TURF AND SOIL SOIL PROFILE Topgrowth (leaves and stolons) Thatch: undecomposed organic matter (roots, shoots, stolons, rhizomes) Decomposed by microorganisms (MO) Mat: thatch integrated with soil Soil THATCH to 1 of thatch is good Excessive thatch is BAD WHY THATCH IS BAD 1. Root system is limited to thatch 2. Dry and temperature extremes WHY THATCH IS BAD 3. Crowns develop in thatch WHY THATCH IS BAD 4. Crowns can be mowed out of turf (scalping) WHY THATCH IS BAD 5. Pathogens and insects supported by thatch 6. Reduces insecticide effectiveness EXCESSIVE THATCH Excessive thatch due to improper management Plant growth exceeds MO activity 1. Excessive N is most common EXCESSIVE THATCH 2. Overwatering slows MO activity Reducing oxygen in soil THATCH 3. Over application of chemicals Reduce MO and worms THATCH and CLIPPINGS Clippings do not contribute to thatch Mostly water, break down rapidly Stolons and rhizomes contain lignin SOIL TEXTURE Texture: size and proportion of soil particles SOIL TEXTURE Clay is smallest High adsorption capacity Holds water TIGHT High degree of micropores SOIL TEXTURE Silt Holds higher amount of PLANT AVAILABLE MOISTURE SOIL TEXTURE Sand 7 classes7 classes Solid particles with no microporesSolid particles with no micropores Good drainage through macroporesGood drainage through macropores Resistant to compactionResistant to compaction SOIL TEXTURE Sand Little adsorptive capacityLittle adsorptive capacity Low micro organism activityLow micro organism activity SOIL STRUCTURE Structure: arrangement of soil particles Good structure provides good pore space Good aeration to provide oxygen to roots SOIL STRUCTURE Compaction destroys structure of soil pH Measure of acidity and alkalinity Scale of 0 to 14, 7 is neutral Ideal pH is between 6 and 7 (slightly acidic) pH Affects nutrient availability Iron and some micronutrients unavailable at high pH RAISING pH Raise low pH with lime application LOWERING pH Lower high pH not feasible Applications of elemental sulfur lowers pH Soil pH rebounds once S used up RAISING pH Irrigation pH injection works RAISING pH Irrigation pH injection works SOIL MOISTURE Saturated condition Water flows down by gravitational force SOIL MOISTURE Unsaturated condition (macropores drained) Water moves through soil by attractive forces SOIL MOISTURE Unsaturated condition (macropores drained) Cohesion: attraction of water molecules to each other Adhesion: attraction of water molecules to soil particles SOIL MOISTURE Unsaturated condition (macropores drained) Capillary flow, or wicking, in any direction Roots pull water away from soil particle forces SOIL MOISTURE Permanent wilting point: roots cannot overcome soil attractive forces Golf Green Construction Sand/peat rootzone California method is all sand Sand used because of Resistance to compaction Good drainage Sand drains TOO MUCH Better than draining to little Golf Green Construction Perched water table concept Fine sand layer over coarse sand layer Smaller pores of fine sand have greater attractive force than larger pores Holds water in root zone Maintains excellent drainage Artificial Golf Green