[DOC] [TLE] Chapter 37 Plant Nutrition - Biology Junction [PAR] In fact, soil, water, and air all contribute to plant growth. ... Mineral nutrients are 
essential chemical elements absorbed from soil in the .... The symptoms of a 
mineral deficiency are often distinctive enough for a plant ..... The following year, 
alfalfa or another legume is planted to restore the concentration of fixed soil 
nitrogen. [DOC] [TLE] Nitrogen Fixation by Legumes [PAR] A common soil bacterium, Rhizobium, invades the root and multiplies within the 
cortex ... for the plant to absorb nitrogen from the soil than to fix it from the air. [DOC] [TLE] NMSU: Nitrogen Fixation By Legumes [PAR] A legume plant root showing nodules attached to the roots. ... When nodules are 
young and not yet fixing nitrogen, they are usually white or gray inside. ... energy 
consuming for the plant to absorb nitrogen from the soil than to fix it from the air. [DOC] [TLE] Nutrient cycling and maintaining soil fertility in fruit and vegetable ... [PAR] Crop rotations; Soil and water conservation practices; Cover crops and green ... 
Plant nutrients are chemical elements that are mostly absorbed by plant roots as 
.... of N-gas in the air to organic-N that becomes available to plants (performed by 
.... In fresh water systems, P is usually the limiting nutrient for growth of algae and
... [DOC] [TLE] chapter 37 - Akron Central Schools [PAR] The upper layers of soil, from which plants absorb the water and minerals they ... 
Loams also have enough coarse particles to provide air spaces that supply .... 
Because water is often the limiting factor in plant growth, no technology has ..... 
alfalfa or another legume is planted to restore the concentration of fixed soil 
nitrogen. [DOC] [TLE] Nitrogen fixation - Wikipedia [PAR] Nitrogen fixation is a process in which nitrogen (N2) in the atmosphere is 
converted into ... Nitrogen fixation occurs naturally in the soil by nitrogen fixing 
bacteria affiliated ... When the plant dies, the fixed nitrogen is released, making it 
available to ... or buckwheat (non-legume family Polygonaceae), often referred to 
as "green... [DOC] [TLE] Restoring Soil Nutrients - Organic Gardening - MOTHER EARTH ... [PAR] Here are twelve critical soil nutrients your plants need for healthy growth and ... 
Intensive plantings of warm-weather crops remove nutrients at a fast clip, ... Then 
I gather all the compost I can spare, and encircle each plant with a few inches of 
mulch. ... Elements with charges opposite that of phosphorus, such as calcium 
and... [DOC] [TLE] Plant Nutrition [PAR] and root hairs, absorb water ... Most of the dry weight of a plant is the result of 
uptake of CO2 through stomata in leaves. ... Hydroponic cultures can be used to 
determine essential nutrients; Air is bubbled into the ... Most Common ... year 
alfalfa or another legume is planted to restore the concentration of fixed soil 
nitrogen. [DOC] [TLE] Plant Nutrition - Canyon ISD [PAR] Plant roots are bathed in aerated solutions of known mineral composition. ... One 
use of hydroponic culture is to identify essential elements in plants. ... Water 
bound less tightly to soil particles can be absorbed by the root. ... as maize is 
planted one year, and the following year a legume is planted to restore the 
concentration... [DOC] [TLE] How Legumes 'Fix' Nitrogen in Your Soil  seattletilth.org [PAR] Growing legume cover crops is one of the most important tools for increasing soil 
... The bacteria take gaseous nitrogen from the air in the soil and feed this 
nitrogen to the legumes; in exchange the plant ... Rhizobacteria are naturally 
present in the soil, but their populations are often too low to maximize nitrogen 
fixation. [DOC] [TLE] Chapter III: Soils and Fertilizers | Vegetable Resources [PAR] Soil air differs from the atmosphere above the soil in that it usually contains 10 ... 
Dark soils absorb a much higher proportion of radiant energy than do light 
colored soils. ... There are 20 essential chemical elements (plant nutrients) 
known to be ... nodules on the roots of legumes are able to take nitrogen from the 
air and fix it... [DOC] [TLE] The importance of soil organic matter

Question: Legumes absorb this element from the air & are often planted to restore it to the soil
Answer: nitrogen