Long-term application of fertilizers on chemical and biological properties of an Alfisol

A long term fertilizer experiment (30 years) at Bengaluru had been started during 1986 with eleven treat-ments and four replications in an Alfisol on finger millet (Elusine coracana) maize (Zea mays) cropping sequence. The results of the ongoing experiment after 27 cycles of finger millet and maize on changes in soil chemical proper-ties revealed that application of inorganics alone resulted in impaired soil fertility status (soil pH, organic carbon con-tent and available nutrients in soil were decreased) over balanced fertilizer application. There was a decline in soil reaction over the initial status and the maximum decrease was observed in 100 % NP (-1.46), 100 % N (-1.20) and other treatments. Application of 100 % NPK+FYM+lime maintained the soil pH (6.2) compared to all the other treat-ments. Organic carbon content of soil in all the treatments was higher (6.46 g kg-1) compared to the initial status; however, maximum increase in organic carbon content was registered on application of NPK+FYM. Application of 10 t ha-1 along with recommended dose of fertilizers and lime was found promising in term of sustaining crop and soil productivity

Effect of harvesting time and desapping on sapburn and quality in mango (Mangifera indica) cv. Langra

Sapburn is one of the most important problems in mango (Mangifera indica L.) which severely downgrade its quality and reduces its market value. In the present study, two experiments were conducted to study the effect of harvesting time on sap flow quantity; and its control through simple desapping treatment. The sap flow was recorded higher from the mango fruits (cv. Langra) harvested during morning hours. For the second experiment, mature mango fruits were harvested with 8 - 10 cm pedicel attached and treated with aqueous solutions of sodium hydroxide (1% and 2%) and potassium hydroxide (1% and 2%) by immersion method, after removing the pedicel. For control, sap was allowed to flow freely over the fruit surface. During storage of fruit at ambient condition (25±2°C) for 12 days, fruits desapped with 1% sodium hydroxide (NaOH) showed about 11-fold lower sapburn injury than control. Treatment with NaOH did not significantly affect TSS, acidity and carotenoids content in the fruit. However, it maintained significantly higher ascorbic acid, total phenolics content and antioxidant activity than control

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Not AvailableThe effect of long-term integrated use of FYM, green manure and fertilizer Non nutrient status of soil and productivity of rice-wheat system was studied in a field experiment conducted with various treatment combinations including FYM, green manure and fertilizer N. After 7 years of continuous cropping under various treatments, the differences in organic carbon, total hydrolyzable N, available and total S and K were significantly influenced. The organic matter and total hydrolyzable N status declined with application of fertilizer N alone and increased with conjunctive use of fertilizer N and organic manure. The continuous use of SSP increased the available and total S in all the treatments. Build-up in S status was mostly through organic S fraction. The use of FYM and green manure increased K availability in soil but a net negative balance in total K was noted irrespective of the treatment. The combined application of organic and inorganic N sustained the productivity, even at lower level of N application. The results indicated that without proper K fertilization, depletion of K may affect the sustainability of the rice-wheat system. Regression equations developed over the years revealed that incorporation of 5 t FYM/6 t GM saved 70–80 kg N ha−1 y−1 without any adverse effect on productivity of rice-wheat system and the soil healthNot Availabl

