Spatial Crop Structure in Agricultural Systems

Abstract

Competition Refers to the process whereby plants share resources (e.g., mineral nutrients, water, and light) which are in insufficient supply for their joint requirements [71]. - Crop structure Refers to the spatial, temporal, and genetic arrangement of a particular crop species or genotype within a sown area. - Plant vegetative and reproductive plasticity Refers to the ability of a plant individual within a crop to modify the number of vegetative and/or reproductive structures depending on the amount of available resources. - Density Is the number of individuals of a plant species in a unit of area within a crop. - Facilitation Is the process whereby one crop species provides some sort of benefit for another species when in a polyculture. Usually, when facilitation occurs, at least one crop may positively alter the environment for the other crop [77]. - Policulture (also intercrop) Refers to crop arrangements that include more than one crop species or genotypes grown together partially or totally during the growth period of a particular area. - Potential yield Is the crop yield obtained when available resource use is maximized in a particular environmental condition and limiting factors, such as soil nutrients, or reduction factors, such as insect and plant pests and diseases, are absent [41, 78]. - Rectangularity Is a measure used to describe the spatial distribution of individual plants in crops sown in rows. It is the ratio of the mean distance between rows and the distance between individual plants within a row. - Resource complementarity Is a measure of the extent to which the crop species components in a polyculture share common limiting resources, i.e., plant components in a crop that show complete resource complementarity do not compete [71]. - Spatial arrangement Refers to the way that crop plants are distributed in a field. For example, they may be randomly distributed, when seeds or propagules are randomly broadcast or they may be sown in rows, in a regular pattern when drillers are used.