Micronutrients (Cu, Zn, Fe, Mn, Mo) Status of a Sodic Soil under Cultivation of Aromatic Crops.
R. P. Singh, R. K. Singh, S. N. Singh, and R. S. Singh. Dept of Soil Science and Agricultural Chemistry, Udai Pratap Autonomous College, Varansi, 221002, India
Sodic soils occupy extensive area and occur globally. Reclamation of sodic soil is a costly affair especially for poor farmers. It requires additional agricultural inputs like amendments, water and infrastructure for drainage. An alternate approach is the utilization of sodic soils for growing crop species capable of tolerating, producing economic yield and improving the fertility status. Benefits of growing aromatic crops are quite encouraging in terms of bio-reclamation of sodic soils. Therefore, field experiment was conducted to study the effect of aromatic crops alone and in combination of organic and inorganic amendments on micronutrients status of a sodic soil. Accordingly, Water hyacinth (Eichhornia crassipes) compost, digested sludge and gypsum were used for this purpose. Three aromatic crops namely palmarosa (Cymbopogon martinii), lemon grass (Cymbopogon flexuosus) and citronella java (Cymbopogon winterianus) were cultivated for five consecutive harvesting. Experimental soil had pH 9.4; ECe 2.2 d Sm-1; SAR 38; organic carbon 1.5 g kg-1; Cu 0.35; Zn 0.38; Fe 1.1; Mn 0.98 and Mo 0.27 mg kg-1 soil. Experiment was conducted in randomized block design with four replications. The treatments were T0 (control -no amendments), T1 (pyrite at 60% gypsum requirements ha-1),T2 (sludge at 10 t ha-1), T3 (hyacinth compost at 10 t ha-1), T4 (hyacinth compost at 3 t ha-1 + pyrite at 40% GR ha-1), T5 (hyacinth compost at 3 t ha-1 + sludge 5 t ha-1) and T6 (hyacinth compost at 3 t ha-1 + sludge at 2 t ha-1 + pyrite at 40% GR ha-1). Organic and inorganic amendments were applied one month before transplanting of crops. Soil samples were collected after each harvesting and analysed for organic carbon, available (DTPA extractable) Cu, Zn, Fe, Mn and Mo following standard procedures. Cultivation of aromatic crops alone and in combination of organic and inorganic amendments showed steady increase in micronutrients status as compared to initial value. Maximum increase was observed with T6. Among the three crops lemon grass was found superior over palmarosa and citronella java in context of increasing the nutrient status of soil. In case of lemon grass with T6 status of Cu, Zn, Fe, Mn and Mo eventually reached 0.75, 1.05, 10.7, 2.68 and 0.69 mg kg-1 soil, respectively. Increase in status is possibly due to addition of organic matter by biomass through root and leaf fall from the plants, root exudation, solubilization of insoluble mineral and creation of favourable conditions for the growth of microorganisms. Keywords: Aromatic crops, sodic soil, micronutrients.