M.A. Thesis:

the effect of time and type of fertilizer on yield and yield components of cotton in saline condition

In order to evaluate the effect of time and type of fertilizer on yield and yield components of cotton in saline experiment, a factorial experiment was conducted in a randomized complete block design with three replications in a private farm in Sabzevar during 2016-2017. factors were: application time of fertilization as foliar application (vegetative, flowering, vegetative + flowering) and type of fertilizer (urea (0.5%), Humic acid (10 L.ha-1), Nitroplas (5 per thousand) and seaweed extract (2 L.ha-1). The results showed that application time had significant effect on yield and yield components of cotton, except for 1000 grain weight. Foliar application at flowering had the highest chlorophyll index, number of monopodial branches, number of sympodial branches, lint percent, cotton seed yield, fiber yield and fiber index, while the highest plant height, number of bolls per plant, boll weight, cotton per boll and cotton yield was observed with foliar application at flowering + vegetative stage. In the case of most of studied traits, there was no significant difference between spraying at flowering stage and flowering + vegetative time. Foliar application at vegetative stage had only more unopenings boll per plant in comparison with other spray treatments. The reaction of yield and yield components varied to e type of fertilizer, while the highest chlorophyll index, number of seeds per boll and fiber yield were obtained by urea foliar application, Nitroplasm spray had the highest number of closed boll per plant, lint percent and fiber index. Spraying with seaweed extract produced the highest height, number of branches, number of bolls per plant, boll weight, cotton seed yield and seed cotton yield. The weight of 1000 seeds did not show a significant response to type of fertilizer. In general, the results of this experiment showed that in saline conditions, the use of seaweed extract during vegetative + flowering was more suitable for most of studied traits than other fertilizers. Therefore, in order to obtain best seed cotton yield, it is recommended that the seaweed extract used with a concentration of 2 L.ha-1 during vegetative + flowering.

Keywords: Cotton, Salinity, Biological fertilizer, Foliar application