MSc

Quality of raw drug is as important as its quantity in medicinal plant cultivation. Since bulk of the present requirement is met by wild collection from natural habitats, when the crop is brought under cultivation, with improved management techniques, it is indispensable to ensure its quality. Cultivating plants under a micro climate similar to its niche original is found to be the viable solution for ensuring its therapeutic properties.
Sida alnifolia is a valued medicinal plant, belonging to family Malvaceae and known as Kurunthotti in Malayalam. Considering market potential, the State Medicinal Plant Board of Kerala recommended this crop for commercial cultivation.
The present study was taken up in the Department of Agronomy, College of Horticulture, Vellanikkara to assess the effect of variations in growing conditions, manuring and weed management on phytosphere variations and on growth, yield and quality of Sida hemp [Sida alnifolia L.]. The trial was laid out in Randomized Block Design, replicated thrice. The treatments consisted of two growing conditions viz., open and 50 per cent shade, two levels of manuring viz., no manure and FYM @10 t/ha and four weed management practices, viz., black polythene mulching, organic mulching, hand weeding and no weeding.
Growing condition, manuring and weed management significantly influenced the plant height, biomass yield per plant, root:shoot ratio and total root yield of Sida hemp. The highest root yield was obtained from open condition (882 kg/ha), FYM @ 10 t/ha (825 kg/ha) and black polythene mulching (1111 kg/ha).Interaction between growing conditions, manuring and weed management was also significant with the highest root yield in treatment combination of black polythene mulching with FYM @ 10 t/ha under open condition (1466 kg/ha).
The management methods also influenced the soil micro climatic factors such as soil temperature and soil moisture. Higher soil temperature and moisture content were observed under treatments with black polythene mulching.
Among different soil chemical properties studied, content of available P and K were significantly influenced by treatments. Direct effect of growing condition on available N was non significant, although, it was significantly influenced by manuring and weed management.
Physiological, chemical and biochemical parameters were also significantly influenced by growing condition and manuring, but however were unaffected by weed management practices. Total chlorophyll content at the time of harvest was higher under shade (12.28mg g-1) and FYM@ 10 t/ha (11.45mg g-1). Higher total alkaloid content was recorded from open condition (3.13 %). As in the case of root yield, combination of FYM @ 10 t/ha, black polythene mulching and open condition resulted

in higher total alkaloid content of 3.31 %. Crop growth rate and relative growth rates were also higher in this treatment combination.
Total population of bacteria, actinomycetes and fungi were higher under open condition and FYM @ 10 t/ha applied plots. Regarding the effect of weed management practices, total population of bacteria and actinomycetes were higher under organic mulched plots whereas fungi population was higher under unweeded plots. Higher root colonization by AMF and soil microbial biomass carbon were observed under open condition, with the application of FYM @ 10 t/ha in unweeded plots throughout the growth stages.
Weed count and weed dry weight were significantly influenced by the treatments. Lower weed count and weed dry weight were observed under shade, in unmanured plots mulched with black polythene. Among different weed management methods, black polythene mulching was the best practice, followed by organic mulching. Highest weed control efficiency was recorded in unmanured plot with black polythene mulching under shade (93 %) and minimum weed index was recorded in organic mulched plots without manure under shade (26 %).
Simple linear correlation between climatic parameters with yield and quality showed a significant positive correlation between soil temperature, biomass yield, root:shoot ratio and root yield. Soil moisture was positively correlated with plant height and negatively correlated with root yield and alkaloid content of roots. Negative correlation was observed between light intensity and plant height, whereas the correlation was positive with root:shoot ratio.
A higher B:C ratio of 1.73 was obtained from black polythene mulch with manure under open condition. Hand weeding with or without manure under shaded condition recorded lower B:C ratio (0.82).
From the present study, the combination of open condition, application of FYM @ 10 t/ha and weed management by black polythene mulching can be recommended as optimum for better yield, quality and B:C ratio of Sida hemp.