- Developed the Soil Carbon and Nitrogen Turnover Model: A new soil carbon (C) and nitrogen (N) turnover model has been developed by using the soil and crop dataset of long term fertilizer experiments of India. Soil carbon and nitrogen prediction model is controlled primarily by net primary production (yield), mean annual rainfall and temperature, texture (sand, silt, clay content), bulk density and soil initial carbon content. The model includes two soil organic matter pools (active + slow, and passive) with different potential decomposition rates. The model simulates soil carbon dynamics for different annual crops and plant communities. The model works on the principle of soil carbon saturation theory, which suggests soil carbon sequestration rate decreases as the soil carbon content increases and vice-versa. The model computes total organic carbon, Walkley & Black C content, carbon in resistant (passive) and mineralizable (active + slow) pools, carbon stocks, total N, and available N. Soil carbon and nitrogen prediction model uses a yearly time step and the users have to define only initial soil carbon content. The model itself determines the relative allocation of carbon in different pools. This model has the partitioning of soil, climate and vegetation pools. Model assumes soil carbon sequestration rate is the function of soil carbon content, net primary productivity, soil texture, rainfall, temperature and C: N ratio of residue. The model automatically computes the carbon and nitrogen turnover based upon these parameters and model output displayed in excel sheet.
- Database i.e. ‘Information System on Long Term Fertilizer Experiments (ISLTFE): Indian Agricultural Statistics Research Institute (ICAR-IASRI), New Delhi is a repository of the database for each centre of AICRP Long-Term Fertilizer Experiments (AICRP LTFE). It has developed ‘Information System on Long Term Fertilizer Experiments (ISLTFE) for many centres. Data has been uploaded on ISLTFE for various centers with the support of KRISHI project. The latest status of data could be retrieved online from ISLTFE site.
- Identification of Sustainability Indices: This institute (ICAR-IASRI) has facilitated to estimate and work out key indicators of sustainability i.e. Soil Quality Index and Sustainable Yield Index for the data received from each centre of AICRP LTFE. For SQI determination, about 35-40 soil parameters were considered, 20 – 25 soil parameters were taken as Minimum Data Set (MDS) that were based on the highly weighted loading factors (within 10% of the maximum).
- Impact Assessment of Weather Parameters on Yield: For some of the LTFE Centres, the institute has examined the effect of weather parameters on yield for the ten long-term nutrient management treatments. For instance, the data for Pantnagar cooperating centre of 18 years (1991-2008) was analyzed by expressing the effects of changes in weather variables on yield in wth week as a linear function of respective correlation coefficients between yield and weather variables. The weather variables are minimum temperature, maximum temperature, sunshine and relative humidity during the period of crop. Trend effect on yield was removed from yield while calculating correlation coefficients of yield with weather variables to be used as weights. It was observed that effect of sunshine was significant for six treatments while maximum temperature affected four treatments and minimum temperature affected three treatments. Relative humidity has no effect on any of the ten treatments.
( AICRP - LTFE )
