Better cotton farming methods in terms of irrigation, fertilization and plant density: An impression and conclusion from recent research

Abstract

A significant portion of research has focused on cotton to achieve high yield, increase water use efficiency (WUE), nitrogen use efficiency (NUE) and phosphorus use efficiency (PUE). This review is based on the results of recent research and in order to determine the appropriate field operations of cotton plants in terms of irrigation, fertilization and plant density, to achieve maximum yield with high water use efficiency (WUE), nitrogen use efficiency (NUE) and phosphorus use efficiency (PUE). The results of these researches show: 1) Under water stress conditions, high density with low or no nitrogen consumption, but in optimal irrigation conditions, low density with nitrogen consumption, are preferred farming operations, both to increase yield and increase resource use efficiency. 2) in conditions of high nitrogen supply or high densities, in order to control overgrowth and strengthen reproductive organs, consumption of phosphorus or PSB bacteria is one of the useful agronomic operations in all irrigation regimes, but in these conditions, PUE in water stress condition is higher than optimal irrigation conditions. 3) The uptake and response of plants to nitrogen and phosphorus are mostly determined by the sink and the source, respectively. 4) High plant density and limited irrigation, increase the leaf to boll ratio (sink limitation), thus reducing NUE and increasing PUE. In recent years, different and sometimes contradictory results have been obtained from cotton field researches in this regard, and in this review, an attempt has been made to provide a brief and understandable interpretation of these contradictory results.