Magnesium management in the soil-crop system - a crop rotation approach

Abstract

Magnesium (Mg) budgeting was conducted on a production farm at Górzno, Poland during the 2004-2007 growing seasons for 15 crop sequences: nine with oil-seed rape (OR) and six with maize grown for grain or silage (SM) as dominant crops. The impact of cropping sequences (CS) on Mg management was evaluated using two methods: soil surface balance, and soil system balance. The Mg yield output ranged from 4.5-17 kg Mg/ha, but including harvest residues from 8.9-22.9 kg Mg/ha. The average quantity of external Mg, required to balance its yield output reached 5.8 kg/ha in the OR-CS and 10.4 kg/ha in the SM-CS. The net Mg input, through mineral fertilizer, farmyard manure, seeds, and precipitation ranged from 1.3-17.3. The negative value of the total gross Mg balance (-10 kgMg/ha) implicitly indicates on its soil pool as the key source for the growing crops. Plants grown in the OR-CS compared to the SM-CS used both external and soil sources of Mg more efficiently. Plants grown in cropping sequences dominated with maize, with higher needs for Mg, showed strong uptake capability in exploitation of soil Mg available pool.

Keywords

• nutrient
• zea mays
• oilseed rape
• soil magnesium balance