Dose Of Chemical Fertilizers Research Articles

Efficient Microorganism Compost Benefits Plant Growth and Improves Soil Health in Calendula and Marigold

Organic farming needs to be promoted as a means of sustaining soil health and reducing the cost of farming, especially for small farmers. The present study deals with the effect of organic compost, prepared using Efficient Microorganism (EM) consortium and applied along with full or half of the recommended dose of chemical fertilizers, on the growth of Calendula and Marigold plants, soil physico-chemical parameters and soil enzyme activities. Soil enzyme activities were improved with the increase in the rate of EM compost application in both Calendula and Marigold. Carotenoid pigment increased by 46.11% and 12.19% with application of EM compost over the control in Calendula and Marigold flowers respectively. Soil humus, available nitrogen and organic carbon content also increased due to the supplementation of EM compost resulting in better soil fertility. For Calendula, treatment T5 (Half dose NPK + EM compost 20 000 kg⋅hm−2) was found to be the most promising in terms of acid phosphatase (82.63 µg p-Nitrophenyl Phosphate⋅g−1⋅h−1), dehydrogenase (10.46 µg Triphenyl Formazan⋅g−1⋅d−1) and β-glucosidase (0.30 IU⋅g−1) activities. In Marigold, treatment C (Half dose NPK + EM compost 5 000 kg⋅hm−2) was the most promising in terms of amendment in soil enzyme activities.

Evaluation of indigenous rhizobacterial strains with reduced dose of chemical fertilizer towards growth and yield of mustard ( Brassica campestris ) under old alluvial soil zone of West Bengal, India

Abstract A field experiment had been carried out in the Crop Research and Seed Multiplication Farm of The University of Burdwan, West Bengal, India during the two consecutive winter seasons of 2011-2012 and 2012-2013 to study the effect of indigenous rhizospheric bacterial strains on growth, physiology and yield of mustard variety. Pseudomonas putida, Burkholderia cepacia, Burkholderia sp. and their mixture were used as seed inoculants for mustard cultivation. The experiment was laid down in a randomized complete block design (RCBD) with three replications. Results revealed that indigenous inoculation (with reduced dose of chemical fertilizer) significantly increased (p

Soil microbial population and yield of rainfed maize as affected by farmyard manure and biodigester liquid manure

A field experiment was conducted during Kharif (June-October) season 2010, under rainfed condition on red sandy loam soil to study the effect of farmyard manure (FYM) and biodigester liquid manure (BDLM) on soil microbial activity and yield of rainfed maize (Zea mays L.). A total of 13 treatments were laid out in a randomized complete block design with three replicates. The treatment combinations comprised of different levels of FYM (7.5, 10 and 12.5 t/ha) and BDLM-equivalent N (BDLME: 75, 100, 125 and 150 kg N/ha) compared with control [FYM 7.5 t ha-1 + recommended dose of chemical fertilizer (RDF): 100:50:25 kg N:P:K/ha]. Application of FYM (12.5 t/ha) + BDLME (150 kg N/ha) recorded a significantly higher microbial population in soil after crop harvest total bacteria 50.5×106 CFU/g, fungi 26.0×104 CFU/g, and actinomycetes 23.8×103 CFU/g), grain yield and straw yield compared to the rest of the treatments. Application of FYM (7.5 t/ha) + BDLME (75 kg N/ha) resulted in the lowest values for these parameters.

Determining Optimal Dose of Chemical Fertilizer on Biofortified Bean in Sud-Kivu Highlands

<p>Rational application of chemical fertilizer increases crop yield of biofortified bean. This study aimed at determining the optimal dose of chemical fertilizer to apply on two biofortified bean varieties used in the community in order to maximize their yield. Following a split-plot design, a field experiment was carried out on CODMLB001 and HM21-7 varieties, in Kashusha (Kabare territory) in Sud-Kivu Highlands, after a strategic application of increasing doses of chemical fertilizer NPK 17-17-17 (D<sub>0</sub>: Control; D<sub>1</sub>: 50 kg ha<sup>-1</sup>; D<sub>2</sub>: 75 kg ha<sup>-1</sup>; D<sub>3</sub>: 100 kg ha<sup>-1</sup>; D<sub>4</sub>: 125 kg ha<sup>-1</sup> and D<sub>5</sub>: 150 kg ha<sup>-1</sup>). The said doses were applied on the sowing day in a parallel gutter at 5cm from the sowing line. The germination rate, the number of days at both the flowering stage and the stage of physiological maturity, as well as the number of harvested crops and beans per plant, number of beans per pod, weight per 1000 grains and yield were observed. Positive and negative interaction between different increasing doses of chemical fertilizers regarding the two varieties were observed. This strategic application allows increased performance according to considered varieties and doses. For instance, the HM21-7 variety gave the best performance with the D<sub>5</sub> dose, while the CODMLB001 variety did better under <em>D<sub>2</sub></em>.</p>

