Citrus Decline: Soil Fertility and Plant Nutrition

Soil physical properties related constraints (clay gradient in soil profile, drainage/irrigation/waterlogging) and soil fertility constraints induced by soil pH, salinity (specific ion-and cumulative osmotic pressure effect), calcareousness (pedogenic or non-pedogenic CaCO3), besides increasing menace of nutrient mining, are the important pedological factors contributing to citrus decline. But, the orchards established on later two soil orders confronted with subsurface constraints in form of argillic (clay rich horizon with acidic or alkaline pH and varying intensity/forms of calcareousness) and spodic horizonation (organic hardpan with very acidic pH), in addition to multiple soil fertility constraints. Soil condition-based rootstock alternatives, site specific nutrient management coupled with variable rate application, and integrated soil management systems representing different modules of INM, are the viable means of combating an untimely decline in citrus orchards' productivity.