Plant height and aboveground biomass of alfalfa inoculated with two rhizobia seed coat formulations.

<p>Between the four Mo concentrations under the control treatment, bars that do not share capital letters are significantly different (<i>P < 0</i>.<i>01</i>). The data are presented as means ± SE. *** <i>P < 0</i>.<i>001; NS P > 0</i>.<i>05</i>. Abbreviations are as follows: Adhesive agent (AD), Ammonium molybdate concentration (Mo), Carboxymethyl cellulose (CMC), Sodium alginate (AE), Sodium alginate + skimmed milk (AES).</p

Molybdate in Rhizobial Seed-Coat Formulations Improves the Production and Nodulation of Alfalfa

<div><p>Rhizobia-legume symbiosis is the most well researched biological nitrogen fixation system. Coating legume seeds with rhizobia is now a recognized practical measure for improving the production of legume corp. However, the efficacy of some commercial rhizobia inoculants cannot be guaranteed in China due to the low rate of live rhizobia in these products. A greenhouse experiment was conducted to assess the effects of different rhizobial inoculant formulations on alfalfa productivity and nitrogen fixation. Two rhizobia strains, (ACCC17631 and ACCC17676), that are effective partners with alfalfa variety Zhongmu No. 1 were assessed with different concentrations of ammonium molybdate in seed-coat formulations with two different coating adhesives. Our study showed that the growth, nodulation, and nitrogen fixation ability of the plants inoculated with the ACCC17631 rhizobial strain were greatest when the ammonium molybdate application was0.2% of the formulation. An ammonium molybdate concentration of 0.1% was most beneficial to the growth of the plants inoculated with the ACCC17676 rhizobial strain. The sodium carboxymethyl cellulose and sodium alginate, used as coating adhesives, did not have a significant effect on alfalfa biomass and nitrogen fixation. However, the addition of skimmed milk to the adhesive improved nitrogenase activity. These results demonstrate that a new rhizobial seed-coat formulation benefitted alfalfa nodulation and yield.</p></div

The seed coated formulations.

<p>The seed coated formulations.</p

Analysis of variance for the effects of different Mo concentrations, adhesive agents and their interactions on plant height, aboveground biomass, the number of nodules, nodule weight and nitrogenase activity in alfalfa.

<p>Analysis of variance for the effects of different Mo concentrations, adhesive agents and their interactions on plant height, aboveground biomass, the number of nodules, nodule weight and nitrogenase activity in alfalfa.</p

The number, weight and nitrogenase activity of root nodules in alfalfa inoculated with different rhizobia seed coat formulations.

<p>Note: Between the four Mo concentrations under the control treatment, bars that do not share a capital letters are significantly different (<i>P < 0</i>.<i>01</i>). The data are presented as means ± SE. *** <i>P < 0</i>.<i>001</i>;** <i>P < 0</i>.<i>01; NS P > 0</i>.<i>05</i>. Abbreviations are as follows: Adhesive agent (AD), Ammonium molybdate concentration (Mo), Carboxymethyl cellulose (CMC), Sodium alginate (AE), Sodium alginate + skimmed milk (AES).</p

Impact of different concentrations of ammonium molybdate on the growth of rhizobia strains.

<p>Impact of different concentrations of ammonium molybdate on the growth of rhizobia strains.</p

Plant height (a) and aboveground biomass (b) of alfalfa inoculated with different rhizobia.

<p>Plant height (a) and aboveground biomass (b) of alfalfa inoculated with different rhizobia.</p

The effect of inoculation with different rhizobia strains on the number of alfalfa nodules and effective nodules.

<p>The effect of inoculation with different rhizobia strains on the number of alfalfa nodules and effective nodules.</p

Data_Sheet_1_Trichoderma Biofertilizer Links to Altered Soil Chemistry, Altered Microbial Communities, and Improved Grassland Biomass.docx

In grasslands, forage and livestock production results in soil nutrient deficits as grasslands typically receive no nutrient inputs, leading to a loss of grassland biomass. The application of mature compost has been shown to effectively increase grassland nutrient availability. However, research on fertilization regime influence and potential microbial ecological regulation mechanisms are rarely conducted in grassland soil. We conducted a two-year experiment in meadow steppe grasslands, focusing on above- and belowground consequences of organic or Trichoderma biofertilizer applications and potential soil microbial ecological mechanisms underlying soil chemistry and microbial community responses. Grassland biomass significantly (p = 0.019) increased following amendment with 9,000 kg ha−1 of Trichoderma biofertilizer (composted cattle manure + inoculum) compared with other assessed organic or biofertilizer rates, except for BOF3000 (fertilized with 3,000 kg ha−1 biofertilizer). This rate of Trichoderma biofertilizer treatment increased soil antifungal compounds that may suppress pathogenic fungi, potentially partially responsible for improved grassland biomass. Nonmetric multidimensional scaling (NMDS) revealed soil chemistry and fungal communities were all separated by different fertilization regime. Trichoderma biofertilizer (9,000 kg ha−1) increased relative abundances of Archaeorhizomyces and Trichoderma while decreasing Ophiosphaerella. Trichoderma can improve grassland biomass, while Ophiosphaerella has the opposite effect as it may secrete metabolites causing grass necrosis. Correlations between soil properties and microbial genera showed plant-available phosphorus may influence grassland biomass by increasing Archaeorhizomyces and Trichoderma while reducing Ophiosphaerella. According to our structural equation modeling (SEM), Trichoderma abundance was the primary contributor to aboveground grassland biomass. Our results suggest Trichoderma biofertilizer could be an important tool for management of soils and ultimately grassland plant biomass.</p

Additional file 1 of Assessing soil microbes that drive fairy ring patterns in temperate semiarid grasslands

Additional file 1: Figure S1. Leymus chinensis biomassproduction under different Stoichiometric ratios in greenhouse experiment