Long-term impact of silviculture systems on phosphorus transformation and adsorption behaviour in semi-arid restored lands

Abstract

Phosphorus (P) is a key nutrient in silvicultural ecosystems, where its cycling influences both primary productivity and ecosystem development. Different trees affect P availability in distinct ways. Analyzing impact of various trees on soil P fractions and the its adsorption-desorption behavior helps better understand soil P availability in these ecosystems. Therefore, this study aims to investigate the impact of silviculture systems (SCSs) on depth distribution of P fractions, the P adsorption-desorption pattern, and P availability in eco-restored land. Three distinct silviculture systems, namely Leucaena leucocephala (LL), Hardwickia binata (HB), and Azadirachta indica (AI) SCSs were compared with degraded fallow (F) to assess their influence on soil properties and P dynamics in a Typic Haplustepts of semi-arid ecosystem. Soil samples were collected from three different depths 0–15 cm, 15–30 cm, and 30–45 cm of these SCSs. The LL, HB and AI showed 2.50, 2.01 and 1.39 times increase in available P over fallow, respectively. Microbial biomass phosphorus (MBP) content increased in LL by 99, 97, and 53 % at 0–15, 15–30, and 30–45 cm, respectively, over fallow. For acid phosphatase activity, LL, HB, and AI exhibited 3.15, 2.43, and 1.56 folds increase over fallow. The distribution of different phosphorus fractions followed the order: Fe-P (39.9–36.7 %)> Organic P (25.7–24.4 %) > Al-P (24.8–19.1 %)> Ca-P (8.64–4.05 %)> Res-P (8.61–7.37 %)> Saloid P (0.63–0.50 %). Additionally, P adsorption-desorption revealed that SCSs could lower the adsorption capacity and P desorption than fallow. Thus, different silviculture systems exhibit the potential to enhance the P-supplying capacity of soil and restore degraded soils in semi-arid regions.