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Not AvailableRepeated application of phosphorus (P) as superphosphate either alone or in conjunction with cattle manure and fertilizer N may affect the P balance and the forms and distribution of P in soil. During 7 years, we monitored 0.5 M NaHCO3 extractable P (Olsen- P) and determined the changes in soil inorganic P (Pi) and organic P (Po) caused by a yearly dose of 52 kg P ha–1 as superphosphate and different levels of cattle manure and fertilizer N application in a soybean-wheat system on Vertisol. In general, the contents of Olsen-P increased with conjunctive use of cattle manure. However, increasing rate of fertilizer nitrogen (N) reduced the Olsen-P due to larger P exploitation by crops. The average amount of fertilizer P required to increase Olsen-P by 1 mg kg–1 was 10.5 kg ha–1 with- out manure and application of 8 t manure reduced it to 8.3 kg ha–1. Fertilizer P in excess of crop removal accumulated in labile (NaHCO3-Pi and Po) and moderately labile (NaOH-Pi and Po) fractions linearly and manure application enhanced accumulation of Po. The P recovered as sum of different fractions varied from 91.5 to 98.7% of total P (acid digested, Pt). Excess fertilizer P application in presence of manure led to increased levels of Olsen-P in both topsoil and subsoil. In accordance, the recovery of Pt from the 0–15 cm layer was slightly less than the theoretical P (P added + change in soil P – P removed by crops) confirming that some of the topsoil P may have migrated to the subsoil. The P fractions were significantly correlated with apparent P balance and acted as sink for fertilizer P.Not Availabl

Antimony(III)-selenium complexes with synergetic effect between Sb-Se bond and Sb center dot center dot center dot pi interactions

The imidazole-selone antimony(III) complexes have been described with unique bonding situations around the antimony center. The mononuclear complexes, (L-1)SbCl3 (1) and (L-2)SbCl3 (2) were isolated from the reaction between SbCl3 and corresponding symmetrically crowded, 1,3-bis(2,6-diisopropyl phenyl) imidazole selone (L-1) and unsymmetrically crowded, 2,(2,6-benzhydryl-4-methyl phenyl) imidazole pyridine selone (L-2), respectively. The bonding nature of 1 and 2 differ remarkably due to the unique steric hindrance around the antimony center. Besides, the lone-pair-pi-hole interaction was observed in 1 and 2. The extent of Se -{\textgreater} Sb bonding and (aryl)C -{\textgreater} Sb bonding were further investigated by density functional theory (DFT), including natural bond orbital (NBO), natural population analysis (NPA), and electron density difference (EDD) methods. The theoretical predictions are nearly convincing with a single crystal X-ray analysis. The increasing steric bulk of the imidazole-selone from symmetric to unsymmetrical nature was found to greatly influence the donor-acceptor magnitude of Se -{\textgreater} Sb bonding and (aryl)C -{\textgreater} Sb bonding and lone-pair-pi-hole interactions. The L-2 in 2 acts as a good sigma-donor and pi-donor to Sb(III) compare to L-1 in 1

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Not AvailableIntegrated 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.Not Availabl

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Not AvailableThe mineralization of sulfur (S) was investigated in a Vertisol and an Inceptisol amended with organic manures, green manures, and crop residues. Field-moist soils amended with 10 g kg—1 of organic materials were mixed with glass beads, placed in pyrex leaching tubes, leached with 0.01 M CaCl2 to remove the mineral S and incubated at 30 °C. The leachates were collected every fortnight for 16 weeks and analyzed for SO4-S. The amount of S mineralized in control and in manure-amended soils was highest in the first week and decreased steadily thereafter. The total S mineralized in amended soils varied considerably depending on the type of organic materials incorporated and soil used. The cumulative amounts of S mineralized in amended soils ranged from 6.98 mg S (kg soil)—1 in Inceptisol amended with wheat straw to 34.38 mg S (kg soil)—1 in Vertisol amended with farmyard manure (FYM). Expressed as a percentage of the S added to soils, the S mineralized was higher in FYM treated soils (63.5 to 67.3 %) as compared to poultry manure amended soils (60.5 to 62.3 %). Similarly the percentage of S mineralization from subabul (Leucaena leucocephala) loppings was higher (53.6 to 55.5 %) than that from gliricidia (Gliricidia sepium) loppings (50.3 to 51.1 %). Regression analysis clearly indicated the dependence of S mineralization on the C : S ratio of the organic materials added to soil. The addition of organic amendments resulted in net immobilization of S when the C : S ratio was above 290:1 in Vertisol and 349:1 in Inceptisol. The mineralizable S pool (So) and first-order rate constant (k) varied considerably among the different types of organic materials added and soil. The So values of FYM treated soils were higher than in subabul, gliricidia, and poultry manure treated soils.Not Availabl

