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Root Distribution of Temperate Forage Species Subjected to Water and Nitrogen Stress
Author(s) -
Skinner R. Howard,
Comas Louise H.
Publication year - 2010
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2009.08.0461
Subject(s) - biology , shoot , agronomy , forage , forb , temperate climate , legume , biomass (ecology) , growing season , field experiment , biomass partitioning , nutrient , botany , grassland , ecology
ABSTRACT Root allocation and distribution patterns can influence forage yield during periods of moisture or nitrogen stress, as deep‐rooted species access water and nutrients found deeper in the soil profile. In a greenhouse study, we examined rooting characteristics to a depth of 50 cm for 21 cool‐season forage species (9 grasses, 6 legumes, and 6 forbs) exposed to drought and low N conditions. The goal of this research was to compare root distribution under uniform growing conditions for common grass, legume and non‐leguminous forb species found in humid‐temperate pastures of the northeast United States. Nitrogen or water stressed grasses generally had greater root biomass and a greater proportion of roots in the 30 to 40 cm soil layer than did stressed legumes or forbs. Low N significantly reduced root weight, but to a lesser extent than the decrease in shoot weight, resulting in an increase in root/shoot ratio. Drought stress reduced shoot weight but had no effect on root weight, also resulting in a greater root/shoot ratio. Drought stress also increased the proportion of deep roots compared with controls, whereas, N stress did not. Comparisons with previously published field studies suggested that information from container‐grown plants could provide insights into field results, and also suggested that inherent species differences in root distribution could explain some, but not all, rooting patterns observed in multi‐species forage mixtures.