Micronutrients status of soils and rice crop in alkali land under reclamation
1988
Chhibba, I.M. | Arora, C.L. | Nayyar, V.K. | Takkar, P.N. (Punjab Agricultural Univ., Ludhiana, Punjab (India). Soils Dept.)
Crops grown on previously uncultivated salt-affected soils are expected to suffer from micronutrient deficiencies because of high pH and large amounts of Na, HCO3, and CO3 ions. The micronutrient status of surface (0-15 cm) soils and lowland rice crops in 50 alkali fields in 4 villages was studied after 5-7 yr reclamation. Leaf blade samples (top leaves) were collected at late tillering and soil samples were taken after harvest. The soils were sandy loam to loam and had pH 8.5 to 10.1, electrical conductivity 0.30 to 1.25 dS/m, 0.18-0.45% organic C, and 0-4.15% CaCO3. DTPA-Zn content varied from 0.06 to 1.50 ppm on the basis of a 0.80 ppm threshold, 60% of the soil were rated deficient in available Zn. DTPA-Fe was below the critical limit of 4.50 ppm in 14% of the samples. Available Cu (critical level 0.20 ppm) was adequate in all samples. DTPA-Mn (critical value 3 ppm) was deficient in 20% of the samples. Leaf analysis also indicated variation in Zn content (1.2 to 23.9 ppm), 42% samples were inadequate (70 ppm threshold) in 30% of the samples. Mn was adequate in all samples. Cu content was inadequate (3 ppm threshold) in 92% of the leaf samples. Both soil and plant analysis confirmed Zn deficiency in this area, but the degree of deficiency differed considerably. While soil analysis showed 14% Fe deficiency and no Cu deficiency, leaf analysis showed that the rice crop suffered from 30% Fe and 92% Cu deficiency. Although Mn was deficient in 20% of the soil samples, leaf analysis did not show any deficiency.
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