The document summarizes key concepts about soils and plant nutrition: - Soil is made up of particles classified by size and arranged in horizons, with loam being the most fertile topsoil. The soil contains inorganic components like minerals and organic components like humus. - Plants obtain essential inorganic nutrients from the soil, and have evolved relationships with soil microbes to aid nutrient uptake through processes like nitrogen fixation and mycorrhizal associations. - Sustainable agriculture aims to farm in an environmentally-friendly way through practices such as irrigation, fertilization, erosion control and composting.

1. Ally Bove, Laura Cox & Lindsey Richards

2. -Anchors plant -Basic physical properties of soils and
-Fertilizer the factors that govern soil qualities.
-Helps retain water -Why certain inorganic nutrients are
-Holds nutrition for plants essential for plant function.
-Nutritional adaptations that have
evolved in plants, often in
relationships with other organisms.

3. Soil particles are classified
by size from largest to
smallest:
-Sand
-Silt
-Clay
-Soil is stratified into
layers called soil
horizons.
A type of topsoil called
loam is the most fertile.

4. Inorganic Components
Cations adhere to
negatively charged
soil particles.
During cation
exchange, cations
are displaced from
soil particles by
other cations.

5. Organic Components
Humus retains water and
mineral nutrients. Also it
increases the soils
capacity to exchange
cations.
Topsoil contains many
organisms that help
decompose organic
material.

6. The goal of sustainable agriculture is to use faming methods that are
conservation-minded, environmentally safe, and profitable.
Irrigation
Fertilization
Adjusting Soil pH
Controlling Erosion
Preventing Soil Compaction
Phytoremediation

7. Irrigation Fertilizer

8. Adjusting
Soil pH Controlling Erosion

9. Preventing Soil
Compaction Phytoremediation

11. (Macronutrients)

12. (Micronutrients)

15. -Plants & soil have two-way relationship
Many of the soil bacteria are called
saprobes-lives on decaying organic material
-Rhizobacteria-soil bacteria w/especially
large population in rhizosphere (soil layer
bound to plant roots)
Some are called plant-growth-promoting rhizobacteria
then enhance plant growth by a variety of mechanisms

16. -Nitrogen Cycle-describes transformations of
nitrogen & nitrogenous compounds in nature
-Nitrogen-fixing bacteria converts atmospheric N2
to nitrogenous minerals that plants

17. •Plants absorb nitrogen as either NO3–or NH4+
•Bacteria break down organic compounds or use N2to produce NH3, which is
converted to NH4+
•Nitrification is carried out by bacteria that convert NH3 into NO3–

18. Nitrifying bacteriaadds free nitrogen or nitrates to the soil by the process of
nitrification.
Ammonifying bacteriaconverts ammonia into nitrates which is converted
into free soil nitrogen by nitrifying bacteria.
Denitrifying bacteriareduces nitrates or nitrogen gas; most are found in soil
Nitrogen fixing bacteriahas an association with bacteria which infect their
roots and in return for sugars from the plant, fix nitrogen which can be used by
the plant for growth.

19. -Nitrogen fixation: conversion of nitrogen
from N2to NH3
-The agricultural perks of mutualistic
nitrogen fixation underlies most types of
crop rotation

20. -Mycorrhizae: mutualistic
associations of roots & fungi
-The fungal hyphae of both
ectomycorrhizae and arbuscular
mycorrhizae absorbs minerals
and water to which they supply
to their roots.

21. Epiphytes
Absorb water & minerals from rain, mostly through leaves
not roots. Ex: staghorn fern
Parasitic Plants
Absorb sugars & minerals from living hosts, although some
species are photosynthetic. Ex: mistletoe
Carniverous Plants
Photosynthetic, but they obtain some of the minerals by
killing & digesting insects & other small animals. Ex: venus fly
trap

22. Mistletoe
Staghorn Fern Venus Fly Trap