Submitted to: Journal of Plant Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/13/2011
Publication Date: 1/17/2014
Publication URL: http://handle.nal.usda.gov/10113/59063
Citation: Fageria, N.K., Baligar, V.C., Li, Y.C. 2014. Nutrient Uptake and Use Efficiency by Tropical Legume Cover Crops at varying pH of an Oxisol. Journal of Plant Nutrition. 37:294-311. Interpretive Summary: In Oxisol soils of South America low soil fertility and high soil acidity are major chemical constraints that limit plant growth. Inclusion of legume cover crops in cropping system provide vegetative cover to reduce soil and nutrient loss by erosion, improved soil fertility by fixing atmospheric nitrogen and weed suppression. Cover crops tested showed significant differences in growth and nutrient use efficiency and these parameters were influenced by level of soil acidity. Use of nutrient efficient cover crops to improve fertility of degraded soils appears to be an important management strategy. Farmers would benefit from use of these nutrient efficient cover crops due to reduced cost of fertilizer inputs, and improved soil fertility and crop yields. Nutrient use efficiency traits identified could be useful in selection of cover crop species in cultivar improvement programs.
Technical Abstract: Oxisols comprise large soil group in tropical America. These soils are acidic and having low fertility. Use of tropical legume cover crops in cropping systems is an important strategy to improve fertility of these soils for sustainable crop production. Data are limited on nutrient uptake and use efficiency of tropical cover crops under different acidity levels. The objective of our study was to evaluate growth and nutrient uptake parameters of 16 tropical legume cover crops under three soil pH (5.1, 6.5, and 7.0) of an Oxisol. Shoot dry weight was influenced significantly by pH and cover crop treatments and their interactions, indicating that cover crops used had differential responses to changing soil pH levels. Overall, shoot dry weight decreased when soil pH was raised from 5.1 to 7.0, indicating acidity tolerance of cover crops. Nutrient concentration (content per unit of dry weight), uptake (concentration X dry weight) and nutrient use efficiency (dry weight of shoot per unit of nutrient uptake) varied significantly among cover crops. The variation in nutrient uptake and use efficiency among cover crop species was associated with variation in shoot dry matter production. Significant variation among crop species in dry matter production and low C/N ratio (average value of 14.25) suggest that cover crops which produced higher dry matter yield like white jack bean, gray mucuna bean, black mucuna bean, mucuna bean ana, and lablab are important choices for planting in tropical soils to recover large amount of macro and micro nutrients and prevent in their leaching in soil plant systems.