RESUMO
To understand the effects of activated water irrigation on soybean growth under different drought conditions and explore the underlying mechanisms, an indoor pot experiment was conducted under four moisture conditions of 95%-100%, 75%-85%, 55%-65% and 35%-45% of the maximum water holding capacity (80% moisture) of the medium. Soybean was irrigated with tap water, magnetized water, aerated water, and magnetized and then aerated water, respectively. The results showed that total biomass, leaf area, root to shoot ratio, and root length of magnetized water irrigation increased by 67.6%, 23.5%, 84.6% and 122.8%, respectively compared with tap water irrigation after 30 days of growth under 35%-45% severe drought condition. All the variables were increased by 70.8%, 24.0%, 61.9% and 162.3% respectively in magnetized and aerated water treatment. There was no significant difference for foliar chlorophyll content. The values of the other water treatments were slightly lower than that of tap water. In conclusion, magnetized water irrigation effectively enhanced root growth, root-shoot ratio, and water use efficiency of soybean, and alleviated the negative effects of drought stress under severe drought condition.
Assuntos
Secas , Glycine max , Folhas de Planta , Raízes de Plantas , ÁguaRESUMO
Understanding the effects of land use patterns on soil water and gas transport in the water-wind erosion crisscross region can provide guidance for high-efficiency use of limited soil and water resource in the ecological rehabilitation process on the Loess Plateau. To investigate the cha-racteristics of soil water and gas transport under different land use patterns and to study the relationships between soil saturated hydraulic conductivity (Ks), air permeability (Ka) and relative gas diffusivity (DP/D0), we collected soil samples (0-5 cm depth) from Caragana korshinskii land, abandoned land, alfalfa land, cropland, and bare land. Ks was measured by constant-head method. DP/D0 was measured by gas chamber method. Ka under field capacity (FC) was measured using the soil gas permeability meter. Results showed that soil bulk density (ρb) ranked as alfalfa land>bare land>abandoned land>C. korshinskii land >cropland, with that of abandoned land, bare land and alfalfa land being significantly different from that of cropland. Total soil porosity (Φ) ranked as cropland>C. korshinskii land>abandoned land>bare land>alfalfa land. Compared with cropland, Φ of alfalfa land, bare land and abandoned land was lower by 7.5%, 4.7% and 3.1%, respectively. Air filled porosity (ε100) ranked as cropland>abandoned land>C. korshinskii land>bare land>alfalfa land. ε100 of alfalfa land, bare land, C. korshinskii land and abandoned land was lower by 38.3%, 33.6%, 12.8% and 10.1%, respectively, as compared with cropland. Soil Ks ranked as abandoned land>C. korshinskii land>alfalfa land>bare land>cropland, with that of the abandoned land being significantly higher than the other four land use patterns. Soil Ka ranked as abandoned land>alfalfa land>C. korshinskii land>bare land>cropland, with that of abandoned land being significantly diffe-rent with cropland. Soil DP/D0 ranked as abandoned land> C. korshinskii land> alfalfa land>cropland>bare land, in which DP/D0 of C. korshinskii land and abandoned land was significantly higher than cropland by 36.8% and 61.6%, respectively. There were significant correlations between Ks and Ka, DP/D0 under FC conditions. Land use patterns significantly changed soil permeability. Farmland, abandonment, C. korshinskii, and alfalfa plantation improved hydraulic and gas transport parameters of the surface soil. In contrast, farmland and bare land had poor capability of soil water and gas transport.
