MSc

A field experiment was conducted at Instructional Farm, College of Agriculture, Vellayani during 2004-05 to study the effect of organic manures and microbial inoculants on growth, yield and quality of chethikkoduveli (Plumbago rosea L.), so as to formulate an organic manurial schedule for chethikkoduveli in a coconut based cropping system. The experiment was laid out in RBD with three replications and the treatments included three different combinations of organic manures (FYM, NC and VC), three microbial inoculants (AMF, Azospirillum and Phosphobacteria) and one control (package of practice recommendation of Kerala Agricultural University, 2002).
The treatment supplied with FYM (75 % N of POP) and microbial inoculants (T3) recorded highest plant height, leaf area, CGR, specific leaf weight, LAI and HI. Highest HI was recorded by the treatments supplied with FYM and NC supplying 50% N of POP and microbial inoculants (T7), which also had the highest leaf count, fresh weight of plants, total dry matter production and highest fresh and dry root yield per plant. The treatments supplied with organic manures and microbial inoculants recorded better dry root yield. The fresh root yield was the highest for the treatment T7 followed by T3. The highest root length and root girth were recorded by T7 and T3 plants respectively. T3 (FYM supplying 75 % N + mi) plants recorded the highest alcohol soluble extracts and plumbagin content. The application of organic manures and mi at different combinations significantly increased the nutrient uptake of P. rosea. Analysis of the soil samples before and after the experiment revealed that the nutrient supplying capacity of soil and the microbial population had a direct correlation. Soil microbial population was the highest for plots with better yield. From the results it can be concluded that microbial inoculants can be effectively used as nutrient substitutes. In the above treatments 25 % and 50 % of N is substituted by microbial inoculants in T3 and T7 plants respectively.
In conclusion, the study revealed that treatments T7 {FYM + NC + mi (50 % N)} and T3 {FYM + mi (75 % N)} had significant effect in enhancing growth, yield and quality of chethikkoduveli (P. rosea). From the point of view of quality (plumbagin content) FYM + mi (75 % N) is found to be the best treatment. Based on the benefit cost ratio, the treatment supplying only 50 % N of POP recommendation through FYM and neem cake along with microbial inoculants can be considered as the best for better root yield, quality and profit in P. rosea when grown as an intercrop in coconut plantations.