Thirteen Year Long Term Fertilization Effect on Soil Phosphorus Fractions of an Acid Inceptisol and Their Contribution to Phosphorus Uptake by a Double Crop of Rice under Sub-Tropical Climate
Sugyata Shivhare *
Department of Soil Science and Agricultural Chemistry, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha 751003, India.
Kumbha Karna Rout
Department of Soil Science and Agricultural Chemistry, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha 751003, India.
Mitali Mandal
Department of Soil Science and Agricultural Chemistry, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha 751003, India.
Prasanna Kumar Samant
Department of Soil Science and Agricultural Chemistry, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha 751003, India.
Pradipta Majhi
Krishi Vigyan Kendra, Odisha University of Agriculture and Technology, Jagatsinghpur, Odisha 754160, India.
Amit Phonglosa
Directorate of Extension Education, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha 751003, India.
Raghabananda Nayak
Department of Soil Science and Agricultural Chemistry, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha 751003, India.
Akhilesh Kumar Gupta
Department of Agricultural Statistics, College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar, Odisha 751003, India.
*Author to whom correspondence should be addressed.
Abstract
A 13 year old long term fertilizer experiment conducted on an acid soil with rice-rice system was used to study the impact of continuous application of fertilizer nutrients and amendments on changes in soil phosphorus fractions and their relative contribution to P nutrition. There was accumulation of total P on surface soil in all P fertilized treatments and depletion in P minus treatments. Depending on the P balance the treatments differed significantly with respect to P accumulation. 150%NPK treatment had highest P accumulation (841.92kgha-1) in surface soil. The high yielding treatments viz. 100%NPK+FYM and 100% NPK +FYM+Lime had relatively less P built up than 100%NPK. The total P comprised of inorganic P, 64.43-89.60% and organic P, 10.40– 35.57%. The inorganic fraction in terms of their abundance were in the order: Sal-P (42.13 kgha-1) <Occl-P (52.16 kgha-1) < Al-P (52.98 kgha-1) < Ca-P (55.44 kgha-1) < Red–P (134.22 kgha-1) < Fe-P (218.70 kgha-1). Olsen P which was significantly influenced by the fertilizer treatments had a very strong positive correlation (p<0.01) with Sal-P(r= 0.469***), Occl-P(r=0.639***) and Ca-P (r=0.739***). Among the inorganic P fractions, Ca-P contributed highest of 42.57% to P uptake, followed by Occl-P (28.59%), Sal-P (18.56%) and Al-P (7.63%). The fractions in order of their relative importance for P uptake under submerged rice-rice situation are Ca-P > Occl-P > Sal-P > Al-P > Red-P > Fe-P. The study indicated that 100%NPK+FYM and 100% NPK+FYM+Lime are the best treatments for maintaining more active fractions of P required for P nutrition of rice-rice system under the tropical acid situation.
Keywords: Rice-rice system, phosphorus fractions, phosphorus uptake, long term fertilization, FYM