Influence of water potential and soil strength on seedling emergence of a few selected forage legumes species
2003
Njarui, D.M.G.(KARI-National Dryland Farming Research Centre-Katumani, Machakos, Kenya) | Bahnisch, L.M.(The University of Queensland Gattan, Qld, Australia) | O'hagan, B.(The University of Queensland Gattan, Qld, Australia) | So, B.(The University of Queensland Gattan, Qld, Australia)
The effects of water potential and soil strength on seedling emergence of three forage legume species, desmanthus (Desmanthus virgatus CPI 91146), glycine (Glycine latifolia CQ 3368) and cowpea (Vigna unguiculata cv. Red Caloona) were studied under a controlled temperature using red-brown earth and black earth in a growth chamber. The water potentials, -10, -300 and -750 kPa applied were achieved by using different concentrations of polyethylene glycol solution of molecular weight 10,000. Soil strength increased with decreased water potential and the effect was rapid in red-brown earth than in the black earth. Seedling emergence in the black earth occurred at water potentials of -10 kPa and -300 kPa (soil strength of 0.64 and 1.98 kg/cm2 respectively) while in the red-brown earth seedling emergence was restricted to -10 kPa (soil strength of 1.75 kg/cm2). However cowpea showed a greater emergence force by emerging at water potential of -750 kPa (soil strength 2.66 kg/cm2) in the black earth and at -300 kPa (soil strength of 5.27 kg/cm2) in the red-brown earth. Time to emergence increased with decreasing water potential and increased soil strength. Seedling emergence was rapid at both 0.64 and 1.75 kg/cm2 and delayed above this soil strength. It was concluded that low water potential and high soil strength restrict seedling emergence.
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Эту запись предоставил Kenya Agricultural Research Institute