plant nutrient loss

Question 1

what is the major nutrient loss source

Answer 1

senescence

Question 2

how are nutrients lost reduced from senescence

Answer 2

1. reducing tissue turnover rates (esp in unproductive environments) (e.g. root and leaf longevity increases in low nutrient and low water environments)
2. re-absorption of nutrients prior to senescence (through phloem; often stored in roots)

Question 3

what is the second major avenue of loss

Answer 3

leaching
accounts for 15% of nutrient return to soil
rain dissolves nutrients on plant surfaces + returns to soil via stem flow (10%) and throughfall (90%)

Question 4

what does herbivory contribute to

Answer 4

less than 10% of NPP
loss of nutrients (can stimulate nutrient cycling/return to soil)
- precedes reabsoprtion
herbivores prefer to feed on highly nutrient rich tissues

Question 5

how does disturbance lead to nutrient loss

Answer 5

fire,wind,landslides,harvesting,flood,disease, herbivore epidemics
- large pulses but small overall impact long term
-usually nutrient transfer to soil rather than ecosystem loss (except fire,harvest)