Contrasting ability of deep and shallow rooting rice genotypes to grow through plough pans containing simulated biopores and cracks

Abstract

Aims Cracks and biopores in compacted soil such as plough pans could aid deep rooting, mitigating constraints to seasonal upland use of paddy fields for rice production. This research investigated how soil macropores through a simulated plough pan affects root growth of contrasting deep and shallow rooting rice genotypes. Methods Deep rooting Black Gora and shallow rooting IR64 rice varieties were grown in packed cores of unsaturated soil in a controlled greenhouse. Simulated biopores and cracks (macropores) were inserted through the plough pan to form treatments with no macropores, biopores, cracks, and combined cracks and biopores. Different root parameters such as root length density (RLD), root volume, root diameter, number of root tips and branches were measured. The number of roots was calculated manually, including the number of roots growing through macropores in the plough pan layer. Results Plough pans with macropores had 25–32% more roots than with no macropores. RLD was 55% greater in the plough pan layer if cracks were present compared to biopores. Conversely, RLD was 26% less in subsoil if the plough pan had cracks compared to biopores. Different root parameters were greatly influenced by the presence of macropores in the plough pan, and deep-rooted Black Gora produced 81% greater RLD, 30% more root numbers and 103% more branching than the shallow rooted rice genotype IR64 within the plough pan layer. Conclusions Macropores greatly improve rice root growth through plough pans for a deep rooting but not a shallow rooting rice variety. Whereas cracks produce a greater number of roots in the plough pan, biopores result in greater root branching and root numbers deeper in subsoil.

Plant growth regulators improve root growth of rice seedlings after mechanical transplanting and increase grain yield

“…All data are presented as mean ± LSD. The growth rate of rice roots after transplantation was computed following the method described by Islam et al (2021): Increase in white root number per day = [(white root number per plant at 7 days after transplanting) -(white root number per plant at 3 days after transplanting)]/4 days; Increase in total root number per day = [(total root number per plant at 7 days after transplanting) -(total root number per plant at 3 days after transplanting)]/4 days; Increase in the length of the longest white root per day = [(the length of the longest white root at 7 days after transplanting) -(the length of the longest white root at 3 days after transplanting)]/4 days.…”

Varietal Differences in the Root Systems of Rice (Oryza sativa L.) under Drip Irrigation with Plastic Film Mulch

“…However, the ability of the roots to effectively carry out their role depends on their type, structure, and modification. This significance extends to water-saving rice production systems, where root growth and structure can be instrumental to the development of the rice plant and grain yield production [8]. Therefore, it is necessary to determine the variation in the root responses of different rice cultivars under DI.…”

Soil hydraulic properties and field-scale hydrology as affected by land-management options

“…As a result, the macropores are sealed off when the particles are settled down (Islam et al, 2014). Moreover, the macropore volume decreases, which remarkably reduces the soil pore connectivity (Chen et al, 2014;Islam et al, 2021) and hydraulic conductivity (Talukolaee et al, 2018). An illuviation process-accumulation of dissolved or suspended soil materials in one area or layer as a result of percolation from another-occurs between puddled topsoil and non-puddled subsoil that helps develop a plow pan with the lowest hydraulic conductivity (Shao et al, 2017).…”