Growth and development of pistachio seedling root at different levels of soil moisture and compaction in greenhouse conditions

Abstract

Soil moisture and compaction are important factors for growth and development of plant root. This study was conducted as a nested design with two factors and three replications to investigate the behaviour of pistachio seedling roots at different levels of soil compaction and moisture in a sandy loam soil under greenhouse conditions. The first factor was soil compaction at four levels of bulk density (1.35, 1.5, 1.65, and 1.8 g/cm<sup>3</sup>). The second factor was soil moisture with six levels ranging 0.07–0.49 cm<sup>3</sup>/cm<sup>3</sup>. Moisture monitoring at each treatment was carried out by a time domain reflectometer device every two days. At the end of experiment, root and shoot dry weight, shoot to root weight ratio, root length, and rooting depth were measured. Results showed that soil compaction and moisture content effects on all measured characteristics were significant (P < 0.01). At the bulk density of 1.35 and 1.5 g/cm<sup>3</sup> and moisture ranges of 0.14–0.49 cm<sup>3</sup>/cm<sup>3</sup> (levels 1–4) the values obtained for all the measured characteristics were the highest. At the bulk density of 1.65 g/cm<sup>3</sup> the optimum moisture range was 0.22–0.33 cm<sup>3</sup>/cm<sup>3</sup>; at the bulk density of 1.8 g/cm<sup>3</sup> the moisture range optimum for root growth and development was 0.23–0.27 cm<sup>3</sup>/cm<sup>3</sup>. A drop in soil moisture from 0.49 to 0.07 cm<sup>3</sup>/cm<sup>3</sup> and concomitant increase in soil bulk density from 1.35 to 1.80 g/cm<sup>3</sup> led to a severe decline in root dry weight, shoot dry weight, shoot to root dry weight ratio, root length, and rooting depth by as much as 65, 92, 69, 73 and 66%, respectively.