Effects of Irrigation Amount on Soil Water Content of Gentiana macrophylla.

[Objectives] This study was conducted to investigate the effects of different irrigation quotas and irrigation times on soil physical and chemical properties and water content in the planting areas of Gentiana macrophylla in dry farming areas of southern Ningxia. [Methods] G. macrophylla planted for three years was selected as the experimental material, and the water content, nutrients, bulk density and total porosity of the soil at different depths (0 -20 and 20 -40 cm) were measured under different irrigation quotas and irrigation times. [Results] Compared with the CK, different irrigation quotas and irrigation times could significantly improve the water contents of the 0-20 and 20 -40 cm layers in the planting areas of G. macrophylla. The change trend of water content at the 0-20 cm soil depth was 3 times of irrigation >2 times of irrigation > 1 time of irrigation > CK, and that at the 20 -40 cm soil depth was 2 times of irrigation >3 times of irrigation > 1 time of irrigation > CK. With the increase of irrigation times, soil urease in the 0 - 20 cm soil showed a trend of decreasing at first and then increasing, reaching a maximum value of 0.415 mg/g • 24 h with 1 time of irrigation, which increased by 84. 44% compared with the CK, and the value with two times of irrigation was basically the same as that of the CK, but 3 times of irrigation resulted in a value 57.33% higher than the CK. However, the changes of 20 -40 cm were the opposite. The change trends of alkali-hydrolyzable nitrogen in the 0-20 and 20 -40 cm soil layers with irrigation times was smaller, and the contents of soil organic carbon, available phosphorus and available potassium increased first and then decreased with the increase of irrigation times, and were generally higher than those in the CK. [Conclusions]This study provides a theoretical and technical basis for the artificial cultivation of G. macrophylla in dry farming areas of Ningxia. [ABSTRACT FROM AUTHOR]