Agriculture Reference
In-Depth Information
output (economic yield) to input (fertilizers) for a process or complex system (Crop Science Society
of America, 1992). Some of these definitions pertaining to two subjects (nutrient-efficient plants and
nutrient use efficiency) reported in the literature are presented and discussed in Table 5.1. NUE in
crop plants has been defined in several ways in the literature. Graham (1984) defined NUE as the
ability of a genotype to produce superior grain yields under low soil N conditions in comparison
with other genotypes. However, most of them denote the ability of a system to concert inputs into
outputs (Fageria and Baligar, 2005).
Bandyopadhyay and Sarkar (2005) also reported that NUE can be described in different
ways depending on whether the focus is on grain only or on the total biomass. Moll et al.
(1982, 1987) defined NUE as the yield of grain per unit of available nitrogen in the soil. This
NUE can be divided into two processes: uptake efficiency, the ability of the plant to remove
N from the soil normally present as nitrate and ammonium ions; and the utilization efficiency
(UE), the ability of the plant to transfer N to the grain, predominantly present as protein. There
has recently been considerable interest in identifying the processes involved in regulating the N
uptake and metabolism within the plant (Andrew et al., 2004; Gallais and Hirel, 2004; Lea and
Azevedo, 2006).
TABLE 5.1
Definitions of Nutrient-Efficient Plants
Definition
Reference
Nutrient-efficient plant is defined as a plant that absorbs, translocates, or
utilizes more of a specific nutrient than another plant under conditions of
relatively low nutrient availability in the soil or growth media
Soil Science Society of America (2008)
The nutrient efficiency of genotypes (for each element separately) is
defined as the ability to produce a high yield in a soil that is limiting in
that element for a standard genotype
Graham (1984)
Nutrient efficiency of a genotype/cultivar is defined as the ability to acquire
nutrients from a growth medium and/or to incorporate or utilize them in
the production of shoot and root biomass or utilizable plant material
(grain)
Blair (1993)
An efficient genotype is one that absorbs relatively high amounts of
nutrients from the soil and fertilizer, produces a high grain yield per unit
of absorbed nutrient, and stores relatively little nutrients in the straw
Isfan (1993)
Efficient plants are defined as those that produce more dry matter or have a
greater increase in harvested portion per unit time, area, or applied
nutrient, have fewer deficiency symptoms, or have greater incremental
increases and higher concentrations of mineral nutrients than other plants
grown under similar conditions or compared to a standard genotype
Clark (1990)
Efficient germplasm requires less nutrients than an inefficient one for
normal metabolic processes
Gourley et al. (1994)
Efficient plant is defined as one that produces higher economic yield with a
determined quantity of applied or absorbed nutrient compared to other or
a standard plant under similar growing conditions
Fageria et al. (2008)
Source:
Adapted from Graham, R. D. 1984.
Advances in Plant Nutrition
, Vol. 1, pp. 57-102. New York: Praeger Publisher;
Clark, R. B. 1990.
Crops as Enhancers of Nutrient Use
, pp. 131-209. San Diego, California: Academic Press; Blair,
G. 1993.
Genetic Aspects of Mineral Nutrition
, pp. 205-213. Dordrecht: Kluwer Academic Publishers; Isfan, D.
1993.
Plant Soil
154:53-59; Gourley, C. J. P., D. L. Allan, and M. P. Russelle. 1994.
Plant Soil
158:29-37; Fageria,
N. K., V. C. Baligar, and Y. C. Li. 2008.
J. Plant Nutr.
31:1121-1157; Soil Science Society of America. 2008.
Glossary of Soil Science Terms
. Madison, Wisconsin: Soil Science Society of America.