Knowledge and adoption of recommended ratoon management practices by the sugarcane growers

The efforts were made to study the knowledge and adoption of ratoon management practices by the sugarcane cultivators from Kolhapur district of Maharashtra. The study was undertaken in purposively selected Karveer tahsil of Kolhapur district of Maharashtra in the year 2008. It is observed that most of the respondents had knowledge in respect of MPKV recommended ratoon management practices like arrangement of sugarcane trash in the furrows (100.00%), stubble shaving (100.00 %), spraying of 0.1 per cent bavistin on stubbles (96.00%), application of decomposing material (86.00 %) and application of 1st dose of chemical fertilizers (92.00%). Adoption of recommended ratoon management practices reveal that level of adoption was less as compared to their level of knowledge.

Effect of integrated nutrient management on growth, yield and yield attributing characters in cluster bean [Cymopsis tetragonaloba (L.) Taub.

The experiment was carried out during kharif season of 2013. The experiment was conducted in randomized block design with three replications using cv. HG - 365, with eleven treatments. The combination of FYM and vermicompost with two kinds of bio-fertilizers (Azotobacter and PSB) and reduced doses of chemical fertilizers were tested in comparison to recommended dose fertilizer. The yield components viz., number of clusters plant-1, number of pods in a cluster, length and diameter of pod differed significantly due to the different INM treatment. The treatment 75% of recommended dose of inorganic fertilizers and 25% RDF through vermicompost along with biofertilizers (Rhizobium at 25 g kg-1 seed + PSB at 5 kg ha- 1) recorded significantly highest pod yield (159.58 g plant-1). Hence, it was concluded that, for getting optimum growth, and higher pod yield the crop should be supplied with the 75% of recommended dose of inorganic fertilizers and 25% RDF through vermicompost alongwith biofertilizers (Rhizobium at 25 g kg-1 seed + PSB at 5 kg ha-1).

Influence of integrated supply of AM, PSB, Azotobacter and inorganic fertilizer on growth, yield and quality in coriander (Coriandrum sativum) and micro-flora population in the soil

A field experiment was conducted at the Horticulture Unit of NRC on Seed Spices, Ajmer to find out the response of coriander (Coriandrum sativum L.) to the application of biofertilizers in combinations with different doses of chemical fertilizers. The treatment included various combinations of Azotobacter, Arbuscular Mycorrhizal Fungi (AMF), phospahte solublizing bacteria (PSB) in combination with 80 and 100% Recommended Dose of Fertilizer (RDF). The effects of these treatments were evaluated for various growth, yield and quality traits. Plant height, number of primary and secondary branches, number of umbel per plant, number of umbellet per umbel, number of seeds per umbellet, total seed yield per plot, chlorophyll ‘a’, ‘b’ and total chlorophyll were found maximum in treatment Azotobacter+AM+PSB+100% RDF which was at par with Azotobacter+AM+PSB+80% RDF while it was found minimum in treatment having only biofertilizer . Thus the treatment Azotobacter+AM+PSB+80% RDF was found superior for better growth, yield, and quality of the plants while taking into consideration of long term beneficial effects of organic sources of plant nutrition.

Effect of Some Fertilization and Micro-Nutrients Treatments on Growth and Chemical Constituents of Echinacea purpurea plant

