Agriculture Reference
In-Depth Information
trate concentrations increased with depth, the N-fertilizer source had been
solid organic matter (compost and guano) mixed into the soil, a method
that is commonly practiced in organic farming. On the other hand, in the
organic greenhouse that exhibited low nitrate concentrations, N-fertiliza-
tion relied mainly on the water extracts of guano excrement that had been
applied directly through the drip irrigation throughout the growing season,
and not as solid compost mixed with the soil prior to the growing season.
Fertilization with the irrigation water (fertigation) throughout the growing
season in response to the plant nutrient demand is a common practice in
conventional agriculture.
FIGURE 6:
Nitrate concentrations in sediment samples (soil extraction) and pore water
(average VMS) in the vadose zone underlying organic and conventional greenhouses.
