Impact of cover crop and mulching on soil physical properties and soil nutrients in a citrus orchard.

Background: Cover crops and mulching can ameliorate soil porosity and nutrient availability, but their effects on the physical characteristics and nutrients in the raised bed soils are unclear. Methods: The field experiment was conducted in a pomelo orchard from 2019 to 2021, with an area of 1,500 m2. The treatments included control (no cover crop), non-legume cover crop (Commelina communis L.), legume cover crop (Arachis pintoi Krabov & W.C. Gregory), and rice straw mulching (Oryza sativa L.). At the end of each year (2019, 2020, and 2021), soil samples were collected at four different layers (0-10, 10-20, 20-30, and 30-40 cm) in each treatment. Soil bulk density, soil porosity, and the concentration of nutrients in the soil were investigated. Results: The results revealed that soil bulk density at two depths, 0-10 and 10-20 cm, was reduced by 0.07 and 0.08 g cm-3 by rice straw mulch and a leguminous cover crop, thus, increasing soil porosity by ~2.74% and ~3.01%, respectively. Soil nutrients (Ca, K, Fe, and Zn) at topsoil (0-10 cm) and subsoil (10-20 cm) layers were not significantly different in the first year, but those nutrients (Ca, K, Fe, and Zn) improved greatly in the second and third years. Conclusions: Legume cover crops and straw mulch enhanced soil porosity and plant nutrient availability (Ca, K, Fe, and Zn). These conservation practices best benefit fruit orchards cultivated in the raised bed soils.

A new species of the Cyrtodactylus irregularis complex (Squamata: Gekkonidae) from Gia Lai Province, Central Highlands of Vietnam.

We describe a new species of the genus Cyrtodactylus from Gia Lai Province, Central Highlands of Vietnam based on morphological and molecular differences. Cyrtodactylus gialaiensis sp. nov. is differentiated from other congeners by a unique combination of the following characters: Size small, maximum known SVL reaching 62.8 mm; dorsal pattern consisting of six or seven dark transverse bands between limb insertions; intersupranasals two or three; dorsal tubercles at midbody in 16-21 irregular rows, strongly developed on flanks; lateral folds poorly defined with interspersed tubercles; ventral scales between ventrolateral folds 38-45; precloacal pores nine or 10 in males, eight pitted scales in the adult female, in a continuous row; femoral pores absent; enlarged femoral scales present; postcloacal tubercles two or three; dorsal tubercles present to half of tail; subcaudal scales not enlarged. In molecular analyses, the new species is weakly supported as a member of the Cyrtodactylus irregularis species group with a minimum pairwise genetic distance of 13.7% from others within the group.