Evaluation of four crops for nitrogen utilization and carbohydrate yield

Abstract

Field experiments with 5 levels of Nitrogen (0 to 200 kg/ha) and 4 crops—chicory(Chocorium intybus), fodder beet(Beta vulgaris), Jerusalem artichoke(Helianthus tuberosus) and grain sorghum(Sorghum bicolor) that have shown promise for alcohol production were conducted at 2 locations in California. Nitrogen uptake patterns, were evaluated and N cost for producing plant storage parts and fermentable carbohydrate were calculated. The crops were compared on these criteria. The yields of vegetative and storage organs during the crop growth are reported and their rate of change with growing time were determined. Yields of vegetative parts and total biomass of Jerusalem artichoke (JA) and grain sorgum (GS) were higher than to that of chicory (CH) and fodderbeet (FB). However, due to their lower harvest index, JA and GS produced lower yields of fermentable carbohydrate and at a much higher N cost than CH and FB. Fodder beet had the highest N uptake and the response to applied N was linear. Chicory and fodder beet which had lower N uptake rates continued N uptake from soil for a longer period than either grain sorghum or Jerusalem artichoke. The N uptake of the four crops were in the decreasing order of fodder beet, grain sorghum, Jerusalem artichoke, and chicory. With N application, N concentrations of vegetative as well as storage part increased in all the crops, however, a greater proportion of applied N went into vegetative parts. At both locations, CH had the lowest N cost per unit fermentable carbohydrate produced.