Water Uptake by Seeds as Affected by Water Stress, Capillary Conductivity, and Seed-Soil Water Contact. II. Analysis of Experimental Data1
- A. Hadas and
- D. Russo2
Chickpea, pea and vetch seeds were germinated in pure, aerated water and in sand or aggregate fractions of various grain-size classes. These were either 1) packed in columns at various water contents kept constant by passing water at different rates equaling the conductivity of the least conductive layer in every column or 2) sown in aggregated soil at equilibrium with different matric water potentials. Water uptake rates, seed diameter, and time of germination were determined, and seed-soil water contact area was calculated. Water uptake data were analyzed to yield an approximation of the seed-soil water contact impedance by using a simplified model.
The results show that the seed-soil water contact impedance increased as the wetted seed area and/or soil hydraulic conductivity decreased. The data also show that for optimal seed-soil water contact in aggregated soils, the mean aggregate size should be one-fifth to one-tenth of the seed's diameter. Possible application to field practice, such as seed-bed preparation, is discussed.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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