CARBON Stocks and SPECTROSCOPIC Assesment of CARBON Stability IN Kenyan SOILS.

In the present study was developed a comparative analysis of the capacity agricultural of important cropping systems and native areas located in Sub-Saharan Africa to soil carbon assessment. With the aim to determine soil carbon stocks (CS) according to soil classes, altitude, temperature gradient, climatic parameters, crop classes and native vegetation, as related to global change, soils from main cropping systems as tea, coffee and maize, located in Embu, Nairobi, Kenya, were sampled. These soils were sampled, in triplicates, in five layers from 0 to 30 cm depths and processed for total carbon analysis in duplicate. CS (Mg ha^-1) were calculated in equivalent soil mass taking the native vegetation as reference. Using a linear additive model for a nested sampling scheme, CS were compared, among cropping systems using MANOVA and orthogonal contrasts. The whole soil samples were analyzed using the Laser-Induced Fluorescence spectroscopy (LIFS) to assess the carbon stability of these areas. We used a new device, developed by EMBRAPA-Agricultural Instrumentation, employing laser-induced optical techniques to measure the carbon levels and their stability in whole soil samples. The device is so light and convenient that it can be used directly in the field. Also, the portable LIFS system is of outmost importance in agro ecosystems contributing with studies of capture of carbon under variable climatic conditions. The results showed wide variations in the levels and stability of carbon stored in the soil depending on factors such as land use, crops grown, water content, elevation, and agricultural practices.