|Neel, James - Jim|
Submitted to: Journal of Agronomy and Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2002
Publication Date: 9/15/2002
Citation: NEEL, J.P., ALLOUSH, G.A., BELESKY, D.P., CLAPHAM, W.M. INFLUENCE OF RHIZOSPHERE IONIC STRENGTH ON MINERAL COMPOSITION, DRY MATTER YIELD AND NUTRITIVE VALUE OF FORAGE CHICORY. JOURNAL OF AGRONOMY AND CROP SCIENCE. 2002. v. 188. p. 398-407.
Interpretive Summary: Grazing livestock deposit manure and urine creating patches of highly concentrated nutrients, which influences plant production, sward composition and nutritive value. Feedlots and areas where manure is stored or composted have similar localized zones of nutrient enrichment but on a much larger scale. Plants that tolerate high nutrient concentrations and associated soil conditions could help stabilize pasture production or be utilized as a nutrient "mops". Chicory appears to thrive in high nutrient input situations, but no information is available on just how much of a nutrient load chicory can tolerate. A greenhouse experiment was conducted to determine chicory tolerance of nutrient induced salt stress in the root zone. Chicory grew well in relatively high root zone salt stress. Herbage mineral content and nutritive quality were measured. Some minerals in herbage such as nitrate-nitrogen and potassium exceeded maximum recommendations for ruminant diets, whereas protein and energy indicate chicory is comparable to other high quality, mineral-rich forages. Chicory appears to be a good choice for forage mixtures to help control excess nutrients in feedlot areas or in localized nutrient-rich patches in pasture to stabilize herbage production.
Technical Abstract: Localized patches of high ionic strength (IS) can occur with manure and urine deposition in pastures, influencing plant production, sward composition and nutritive value. Abandoned feedlots and areas where manure has been composted, also have similar soil environments but on a much larger scale. Plants that tolerate IS challenges could help stabilize pasture production or "mop" up nutrients in feedlot areas. Chicory (Cichorium intybus L.) appears to thrive in high nutrient input situations, but no information is available on chicory response to increasing IS. We conducted a greenhouse experiment to evaluate the effect of rhizosphere ionic strength (0.9, 4.0, 8.0 and 12.0 dS m-1) on the productivity and nutritive value of chicory. Dry matter production decreased linearly as IS increased and indicated chicory is moderately tolerant to soil salinity. Shoot mineral concentrations for Ca, Na and Cl increased as IS increased. All concentrations of minerals, except Cu, were either substantially highe or equal to the highest concentrations reported for forages. In vitro organic matter disappearance increased and nitrate-N decreased as IS increased. At all IS, nitrate-N and K exceeded maximum recommendation for ruminant diets. Sodium was below the maximum tolerable level for ruminants but may influence dry matter intake at the highest IS level. Crude Protein and energy estimates indicate animal production levels equivalent with other high quality forages while mineral content would make it a good dietary supplement at any IS. Chicory as a component of a forage mixture could help stabilize forage yield in pastures with localized or generally high IS patches arising from nutrient inputs. It also shows promise as a nutrient mop in feedlot areas where excess soil nutrients are a problem.