Laik, RanjanNath, Debabrata2023-10-302023-10-302022D/SS/365/2019-20https://krishikosh.egranth.ac.in/handle/1/5810199881There are many factors that contribute to soil health, including physical, chemical, and biological factors. Some of them are dynamic in nature and behave differently based on the agro-ecological zone in which they occur and therefore are quantified using a soil health index (SHI), which measures the soil health in various agroecological zones (ACZs). A study entitled “SOIL HEALTH STUDY OF DIFFERENT SOIL TYPES UNDER PROMINENT CROPPING SYSTEMS OF BIHAR” was conducted at the Department of Soil Science, Dr. Rajendra Prasad Central Agricultural University Pusa (Bihar) with the objective to evaluate the variability in soil health parameters, minimum data sets (MDSs) to construct a soil health index (SHI) and correlation and regression to find out the direct determinants yield which will be useful in evaluating the sustainability of crops in different agroecological zones of Bihar, under rice-wheat and rice-maize cropping systems including four different ACZs, namely Sitamarhi (ACZ-I), Saharsa (ACZ-II), Banka (ACZ-IIIA) and Rohtas (ACZ-IIIB). Based on the properties of the surface soil layer (0-15 cm) that were measured by Comprehensive Assessment of Soil Health (CASH), 20 parameters were utilized to develop the soil heath index (SHI). Under R-W and RM cropping system a wide range of variations were observed in soil properties in surface soil samples that was found by descriptive analysis. Pearson’s correlation studies revealed that strong significant correlation among SOC, available N, available P2O5, WAS, AWC, sand content, soil respiration and system yield (R-W and R-M). Stepwise regression analyses showed that under the R-M cropping systems, the key soil properties like SOC and available N were the main determinants for R-M system yield in all the four ACZs, available K2O in ACZ-I and II, WAS in ACZ-I and IIIA and AWC in ACZ-IIIB. However, stepwise regression analyses showed that under the R-W cropping system also SOC and available N were the main soil determinants for R-W system yield in all the four ACZs, along with available P2O5 in ACZ-I and II, Clay in ACZ-I, IIIA and IIIB and soil respiration in ACZ-IIIB. A scoring function (non-linear) was used to convert each indicator of the MDS into a dimensionless score which in turn was integrated into four separate SHIs based on scoring functions (nonlinear). Soil health index (SHI) of R-M system showed that the overall SHI varied from 0.41-0.49. The highest SHI was found in Rohtas (0.49) followed by Saharsa (0.48). Among all the soil health parameters SOC, available N, available P2O5, available K2O, available S, soil respiration and AWC were the main contributor for the SHI. Maximum contribution was found for SOC is 13.50% in Sitamarhi (ACZ-I) followed by 12.50% in Saharsa (ACZ-II). Soil health index (SHI) of R-W system revealed that the overall SHI varied from 0.43-0.51. The highest SHI was found in Rohtas (0.51) followed by Sitamarhi (0.50). Maximum contribution was found for SOC is 15 % in Rohtas (ACZ-IIIB) followed by 14 % in Sitamarhi (ACZ-I). Quantitative predictive relationship between R-W and R-M system yield and SHI showed a positive correlation. The results demonstrated that R2 values are 0.79, 0.54, 0.65 and 0.76 in R-W system and 0.70, 0.62, 0.65 and 0.64 in R-M system for Rohtas, Banka, Saharsa and Sitamarhi respectively. On the basis of this index, it was determined that prominent cropping systems were able to be used to quantify soil health under four different ACZs. Based on this result, it was determined what would be the most suitable cropping system. Thus, it can be concluded that SHI can be used as a tool for quantifying soil health to a satisfactory level. Based on the variability observed across 20 soil health indicators across two prominent cropping systems under four different agro-climatic zones (ACZs) of Bihar, this study provides a framework for the quantitative assessment of soil health throughout four ACZs. It also helps to identify which cropping system for a given ACZ is the most suitable among existing cropping systems carried out in a particular ACZ.EnglishThesis