Root Mass Distribution Research Articles

Fine root growth dynamics in teak (Tectonagrandis Linn. F.)

Temporal variations in the spatial distribution of fine root mass were studied in a 19-year-old teak plantation in a dry tropical region. The soil block method was used to investigate fine root dynamics. Quantification of fine root mass was achieved in terms of live teak roots (separated by diameter), dead teak roots, teak root bark, herb roots, and fragmented soil organic matter. The annual mean fine root biomass was 5420 kg•ha−1 and the net production was 5460 kg•ha−1•year−1. The bulk of the root mass was distributed at a depth of 10–30 cm and roots ≤2 mm constituted one-half or more of the total root biomass. Maximum live root growth occurred during the rainy season. All root sizes showed similar bimodal seasonal patterns, but the maximum:minimum ratio generally declined with greater root size.

A Growth Model of Root Mass and Vertical Distribution, Dependent on Carbon Substrate from Photosynthesis and with Non-limiting Soil Conditions

A Growth Model of Root Mass and Vertical Distribution, Dependent on Carbon Substrate from Photosynthesis and with Non-limiting Soil Conditions

Effect of moisture level on the root pattern of Alfalfa

There have been a few investigations on the effect of moisture on root development of alfalfa (Medicago sativa L.), but none have attempted to describe the relationships in a quantitative manner. Therefore, alfalfa root patterns along with yield and evapotranspiration (ET) were examined under different moisture levels, using a line-source sprinkler system. Water application ranged from 28 to 153 cm, the latter representing the potential evapotranspiration. Alfalfa root mass and yield were highest under high moisture levels, and the shoot/root ratio increased with increasing moisture level. The relationships between ET and root mass and between ET and shoot/root ratio were curvilinear. The largest percentage of root mass under all moisture treatments was found in the top 45 cm of the soil profile where the largest differences in total root mass between treatments were observed. The percentages of roots at each soil depth averaged over three ranges of moisture levels were curvilinear functions of soil depth. Although alfalfa roots were found to a depth of at least 150 cm for all moisture levels, there was a greater rooting depth with a higher moisture level. Roots were detected to a depth of 210 cm for the high moisture treatment, although root biomass was small below 170 cm where a sand layer was encountered which may have impeded root penetration. The root diameter was found to be independent of moisture level, which means that there was a greater root surface area with higher moisture levels. Root length density distribution was similar to root mass distribution.

An Improved Mechanical Soil-Root Sampler

ABSTRACT A mechanical sampler has been developed to rapidly extract large undisturbed soil samples. The sampler utilizes a commercially available fence-post driver. A hydraulic cylinder mounted in a pulling frame is used to remove the undisturbed soil samples. A fractionator has been designed to further separate the large samples into small cubes. The densities of soil samples taken by the new mechanical sampler compared well with that of a conventional core sampler. The sampler is used to obtain root mass distribution as influenced by soil compaction.