Two field experiments were carried out at special Farm at El Khatatba region Minofia Governorate , Egypt and in the Laboratory of Horticulture Department, Faculty of Agriculture at Moshtohor, Benha Univ., during 2014 and 2015 seasons to evaluate the effect of some fertilization treatments i.e. control (compost at 10 ton/fed.),100 % full chemical fertilizer dose, 75% chemical fertilizer (NPK) dose + compost at 10 ton/fed. + bio fertilizer (nitrobein + phosphorein) , 50% chemical fertilizer (NPK) dose + organic fertilizer (compost) + bio fertilizer (nitrobein + phosphorein) and 25% chemical fertilizer (NPK) dose + organic fertilizer (compost) + bio fertilizer(nitrobein + phosphorein) and some micro-nutrients i.e. Zn and B each at 100 ppm as well as their combinations on growth, total caffeic acid derivatives and total alkamides as well as chemical constituents of Echinacea purpurea plants. Results showed that different tested treatments of fertilization and micro-nutrients treatments as well as their combination led to significant increase of the studied growth parameters i.e. plant height, number of branches, fresh and dry weights of herb/plant, number of suckers/plant, number of flowering heads/plant, fresh and dry weights of flowering heads/plant as compared with control plants in both seasons. Additionally, the enhanced growth of Echinacea purpurea plants due to the different treatments was accompanied by pronounced increase in leaves N, P and K content of treated plants in both seasons. Furthermore, total caffeic acid derivatives and total alkamides were increased by all fertilization and micro-nutrients treatments as well as their combinations, especially the combined treatment between 75% chemical fertilizer dose + compost at 10 ton/fed. + bio fertilizer and Zn or B each at 100 ppm. Conclusively, from the obtained results, it is preferable to fertilize Echinacea purpurea plants with 75% chemical fertilizer (NPK) + 10 ton compost/fed. + bio fertilizer(nitrobein + phosphorein) in combination with some micro-nutrients (Zn or B each at 100 ppm) as foliar spray to enhance plant growth and chemical composition which led finally to a safe product of high quality suitable for exportation and safe on human health

Endophytic occupation of legume root nodules by nifH-positive non-rhizobial bacteria, and their efficacy in the groundnut (Arachis hypogaea)

Despite the high specificity between Rhizobium and legumes, the presence of non-rhizobia in root nodules has been reported. The present investigation was carried out to isolate plant growth-promoting endophytic non-rhizobial bacteria from leguminous crops viz. Glycine max, Vigna radiata, Vigna unguiculata, Arachis hypogaea and Vigna mungo, and their influence on groundnut growth. Seven endophytic non-rhizobial bacteria were isolated possessing the nifH gene showing amplification of a ~380-bp fragment. Analysis by 16S rDNA gene sequence similarity characterized them as Enterobacter cloacae AS1 (accession no. KF758544), Chryseobacterium indologenes AM2 (KF758545), Enterobacter cloacae ACP3 (KF758546), Klebsiella pneumoniae AG4 (KF758547), Pseudomonas aeruginosa ABG5 (KF758548), Enterobacter ludwigii ABG6 (KF758549) and Klebsiella variicola ABG7 (KF758550). Qualitative estimation of nitrogen fixation confirmed the efficiency of isolates to fix atmospheric nitrogen in a range of 11.55 to 62.10 mg N g−1 of glucose consumed. All strains were found to produce indoleacetic acid ranging from 34.86 to 119.44 μg ml−1. The highest phosphate solubilization index was shown by K. pneumoniae AG4 (14.67). Siderophore production was observed only in P. aeruginosa ABG5, and the highest 1-aminocyclopropane-1-carboxylate deaminase activity was shown by C. indologenes AM2, E. cloacae ACP3 and P. aeruginosa ABG5. Plant growth stimulation was confirmed by seed application in groundnuts in a gnotobiotic system and in pots. The results showed that isolates had a positive effect on groundnut growth, with no negative influence. In addition, treatment with 50 % recommended dose of chemical fertilizer demonstrated a positive influence on groundnut growth, but an increase in concentration from 50 to 100 % resulted in adverse effects on populations of non-rhizobial bacteria and groundnut growth. Thus the results of this study clearly suggest that root nodules accommodate endophytic non-rhizobial bacteria, which stimulates plant growth, and that chemical fertilizers greatly affect their number and activity.

A comparative study on field scale demonstration of fly ash and pond ash for cultivation of maize-groundnut crops in sequence on a wasteland

ABSTRACTIn India, the major source of energy is thermal power plants that contribute about 70% of the total energy requirement and produce a huge amount of fly ash per year. The fly ash and pond ash collected from the Ramagundam Super Thermal Power Station, India, were mixed with soil at different doses, 50, 100, and 200 t ha−1 separately to compare their impact on crop yield and soil characteristics. Ash application had a beneficial effect on the crop yield, apart from reduction in the required doses of chemical fertilizers by half of the recommended doses. Addition of ash resulted in a significant increase in the contents of N, P, K, S, Ca, Mg, and micro-nutrients in maize and groundnut crop produce. The uptake of toxic trace elements (Cu, Zn, Mn, Fe, Pb, and Ni) was below the threshold levels. The residual effect of ash on crop yield and the nutrient composition of the subsequent maize and groundnut crops was also significant. The overall beneficial effect of ash could be attributed to the improvement in the soil. The results indicated that both the ashes could be applied safely for reclamation of uncultivated wastelands and pond ash is found to be better than the fly ash.