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Not AvailableThe mineralization of sulfur (S) was investigated in a Vertisol and an Inceptisol amended with organic manures, green manures, and crop residues. Field-moist soils amended with 10 g kg-1 of organic materials were mixed with glass beads, placed in pyrex leaching tubes, leached with 0.01 M CaCl2 to remove the mineral S and incubated at 30 °C. The leachates were collected every fortnight for 16 weeks and analyzed for SO4-S. The amount of S mineralized in control and in manure-amended soils was highest in the first week and decreased steadily thereafter. The total S mineralized in amended soils varied considerably depending on the type of organic materials incorporated and soil used. The cumulative amounts of S mineralized in amended soils ranged from 6.98 mg S (kg soil-1) in Inceptisol amended with wheat straw to 34.38 mg S (kg soil-1) in Vertisol amended with farmyard manure (FYM). Expressed as a percentage of the S added to soils, the S mineralized was higher in FYM treated soils (63.5 to 67.3 %) as compared to poultry manure amended soils (60.5 to 62.3 %). Similarly the percentage of S mineralization from subabul (Leucaena leucocephala) loppings was higher (53.6 to 55.5 %) than that from gliricidia (Gliricidia sepium) loppings (50.3 to 51.1 %). Regression analysis clearly indicated the dependence of S mineralization on the C : S ratio of the organic materials added to soil. The addition of organic amendments resulted in net immobilization of S when the C : S ratio was above 290:1 in Vertisol and 349:1 in Inceptisol. The mineralizable S pool (So) and first-order rate constant (k) varied considerably among the different types of organic materials added and soil. The So values of FYM treated soils were higher than in subabul, gliricidia, and poultry manure treated soils.Not Availabl

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Not AvailableUnder soybean-wheat system the influence of 4-year continuous cropping with different fertilizer and organic manure inputs on the transformation of different N fractions, mineralizable N, total N, and organic C in both surface and subsurface soils was investigated in a Vertisol. Repeated applications of fertilizer N alone, N with FYM or poultry manure or urban compost, FYM alone led to a significant increase in organic C, total N, hydrolysable N (i.e., amino acid N, hydrolyzable NH4-N, hexose amine N) and nonhydrolysable N in both surface and subsurface soils as compared to initial status. The status of various organic N fractions was higher in surface than the subsurface soils. On the other hand, continuous cropping without fertilization and manuring resulted in depletion of total hydrolysable N in control over the initial status by 8.5% in surface soils and 6.4% in the subsurface soils. About 3–6% of total N in surface soils and 2–5% of total N in subsurface soils got mineralized under waterlogged incubation conditions. The results clearly indicate that the subsurface soils in addition to surface soils also substantially contributed to the N requirement of the crops. The correlation studies revealed that the amino acid and hexose amine N fractions in surface soils and hydrolyzable NH4-N and amino acid N fractions in subsurface soils were better indices of soil N mineralization. This was further supported by a better correlation between amino acid N in surface and hydrolyzable NH4-N in the subsurface soils with yield of and N uptake by soybean and wheat cropsNot Availabl

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Not AvailableSulphate sorption behaviour of a Kandic Paleustalf was studied in relation to continuous addition of S with NPK or in combination with NPK plus FYM over the last decade under finger millet-maize-fodder cowpea rotation. Soil samples from the six differentially S fertilized plots differed widely in their sulphate sorption behaviour consistent with variations in apparent S balance (addition-crop removal). The extent of sulphate sorption was strikingly higher in soils that received 100% NPK without S as compared to adjacent fallow plot. Consequently in plots that received S with NPK, the sulphate sorption progressively decreased with increased rates of fertilizer S. Continuous addition of farmyard manure reduced the sulphate sorption by soil in 100% NPK ( + S) + FYM plot as compared to 100% NPK( + S) alone treatment. The sulphate sorption maxima (b) was highest for 100% NPK(−S) treatment and decreased with increasing rates of S fertilization.Not Availabl