Diagnostic Techniques for Nitrogen Requirements in Crop Plants - Nitrogen Management in Crop Production - page 133

TABLE 3.4
Adequate Total Nitrogen Concentration in the Plant Tissue of Principal Food Crops

Crop Species Growth Stage Plant Part Analyzed N Concentration (g kg − 1 )

Rice 1 Heading Uppermost mature leaves 26-42

Wheat Tillering Leaf blade 43-52

Wheat Shooting Leaf blade 36-44

Wheat Heading Leaf blade 21-30

Wheat Flowering Leaf blade 27-30

Barley Tillering Leaves 47-51

Barley Shooting Leaves 45-47

Barley Heading Whole tops 20-30

Barley Flowering Leaves 29-35

Corn 30-45 DAE Whole tops 35-50

Corn Before tasseling LB below the whorl 30-35

Corn Silking BOAC

>32

Corn Silking Ear LB 28-35

Sorghum Seedling Whole tops 35-51

Sorghum Early vegetative Whole tops 30-40

Sorghum Vegetative YMB 32-42

Sorghum Bloom 3BBP 33-40

Soybean Prior to pod set UFDTU 45-55

Dry bean Early flowering UMB 52-54

Dry bean Peak harvest Pods 31

Cowpea 30 DAS Whole tops 28

Cowpea Early flowering PUMB 11-17

Peanut Early pegging USL 35-45

Sugarcane 3 month plants TVD 24-25

Sugarcane 6 month plants TVD 19

Sugarcane 4-5 month ratoon TVD 19

Cassava Vegetative UMB 50-60

Potato 42 DAE 40-50

UMB + P

Potato Early flowering 55-65

UMB + P

Potato Tubers half grown 30-50

UMB + P

Cotton 45 DAS LB

>50

Cotton First flowering YMB 38-45

Source: Compiled from Fageria, N. K., V. C. Baligar, and C. A. Jones. 2011a. Growth and Mineral Nutrition of Field Crops ,
3rd edition. Boca Raton, Florida: CRC Press. With permission.
Note: DAE = days after emergence; LB = leaf blade; BOAC = blade opposite and above cob; YMB = younger upper most
mature leaf blade; UFDT = upper fully developed trifoliate; UMB = uppermost mature leaf blade; DAS = days after
sowing; PUMB = petiole of uppermost mature leaf blade; USL = upper stems and leaves; TVD = top visible dewlap,
which is approximately the third leaf from the shoot apex; UMB + P = uppermost mature leaf blade + petiole.

( Brassica oleracea L.). The curve for C4 crop species is N c = 4.1 W −0.5 , which is mainly for crops
such as corn, sorghum, pearl millet, and sugarcane. Justes et al. (1994) estimated the critical N
dilution curve for winter wheat in France as N c = 5.35 W −0.442 when the aboveground biomass was
between 1.55 and 12 Mg DM ha −1 . When the aboveground biomass was <1.55 mg DM ha −1 , the
constant critical value N = 4.4% DM was applied, which was independent of the aboveground
biomass. This critical N dilution curve is used for wheat production worldwide (Stockle and
Debaeke, 1997). However, some investigators have reported variations in the critical N curve