Chapter 8 Soil Fertility and Nutrient Bioavailability
Soil Fertility and Nutrient Bioavailability Chapter 8
Soil fertility Soil fertility is the characteristics of soil that enables it to Provide nutrients in adequate amounts in adequate time in appropriate balance for growth of particular plant(s)
Soil Fertility Soil fertility is the characteristics of soil that enables it to: • Provide nutrients • in adequate amounts • in adequate time • in appropriate balance • for growth of particular plant(s)
Soil Fertility Depends on the Forms of the nutrient in soil Processes of nutrient release to soil solution(weathering, decay, dissolving and desorption) Movement of nutrients to the absorbing surfaces(of plant/mycorrhiza) Mechanism of absorption by roots
◼ Depends on the: ◼ Forms of the nutrient in soil ◼ Processes of nutrient release to soil solution (weathering, decay, dissolving, and desorption) ◼ Movement of nutrients to the absorbing surfaces (of plant/mycorrhiza) ◼ Mechanism of absorption by roots Soil Fertility
Topics Cycling of different elements Soil processes and the supply of nutrients relative importance of organic and inorganic pools/biological activity effects of pH on nutrient availability effects of soil moisture on nutrient availability and movement Movement of nutrients in soil to roots Importance of soil structure in soil fertility Bioavailability of soil nutrients
Topics • Cycling of different elements • Soil processes and the supply of nutrients – relative importance of organic and inorganic pools/biological activity – effects of pH on nutrient availability – effects of soil moisture on nutrient availability and movement • Movement of nutrients in soil to roots • Importance of soil structure in soil fertility • Bioavailability of soil nutrients
Plants absorb nutrients from the soil solution Concentrations in soil solution(uM) at sites in UK Na K Mg Ca Fe P Grassland/ arable4653901352120|3432764 (24 soils Woodland 33538410459224139817 (5 soils values for P can be much lower than those quoted 10 um from Tinker and nye, 2000
Plants absorb nutrients from the soil solution Concentrations in soil solution (µM) at sites in UK Na K Mg Ca Fe S P Grassland/arable (24 soils) 465 390 135 2120 3.4 327 64 Woodland (5 soils) 335 384 104 592 24.1 398 17 from Tinker and Nye, 2000 values for P can be much lower than those quoted < 10 µm