Cluster C: Patterns of land use, social fabric, and consumption

I-C01: Integrating air- and space-borne spectroscopy and laser scanning to assess structural and functional characteristics of crops and field margin vegetation

Project summary

Agricultural production on fields in the wider area of megacities plays an important role for the supply of urban people with cereals, forages, and vegetables, but rapid urban growth constantly changes the conditions for crop production and exerts increasing pressure on farmers to adopt the cropping systems to the altered situation. Better knowledge about the nature, dynamics, and direction of changes in crop production will support the decision making of stakeholders in planning processes of megacities and avoid negative repercussions of false decisions. Significant and rapid growth in urbanization in and around Bangalore has brought about substantial changes in agriculture, natural vegetation including forest and field margins, and water resources. Especially the productive agriculture lands of the rural areas of Bangalore have been undergoing transformations which affect the quality, diversity, and scale of agricultural crop production and spatial patterns. This project examines the application and integration of high resolution terrestrial and remote sensing to better understand the dynamics of crop production in the process of urbanization and to gain insight into the effects of growing cities on the structure, management intensity, and diversity of crop species in cropping systems.

Based on plot level hyperspectral point measurements and field scale hyperspectral images, discrimination models for locally important cereal, forage, and vegetable crops will be developed and relationships between crop characteristics and spectral signatures will be established. The potential of terrestrial high-resolution 3D laser scanning techniques to compensate for saturation effects with spectrometry at higher levels of crop leaf area index will be investigated. The plot level spectral and laser scanning derived knowledge on models and discriminations will be up-scaled to field level using advanced remote sensing techniques applied on air-borne 3D laser scanning and space-borne high resolution multi-spectral remote sensing data for various spatial and temporal conditions along the rural-urban transects in and around Bangalore. To capture the key stages of phenology and the variability of crop production in the transects, multi-temporal spectral and laser measurements will be taken at different stages of summer and winter crops grown at different levels of mineral nitrogen supply and irrigation in the central experiment at UAS in close cooperation with C01 of FOR2432. Further, crop management intensity along the transects will be assessed based on space-borne multi-spectral imagery on the experimental transects using the hyperspectral libraries created for crop management intensity using N application rate and irrigation as classifiers. Eventually, spatial patterns in crop production and their temporal change will be presented with maps developed from model predictions.

Natural vegetation along the field margins plays a key role in maintaining the biodiversity and biological equilibrium in agricultural landscapes with no direct effect on agricultural production. However, it limits the effects of water and wind erosion and acts as a buffer, reduces non-point pollutions and the discharge of biogenes from the fields, and creates refuges for many species of fauna and flora non-specific for the neighbouring agricultural land. There is no published data on the abundance and diversity of vegetation along the field margins in the rural-urban transition region. One of the outputs of this project will thus be maps based on the remotely sensed data combined with targeted in situ measurements and reference data of biodiversity of field margin vegetation along the rural-urban transects selected for joint Indo-German studies.

Much of the analytical work builds on data from other projects dealing with soil-plant systems (I-A01, I-A02 together with their German co-projects), but at the same time we provide spatio-temporally explicit data on crop production which constitutes important information for projects addressing land use, ecosystem services, and socio-economic issues.