Critical limits of zinc in soil and rice plant grown in alluvial soils of West Bengal, India

Mk Mahata,P Debnath,Sk Ghosh

doi:10.3329/sja.v10i2.18334

Abstract

A study was conducted in 22 alluvial soils of West Bengal, India to estimate the critical limit of Zn in soil and rice plant for predicting the response of rice (Oryza sativa) to zinc application. The DTPA-extractable Zn was positively and significantly correlated with CEC, organic carbon and clay contents and negatively correlated with pH, silt and sand contents of soil. The DTPA-extractable Zn also showed a positive correlation with dry matter yield and plant Zn content. The critical concentration of Zn in these soils was established at 0.75 mg kg-1 for rice and that of 28.0 mg kg-1 in the plant tissue. Soil containing Zn below the critical limit responded appreciably to Zn fertilization. A negative response to Zn application was also observed at its higher level. The average dry matter yield increases with increasing level of Zn application up to 2.5 mg kg-1 in Zn deficient soils. The average response to Zn application in rice in Zn deficient soils was found to be 68.5% and 19.9% in Zn adequate soils. DOI: http://dx.doi.org/10.3329/sja.v10i2.18334 SAARC J. Agri., 10(2): 137-146 (2012)

Highlights

Rice is one of the most important food crops and a primary food source for more than one third of world’s population (Prasad et al, 2010)
Available zinc content of the soil samples was extracted with DTPA-TEA extractant following the method of Lindsay and Norvell (1978) and the concentration of Zn in the extracted solution was estimated with the help of Atomic Absorption Spectrophotometer (AAS)
The data of DTPA-extracted zinc and relevant physical and chemical properties of the soils of alluvial zone of West Bengal are presented in table 1

Summary

INTRODUCTION

Rice is one of the most important food crops and a primary food source for more than one third of world’s population (Prasad et al, 2010). The deficiencies of micronutrients are of critical importance for sustaining high productivity of rice in India. Zinc is one of the essential plant micronutrients and its importance for crop productivity is similar to that of major nutrients (Rattan et al, 2009). Widespread and extensive Zn deficiency has been reported in the soils of lowland rice cultivation of India, Bangladesh, Pakistan, Philippines, Myanmur, Indonesia, Japan, Korea, Taiwan and Thailand (IRRI, 1978). Realising the importance of Zn in plant growth and at the same time seriousness of its deficiency in soils and plants, an attempt was, made to study the critical concentration of Zn in soils and rice crop which is widely grown in the region of West Bengal for making Zn application more rational

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSION

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