Effects of Various Doses of Mineral Fertilizers (NPKS and Urea) on Yield and Economic Profitability of New Varieties of Zea mays L. in Faranah, Guinea

In Faranah Province (Guinea), the ratio of supply and demand of corn is approximately 1:2. The production is low and the deficit is covered by maize importation. This study was initiated in order to improve corn production by evaluating the effects of increasing doses of mineral fertilizers on the yield and economic profitability of corn. The experiment was conducted on a farm in Kamedankoude in a split plot with three replicates. Treatments included two varieties of maize (Perta and Kilissi113) and five doses of chemical fertilizers (D0=unfertilized control, D1=300 kg NPKS+200 kg urea • hm−2; D2=400 kg NPKS+800 kg urea • hm−2; D3= 200 kg NPKS+400 kg urea • hm−2 and D4=500 kg NPKS+600 kg urea • hm−2). The results showed that all the agronomic parameters increased with increasing dose of fertilizers, except for the number of ears per plant. The two varieties of corn tested produced similar yields. However, the profitability of mineral fertilizers decreased with increased doses and with value/cost ratio of 3. We recommended a mineral fertilizer dose of 300 kg NPKS + 200 kg urea. The high prices of mineral fertilizers were often barriers to intensive maize cultivation, especially for low-income farmers. This study was a contribution to rational fertilization and adapted the socio-economic conditions of the region, with the background knowledge that most farmers in the regions earned low incomes.

Organic and Inorganic Amendments on Rice (Oryza sativa L.) and Soil in Salt Affected Areas of Bangladesh

Salinity is a limiting factor for growth and development, since it affects several physiological processes in plants. An experiment was conducted to evaluate rice yield and quality of soil using different organic and inorganic amendments. Field experiment was laid out in a randomized block design with three replications and six treatments. Each treatment was received recommended doses of chemical fertilizers also. Based on these results, 50% of rice straw and gypsum amendments could be recommended to mitigate soil salinity thereby, improving the crop productivity of the salt affected lands. Maximum plant height, panicle length, total and effective tillers per hill and filled grains per panicle were observed in 50% (rice straw + gypsum) treated plots. Nutrients uptake were increased in grain and straw using different treatments compared to control and rice straw alone treated plots. In post harvest soil, there was a slight change of salinity and pH as affected by different treatments. Addition of rice straw and gypsum showed positive impact on organic carbon in soil.J. Environ. Sci. & Natural Resources, 8(2): 109-113 2015

Boosting Fennel Plant yield and Components using Combination of Manure, Compost and Biofertilizers

Field experiments were conducted during the two successive seasons of 2013/2014 and 2014/2015 to investigate the response of Fennel plants to manure, compost and biofertilizers. Thus, natural possible alternatives to highly soluble fertilizers had been used as manure and compost mixture with and without biofertilizers (two bacterial strains) inoculation on fennel plants yield, essential oil production and constituents in comparison with recommended dose of chemical fertilizers (NPK) as control. The results revealed that manure and compost mixture with biofertilizers gave significant increases over control plants in all growth and chemical parameters. Where, the maximum value of fruit yield was recorded for plants received manure+compost +biofertilizers treatment in both seasons. The combined treatment of manure + compost + biofertilizers significantly increased the essential oil percentage as compared with the other treatments .The highest content of anethole as well as fenchone was obtained from NPK treatment. On the other hand, limonene resulted from the manure+ compost +biofertilizers treatment was higher than control. Myrcene compound was increased with manure + compost treatment in comparison with control. The highest value of estragole resulted from control plants, while the lowest amount of this compound was recorded from the treatment with manure+ compost +biofertilizers.

