Nitrogen calibration strip: An on‐farm tool to further reduce N requirements in cotton on an integrated crop‐livestock rotation system. (19th July 2021)

• Record Type: Journal Article
• Authors: Sidhu, Sudeep Singh; Wright, David L.; George, Sheeja; Small, Ian
• Is Part Of: Agronomy Journal. Volume 113:Number 4(2021)
• Page Start: 3615
• Page End: 3627
• Publication Date: 2021-07-19
• Subjects: Agronomy -- Periodicals; 630
• DOI: 10.1002/agj2.20730
• Languages: English
• ISSNs: 0002-1962

Abstract

Abstract: In cotton ( Gossypium hirsutum L.) production systems, mineral N is the most managed nutrient because of its mobility and therefore optimal use of N is an important goal for sustainable management of cotton. Soil characteristics influence the availability of N for plant growth and therefore spatial variability in soil should be considered for optimal N fertilization. The study was established in a 4‐yr rotation with 2 yr of bahiagrass ( Paspalum notatum Flueggé) followed by peanut ( Arachis hypogaea L.) and cotton. A 2‐yr study was conducted to develop zone‐specific in‐season N recommendations based on soil electrical conductivity (EC) variations captured by Veris MSP3. Each year, nitrogen calibration strips (NCS) were established in the cotton quadrant to inform in‐season N fertilization rate decisions. The NCS informed in‐season N rates varied from 34 to 101 kg N ha –1 for two EC zones. In 2019, NCS informed N rate (34 kg N ha –1 ) was a 50% reduction from the standard N rate of 67 kg ha –1 with no loss in cotton lint yield in zone 1. In zone 2, in‐season N application was reduced to 50 kg N ha –1 from the standard N rate with no loss in cotton lint yield. Nitrogen calibration strips have the potential to be used as an on‐farm tool to assist growers in making optimal in‐season N application decisions. Core Ideas: Variability within a field is captured based on soil electrical conductivity (EC). Differential response of N is captured by establishing nitrogen calibration strips (NCS). Nitrogen calibration strips consist of incremental rates of N established at planting. Normalized difference vegetation index (NDVI) and visual quality ratings (VQR) were used to evaluate N response. Strip informed in‐season N application rates were 25–50% lower than standard rate.