Soil organic matter in various land uses and management, and its accuracy measurement using near infrared technology

Abstract

The aim of this study is to investigate the soil organic matter (SOM) status in various land uses and management in Kayangan Sub-District, North Lombok, and its accuracy measurement using near infrared spectroscopy (NIRS). A total of 100 soil samples (0-10 cm depth) were collected from several land uses and management (rain-fed areas, irrigated areas, areas planted 1-3 times with seasonal crops, areas planted with 1-3 perennial plants) in the study area, which were dried, ground and sieved, then analyzed using Walkley and Black method and scanned using near infrared spectroscopy (NIRS). Partial least square regression (PLSR) was used to create SOM prediction models. The results showed that the SOM content varied from very low to moderate with most of them were low. The content of SOM was significantly higher in the irrigated areas compared to that of in the rain-fed areas, and also higher in the areas planted with seasonal crops 3 times a year compared to the areas planted 1-2 times a year. SOM content was higher in areas planted with 2-3 types of perennial plants, compared to with 1 type of perennial plant. NIRS technology was moderately accurate in measuring SOM, which can be used to monitor spatially changes in SOM.