revSupply {Rquefts} | R Documentation |
Estimate soil nutrients supply
Description
Estimate the apparent base (unfertilized) soil supply of N, P and K based on nutrient omission trial data and a "reverse" QUEFTS approach. The apparent supply is found with optimization.
Usage
revSupply(obs, crop, soil, Ya, leaf_ratio, stem_ratio, SeasonLength = 120, ...)
Arguments
obs |
data.frame with observed data from a nutrient omission trial. It must have these four columns: "N", "P", "K" and "Y"; that give the N, P, and K fertilizer application and the crop yield in kg/ha |
Ya |
numeric. Attainable yield |
soil |
list with named soil parameters. See |
crop |
list with named crop parameters. See |
leaf_ratio |
positive numeric (typically between 0 and 1) indicating the leaf weight relative to the storage organ weight. For example: 0.46 for maize, 0.17 for potato, and 0.18 for rice |
stem_ratio |
positive numeric (typically between 0 and 1) indicating the stem weight relative to the storage organ weight, For example: 0.56 for maize, 0.14 for potato, and 0.67 for rice |
SeasonLength |
positive integer |
... |
additional arguments supplied to |
Value
numeric vector with the N, P, and K supply in kg/ha
References
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Examples
set.seed(777)
trial_data <- data.frame(treat = c("CON", "NPK", "NPK", "PK", "NK", "NP"),
N = c(0, 120, 120, 0, 120, 120),
P = c(0, 30, 30, 30, 0, 30),
K = c(0, 60, 60, 60, 60, 0),
Y = c(2000, 6000, 6000, 2500, 4500, 5500) + rnorm(6, 0, 500))
Ya <- max(trial_data$Y) + 1000
crop <- quefts_crop("Potato")
soil <- quefts_soil()
revSupply(trial_data, crop, soil, Ya, leaf_ratio=.17, stem_ratio=.14)