3) showed an ‘ inverted pyramid-shape ’ in vertical section view under different irrigation treatments. The seedlings distributed biomass mainly to shoots early in the fi rst growing season to capture more light and other resources, but distributed more biomass to roots for reserves in the next two growing seasons. Thus, plant may regulate their root/shoot ratio to adapt to drought and water stress. distributed more biomass to roots under drought conditions. During less irrigation, the root/shoot ratio was higher, particularly in October at the end of the growing season. Total biomass decreased with decreasing irrigation but below-ground biomass decreased at a slower rate than above-ground biomass. The total number of root branches, seed yields and total root system length was greater after irrigation and with an increase in shoot dry weight. The plants growing on irrigation (0.1 m /m, 0.2 m /m ) were more vigorous than those control (Table 3). The vertical tap roots were 6 – 25 mm in diameter, and penetrated depths were from 160 cm to 450 cm (Fig. Horizontal roots were typically 6 – 20 mm in diameter, emerging radially from the tap root and creeping at a depth of 30 – 100 cm. The root system consisted of clearly distinguishable horizontal and vertical roots, and extended approximately 1.5 – 2 m in radius and 120 cm in depth at least. grown in the plots had extended its territories producing new shoots through ramets that grow on horizontal coarse root (usually with diameter more than 0.7 mm). Shoot from the root system occurs in the fi rst growing season (0.2 m 3 /m 2 ).
#Soil excavator last oasis pro#
grows new entire shoots each season, and no fi ne roots were detected in the dry soil pro fi le (Fig. under irrigation fall into the specialized prominent lateral type, shoots arise from the laterals, the tap roots penetrate to a depth of 450 cm. under 0.2 m 3 /m 2, a total of fi ve new shoots were connected to a single root system (Fig. under 0.1 m 3 /m 2 had 16 m long lateral roots and a tap root of only 2 m, and developed a highly branched coarse root system with no distinct tap root. Adventitious fi ne roots were detected between 1 m and 2.2 m. under CK developed tap roots that descended to deeper soil layers, and showed (1) no lateral roots within the top 1 m soil, (2) no living fi ne root or nodule at the top 0.6 m soil, (3) small lateral fi ne root branches at deeper soil layers. Exca- vation revealed strong differences among the different irrigation. 1) is composed of a taproot, lateral roots, horizontal roots, and adventitious roots. Tukey's test was used to test the differences among treatments when ANOVA showed signi fi cant effects ( p b 0.5). One way ANOVA was used to compare biomass, root:shoot ratio, root depth, and ramet quantity differences in three years. Biomass, and soil chemical properties were tested for normal distribution by calculating the Shapiro – Wilk W statistics (SAS version 8.1, The SAS Institute, Cary, NC, USA) for each sets (n = 6 for biomass variables, n = 13 for soil chemical properties variables). Though the excavations failed to recover some unknown pro- portion of the fi ne roots that are likely to contribute to root length, we were successful in recovering the majority of the larger roots that contribute most to root biomass. Even with careful hydraulic excavation an unknown fraction of fi ne roots was inevitably lost, particularly when target roots were tender. The roots were quite fragile and dif fi cult to remove intact.
Measurements were made on the day of excavation. The roots were carefully separated from the surrounding soil and collected for further measurements. Visual assessment was used to separate live and dead roots, dead roots were eliminated in the calculation of the biomass. Parameters of root dry biomass, root:shoot ratio, and root depth were determined in an age sequence. The roots were dried in an oven (75 ☌, 48 h). The position of branching, termination or bud formation was recorded on a map. thicker than 0.5 mm in diameter at their origin or branching points) were traced by careful digging as long as they were visible. Large roots were removed from the excavated soil. The roots were collected every 20 cm of vertical distribution. A pedrail hydraulic excavator was used to dig up pro- fi les around each plot before three-year roots of A. were excavated arti fi cially with spades, homemade iron rakes and pickaxes. Six different individuals were sampled at each time. treatments were monitored after root material was excavated in the late fall after growth had been completed in a strati fi ed random fashion with tools in the subsequent three growing seasons.
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