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P. K. Samant ¹, S. K. Swain ², H. K. Senapati ², S. K. Sahu ²

Affiliations
1 Department of Soil Science, Krishi Vigyan Kendra, Jajang, Kapaleswar, Kendrapara (Orissa), IN
2 Krishi Vigyan Kendra, Jajang, Kapaleswar, Kendrapara (Orissa), IN

Abstract

A field experiment was conducted for five years in the Central Research Station of Orissa University of Agriculture and Technology, Bhubaneswar, Orissa during 1994-1995 in order to study the long-term effects of phosphate rocks for rice-groundnut cropping system. Rice variety Lalat and groundnut variety ICGS 11 were taken as the test crop. Altogether there were ten treatments including control. The soil of the experimental site was sandy to sandy clay loam (Fluventic Ustochrept) having pH 5.6, low organic carbon, medium available ‘P’, (Olsen and Bray) and low CEC. Three rock phosphates (water insoluble) namely Yousouffia, Gafssa and Tebessa (YRP, GRP, and TRP) imported from Morocco along with one indigenous i.e. Mussoorie rock phosphate (MRP) were applied @ 250 kg and 500 kg P₂O₅ ha^-1 once before planting of rice was compared with water soluble form of fertilizer i.e. DAP was applied @ 50 kg ha^-1 to each crop on each seasons for five years. Application of rock phosphate increased the yield of rice and groundnut over control and DAP. Application of 500 kg P₂O₅ ha^-1 from rock phosphate source produced significantly higher yield over 250 kg P₂O₅ ha^-1 but reverse trend was marked in case of apparent ‘P’ recovery (APR), agronomic efficiency (AE) and production efficiency (PE). Available ‘P’ status showed an increasing trend from the initiation of the experiment till the end of the experiment. The sustainable yield index (SYI) indicated almost all the treatments to be recommendable excepting control in case of groundnut.

Keywords

Rock Phosphate, ARP, AE, PE, SYI.

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H. K. Senapati ¹, A. K. Dash ², G. H. Santra ², B. Mohanty ²

Affiliations
1 Department of Soil Science and Agricultural Chemistry, Orissa University of Agriculture and Technology, Bhubaneswar (Orissa), IN
2 Department of Soil Science and Agricultural Chemistry, College of Agriculture, Orissa University of Agriculture and Technology, Bhubaneswar (Orissa), IN

Abstract

The long term fertilizer experiment was designed in Aeric Haplaquept of Bhubaneswar, Orissa with rice-rice cropping system. The treatments comprised of 100% N, NP, NPK (with and without S, Zn, FYM and Weedcide) 50 % and 150 % NPK along with control (no fertilizer) and an additional treatments receiving lime+NPK (based on soil test). In the preceding years substantial yield reductions of kharif rice were observed in the treatment receiving either to K or low rates of K application. Moreover, K balance sheet was found to be negative in all the treatments. In spite of negative K balance there was gain of NH₄OAC extractable K from 10 to 30 kg ha^-1 and loss of non exchangeable K from 17 to 121 kg ha^-1 in all the treatments over initial value. Equilibrium activity ratio (AR Ke) was found to be the lowest 1.2 x 10^-3 (M/l)^1/2 in 100 % NP and highest (3.2 x 10^-3 (M/L)^1/2 in 150 % NPK treatment. Potential building capacity (PBC-K) was highest in the treatment receiving lime + NPK (soil test). Labile K (-DKe) was lowest (2.2 x 10^-2 meq/100 g) in 100 % NP treatment as against 3.4 x 10^-2 meq/100 g in the treatments receiving lime + NPK (soil test). K/N ratio of plant was much lower at the PI stage and also decreased with increasing levels of NPK which showed that K availability was not in proportion to availability of N. K/Fe ratio increased 2 to 3 fold and there was also increase of Mn/Fe ratio of PI stage with increasing levels of K. Variations in K content in plant were found to be significantly related to the variation in equilibrium concentration of K, ARKe, NH₄ OAC-K and HNO₃-K. Fe content in plant decreased with increasing levels of K application. Yields were significantly higher with higher levels of K.

Keywords

Long Term Fertilizer Use, K Nutrition, Rice-Rice Cropping System, Rice Yield.

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H. K. Senapati ¹, A. K. Das ¹, R. Acharya ¹

Affiliations
1 Department of Soil Science and Agricultural Chemistry, Orissa University of Agriculture and Technology, Bhubaneswar (Orissa), IN

Abstract

A field experiment was conducted in the central farm of OUAT during 2005-2008 with rice-rice cropping sequence using inorganic, organic and integration of both type of fertilizers. The soil samples after completion of Rabi rice crop was taken for present study purpose. Due to application of readily available sources of energy along with organic nutrients the microbial population in soil was increased which influenced the microbial decomposition process. The rate of organic matter decomposition was studied by incubation method, from the result it was observed that during fifth week of incubation with dextrose the highest value of 21.98 mg carbon/100g soil was obtained in silicate slag (Soil conditioner) treated plot, where as lowest value was observed with unammended soil of control plot. On the other hand the highest population counts of 13.7×10⁷ number of bacteria and 3.14×10⁶ number of fungi were observed in FYM treated plot where as the highest of 2.6×10⁵ number of actinomycetes were observed in silicate slag treatment.

Keywords

Manuring, Microbial Activity, Organic Matter Decomposition, Rice-Rice Cropping System.

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