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A profound consideration of soil organic carbon (SOC) and SOC pools as affected by the long-term use of fertilizer in a fixed crop sequence is essential to understand and maintain the health and productivity of soil. The dynamics of SOC pools, i.e. total soil organic carbon (TOC) and its different fractions under a rice-wheat cropping system subjected to various fertilizer management strategies over 42 years was investigated near Uttarakhand, India. The soil at the experimental site was an Aquic Hapludoll consisting of a poorly drained silty clay loam (1–1.5 m deep) overlying loamy to sandy sediments. Over 42 years, application of 100% NPK+ FYM (Farm Yard Manure) was the most effective management system in increasing organic C up to 0 to 60 cm soil depths under rice-wheat sequence. The combination of this integrated input application (100% NPK + 15 t ha−1 FYM) significantly built organic carbon fractions like total organic carbon, microbial biomass C (MBC), particulate organic C (POC), KMnO4 oxidizable C, Humic C, Fulvic C, Humin C, water-soluble carbon and hot water extractable carbohydrates at all four soil depths. Hence, application of FYM along with NPK resulted in a significant positive building up of all pools in the treatment at all four depths. Therefore, balance fertilization is panaceally important for sustaining improved soil health with balanced organic status and production potentiality of the soil for rice-wheat cropping sequence. [ABSTRACT FROM AUTHOR]

The sequencing and availability of inorganic and organic fractions of phosphorus at different days interval in two soils after the fertilizer (SSP) application was the objective of this investigation. The study helped to obtain the sequence of dominating pool of phosphorus at different days intervals and the rate of release in the soil. This sequential fractionation was used for two native soils i) Alluvial soil and ii) Acidic soil, with 0 to 80 ppm SSP/ 100 gm soil added in a pot experiment and the soil samples were analyzed at different days intervals started from 5 days to 60 days. The result revealed that amount of maximum total P fell in the range from 325.14 to 387.30 mg kg-1 and 284.60 to 330.25 mg kg-1 for alluvial soil and acid soil, respectively up to 30 days. In case of inorganic P fractions under alluvial soil the dominating species were like Ca-P > Fe-P > Al-P >Saloid-P, while under acidic soil the following order Fe-P > Al-P > Ca-P > Saloid-P was observed. These two observations also drew the concentration of organic- P fractions in soil. The work concluded that the availability of dominant phosphorus fraction up to 30 days received the maximum Ca-P concentration in alluvial soil and Fe-P up to 60 days in acidic soils, respectively. [ABSTRACT FROM AUTHOR]

In order to develop the relationship between soil test and response of lentil to applied fertilizers under Integrated Plant Nutrition System (STCR-IPNS), a field experiment was conducted on Aquic Hapludoll of Uttarakhand during Rabi 2009-10 following Ramamoorthy's targeted yield model. Using the data on grain yield, initial soil test values on available NPK, doses of fertilizers and farm yard manure (FYM) applied and NPK uptake, the basic parameters viz., nutrient requirement, contribution from soil, fertilizers and FYM were computed. It was found that 5.24, 0.72 and 3.58 kg of N, P and K respectively were required for producing one quintal of grain. The percent contribution of nutrients from soil, fertilizer and FYM were 32.01, 43.02 and 11.02 for N; 30.0, 32.03 and 8.04 for P; 31.06, 42.01 and 9.00 for K respectively. Making use of these basic parameters, fertilizer prescription equations were developed for lentil (var. PL-5) and an estimate of fertilizer doses were formulated for a range of soil test values and desired yield targets under NPK alone and IPNS (NPK plus FYM). Coefficient of determination (R²) was significant (0.805 **) between yield and soil test values. Verification trial was also conducted to test the validity of fertilizer prescription equations in next season i.e. Rabi 2010- 11. The variation in yield obtained from targeted yield ranged from -5.0 to +1.9%.The farmer's practice of fertilizer application was least efficient to produce grain yield of lentil in comparison to other treatments. Highest response ratio was found with farm yard manure 10 t ha-1+ yield target 16 q ha-1. [ABSTRACT FROM AUTHOR]

Incessant and disproportionate application of inorganic nutrients has deteriorated soil properties. An investigation was carried out to validate fertilizer requirement developed through soil test based crop response study to obtain desired yield of brinjal in Mollisol of Pantnagar during kharif season of 2019. The study revealed that maximum fruit yield, number of fruits per plants, fruit length and fruit diameter of brinjal was obtained under treatment with TY1 (250q ha−1) +10t ha−1 FYM (T6) (128:111:39 of N, P2O5, and K2O, respectively). In the initial phase of the investigation, experimental field was divided into three strip to which different doses of fertilizers were applied in low (no fertilizer application), medium (100:100:100 kg ha−1 of N, P, and K, respectively) and high (200:200:200 ha−1 of N, P, and K, respectively) proportion to create an artificial fertility gradient to bring heterogeneity in the experimental soil for the test crop. Further, in the second phase the response of brinjal to selected combinations through FYM, nitrogen, phosphorus and potassium in different soil fertility strips was also computed for spring and kharif seasons. With soil analysis, nutrient uptake studies, and yield the basic data for fertilizer prescription was worked out for both seasons. Further, using pooled data fertilizer prescription equation was generated for brinjal at different soil test values and yield targets. Response of brinjal in terms of growth, yield and nutrient uptake was studied to various soil test based fertilizer prescription at verification trial. The maximum microbial biomass carbon (427.29 μg g−1 soil), microbial biomass nitrogen (39.30 μg g−1), phosphates activity and dehydrogenase (150.36 µg TPF 24 h−1 g−1 soil) was reported under treatment TY2 (250q ha−1) +10t ha−1 FYM (T6) (128:111:39, of N, P2O5 and K2O, respectively). The balanced application of nutrients along with application of organic manure has ensured improvement in response of brinjal over general recommendation. [ABSTRACT FROM AUTHOR]

In the present research work, heat transfer and friction characteristics of in-line elliptical tubes are studied experimentally and numerically with the aiming to enhanced the thermal performance. The elliptical tubes with an aspect ratio (AR) of 0.35 and 0.50 and with circular tubes of the aspect ratio of 1 are selected for Reynolds number (Re) ranging from 5000 to 21000. The results indicate that the elliptical tube shows higher heat transfer rate with a significant reduction in the friction factor for the entire range of Reynolds number. The superior performance of the elliptical tube is often due to the aerodynamic cross-section profile of the tubes which promotes better heat transfer with a reduction in the frontal area of the tubes. The study is performed for the two different pitch to major axis ratios (PR) of 1.25 and 1.5, respectively. The results show that at a pitch ratio of 1.25 the elliptical tube with an aspect ratio of 0.50 leads to the superior heat transfer rate, while at pitch ratio of 1.50 elliptic tubes with an aspect ratio of 0.35 indicate better thermo-hydraulic efficiency relative to 0.50. [ABSTRACT FROM AUTHOR]