Ecological Risk of Heavy Metal in Agricultural Soil and Its Potential Transfer to Rice Grains

Mahmud, Upoma; Salam, Mohammed Abdus; Khan, Shamim Ahmed Kamal Uddin; Ms, Rahman

doi:10.5455/jbau.21185

Cited by 1 publication

(1 citation statement)

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“…The role of mechanised tillage in alleviating or exacerbating the strength of a hard pan is therefore critical in determining the success of crop establishment, but this needs further investigation [39,40]. In addition, when the seedbed is created by mechanised tillage equipment, the trafficking by the farm machinery can create compacted surface soils, which limits seedling emergence [41]. However, there are benefits to some compaction of the soil above the seedbed to improve seed/soil contact and retain soil water for crop establishment and growth [42].…”

Section: Implications For Field Conditionsmentioning

confidence: 99%

Physical Conditions That Limit Chickpea Root Growth and Emergence in Heavy-Textured Soil

Vance,

Bell,

Johansen

2023

Seeds

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The tillage method determines several soil physical parameters that affect the emergence of post-rice chickpea (Cicer arietinum L.) in the Indo-Gangetic Plain of South Asia. Mechanised row-sowing with minimum soil disturbance and crop residue retention in medium-to-heavy-textured soils will alter the seedbed when compared to that prepared after traditional full tillage and broadcast sowing. Whilst minimum soil disturbance and timely sowing may alleviate the soil water constraint to crop establishment, other soil physical properties such as soil strength, bulk density, and aggregate size may still inhibit seedling emergence and root elongation. This study’s objective was to determine the limitations to chickpea crop establishment with increasing bulk density and soil strength, and different aggregate sizes below and above the seed. In two growth cabinet studies, chickpea seed was sown in clay soil with (i) a bulk density range of 1.3–1.9 Mg m−3 (Experiment 1) and (ii) the combination of bulk densities (1.3 and 1.8 Mg m−3) and aggregate sizes (<2 mm and >4 mm) above and below the seed (Experiment 2). Root length was significantly reduced with increasing bulk density (>1.4 Mg m−3), and soil strength impeded early root growth at >1 MPa. Where main root growth was impeded due to high bulk density and soil strength, a greater proportion of total root growth was associated with the elongation of lateral roots. The present study suggests that the soil above the seed needs to be loosely compacted (<1.3 Mg m−3) for seedling emergence to occur. Further research is needed to determine the size of the soil aggregates, which optimise germination and emergence. We conclude that soil strength values typical of field conditions in the Indo-Gangetic Plain at sowing will impede the root growth of chickpea seedlings. This effect can be minimised by changing tillage operations to produce seedbed conditions that are within the limiting thresholds of bulk density and soil strength.

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