Interactions among irrigation and nitrogen fertility regimes on Mid-South cotton production

Authors: Pettigrew, William; Zeng, Linghe

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2014
Publication Date: 7/18/2014
Citation: Pettigrew, W.T., Zeng, L. 2014. Interactions among irrigation and nitrogen fertility regimes on Mid-South cotton production. Agronomy Journal. 106:1614-1622.

Interpretive Summary: Agricultural production inputs have steadily increased in prices during the past few years. Two inputs closely tied to price of petroleum, nitrogen fertilizer and irrigation, have seen considerable cost increases. Petroleum products are used in the manufacture of most nitrogen fertilizers and diesel is used to power many of the irrigation pumps throughout the cotton production belt. Scientists at the USDA-ARS Crop Production Systems Research Unit and Crop Genetics Research Unit at Stoneville, MS conducted research to address how cotton’s growth, lint yield, and fiber quality were affected by varying irrigation regimes and levels of nitrogen fertilization. Four cotton varieties were grown under either irrigated or non-irrigated conditions and treated with one of three nitrogen fertilization levels (0 lbs N/acre, 50 lbs N/acre, and 100 lbs N/acre). All the cotton varieties responded the same to both nitrogen fertilization and irrigation. Additional water or nitrogen did not produce additional growth or yield benefits if the other was not present in sufficient quantities so that it did not become a limiting factor. This research provides information on what to expect in terms of cotton growth and productivity from varying irrigation or nitrogen fertilization regimes when the other input is not available at optimal levels. Agronomists, crop physiologists, extension personnel, consultants, and producers will be able to utilize information from this research to make decisions about input allocation for each individual field.

Technical Abstract: Increasing costs for irrigation and nitrogen fertilization has led to the desire from cotton (Gossypium hirsutum L.) producers to make the most efficient use of these inputs. Objectives for this research were to determine how cotton responded to varying levels of irrigation and nitrogen fertilization. Field studies were conducted from 2009-2012 at Stoneville, MS using four cotton cultivars. Two soil moisture regimes (dryland and irrigated) and three N fertilization levels (0, 56, 112 kg N ha-1) were imposed upon these varieties. Dry matter partitioning, leaf chlorophyll concentration, lint yield, yield components, and fiber quality data were collected on all the plots. All the cotton cultivars responded similarly to nitrogen fertilization and irrigation. Although cotton responded to both nitrogen and irrigation, the level of the benefit from one of these inputs was dependent upon the availability of the other component. Lint yield did not respond to irrigation when no nitrogen had been applied. Similarly the lint yield nitrogen response was muted when the soil moisture was limited. These data aid the decision making process when circumstances limit the optimal availability of one of these two vital components.