Effect of organic amendment on stem canker and black scurf disease of potato (Solanum tuberosum)

: An experiment was conducted at Tuber Crops Research Centre, BARI, Bogra during 2008-2009 to evaluate the organic amendment for controlling the stem canker and black scurf of potato. The different kinds of organic amendments were: T 1 =Poultry refuse (PR) at 4 t ha -1 , T 2 =PR at 5 t ha -1 , T 3 =PR at 6 t ha -1 , T 4 =Mustard oil cake (MOC) at 300kg ha -1 , T 5 =MOC at 500kg ha -1 , T 6 =Neem oil cake (NOC) at 300kg ha -1 , T 7 =NOC at 500kg ha -1 , T 8 =Sawdust burning and T 9 = Control. The experiment was laid out in a randomized complete block design (RCBD) with four replications. The organic amendment significantly influenced the disease incidence, yield attributes and yield of potato. The lowest disease incidence (17.5%) and per cent disease index (9.99) were found in T 3 (poultry waste at 6 t ha -1 ). The minimum russet, deformed and Sclerotia infected tubers were also recorded in poultry waste at 6 t ha -1 . The highest healthy tubers and tuber yield were found in the same treatment. Therefore, poultry manure 6 t ha -1 along with recommended dose of chemical fertilizer can be recommended to produce healthy tubers and maximum tuber yield of potato.

Effect of inorganic and organic sources of nutrients on physico-chemical composition of mango (Mangifera indica L) cv. Amrapali

A field investigation was conducted to study the Effect of inorganic and organic sources of nutrients on physico-chemical composition of mango (Mangifera indica L) cv. Amrapali under high density orchard at Horticulture Complex, Maharajpur, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur (M.P.) during 2012–13 and 2013–14. A total of twenty four treatment combinations of inorganic and organic sources on nutrient were tested in factorial randomized block design with three replications. The fruit weight (177.5 g), length (9.67 cm) and width (7.68 cm) was recorded with the application of 125% recommended dose of chemical fertilizer and the higher TSS (22.60°B), total sugar (18.87%), non-reducing sugar (13.94%), reducing sugar (4.94%), ascorbic acid (60.08mg 100g pulp−1) and TSS: Acid ratio (66.86) was recorded with recommended dose of chemical fertilizer applied in combination of Vermicompost (25 kg plant−1) + Oil cake (2.5 kg plant−1) + Azotobacter + VAM + Trichoderma viridi + PSB (100g plant−1 of each inoculants).

The Impact of Bio fertilizer (EM1) and the Different Levels of Nitrogen and Mixed Chemical Fertilizers Addition on the Yield of Rice and it's component

A field experiment is carried out during June to November, 2014 to study the impact of chemical fertilizers with biofertilizer (EM1) on the yield of rice and its components (Oryza sativa L.), cv.Yasamin. The experiment is done using Completely Randomized Block Design with three replicates. There are four treatments of mixed fertilizers, urea and biofertilizer (EM1) that is used in this study, T1 (recommended dose of chemical fertilizer for rice), T2 (biofertilizer + 1/4 recommended dose of chemical fertilizer for rice), T3 (1/2 recommended dose of chemical fertilizer for rice) and T4 (biofertilizer + whole recommended dose of chemical fertilizer for rice). Significantly, increases are observed in seeds per panicle, 150.9, number of tillers.m-2 462 and grain yield, 5.31 Mg. ha-1 in T4 treatment). Using biofertilizer (EM1) reduces spikelet sterility to 4%.

Effect of bio-fertilizers with different doses of chemical fertilizers on growth and yield of pea (Pisum sativum L.)

The present investigation was conducted during Rabi season of 2007 at the instructional Farm, I.G.K.V., Raipur (C.G). The experiment was laid out in Factorial Randomized Block Design, with three replications. The growth and yield attributes like, shelling per cent, length of the pod, width of the pod, available nutrient (nitrogen, phosphorus, potassium and sulphur) in soil were recorded and found superior with 40 kg P ha ?1 , 30 kg S ha ?1 and with PSB inoculation, as compared to other treatments. It not only increased the green pod yield of pea but also improved the quality of the green pea but also improved the soil health and sustained the productivity of the crop.

