Organic soil amendments using vermicomposts under inoculation of N2-fixing bacteria for sustainable rice production

Organic and biological fertilizers are considered as a very important source of plant nutrients. A field experiment was conducted during 2017−2018 in paddy soil to investigate the effect of vermicomposting of cattle manure mixture with Azolla and rice straw on soil microbial activity, nutrient uptake, and grain yield under inoculation of N2-fixing bacteria. Experimental factors consisted of organic amendments at six levels (vermicomposts prepared from manure (VM); manure + rice straw (VRM); manure + Azolla mixture (VAM); manure + rice straw + Azolla mixture (VRAM); raw manure without vermicomposting (M), and a control) and N2-fixing bacteria at three levels (Azotobacter chroococcum, Azospirillum brasilence, and non−inoculation). The results showed that, vermicompost treatments compared to control and raw manure significantly increased the number and biomass−C of soil microorganisms, urease activity, number of tillers hill−1, phosphorus (P) and potassium (K) uptake, and grain and protein yield. Inoculation of plants with N2-fixing bacteria, especially Azotobacter increased the efficiency of organic amendments, so that the maximum urease activity, soil microbial activity, P and N uptake, and grain yield (4,667 (2017) and 5,081 (2018) kg/h) were observed in vermicompost treatments containing Azolla (VAM and VRAM) under inoculation with Azotobacter. The results of the study suggested that, using an organic source along with inoculation with appropriate N2-fixing bacteria for vermicompost has a great effect on enzyme activity, soil biology, nutrient uptake and grain yield has a synergistic interaction on agronomic traits under flooded conditions. Therefore, this nutrient method can be used as one of the nutrient management strategies in the sustainable rice production.

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Effect of biofertilizers and foliar application of organic acids on yield, nutrient uptake and soil microbial activity in soybean

Legume Research - An International Journal ◽

10.18805/lr.v0iof.6784 ◽

2015 ◽

Author(s):

N. N. Lingaraju ◽

C. S. Hunshal ◽

S. R. Salakinkop

Keyword(s):

Humic Acid ◽

Organic Acids ◽

Nutrient Uptake ◽

Microbial Activity ◽

Foliar Application ◽

Foliar Spray ◽

Soil Microbial Activity ◽

Flower Initiation ◽

Soil Microbial ◽

And Control

A field experiment was undertaken during kharif 2012 to study effect of biofertilizers and foliar application of organic acids on yield, nutrient uptake and microbial activity of soybean at MARS, Dharwad under rainfed condition. The experiment was laid out in RCBD factorial having twenty treatment combinations and replicated thrice. The treatments comprised of four P-Solubilizers (PSB, VAM, PSB + VAM and Control) and five foliar spray of organic acids (Humic acid, Lecithin, Citric acid, Maleic acid and control). The results revealed that higher seed yield of soybean (35.96 q ha-1) was obtained with the treatment combination of dual inoculation of PSB+VAM with foliar spray of 0.1% humic acid at flower initiation and was higher to an extent 22.5 per cent compared to control (27.90 q ha-1). Similar trend was observed on microbial activity and nutrient uptake (N, P2O5 and K2O) of the soybean crop.

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Tea Bag Index as potential indicator for soil microbial activity.

10.5194/egusphere-egu2020-5344 ◽

2020 ◽

Author(s):

Gera Van Os ◽

Karin Pepers ◽

Jaap Bloem ◽

Joeke Postma ◽

Johnny Visser

Keyword(s):

Organic Matter ◽

Biological Activity ◽

Microbial Activity ◽

Management Practices ◽

Organic Amendments ◽

Soil Management ◽

Soil Microbial Activity ◽

Soil Microbial ◽

Rooibos Tea ◽

Tea Bag Index

Worldwide there is an enormous interest in microbial indicators for soil quality, since this reflects the potential capacity for soil ecosystem functions i.e. nutrient cycles, carbon storage, biodiversity and resilience to climate change. Farmers are anxious to measure the effects of different soil management practices in order to improve soil quality and attain sustainable food production. Despite the rapid developments in (molecular) measurement techniques, adequately validated and affordable methods for field measurements on soil microbial activity are still lacking. Nowadays, farmers participate in campaigns to bury cotton undies in order to measure biological activity in their fields (Soil your undies).&#160; If there&#8217;s not much left of the undies after a couple of months, this supposedly indicates good soil health. Of course this is by no means a quantitative nor validated indicator.An elegant, cheap and simple method to measure biological activity in soil is the Tea Bag Index (TBI). This method was developed to determine the global variation in decomposition rate of organic matter by the soil microflora as influenced by abiotic circumstances. The TBI consists of two parameters describing decomposition and stabilization of organic matter by measuring weight loss of green tea and rooibos tea bags that have been buried in the soil for three months. The method is designed to discriminate contrasting ecosystems and, within ecosystems, differences in factors such as soil temperature and moisture content (Keuskamp et al. 2013, doi: 10.1111/2041-210X.12097).Our research aimed to assess the possibility to use the TBI as an indicator for soil microbial activity, considering its sensitivity and robustness to discriminate between agricultural soil management practices that are known to have a significant impact on soil microbial diversity and activity. The responsiveness to soil pasteurization and organic amendments was investigated under both controlled and field conditions. The TBI decomposition rate differed significantly between both tea varieties (green tea > rooibos tea). Organic amendments had little or no effect. The TBI-results were plotted against some more established biochemical indicators which are sensitive to soil management and often related to microbial biomass, i.e. hot water extractable carbon, potentially mineralizable nitrogen and fungal biomass. Results are discussed, as well as factors which complicate the interpretation of TBI data with respect to soil microbial activity.

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