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Effect of plant density on (a) total shoot mass and (b) seed mass per unit ground area. Schematised figure, inspired a.o. by experiments with maize by Li et al. (2015). Many of the processes related to plant density can well be studied in monocultures of even-aged individuals that are sown or planted at the same time. These can be referred to ...
Density, bulk density, or wet density, , are different names for the density of the mixture, i.e., the total mass of air, water, solids divided by the total volume of air water and solids (the mass of air is assumed to be zero for practical purposes):
Soil bulk density is equal to the dry mass of the soil divided by the volume of the soil; i.e., it includes air space and organic materials of the soil volume. Thereby soil bulk density is always less than soil particle density and is a good indicator of soil compaction. [47]
Arable density (m² per capita) by country. This is a list of countries ordered by physiological density."Arable land" is defined by the UN's Food and Agriculture Organization, the source of "Arable land (hectares per person)" as land under temporary crops (double-cropped areas are counted once), temporary meadows for mowing or for pasture, land under market or kitchen gardens, and land ...
where A is the area of a given leaf or all leaves of a plant, and M L is the dry mass of those leaves. Typical units are m 2 /kg or mm 2 /mg. Leaf mass per area (LMA) is its inverse and can mathematically be decomposed in two component variables, leaf thickness (LTh) and leaf density (LD): [4] = =.
A special type of area density is called column density (also columnar mass density or simply column density), denoted ρ A or σ. It is the mass of substance per unit area integrated along a path; [ 1 ] It is obtained integrating volumetric density ρ {\displaystyle \rho } over a column: [ 2 ] σ = ∫ ρ d s . {\displaystyle \sigma =\int \rho ...
D 50: Mass-median-diameter (MMD). The log-normal distribution mass median diameter. The MMD is considered to be the average particle diameter by mass. σ g: Geometric standard deviation. This value is determined mathematically by the equation: σ g = D 84.13 /D 50 = D 50 /D 15.87. The value of σ g determines the slope of the least-squares ...
The measured leaf area can then be divided by the area of the traps to obtain LAI. Alternatively, leaf area can be measured on a sub-sample of the collected leaves and linked to the leaf dry mass (e.g. via Specific Leaf Area, SLA cm 2 /g). That way it is not necessary to measure the area of all leaves one by one, but weigh the collected leaves ...