SPECIES AND FUNCTIONAL DIVERSITY OF RHIZOBACTERIA OF RICE PLANT IN THE COASTAL SOILS OF INDONESIA

Rhizobacteria are important components of soil and directly or indirectly influence the soils quality and plant growth for maintaining adequate plant nutrition and reducing the negative environmental effects of fertilizers. Applying high dose of chemical fertilizers in most of rice fields in the coastal areas could reduce the quality of the soil in the long time. There are few studies addressed to verify the species and functional diversity of cultivable rhizobacteria associated with rice plant in the coastal soils. The objective of the study was to verify the species and functional diversity of rhizobacteria isolated from the coastal soils of two rice production areas of Subang and Indramayu, West Java. Special focus was given to verify phosphate solubilization, nitrogen fixation, IAA and cellulase production of the selected 78 strains of rice rhizobacteria isolated from the coastal paddy field, as well as taxonomical analyses based on 16S rRNA. The results showed that among 78 bacterial isolates from the coastal paddy field, mostly were belonging to the Firmicutes, most of them affiliated with genera Bacillus, 75 strains produced IAA, 32 strains fixed nitrogen, 37 strains solubilized phosphate and 33 strains produced cellulase. Several strains of the rhizobacteria were capable of producing plant growth promoting substances (PGPR), alone or in combination, such as IAA, fixing nitrogen, solubilizing phosphate, and producing cellulase. Taking all of these diverse PGPR characteristics into account, it is clear that the 78 identified isolates have great potential for improving saline soils of the coastal paddy fields in Indonesia.

SPECIES AND FUNCTIONAL DIVERSITY OF RHIZOBACTERIA OF RICE PLANT IN THE COASTAL SOILS OF INDONESIA

Rhizobacteria are important components of soil and directly or indirectly influence the soils quality and plant growth for maintaining adequate plant nutrition and reducing the negative environmental effects of fertilizers. Applying high dose of chemical fertilizers in most of rice fields in the coastal areas could reduce the quality of the soil in the long time. There are few studies addressed to verify the species and functional diversity of cultivable rhizobacteria associated with rice plant in the coastal soils. The objective of the study was to verify the species and functional diversity of rhizobacteria isolated from the coastal soils of two rice production areas of Subang and Indramayu, West Java. Special focus was given to verify phosphate solubilization, nitrogen fixation, IAA and cellulase production of the selected 78 strains of rice rhizobacteria isolated from the coastal paddy field, as well as taxonomical analyses based on 16S rRNA. The results showed that among 78 bacterial isolates from the coastal paddy field, mostly were belonging to the Firmicutes, most of them affiliated with genera Bacillus, 75 strains produced IAA, 32 strains fixed nitrogen, 37 strains solubilized phosphate and 33 strains produced cellulase. Several strains of the rhizobacteria were capable of producing plant growth promoting substances (PGPR), alone or in combination, such as IAA, fixing nitrogen, solubilizing phosphate, and producing cellulase. Taking all of these diverse PGPR characteristics into account, it is clear that the 78 identified isolates have great potential for improving saline soils of the coastal paddy fields in Indonesia.

English

The aim of this research work was to prepare rock phosphate enriched compost using low-grade mineral such as rock phosphate (RP) mixed with rice straw and Aspergillus awamori and to study their effect on microbial biomass phosphorus (MBP), phosphatase activity and phosphorus (P) fractions in a wheat-soybean cropping system. The experiment was carried out in a randomized block design with four treatments namely, control, recommended dose of NPK fertilizers (100% RDF), rock phosphate enriched compost (RPEC) at the rate of (5 t ha-1 and 50% RDF + Rock phosphate enriched compost (RPEC) at 5 t ha-1. Application of RPEC at 5 t ha-1 along with 50% recommended dose of chemical fertilizers (RDF) significantly improved microbial biomass P (MBP) (5.62 and 4.28 mg kg-1 soil) and alkaline phosphatase activity (194.0 and 174.0 μg PNP g-1 soil h-1) in surface (0-15 cm) and sub-surface (15-30 cm) soil respectively, than unfertilized control plot after harvest of wheat. The magnitude of changes of P fractions as well as microbial activities was higher in surface soil than sub-surface soil. Data generated from the field study revealed that phosphorus (P) fractions significantly increased due to application of RPEC either alone or in combination of chemical fertilizers over unfertilized control plot. Application of RPEC plus chemical fertilizers significant increased Olsen P compared to unfertilized control plot after harvest of wheat and soybean. Treatment T4 increased by 68.8 and 58.7% higher Olsen-P over control at 0-15 and 15-30 cm soil depth, respectively after wheat harvest. Key words: Microbial biomass P, phosphatase enzyme, phosphorus fractions, Olsen P, rock phosphate, rice straw.