A01: Plant growth, water quality, carbon and nutrient fluxes in rural-urban cropping systems at different spatial scales.

Project A01 examines plant growth, water quality, and matter flows in the urban, peri-urban and rural areas of Bengaluru using as an experimental base the two central on-station experiments at UASB (GKVK Campus) as well as 12 farmer field sites along the common rural-urban transect. The comprehensive data collection in the field experiments aims at modelling carbon and nutrient cycles under different management intensity with regard to yield potentials, water and nutrient use efficiency, long-term effects on soil fertility, and provision of other ecosystem services. In addition, surveys are carried out in cooperation with A02 and C01/C02 to determine the extension over time and water quality of waterbodies / lakes on the N-/S-transect (analysis of Pb, Cd, As and pesticide residues BHC and chlorophyripos, DDT and of antibiotic residues). Their results will serve to analyze and select monitoring sites with critical pollution loads in roughage traditionally cut for feeding of dairy cows (A03). As such the project follows the "One Health" concept, focusing on the beginning of the trophic food chain.

In Phase III, the matter turnover and fluxes are to be scaled to the level of Bengaluru Metropolitan Region using the land use maps prepared by projects C01 and C02.

Prof. Dr. A. Bürkert
OPATS
University of Kassel

Suman Kumar Sourav
PhD-Student

Andrea Mock
Technician

Indian partner project:
Soil and water quality in agricultural systems along the rural-urban interface
V.R.R. Parama, University of Agricultural Sciences, Bangalore

Intensification effects on matter flows in rural-urban cropping systems

Scarcity of land, water, and labour are the main constraints to agricultural production along the rural-urban interface of Bangalore. This has led to the widespread replacement of diverse dryland farming systems by intensive irrigated vegetable production on open lands at the city fringe and in scattered city areas. The consequences of such changes in traditional Indian farming systems on the nutrient dynamics and soil fertility are largely unknown.

This project therefore addresses transformation-related changes in the intensity of agricultural production systems at the micro(plot)- and meso-scale (field and household) by analysing horizontal and vertical flows of nutrients and carbon in field and laboratory experiments, turnover of soil organic carbon and soil nitrogen in different pools, and their effects on nutrient and water use efficiency under rainfed and irrigated conditions on-station and on 72 selected farmer fields. It combines expertise in agronomy, plant nutrition and non-destructive measurements of soil physical properties and plant growth (Bürkert) with modelling of water dynamics, crop growth, and carbon (C) and nutrient fluxes (Ludwig).

The project will contribute to the overall goals of FOR2432 by providing spatially explicit data on the effects of intensification-related land use changes on nutrient and water use efficiencies for major food crops in the study region. It also aims at assessing the impact of these changes on key chemical soil parameters (pools of C and nitrogen N, phosphorus P, potassium K, and sulphur S) that govern crop output and ecosystem services. It thereby provides data for the calibration and validation of models to predict medium- and long-term changes of key soil parameters determining crop productivity and ESS. To this end we will investigate the plant uptake and turnover of C and N, P, K, and S including gaseous (N₂O, NH₃, CO₂) and leaching losses (NO₃-, dissolved organic carbon, organic P, and SO₄^2-), by photo-acoustic spectroscopy, gas chromatography, and resin cartridges /micro-lysimeters, respectively, and relate them to the soil hydrological data of A02 and the multi-spectral cropping / land use signatures of C01 and C02. The use of ¹⁵N in the central experiment will allow to determine the fate of added fertilizer N (and manure in Phase II of FOR2432, in collaboration with A03). The data will also be used to parameterize the DNDC model. High resolution aerial photography and multispectral canopy scanning from hexacopters will be used to non-destructively monitor, in cooperation with C01, plant growth in the on-station experiments and the spatial variability of final biomass on-farm and to collect high resolution, low altitude multispectral crop signature data.

Thereby this project will contribute to the estimation of the current productive value of agricultural lands which partly explain a decisions of farmers to intensify crop production or give up land for urban development (an objective of B02).

Dr. Renuka P. Suddapuli Hewage

Dr. Rajasekaran Murugan

Beate Madan