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Subject: Horticulture × Author: KAU × End date: 1994 × Start date: 1994 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Influence of cover crops on growth of rubber and on soil fertility status
    (Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1994) Sushama Kumari, K R; KAU; Alice, Kurien
    The study was conducted in Ottapalam taluk (Palakkad district, Kerala state) to make a comparative evaluation of two cover crops (pueraria phaseoloides and Mucunna bracteata) with respect to yield of biomass, leaf litter addition , nutrient composition , soil enrichment through added nutrient , competition , soil enrichment through added nutrient , moisture regime of the soil and its impact on growth of rubber . The salient findings of study are summarized below. Mucuna bracteata recored higher biomass on per hectare basis than pueraria phaseoloidies . The status of nutrients N, p and k were higher in Mucuna bracteata than pueraria phaseoloides and the difference was much evident in the case of N content. Calcium and magnesium were found to be high in pueraria phaseolodies. The leaf litter from the cover crop was quantified and found that the mucuna bracteata produced higher leaf little (2324.09 kg ha -1) Compared to pueraria (1205.72 kg ha-1). Content of organic carbon, available p and available K in the soil at two depths (0-15 cm and 15-30 cm ) was higher in plots cover-cropped with M. bracteata than other three plots cover-cropped with P. phaseolodies, inter -cropped and those with natural cover. The availability of magnesium was found to be highest in plots inter -cropped with banana . M. bracteata recorded lowest magnesium status of the soil and this can be attributed to the higher up take due to high biomass production . Any sort of the cropping whether cover-cropping or inter-cropping helps to improve the nutrient status of soil and conserve the moisture. The area under natural cover recorded the lowest moisture content during both the months. P. phaseoloides was found to be the most efficient with regard to moisture conservation and recorded the highest moisture content during April and may. Cover –cropping or inter-cropping was found to augment the growth of rubber and maximum girth increment was observed for Mucuna bracteata covercropped plots. The study also revealed that in general Mucuna bracteata was much superior to pueraria phaseolodies with regard to biomass production , and addition of major nutrients to the soil . The low moisture content in Mucuna cover-cropped plots demands further investigations to arrive at definite conclusions regarding the competition for soil moisture between rubber and the cover crop.
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    ThesisItemOpen Access
    Diversity interrelationships among capsicum spp. and forms and developement of papricas
    (Department of Olericulture, College of Horticulture, Vellanikkara, 1994) Indira, P; KAU; Peter, K V
    Capsicum, a new world genus, has richness in diversity that has not yet received the needed attention. The cultivated chilli varieties offer many problems in classification because of their great number, the transitory nature and creation of new ones through hybridization and selection processes. The present studies on “Diversity inter relationships among Capsicum spp. And forms and development of paprikas” were conducted at the College of Horticulture, Vellanikkara. The main objectives were grouping of chilli genotypes biometrically and biochemically and development of paprikas. For biometrical grouping chilli genotypes belonging to four cultivated species of Capsicum were evaluated during two seasons (August, 1991- January, 1992 and May, 1992- September, 1992). They were clustered into different groups based on D2 values. There were 9 clusters during first season and 6 clusters during second season. The distribution of genotypes into clusters showed no regularity. The isozyme patterns of two enzymes viz.peroidase and esterase were studied in the three cultivated species of Capsicum and also for the nine biometrical groups. Among the different plant parts studied roots showed clear bands in case of peroxidase and mature leaves were the best sampling tissue for esterase enzyme. There were species specific bands in all the three species. The nine biometrical groups showed variation for banding pattern in case of peroxidase and esterase. There were some common bands for both the enzymes. Twenty paprika genotypes were collected from different sources and their morphological descriptions were made as per IBPGR descriptor. Field evaluation was done for two seasons (October –March, 1991; May – October, 1992). There was significant difference among genotypes for the different characters studied. There was much seasonal variation also. CA 517 recorded minimum incidence of bacterial wilt during both seasons under the field conditions. CA 582 showed highest colour value but CA 604 and CA 605 recorded minimum pungency.