Soil Fertility and Nutrient management (1+1)

Consumption of secondary nutrients by plants

• The amount of secondary nutrients removed by crops depends on the soil type, crop species, fertilizer sources and yield level. Generally, legumes and root crops remove more Ca and Mg than do cereals and other grasses. Cereals may remove 10-20 kg Ca per ha, a good crop of Brassica oleracea may remove 150 kg Ca per ha. A continuous cropping may result in the reduction of exchangeable Ca in soil.
• Banana and pineapple crops with yield levels of 40 to 50 t/ha may remove 120 to 140 kg of Ca and Mg . As a thumb rule, S removal per tonne grain production can be taken as 3-4 kg for cereals, about 8 kg for pulses, about 12 kg for oil seeds and 18 kg for cruciferous and 38 kg for mustards. In most of the crop species, the critical limits of S in plants are 0.20 to 0.25%. Plants use approximately as much S as P.