Sharma, VivekAsima2018-02-092018-02-092017http://krishikosh.egranth.ac.in/handle/1/5810040737Land degradation due to improper land use management leads to deterioration of soil health. Increasing population, urbanization and demand for food enforced the system to convert the forest to agricultural land results in decline of soil fertility and productivity. Maintenance of soil heath is a key component of agriculture sustainability and soil biochemical properties are considered as sensitive indicators of soil health. Hence it is essential to study the effect of different land use systems on key indicators of soil health viz. soil biochemical properties and soil organic carbon for sustainable agricultural system. A study was conducted to determine the effect of different land use systems (forestry, agroforestry, agri-horticulture, horticulture, agriculture and eroded land) and seasonal variations (summer, rainy and winter season) on soil biochemical properties under rainfed conditions in sub montane Punjab. A total of 180 soil samples were collected from two locations i.e. Balachaur (SBS Nagar) and Talwara (Hoshiarpur). Soil samples were collected in summer, rainy and winter season from same place using global positioning system to study the seasonal changes. The results revealed that soils were slightly alkaline (7.3-7.9) at Balachaur and slightly acidic at Talwara (6.4-6.9) with electrical conductivity varied from 0.31-0.61 dSm-1 at Balachaur and 0.09-0.23 dSm-1 at Talwara, respectively. Soils were loamy sand to sandy loam in texture at both the locations. The organic carbon content, available nitrogen, phosphorus and potassium content in soil ranged from 0.20 to 0.63 per cent, 110 to 381, 29.8 to 32.6 and 99 to 196 kg ha-1 at Balachaur and 0.14 to 083 per cent, 86 to 406, 29.3 to 32.6 and 65 to 226 kg ha-1 at Talwara, respectively. Among DTPA extractable micronutrient cations, DTPA-Mn, DTPA-Fe, DTPA-Cu and DTPA-Zn content in soil varied from 9.5 to 15.1, 9.0 to 25.2, 0.31 to 1.02 and 0.71 to 0.96 mg kg-1 at Balachaur and 10.3 to 21.2, 12.1 to 34.5, 0.34 to 1.01 and 0.76 to 1.15 mg kg-1 at Talwara region, respectively. Among soil biochemical properties, dehydrogenase, acid and alkaline phosphatase, basal soil respiration and urease activity were higher under agri-horticulture and forestry based land use systems. In sub systems, the soil dehydrogenase activity varied from 5.4 to 10.9 µg TPFg-1h-1 and 7.4 to 12.8 µg TPFg-1h-1 at Balachaur and Talwara, respectively. The acid and alkaline phosphatase activities varied from 17.0 to 36.5 µg pNPg-1h-1, 36.3 to 61.3 µg pNPg-1h-1and 22.3 to 34.5 µg pNPg-1h-1, 43.4 to 60.1 µg pNPg-1h-1 at Balachaur and Talwara, respectively. The urease activity was observed to be highest for guava based agri-horticulture system at Balachaur and mango based agri-horticulture system at Talwara. The microbial biomass carbon was observed to be higher in mango based agri-horticulture system at Balachaur and eucalyptus based agroforestry sub system in Talwara. The total and easily extractable glomalin content was observed to be higher in guava and mango based agri-horticulture land use systems in Balachaur and Talwara, respectively. The soil carbon fractions (labile fractions, organic matter fractions, total organic carbon and carbon management index) were observed to be higher in agri-horticulture system and forestry system as compared to other land use systems. Among seasons, rainy season had higher soil properties as compared to the winter and summer seasons. The principal component analysis revealed that the soil properties were highly correlated with agri-horticulture system and rainy seasons. The dehydrogenase activity, urease, basal soil respiration and total organic carbon were observed to be best soil quality indicators among the land use systems and seasons in sub montane region of Punjab.enThesis