Agricultural design: buffer width, wetland sizing, range condition, rotations, variable-rate zones, drain spacing
Source:R/AgriDesign.R
BufferStripWidth.RdBufferStripWidth: first-order trapping E(w) = 1 - exp(-k w),
width -ln(1 - target) / k, with k estimated through the origin
from observed widths and efficiencies when not given.
WetlandAreaPkc: Kadlec-Knight P-k-C* sizing, plug flow
A = (365 Q / k) ln((C_i - C*) / (C_o - C*)) (m^2, Q m^3/d,
k m/yr) or n_tanks tanks in series.
RangeCondition: Dyksterhuis (1949) similarity
sum min(current, climax) and its class. RotationScore: cyclic
pre-crop effect sum with ROTAT return-time, frequency and sequence screens
(crop codes are 0-based). VariableRateZones: yield-quantile zones and
Stanford mass-balance rates max((n_per_yield Y - N_soil) / efficiency, 0).
HooghoudtSpacing: q L^2 = 8 K_b d h + 4 K_a h^2 with Moody's
equivalent depth. DrainWaterTable: the mid-drain head for a given spacing.
Usage
BufferStripWidth(target, k = NULL, widths = NULL, efficiencies = NULL)
WetlandAreaPkc(flow, c_in, c_out, k, c_star = 0, n_tanks = NULL)
RangeCondition(current, climax)
RotationScore(
sequence,
effect,
min_return = NULL,
max_frequency = NULL,
forbidden = list()
)
VariableRateZones(
yield_map,
n_zones = 3,
n_per_yield = 20,
soil_n = NULL,
efficiency = 1
)
HooghoudtSpacing(
q,
h,
k_above,
k_below,
depth_to_barrier,
radius = 0.1,
tol = 1e-10,
max_iter = 200
)
DrainWaterTable(q, spacing, k_above, k_below, equivalent_depth)Arguments
- target
Target removal efficiency (0 to 1).
- k
First-order width constant (1/m), or areal rate constant (m/yr).
- widths, efficiencies
Observed widths and removal efficiencies.
- flow
Inflow (m^3/d).
- c_in, c_out, c_star
Inlet, target outlet and background concentrations.
- n_tanks
Number of tanks in series, or NULL for plug flow.
- current, climax
Percent species composition now and in the climax community.
- sequence
Crop codes of one rotation cycle (0-based).
- effect
Matrix of pre-crop effects.
- min_return
Minimum return times per crop, or NULL.
- max_frequency
Maximum shares per crop, or NULL.
- forbidden
List of forbidden (preceding, following) pairs.
- yield_map
Cell yields.
- n_zones
Number of zones.
- n_per_yield
Nitrogen requirement per unit yield.
- soil_n
Soil nitrogen per cell, or NULL.
- efficiency
Fertiliser recovery efficiency.
- q
Drainage rate (m/d).
- h
Mid-drain head above drain level (m).
- k_above, k_below
Hydraulic conductivities above and below drain level (m/d).
- depth_to_barrier
Depth of the impermeable layer below drain level (m).
- radius
Drain radius (m).
- tol, max_iter
Fixed-point tolerance and iterations.
- spacing
Drain spacing (m).
- equivalent_depth
Equivalent depth (m).
References
Zhang, X. et al. (2010). J. Environ. Qual. 39, 76-84. Kadlec, R. H. and Knight, R. L. (1996). Treatment Wetlands. CRC Press. Kadlec, R. H. and Wallace, S. D. (2009). Treatment Wetlands, 2nd ed. Dyksterhuis, E. J. (1949). J. Range Management 2, 104-115. Dogliotti, S. et al. (2003). Eur. J. Agron. 19, 239-250. Stanford, G. (1973). J. Environ. Qual. 2, 159-166. Ritzema, H. P. (1994). Drainage Principles and Applications, ILRI 16. Moody, W. T. (1966). J. Irrig. Drain. Div. ASCE 92, 1-9.