Regional Agricultural Research Station, Assam Agricultural University, Nagaon – 782 002, India
*Corresponding author's e-mail: duttasamiron@rediffmail.com, Present Address: Department of Soil Science, Assam Agricultural University, Jorhat, 785013, Assam, India
Online published on 27 January, 2014.
Plant samples from summer rice crop and corresponding surface soil samples (0–15 cm) were collected from farmer's fields of Shallow Tube Well command areas of Central Brahmaputra Valley Zone, Assam. Analysis of soil and plant samples revealed widespread potassium deficiency in soil and rice crop. The average 1 N NH4OAc extractable K in the soils of different agricultural subdivisions of the zone varied from 48 to 63 mg kg−1 and rated as low as per the nutrient index, except Kaliabar sub-division. On an average, 28 and 58% rice plants grown in the zone were categorized as moderately and extremely deficient in potassium respectively. Potassium deficiency was observed despite higher amount of non-exchangeable K (812 – 1598 mg kg−1) content in the soils.
Available K, Potassium indexing, Reserve K, Summer rice
