Soil assessment builds information for improved decision in
    soil management. It analyzes soil conditions with regard to
    agriculture crop suitability requirements [such as those given by FAO
    <https://www.fao.org/land-water/databases-and-software/crop-information/en/>]
    soil fertility classes, soil erosion, and soil salinity classification
    [<doi:10.1002/ldr.4211>]. Suitability requirements are for
    crops grouped into cereal crops, nuts, legumes, fruits, vegetables,
    industrial crops, and root crops.

Facilitates basic and equation-based analyses of some important soil properties related to soil chemical environment and nutrient availability to plants. Freundlich H (1907). <doi:10.1515/zpch-1907-5723>. Datta SP, Bhadoria PBS (1999). <doi:10.1002%2F%28SICI%291522-2624%28199903%29162%3A2%3C183%3A%3AAID-JPLN183%3E3.0.CO%3B2-A>."Boron adsorption and desorption in some acid soils of West Bengal, India". Langmuir I (1918). <doi:10.1021/ja02242a004> "The adsorption of gases on plane surfaces of glass, mica, and platinum". Khasawneh FE (1971). <doi:10.2136/sssaj1971.03615995003500030029x> "Solution ion activity and plant growth".

A collection of functions for reading soil data from U.S. Department of Agriculture Natural Resources Conservation Service (USDA-NRCS) and National Cooperative Soil Survey (NCSS) databases.

Analyzing soil food webs or any food web measured at equilibrium. The package
  calculates carbon and nitrogen fluxes and stability properties using methods
  described by Hunt et al. (1987) <doi:10.1007/BF00260580>, de Ruiter et al. 
  (1995) <doi:10.1126/science.269.5228.1257>, Holtkamp et al. (2011)
  <doi:10.1016/j.soilbio.2010.10.004>, and Buchkowski and Lindo (2021) 
  <doi:10.1111/1365-2435.13706>. The package can also manipulate the structure 
  of the food web as well as simulate food webs away from equilibrium and run 
  decomposition experiments.

Provides functions for (1) soil water retention (SWC) and unsaturated hydraulic conductivity (Ku) (van Genuchten-Mualem (vGM or vG) [1, 2], Peters-Durner-Iden (PDI) [3, 4, 5], Brooks and Corey (bc) [8]), (2) fitting of parameter for SWC  and/or Ku using Shuffled Complex Evolution (SCE) optimisation and (3) calculation of soil hydraulic properties (Ku and soil water contents) based on the simplified evaporation method (SEM) [6, 7].
    Main references:
    [1] van Genuchten (1980) <doi:10.2136/sssaj1980.03615995004400050002x>, 
    [2] Mualem (1976) <doi:10.1029/WR012i003p00513>, 
    [3] Peters (2013) <doi:10.1002/wrcr.20548>, 
    [4] Iden and Durner (2013) <doi:10.1002/2014WR015937>, 
    [5] Peters (2014) <doi:10.1002/2014WR015937>,
    [6] Wind G. P. (1966),
    [7] Peters and Durner (2008) <doi:10.1016/j.jhydrol.2008.04.016> and
    [8] Brooks and Corey (1964).