Potassium cycling in a corn-brachiaria cropping system

• Published in: European journal of agronomy Vol. 28; no. 4; pp. 579 - 585
• Main Authors: Garcia, R.A., Crusciol, C.A.C., Calonego, J.C., Rosolem, C.A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-05-2008; Elsevier Science
• Subjects: Agronomy. Soil science and plant productions; Animal productions; Biological and medical sciences; Cropping systems. Cultivation. Soil tillage; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Cropping systems and patterns; K dynamic; Livestock-crop integration; No-till; Non-exchangeable K; Nutrient cycling; Terrestrial animal productions; Vertebrates; No-till; Nutrient cycling; K dynamic; Livestock-crop integration; Non-exchangeable K; Translocation; Monocotyledones; Farming animal; Dynamic characteristic; Zea mays; Non-exchangeable potassium; Cropping system; Zero tillage; Biogeochemical cycle; Brachiaria; Inorganic element; Cereal crop; Gramineae; Angiospermae; Nutrient; Herbaceous plant; Spermatophyta; Livestock
• ISSN: 1161-0301; 1873-7331
• DOI: 10.1016/j.eja.2008.01.002

Growing corn mixed with forage crops can be an alternative for pasture and mulch production during relatively dry winters in tropical areas, making no-till feasible in some regions. However, little is known about nutrient dynamics in this cropping system. The objective of the present work was to evaluate K dynamics in a production system in which corn was either grown as a sole crop or mixed with
Brachiaria brizantha. In the second year of the experiment, nitrogen rates ranging from 0 to 200
kg
ha
−1 were applied to the system. Dry matter yields and potassium contents in the soil, as well as residues and plants were determined at corn planting and harvest. Potassium balance in the system was calculated. Corn grain yield in mixed crop responded up to 200
kg
ha
−1
N. The introduction of brachiaria in the system resulted in higher amounts of straw on the soil surface and higher K recycling. Soil exchangeable K balance showed an excess K for both N rates only in the mixed system; however, when non-exchangeable K was also included in calculations, excess K was found in both mixed and sole corn systems. Large amounts of non-exchangeable K were taken up in the system involving brachiaria, which showed a considerable capacity in recycling K, increasing its contents in the surface soil layer.