Phosphorus availability to rice ( Oriza sativa L.)–wheat ( Triticum estivum L.) in a Vertisol after eight years of inorganic and organic fertilizer additions

• Published in: Bioresource technology 2007-05, Vol.98 (7), p.1474-1481
• Main Authors: Singh, Muneshwar, Reddy, K. Sammi, Singh, V.P., Rupa, T.R.
• Format: Article
• Language: English
• Subjects: Agriculture - methods; Agronomy. Soil science and plant productions; Apparent P recovery; Asteraceae; Biological and medical sciences; Biological Availability; Cattle manure; Fertilizer N; Fertilizers; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Green manure; India; Manure; Nitrogen; Organic and inorganic P pools; Oryza - metabolism; Oryza sativa; Other nutrients. Amendments. Solid and liquid wastes. Sludges and slurries; Parthenium; Parthenium hysterophorus; Phosphorus - pharmacokinetics; Soil - analysis; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Time Factors; Triticum; Triticum - metabolism; Use of agricultural and forest wastes. Biomass use, bioconversion; Vertisol
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2006.02.045

Integrated use of inorganic fertilizer N and well decomposed cattle manure (CM) or 30–35 days old Parthenium ( Parthenium hysterophorus L.), a weed grown off site as green manure (GM) under repeated applications of fertilizer P and urea N for eight years in a rice ( Oriza sativa L.)–wheat ( Triticum estivum L.) sequence was studied on transformation of fertilizer P applied to soil at the National Research Center for Weed Science, Jabalpur, India. Based on the results, it appeared that, repeated applications of 52 kg super-phosphate P resulted in a marked increase in Olsen P linearly with time. Conjunctive use of urea fertilizer N with organic manure resulted in a larger increase in Olsen P in the Vertisol. Studies further revealed that the greater accumulation of fertilizer P applied in excess to crop removal occurred in inorganic P in the plots receiving only fertilizer N. However, plots receiving fertilizer N along with organic manures led to P accumulation predominantly in organic forms. The study suggests that these two pools of P acted as a sink when fertilizer P was applied in excess to crop removal and are bio-chemically active. The Olsen P status after 8 cycles of rice–wheat crops revealed that the average amount of fertilizer P required after adjusting for crop uptake to increase Olsen P by 1 mg kg −1 soil was 7.2 kg P ha −1 in the plots receiving only fertilizer N. Whereas, application of 5 t FYM or 6 t GM reduced it to 4.6 kg P ha −1. The plots receiving manure always maintained a greater concentration of Olsen P. The application of CM or GM with fertilizer N enriched short-term inorganic P as well as long-term organic P fertility. After eight years, larger concentrations of organic P in the subsurface layer (16–30 cm), compared to initial values, indicates downward movement of P in organic forms.