Water retention characteristics and available water capacity in three cropping systems of lower Indo-Gangetic Alluvial Plain.

Abstract

This study was conducted in Chinchura-Mogra and Polba-Dapur Blocks of Hugli District, West Bengal to determine the changes in cropping systems on water-retention characteristics (WRC) and available water capacity (AWC) and their relations with other soil properties. In the present study, three sites contained adjacent cropping systems of banana and mango orchard, paddy–paddy, and paddy–potato–vegetables were selected. Soil samples were collected from depths of 0–30 and 30–60 cm in three representative sites of each cropping system with three replications guided by land use and soil map of study area. Analysis of variance was performed to compare the impact of cropping systems on available water content and water-retention characteristics. The mean clay content was greater both on the surface (61.70%) and in the subsurface (55.06%) in the soils under the paddy–paddy cropping system than banana and mango orchard and paddy–potato–vegetable cropping systems. Paddy–potato–vegetables cropping system (0.55%) has lower soil organic carbon compared to the banana and mango orchard (0.63 %) and paddy–paddy cropping system (0.65%) at 0–30 cm deep, whereas no significant difference in soil organic carbon was recorded in 30–60 cm deep. The results of available water capacity indicated that paddy–paddy cropping system recorded lower available water capacity at both ranges of depth. Available water capacity is significantly positively correlated with silt and organic carbon. The results of water-retention studies indicated that 75 and 85% of available water was removed from the soil of paddy–potato–vegetable cropping system by 0.5 M Pa at 0–30 and 30–60 cm deep, respectively, whereas only 56–62% of available water was removed by 0.5 M Pa in the other two systems. The results show that the paddy–potato–vegetable cropping system is more vulnerable to moisture stress during drought periods.