提高受盐碱化影响的田地生产力.pdf

1、Increasing Productivity on Fields Affected by SalinityKen Wall Federated Co-opWhat is Root-zone salinity?The existence of any excess salts in the root-zones tends to disrupt normal crop plant functions.Common salts are;sodium,calcium,and magnesium sulfates.As well there are sodium,calcium,and magnes

2、ium chlorides.Soil SalinityReduced annual crop yield Poor crop emergence and tillering(cereals)Lower yields,even at relatively low EC levelsMechanisms Restricts plant water uptake(osmosis)Toxicity of bicarbonates and other anions Elevated soil pH(caustic effects and low micronutrient availability)Po

3、or soil aeration(soil structure)Root-zone SalinityExtent of the Problem Of the 53.5 million ha of agricultural land across Western Canada,it is estimated that 3 million ha are classified as severely saline.Also,7 million ha of arable land and 3 million ha of permanent pasture are classified as sligh

4、tly to moderately saline.Another 4 million ha at risk to becoming saline.“Invisible”or Hidden Salinity Research indicates many crops are more affected by low to moderate salinity than previously realized.Testing in SCRDC Salt Lab indicated yield losses up to 50%for CWRS at conductivities as low as 4

5、 dS/m.Soil surveys estimate about 7 million ha.of arable land across the prairies are classified as slightly to moderately saline.What Causes Salinity?Presence of dilute salts in the profile is not a problem.However,the movement and accumulation of these salts is.Subsurface water moves salts into di

6、scharge areas.Root-zone salinization occurs when evaporation pulls more water upward than precipitation or snowmelt move water downward.Hence,salinity problems are water management problems.2 mContact/Slope Change Salinity(Saline Seep)Impermeable layerPermeable layer(unsaturated soil)CropWater table