features of fertile soil

• Features of fertile soil

  water content, soluble materials, air content, dead organic matter, pH, soil biota, soil texture, soil structure and soil depth
• Water content


  fertile soil allows good drainage, so water logging doesn't happen but also for the survival of the soil biota
• Waters importance for plants

  water dissolves nutrients as ions and can be taken into the plant
• soluble material


  MACOnutrients- nitrates, phosphates and potassium (ionic form)

  MICROnutrients- boron, cobalt, copper, iron, manganese and magnesium
• Air content


  most living organisms in soil and many processes that increase fertility are aerobic so well arrayed soils are likely to be more fertile
• Dead organic matter


  high dead organic matter= fertile soils with good water retention and provides food for soil biota
• soil PH


  5.5-7.0 tolerance
• what happens if the soil is acidic?

  increases leaching of plant nutrients and damage root cell membrane
• what happens when the soil is alkaline?

  phosphates become insoluble
• soil biota


  refers to all organisms living within the soil, including worms
• worms importance in soil

  worms (detritivores) increase soil drainage and aeration through creating tunnels in the soil
• importance of decomposers in soil

  bacteria and fungi breakdown organic matter

  -they secrete digestive enzymes and rely on detritivores to physically break up dead organic matter + increase its surface area
• soil texture


  controlled by the proportions of the different sized particles present, CLAY: <0.002mm SILT: 0.002-0.02mm SAND: 0.02-2.0mm
• Loam Soils


  even mix of sand, silt and clay (40:40:20)

  ideal mix of properties for cultivating most crops as it has good drainage, water retention and high nutrition content
• Soil Depth


  deeper soils are less likely to become water logged or dry out rapidly. aids good root anchorage.
• Soil Structure


  soil particles from aggregates called peds

  the particles are bound together by polysaccharide gums produced from decomposition by fungal hyphae, roots, action of soil biota and hygroscopic clay particles.
• CRUMB PEDS


  small and round:

  good drainage, aeration, easy root penetration and improves soil fertility
• PLATY PEDS


  large and flat:

  reduces drainage, aeration, root penetration and decreases fertitlity of soil
• Clay Soils 


  drainage rate- poor

  capillary action- small pores in clay allow water to rise to surface

  aeration- more likely water logged with low aeration

  nutrient retention- nutrient ions absorb into clay particles

  thermal capacity- high water content=high thermal capacity

  root penetration- clay particles make it difficult for roots grow

  ease of cultivation- adhesion between soil particles make it hard
• Sand Soils


  drainage rate - large pore space=reduced water content

  capillary action- no capillary water rise

  aeration- pore spaces are well drained so fill with air

  nutrient retention- not efficient

  thermal capacity- lower thermal capacities so warm up quickly

  root penetration- easier then clay

  ease of cultivation- lack of adhesion of soil particles makes it easy