Cotton Biomass Accumulation and Yield in an Irrigated Arkansas Production System.

The goals of this research project are to determine the dry matter production and yield of two modern cotton cultivars (Deltapine 2038 and NexGen 4936) grown in a furrow-irrigated system that is typical of eastern Arkansas production. The study was replicated at three different site years: in 2021 at the University of Arkansas System Division of Agriculture's Lon Mann Cotton Research Station (LMCRS), and in 2022 at the Lon Mann Cotton Research Station and at the Rohwer Research Station (RRS). The 2021 site year was planted on a Zachary silt loam, while the 2022 Lon Mann Cotton Research Station site year was planted on a Convent silt loam, with the 2022 Rohwer Research Station site year on a Sharkey and Desha silt loam. Treatments included two different rates of fertilizer designed to apply 100% and 125% of current University of Arkansas Soil Test Laboratory fertilizer rate recommendations for nitrogen (N), phosphorus (P), and potassium (K) based on soil test nutrient levels where applicable. Fertilizer treatments were applied preplant and at early squaring. For the 100% rate, the sum of the fertilizer treatments was applied as follows: 2021 LMCRS 70 lb P₂O₅, 60 lb K₂O, 110 lb N; 2022 LMCRS 50 lb P₂O₅, 95 lb K₂O, 110 lb N; 2022 RRS 50 lb P₂O₅, 40 lb K₂O, 110 lb N. The sum of the fertilizer treatments applied for the 125% rate were as follows: 87.5 lb P₂O₅, 75 lb K₂O, 137.5 lb N; 2022 LMCRS 62.5 lb P₂O₅, 119 lb K₂O, 137.5 lb N; 2022 RRS 62.5 lb P₂O₅, 50 lb K₂O, 137.5 lb N. Preliminary results show no difference between either the cultivars or the fertilizer treatments. Total averaged aboveground biomass for the first sample time of the year (10 days after emergence) ranged from 11 lb/ac to 33 lb/ac, while the final sample time (at the start of the defoliation period) ranged from 1594 lb/ac to 2722 lb/ac. Lint yields averaged across cultivars and fertilizer treatments within each site year ranged from 427 to 2249 lb/ac. [ABSTRACT FROM AUTHOR]