Effect of Nitrogen Sources on Microbial Biomass Nitrogen under Different Soil Types

Abstract

<jats:p>Knowledge to increase the microbial biomass nitrogen (MBN) as a bulk of free-living microbes in paddy soil is limited. The potential benefit of these microorganisms was evaluated, in this study, under different nitrogen sources and two paddy soils. The results revealed that pots treated with organic matter recorded the maximum value of the total N uptake and MBN, followed by the Urea treated pots. Pots amended with sludge exhibited a higher microbial N forming ability than those amended with straw compost under both soils. But ammonium concentration in soil increased with straw compost application. Under fresh soil treatment, microbial N uptake rate and proportion of plant nitrogen derived from microbial nitrogen sources () were higher than autoclaved soil. A positive correlation was found between the and the total N in rice shoot in both soils. Finally, we can say that MBN was governed not only by the soil nitrogen content but also by the type of the nitrogen source. The addition of sludge to fresh soil increased total MBN and consequently could be indirectly beneficial to rice production especially in poor soils. Thus, soil microbes contribute to plant growth by serving the available nitrogen during the season.</jats:p>

Enhancement of Versatile Extracellular Cellulolytic and Hemicellulolytic Enzyme Productions by Lactobacillus plantarum RI 11 Isolated from Malaysian Food Using Renewable Natural Polymers

“…Under unfavorable conditions, all bacteria will develop starvation-survival strategy to sustain their growth [81,82] and bacterial cell will enter a dormant state [83][84][85] when grown in basal medium without carbon and nitrogen sources. F4 medium (glucose, molasses and soybean pulp) and F5 medium (rice straw, yeast extract and soybean pulp) recorded the highest viable cell count of log 11 CFU/mL at 4-days of incubation, which was also noted at Section 2.1, whereby nitrogen source of soybean pulp [86] was sufficient to promote the growth of L. plantarum RI 11 [48,49] and too much of nitrogen source was reported to cause cell death [87]. Soybean pulp has been reported to increase the cell population of Lactobacillus sp.…”

“…[86,88], whereas rice straw can also act as the nitrogen source [55]. All nitrogen sources used in this study were organic and especially yeast extract [87] in formulated F5 medium supported the rapid growth and high viable count of L. plantarum RI 11. Yeast extract that consists of amino acids, peptides, vitamins and carbohydrates [87] is a good nitrogen source to stimulate metabolic stress [88].…”

Degradation of Green Polyethylene by Pleurotus ostreatus

“…Nitrogen availability is a limiting factor for microbial growth [ 16 , 25 ]. The abundance of this element in the green polyethylene was lower than 3% ( Table 1 ).…”

Nitrogen Uptake Efficiency and Total Soil Nitrogen Accumulation in Long-Term Beef Manure and Inorganic Fertilizer Application

“…In addition to atmospheric N 2 fixation, microorganisms contribute to the availability of mineral N under favorable soil temperature, moisture, and aeration. Free-living decomposer microbes convert organic matter into nutrients for plants and other microorganisms, while rhizosphere organisms are symbiotically associated with plant roots and free-living N fixers [20].…”