Nutrition 81
at least 10 samples from 3 ha area. The NEPZ soils are deficient in boron, zinc and
sulphur. The critical level of different nutrients in the soil of north Bihar is given in
Table 6.2.
A sample provides information on the uptake of nutrients by the plant. Analysis
of the petiole of the youngest fully expanded mature leaf beneath the most recently
opened flower during November is carried out. Approximately 10–20 healthy plants
are selected by walking diagonally through the plantation. The plants should be
homogeneous in appearance and representative of the plantation. Samples should be
collected in the morning after the dew has dried off. Samples should not be taken
if plants are under stress as a result of drought, disease or high temperature. After
heavy rainfall, wait at least for two weeks before taking samples. Normal nutrient
levels in petioles are given in Table 6.3.
FIGURE 6.1 (See colour insert.) Fertiliser application in papaya.
TABLE 6.2
Critical Nutrient Levels in Soils of North Bihar (India)
Sampling
Year
Organic
Carbon
(%)Available
P 2 O 5
(kg/ha)Available
K 2 O (kg/ha)Zn
(ppm)Cu
(ppm)Fe
(ppm)Mn
(ppm)B
(ppm)S
(ppm)2003 0.39 22.85 152 0.29 1.83 10.79 4.98 0.12 3.13
2004 0.59 27.42 169 0.38 1.98 11.54 5.19 0.24 1.56
2005 0.41 9.14 142 0.26 2.18 12.36 4.30 0.20 4.00