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non-peer-reviewed

non-peer-reviewed

Research in the field of precision agriculture is becoming increasingly important due to the growing world population whilst area for cultivation remains constant or declines. In this context, methods of monitoring in?season plant development with high resolution and accuracy are necessary. Studies show that terrestrial laser scanning (TLS) can be applied to capture small objects like crops. In this contribution, the results of multi-temporal field campaigns with the terrestrial laser scanner Riegl LMS-Z420i are shown. Four surveys were carried out in the growing period 2012 on a field experiment where various barley varieties were cultivated in small-scale plots. In order to measure the plant height above ground, the TLS-derived point clouds are interpolated to generate Crop Surface Models with a very high resolution of 1 cm. For all campaigns, a common reference surface, representing the Digital Elevation Model was used to monitor plant height in the investigated period. Manual plant height measurements were carried out to verify the results. The very high coefficients of determination (R² = 0.89) between both measurement methods show the applicability of the approach presented. Furthermore, destructive biomass sampling was performed to investigate the relation to plant height. Biomass is an important parameter for evaluating the actual crop status, but non-destructive methods of directly measuring crop biomass do not exist. Hence, other parameters like reflectance are considered. The focus of this study is on non-destructive measurements of plant height. The high coefficients of determination between plant height and fresh as well as dry biomass (R² = 0.80, R² = 0.77) support the usability of plant height as a predictor. The study presented here demonstrates the applicability of TLS in monitoring plant height development with a very high spatial resolution. Proceedings of the Workshop on UAV-based Remote Sensing Methods for Monitoring Vegetation Kölner geographische Arbeiten, 94 ISSN:0454-1294

Research in the field of precision agriculture is becoming increasingly important due to the growing world population whilst area for cultivation remains constant or declines. In this context, methods of monitoring in?season plant development with high resolution and accuracy are necessary. Studies show that terrestrial laser scanning (TLS) can be applied to capture small objects like crops. In this contribution, the results of multi-temporal field campaigns with the terrestrial laser scanner Riegl LMS-Z420i are shown. Four surveys were carried out in the growing period 2012 on a field experiment where various barley varieties were cultivated in small-scale plots. In order to measure the plant height above ground, the TLS-derived point clouds are interpolated to generate Crop Surface Models with a very high resolution of 1 cm. For all campaigns, a common reference surface, representing the Digital Elevation Model was used to monitor plant height in the investigated period. Manual plant height measurements were carried out to verify the results. The very high coefficients of determination (R² = 0.89) between both measurement methods show the applicability of the approach presented. Furthermore, destructive biomass sampling was performed to investigate the relation to plant height. Biomass is an important parameter for evaluating the actual crop status, but non-destructive methods of directly measuring crop biomass do not exist. Hence, other parameters like reflectance are considered. The focus of this study is on non-destructive measurements of plant height. The high coefficients of determination between plant height and fresh as well as dry biomass (R² = 0.80, R² = 0.77) support the usability of plant height as a predictor. The study presented here demonstrates the applicability of TLS in monitoring plant height development with a very high spatial resolution. Proceedings of the Workshop on UAV-based Remote Sensing Methods for Monitoring Vegetation Kölner geographische Arbeiten, 94 ISSN:0454-1294

Seasonal variability in the physico-chemical features, zooplankton standing stock (biomass) and faunal composition in the Mandovi-Zuari estuarine system of Goa, India, during January to December 1990 were studied. Hydrobiological characteristics were influenced by the southwest monsoon. Salinity fluctuations were drastic (0.1 to 36.6 x 10 sup(-3)). This appeared to cause variations in plankton production and heterogeneity of various taxa. Zooplankton biomass and total numerical counts varied significantly between seasons and estuaries. Highest biomass values (1.9 ml/m sup(3)) were recorded in the Zuari Estuary but the maximum counts (25700/m sup(3)) were obtained in the Mandovi Estuary. Crustaceans particularly copepods predominated (54.9 to 70.6%). Invertebrate larvae, luciferied shrimps, cladocerans and chaetognaths were the other common zooplankton groups. Distribution and abundance of majority of constituent groups and species were influenced by various hydrographical characteristics of the environment.

Seasonal variability in the physico-chemical features, zooplankton standing stock (biomass) and faunal composition in the Mandovi-Zuari estuarine system of Goa, India, during January to December 1990 were studied. Hydrobiological characteristics were influenced by the southwest monsoon. Salinity fluctuations were drastic (0.1 to 36.6 x 10 sup(-3)). This appeared to cause variations in plankton production and heterogeneity of various taxa. Zooplankton biomass and total numerical counts varied significantly between seasons and estuaries. Highest biomass values (1.9 ml/m sup(3)) were recorded in the Zuari Estuary but the maximum counts (25700/m sup(3)) were obtained in the Mandovi Estuary. Crustaceans particularly copepods predominated (54.9 to 70.6%). Invertebrate larvae, luciferied shrimps, cladocerans and chaetognaths were the other common zooplankton groups. Distribution and abundance of majority of constituent groups and species were influenced by various hydrographical characteristics of the environment.

Annual variations in the zooplankton biomass and composition during 1991-92 were studied from the inshore, mouth and upstream regions of the Burhabalanga Estuary located in the Orissa Coast (India). Zooplankton biomass was maximum at all the stations during October 1991 as a result of a mysid swarm. Copepoda was generally the most abundant group. The copepods Pseudodiaptomus bowmani, P. sewelli, Acartia tropica and A. bowmani are recorded for the first time from the east coast of India.

Annual variations in the zooplankton biomass and composition during 1991-92 were studied from the inshore, mouth and upstream regions of the Burhabalanga Estuary located in the Orissa Coast (India). Zooplankton biomass was maximum at all the stations during October 1991 as a result of a mysid swarm. Copepoda was generally the most abundant group. The copepods Pseudodiaptomus bowmani, P. sewelli, Acartia tropica and A. bowmani are recorded for the first time from the east coast of India.