In FI (control), the irrigation water was applied to both sides of the root system such that 35 40% of the available soil moisture was consumed in the 0.90-m root zone.
Three irrigation treatments were based on replenishing the 0.60 m deep root zone to field capacity when the maximum allowable depletion (MAD) of the available soil water holding capacity of 25% (I1), 50% (I2) and 75% (I3) were maintained in the crop experiments.
Creeping bentgrass plants grown under elevated CO2 had significantly greater root length in the upper 0 10 cm and middle 10 20 cm root zones, but there were no differences in root length in the 20 30 or 30 40 cm root zones.
The RML for the surface layer (0 0.20 m) was different from the root zone (0 0.60 m) and the total active soil profile (0 1.20 m), the latter two having adjacent RMLs.
Electrical images from 0 to 2 m depth, incorporating the shallow root zone, were inferred to represent spatiotemporal variability of moisture between tree and non-tree areas resulting from hydraulic redistribution (HR).
When a higher rate of fertiliser (150 kg N ha-1) was applied in a single application, up to 30% was lost by leaching below the main root zone (0.3 m) within the first two months, though little further loss occurred after that (up to 17 months).
In any case, their concentration in the upper root zone (0.3 m) must be reduced to near the tolerance of the crop before any cropping is attempted.
The SCE-UA algorithm of Duan et al. (1994) was adopted to calibrate five essential parameters of BTOPMC; they are saturated soil transmissivity T 0, decay factor m, maximum storage capacity of the root zone Srmax, saturated local saturation deficit Sbar0(k) of sub-basin k and Manning roughness coefficient n, the former four of which are for runoff generation and the other for flow routing.
Mulching had not significant influence on salt accumulation but the drip tape arrangement, under the same condition of irrigation water depth and quality, compared with Md, Ms reduced salt accumulation in root zone and brought about relatively high cotton yield.
Regression analysis was performed to analyze the relationship among soil water recharge, residual soil water (i.e., soil water content at the end of the previous growing season), total precipitation, and available water-holding capacity (AWHC) in the root zone to 1.5 m.
