Micronutrients in the soil and wheat: Impact of 84 years of organic or synthetic fertilization and crop residue management

Authors: SHIWAKOTIA, SANTOSH - Oregon State University; ZHELJAZKOV, VALTCHO - Oregon State University; Gollany, Hero; KLEBER, MARKUS - Oregon State University; XING, BAOSHAN - University Of Massachusetts; ASTATKIE, TESS - Dalhousie University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/12/2019
Publication Date: 8/19/2019
Citation: Shiwakotia, S., Zheljazkov, V.D., Gollany, H.T., Kleber, M., Xing, B., Astatkie, T. 2019. Micronutrients in the soil and wheat: Impact of 84 years of organic or synthetic fertilization and crop residue management. Agronomy. 9(8). https://doi.org/10.3390/agronomy9080464.
DOI: https://doi.org/10.3390/agronomy9080464

Interpretive Summary: Crop residues are an important source of plant nutrients. However, information on the various methods of residue management on micronutrients in soil and wheat over time is limited. A long-term (84 years) agroecosystem experiment was assessed to determine the impact of fertilizer type and methods of crop residue management on micronutrients over time under dryland winter wheat-fallow rotation. The treatments were: no nitrogen (N) application with residue burning in fall (FB), spring (SB), and no residue burn (NB); 40 or 80 lb N/ac with SB and NB; pea vines; farmyard manure (FYM) and a nearby undisturbed grass pasture (GP). Wheat grain, straw, and soil samples from 1995, 2005, and 2015 were used to determine tissue total and soil Mehlich III extractable manganese, copper, boron, iron, and zinc, and soil pH. After 84 years, extractable manganese and born in the top 4 inches of soil decreased in all plots, except for boron in FYM and spring burned treatment. The FYM plots had the highest extractable manganese (114 ppm) in the top 4 inches soil; however, it declined by 33% compared to the grass pasture (171 ppm). Extractable zinc in the top 4 inches of soil increased with FYM while it decreased with inorganic N application in 2015; however, total zinc in grain increased by 7% with inorganic 80 lb N/ac application compared to FYM application. The results suggest that residue management had similar impact on soil micronutrients. Inorganic N and FYM application can be integrated to reduce micronutrient losses from cultivation.

Technical Abstract: Crop residues are an important source of plant nutrients. However, information on the various methods of residue management on micronutrients in soil and wheat (Triticum aestivum L.) over time is limited. A long-term (84 years) agroecosystem experiment was assessed to determine the impact of fertilizer type and methods of crop residue management on micronutrients over time under dryland winter wheat-fallow rotation. The treatments were: no N application with residue burning in fall (FB), spring (SB), and no residue burn (NB); 45 kg N/ha with SB and NB; 90 kg N/ha with SB and NB; pea vines; farmyard manure (FYM) and a nearby undisturbed grass pasture (GP). Wheat grain, straw, and soil samples from 1995, 2005, and 2015 were used to determine tissue total and soil Mehlich III extractable Mn, Cu, B, Fe, and Zn, and soil pH. After 84 years, extractable Mn and B in the top 10 cm soil decreased in all plots, except for B in FYM and SB. The FYM plots had the highest extractable Mn (114 mg/kg) in the top 10 cm soil; however, it declined by 33% compared to the GP (171 mg/kg). Extractable Zn in the top 10 cm soil increased with FYM while it decreased with inorganic N application in 2015; however, total Zn in grain increased by 7% with inorganic N (90 kg/ha) application compared to FYM application. The results suggest that residue management had similar impact on soil micronutrients. Inorganic N and FYM application can be integrated to reduce micronutrient losses from cultivation.