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Punnoose A.,Kerala Agricultural University | Anitha S.,Water Management Research Unit
Journal of Tropical Agriculture

An investigation entitled ‘Production characterisation and quality assessment of biochar’ was conducted to assess the effect of production methods and materials used on the character of biochar at Plant Propagation & Nursery Management Unit (PPNMU), Vellanikkara, Thrissur during 2014-15. Woody wild growth, coconut petiole and herbal waste residues left after composting were the three materials used for biochar production. Biochar was produced using heap and drum methods. Biochar was characterised by physical and chemical distinctiveness. Methods of production and materials used had significant influence on the characteristics of biochar. Drum method gave higher biochar recovery, high porosity and water holding capacity compared to heap method. Porosity, water holding capacity and carbon content were higher in biochar produced from woody wild growth. All biochars showed alkaline pH with the highest pH in coconut petiole biochar, An overall increase in NPK content was noticed in biochar compared to the feedstock materials. © 2015, Kerala Agricultural University. All rights reserved. Source

Wu Z.,Anhui Agricultural University | Wu Z.,Hefei University of Technology | Yin X.,Hefei University of Technology | Banuelos G.S.,Water Management Research Unit | And 6 more authors.
Frontiers in Microbiology

Selenium (Se) has important benefits for crop growth and stress tolerance at low concentrations. However, there is very little information on antimicrobial effect of Se against the economically important fungus Botrytis cinerea. In the present study, using sodium selenite as Se source, we investigated the effect of Se salts on spore germination and mycelial growth of the fungal pathogen in vitro and gray mold control in harvested tomato fruit. Se treatment at 24 mg/L significantly inhibited spore germination of the fungal pathogen and effectively controlled gray mold in harvested tomato fruit. Se treatment at 24 mg/L seems to induce the generation of intracellular reactive oxygen species in the fungal spores. The membrane integrity damage was observed with fluorescence microscopy following staining with propidium iodide after treatment of the spores with Se. These results suggest that Se has the potential for controlling gray mold rot of tomato fruits and might be useful in integrated control against gray mold disease of postharvest fruits and vegetables caused by B. cinerea. The mechanisms by which Se decreased gray mold decay of tomato fruit may be directly related to the severe damage to the conidia plasma membrane and loss of cytoplasmic materials from the hyphae. © 2016 Wu, Yin, Bañuelos, Lin, Zhu, Liu, Yuan and Li. Source

Soldevilla-Martinez M.,Technical University of Madrid | Quemada M.,Technical University of Madrid | Lopez-Urrea R.,Water Management Research Unit | Munoz-Carpena R.,University of Florida | Lizaso J.I.,Technical University of Madrid
Agricultural Water Management

The simulation of the water balance in cropping systems is a useful tool to study how water can be used efficiently. However, this requires that models simulate water balance accurately. Beyond the typical comparison of model outputs with field observations, in this study we present the inter-comparison of models of different complexity with the same field dataset as a powerful method to assess model performance. The compared models were DSSAT (Decision Support System for Agrotechnology Transfer) and WAVE (Water and Agrochemicals in soil, crop and Vadose Environment), both describing one dimensional water transport. The soil water balance in DSSAT uses a simpler "tipping bucket" approach, while the more mechanistic WAVE integrates Richard's equation. The soil parameters were calibrated by using the Simulated Annealing (SA) global optimizing method. A continuous weighing lysimeter in a bare fallow provided the observed values of drainage and evapotranspiration (ET) while soil water content (SW) was supplied by capacitance sensors. An automated weather station recorded the weather data. After optimizing soil parameters with SA, both models performed well simulating the soil water balance components for the calibrated period. The use of cumulative values for ET and drainage in the optimization was more effective than using their daily values. For the validation period, the models predicted well soil evaporation over time but there were differences between models in the soil water and drainage simulations. In particular, WAVE predicted drainage well while DSSAT presented larger errors in the cumulative values. That could be due to the mechanistic nature of WAVE against the more functional nature of DSSAT. Further studies should be conducted to improve the quality of DSSAT drainage simulations. The good results from WAVE indicate that, after soil calibration, it could be used as a reasonable substitute for other models for periods when no drainage field measurements are available. © 2014. Source

Reinhart K.O.,Fort Keogh Livestock & Range Research Laboratory | Dangi S.R.,Water Management Research Unit | Vermeire L.T.,Fort Keogh Livestock & Range Research Laboratory
Plant and Soil

Background and aims: Variation in fire intensity within an ecosystem is likely to moderate fire effects on plant and soil properties. We tested the effect of fire intensity on grassland biomass, soil microbial biomass, and soil nutrients. Additional tests determined plant-microbe, plant-nutrient, and microbe-nutrient associations. Methods: A replicated field experiment produced a fire intensity gradient. We measured plant and soil microbial biomasses at peak plant productivity the first growing season after fire. We concurrently measured flux in 11 soil nutrients and soil moisture. Results: Fire intensity positively affected soil nitrogen, phosphorus (P), and zinc but did not appreciably affect plant biomass, microbial biomass, and other soil nutrients. Plant biomass was seemingly (co-)limited by boron, manganese, and P. Microbial biomass was (co-)limited mainly by P and also iron. Conclusions: In the Northern Great Plains, plant and soil microbial biomasses were limited mainly by P and some micronutrients. Fire intensity affected soil nutrients, however, pulsed P (due to fire) did not result in appreciable fire intensity effects on plant and microbial biomasses. Variable responses in plant productivity to fire are common and indicate the complexity of factors that regulate plant production after fire. © 2016 Springer International Publishing Switzerland (outside the USA) Source

Cabrera J.A.,Water Management Research Unit | Cabrera J.A.,Bayer CropScience | Hanson B.D.,University of California at Davis | Gerik J.S.,Water Management Research Unit | And 4 more authors.
Crop Protection

Pre-plant soil fumigation in California is a common agricultural practice in orchard and vineyard replanting as well as in nursery production of fruit and nut trees. Identification of pest control strategies with low chemical inputs to reduce environmental impact are of interest. Therefore, the objective of this investigation was to evaluate the efficacy of reduced Telone C35 (61% 1,3-dichloropropene and 35% chloropicrin) rates under high density polyethylene (HDPE) or a totally impermeable film (TIF) against plant-parasitic nematodes, soilborne pathogens and weeds. Fumigation at full (605 kg/ha), half, or one quarter of the full rate, was highly effective for controlling plant parasitic nematodes and weeds under both HDPE and TIF. The reduced rates performed well against the soilborne pathogens Pythium ultimum and Verticillium dahliae but did not control Fusarium spp., and Phytophthora cactorum. Soil gas evaluations demonstrated that TIF retained more fumigant in soil compared to HDPE and bare soil when applied at equivalent rates. This investigation demonstrated the potential of reduced rates for the control of a variety of common pests, pathogens and weeds in replanting situations. Source

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