CHAPTER-6
lowest in forest lands. Bulk density increased with soil depth in all the land use systems. The water holding capacity was highest in forest land followed by grassland, horticulture , agriculture, barren and lowest in eroded soils. Maximum water holding capacity decreased with depths in all land use systems.
The results showed that the lowest mean value of CEC was observed in eroded soil and highest in forest soil . CEC was decreased with depths in all land use system.
The lowest mean value of CaCo3 was observed in eroded and highest mean value of CaCO3 was found in forest soils. The CaCo3 was increased with depths in all land use system. The lowest mean value of exchangeable Ca was observed in eroded soil and highest in forest soils. The Ca was decreased with depths in all land use systems. The lowest mean value of exchangeable Mg was observed in eroded and highest mean value of Mg was found in forest soils. The Mg was decreased with depths in all land use systems. The lowest mean value of exchangeable Na was observed in eroded soils and highest in forest soils.
Available macro nutrients
The mean value of available nitrogen in the surface soil was found to be highest in forest soils, lowest in eroded lands. The surface soil of eroded land was found low (< 272 kg/ha) in available nitrogen content. Whereas grass, forest, horticulture and barren were observed medium to low. The mean value of available phosphorus of the surface soil was low (< 10 kg/ha) in eroded lands whereas in forest, grass horticulture, agriculture and barren soils were high to medium (10-25 kg/ha).
The mean value of available potassium of surface soil was highest in forest soils and lowest in eroded soils and followed by trend forest, grassland, agriculture, horticulture and eroded soils pertaining medium to low range. The value of available N, P and K were decreased with the increase in soil depth for all land use systems. The mean value of available sulphur of surface soil was found to be highest in forest and lowest in eroded lands. The available S in other land uses was observed in low to medium range and decreased with depth under all land use systems.
Available Micro Nutrients
The mean value of available Fe in the surface soil was found highest in forest soils and lowest in eroded soils. The available Fe in surface soil under study was highest in the majority of land uses including grass, horticulture and agriculture. The
mean value of available Cu in the surface soil was found to be highest in forest soil and lowest in eroded soils. The available Cu in surface soil among all land uses was higher to medium in range. The mean value of available Zn in the surface soil was found to the highest in forest soil and lowest in eroded soils. The available Zn in surface soil was in medium range. The mean value of available Mn in the surface soil was found in sufficient range in forest soil and lowest in eroded soils. The available Mn in surface soil was found moderate in almost all land use system.
Soil organic carbon pools
The soil organic carbon in surface soil (0-20 cm) was highest in forest land and followed by grassland, horticulture, agriculture, barren, and eroded lands. The forest and grasslands registered highest organic carbon respectively. The high value of soil organic carbon in surface soil under all land use systems viz., forest, grassland, horticulture, agriculture was observed whereas in barren land the percentage was medium and lowest in eroded land. The hot water soluble carbon content in the surface soil (0-20 cm) was highest in forest followed by grassland, horticulture, agriculture, barren and lowest in eroded lands. The decrease of WSC with soil depth was pronounced. The LC in the surface soil (0-20 cm) was highest in forest soils followed by grassland, horticulture, agriculture, barren land and lowest in eroded land. The decrease of LC pool with soil depth was distinct. The MBC in the surface soil (0-20 cm) was highest in forest followed by grassland, horticulture, agriculture, barren and lowest in eroded lands. The decrease of MBC with soil depth was conspicuous. The TC content in the surface soil (0-20 cm) was highest in forest soils and lowest in eroded soils followed by forest, grass, horticulture, agriculture, barren and eroded lands. There was a notable decrease in TC with depth in all land use systems.
Relationship between soil properties and available nutrients
The available macro nutrients in soil (N, P, K and S) were positively correlated with pH, EC, CaCO3, silt, clay and exchangeable Mg at surface and sub surface soil depth. The N, P, K and S were negatively correlated with sand and CEC. The available micro nutrients in soil (Fe, Mn, Zn and Cu) were positively correlated with pH, EC, silt, clay, CEC, exchangeable Ca and Na. The Zn was negatively correlated with exchangeable Mg in soils under different land use systems.
Relationship between soil properties and Carbon Pools
The SOC were positively correlated with pH, EC, CEC, CaCO3, clay, exchangeable Mg and Na at surface and sub surface soil depth under different land use systems. The WSOC was positively correlated with pH, CEC, CaCO3, silt and exchangeable Na. The LC was positively correlated with pH, EC, CaCO3 and CEC.
The MBC was also positively correlated with pH, EC, CEC and CaCO3. Similarly, TC was positively correlated with pH, CEC and CaCO3, however, negatively correlated with sand and clay content in soil under different land use system.
Conclusion
The result of the study concluded with respect to all the parameters taken into consideration under the topic “Spatial availability of soil nutrients and carbon pools under different land uses in hilly zone of Doda district of Jammu and Kashmir” as here under.
Land use systems and soil depth influenced the soil physico-chemical properties and available nutrients.
The spatial variability of available nutrients in soils suggested that some land use system such as barren, eroded and agriculture required judicious application of organic manurers as well as inorganic fertilizer to sustain soil health and improving productivity of concerned land use systems.
With regards to different land use systems, it is observed that eroded and barren land use system were found deficient in major and micro nutrients which required judicious and balanced application of nutrients through organic and inorganic fertilizers to attain the higher crop productivity.
Land use systems significantly influenced the soil organic carbon pools.
Different land use systems showed highest accumulation of the various carbon pools in the surface layer.
Labile carbon was more prevalent under forest land use system followed by grass land use system, horticulture land use system, agriculture land use system, barren land use system and eroded land use system.
Carbon pools were positively and significantly correlated with silt, CEC and WHC.
Sand, bulk density and CaCO3 showed a negative and significant correlation with soil carbon pools.
There was a strong correlation of carbon pools with physico-chemical properties under different land uses system in the surface soils.