). A simulation excessive irrigation 20 mm per day over period 16 days saturated amount lost leaching differed two tested. lowest 8.7% treatment low application highest 22.3% rate. It is concluded gradual but strong match requirements most desired characteristic maximize crop minimize losses.