Integrated nutrient management for coleus

Abstract

An experiment was conducted at the Instructional Farm attached to the College of Agriculture, Vellayani during October 2000 to March 2001 to study the combined effect of organic manures, fertilizers and biofertilizer on the productivity and quality of coleus, to find out the feasibility of reducing the present recommended dose (RD) of fertilizer P and to workout the economics of cultivation. The treatments included different organic manures (RD as FYM, RD as composted coir pith (CCP), 1/2 RD as FYM + 112 RD as neem cake (NC) and 112 RD as CCP + 112 RD as NC on N equivalent basis), levels of P (30 and 60 kg P20S ha-I) and biofertilizer (with and without AMF inoculation). The experiment was laid out as a 4 x 2 x 2 asymmetrical confounded factorial RBD confounding ABC in all replications. A uniform dose of 60 kg Nand 100 kg K20 ha-I was applied to all the plots. Different organic manures had significant influence on plant height, plant spread and leaf number during later stages of growth. Significant influence of organic manures was observed on leaf area index (LAI), crop growth rate (CGR) and net assimilation rate (NAR) at all growth stages. The treatments, FYM and 112 FYM + 112 NC recorded superior values of growth characters. FYM was found to be the best source of organic manure for higher dry matter production irrespective of growth stages. In general, CCP was found inferior to other sources In its effects on growth characters. An increase in applied P from 30 to 60 kg P20S ha-I did not produce any significant influence on growth characters except CGR, NAR and tuber

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bulking rate (BR). Application of 60 kg P20S ha" registered higher values of CGR, NAR and BR during peak vegetative stage of the crop. Inoculation with AMF failed to produce any significant response in terms of growth characters except CGR and NAR. FYM as the source of organic manure had ,positive influence on yield components like number and weight of tubers and weight of marketable tubers per plant. But CCP as the organic manure recorded lower values of the yield components. The yield components were not influenced by increased rate of P application. Inoculation with AMF was also not beneficial with respect to its effect on yield components. Different organic manures exerted noticeable difference in tuber yield. The highest tuber yield was produced by FYM and the lowest by CCP. The effects of the treatments, 112 FYM + 112 NC and 112 CCP + 1/2 NC were on par and in between FYM and CCP. Enhancement of applied P or inoculation with AMF did not help in increasing tuber yield. The quality parameters of the tuber such as starch content, protein content and keeping quality were not affected by the treatments. The treatments, FYM and 112 FYM + 112 NC registered higher nutrient uptake. Uptake of P increased with increase in applied P but the uptake of N -1 .. and K were not influenced by P levels. AMF inoculation did not produce any significant effect on nutrient uptake. Available N, P and K contents of the soil after the experiment were not influenced by the treatments.

Net income and BCR were maximum when FYM was used as the organic manure. CCP recorded the lowest net income. The study clearly revealed that the present recommended dose of 60 kg P20S ha-I can be reduced to 30 kg P20S ha-I along with 60 kg Nand 100 kg K20 ha-I combined with lOt ha-I of FYM. FYM was found to be the best source of organic manure. If there is scarcity of FYM, half the dose of FYM can be substituted with NC on N equivalent basis. Wherever CCP is easily available, FYM can be substituted with CCP and NC in equal proportion.