[Effects of Different Fertilization Patterns on Nitrogen Leaching Loss from Paddy Fields Under Reduced Nitrogen].

Nitrogen leaching loss in paddy fields is one of the main ways of farmland non-point source pollution. To explore the suitable fertilization of rice fields in the Erhai Lake Basin and reduce the nitrogen loss from paddy fields, a field experiment was conducted by setting single applications of chemical or organic fertilizer, combined organic and inorganic application, and single application of controlled release fertilizer under reduced nitrogen conditions. The results showed that, compared with the conventional fertilization treatment(CF), there was no significant difference in rice grain and straw yield between the single chemical fertilizer treatment(T1) and the organic-inorganic combined treatment(T3); the single organic fertilizer treatment(T2) decreased the rice grain yield by 13.0%, and decreased straw yield by 17.1%; single application of controlled-release fertilizer(T4) increased rice grain and straw yield by 15.7% and 21.0%, respectively. Further, compared with CF, the single application of chemical fertilizer(T1), organic fertilizer(T2), and organic-inorganic combined application(T3) reduced the total nitrogen leaching loss at 30 cm depths by 26.9%, 18.0%, and 33.9%, respectively. The loss of ammonia nitrogen leaching with T1, T2, and T3 decreased by 24.4%, 36.9%, and 36.6%, respectively, and the loss of nitrate nitrogen leaching decreased by 40.2%, 4.8% and 46.4%. The total nitrogen leaching at 60 cm soil depths was reduced by 34.2%, 26.3%, and 42.1%, the loss of ammonia nitrogen leaching was reduced by 31.4%, 35.7%, and 46.6%, and the loss of nitrate nitrogen leaching was reduced by 8.0%, 10.1%, and 23.9% for T1, T2, and T3, respectively. The total nitrogen loss at 30 and 60 cm depths increased by 41.6% and 14.0% in the single application of controlled release fertilizer(T4) treatment. Considering factors such as agronomic and environmental benefits of different fertilization modes, T1 and T3 are suitable environmentally friendly alternative fertilization modes.

Whole genome sequencing and comparative genomic analysis of oleaginous red yeast Sporobolomyces pararoseus NGR identifies candidate genes for biotechnological potential and ballistospores-shooting.

BACKGROUND: Sporobolomyces pararoseus is regarded as an oleaginous red yeast, which synthesizes numerous valuable compounds with wide industrial usages. This species hold biotechnological interests in biodiesel, food and cosmetics industries. Moreover, the ballistospores-shooting promotes the colonizing of S. pararoseus in most terrestrial and marine ecosystems. However, very little is known about the basic genomic features of S. pararoseus. To assess the biotechnological potential and ballistospores-shooting mechanism of S. pararoseus on genome-scale, the whole genome sequencing was performed by next-generation sequencing technology. RESULTS: Here, we used Illumina Hiseq platform to firstly assemble S. pararoseus genome into 20.9 Mb containing 54 scaffolds and 5963 predicted genes with a N50 length of 2,038,020 bp and GC content of 47.59%. Genome completeness (BUSCO alignment: 95.4%) and RNA-seq analysis (expressed genes: 98.68%) indicated the high-quality features of the current genome. Through the annotation information of the genome, we screened many key genes involved in carotenoids, lipids, carbohydrate metabolism and signal transduction pathways. A phylogenetic assessment suggested that the evolutionary trajectory of the order Sporidiobolales species was evolved from genus Sporobolomyces to Rhodotorula through the mediator Rhodosporidiobolus. Compared to the lacking ballistospores Rhodotorula toruloides and Saccharomyces cerevisiae, we found genes enriched for spore germination and sugar metabolism. These genes might be responsible for the ballistospores-shooting in S. pararoseus NGR. CONCLUSION: These results greatly advance our understanding of S. pararoseus NGR in biotechnological potential and ballistospores-shooting, which help further research of genetic manipulation, metabolic engineering as well as its evolutionary direction.

Nd@TiO2 Nanocomposite for Photocatalytic Inactivation of Escherichia coli.

In present work, a novel Nd@TiO2 Nanocomposite, synthesized successfully by a facile sol-gel method, reveals significant light-activated antibacterial activity. The X-ray diffraction (XRD), Raman spectroscopy and transmission electron microscopy (TEM) show the anatase phase and globular shape of Nd@TiO2. UV-vis diffuse reflectance spectroscopy and low temperature N2 adsorption (BET) indicate Nd0.02@TiO2 has the narrow band gap (3.0 eV) and a high specific surface area (121.1 m2·g-1). Furthermore, the prepared Nd@TiO2 exhibits unprecedented higher photocatalytic activity than P25 TiO2. In water, Nd@TiO2 has higher inactivation against Escherichia coli (E. coli) bacteria under simulated solar light irradiation 70 min than TiO2, and the highest antibacterial efficiency (91.5%) of E. coli was achieved on Nd0.02@TiO2.

[Effects of the blended nitrogen fertilizers combined with inhibitors on soil nitrogen pools.] / æŽºæ··æ°®è‚¥é æ–½æŠ‘åˆ¶å‰‚å¯¹åœŸå£¤æ°®åº“çš„è°ƒæŽ§ä½œç”¨.

Pot experiment with winter wheat was conducted to investigate the effects of blended nitrogen (N) fertilizer (slow-release fertilizer-N:urea-N=1:1) combined with N fertilizer inhibitor NAM on soil ammonium (NH4+-N), nitrate (NO3--N), microbial biomass nitrogen (MBN) and fixed-ammonium (FN) contents. We analyzed dynamic characteristics of soil mineral N, MBN, FN pools under different treatments. There were six treatments, including no N fertilizer (CK), conventional urea (U), blended N fertilizer (MU), MU plus 2.5‰ NAM (MUN1), MU plus 5‰ NAM (MUN2), and MU plus 7.5‰ NAM (MUN3). Our results showed that, compared to that of MU treatment, MUN2 and MUN3 delayed the appearance time of NH4+-N peak. Averaged across the whole wheat growing period, soil mineral N content for NAM treatments decreased by 5.3%-11.7%. From tillering to maturity stage, MBN mineralization and mineralization rates were 38.96 mg·kg-1 and 91.5%, which was higher than that of U treatment; MBN mineralization and mineralization rates for MUN1, MUN2 and MUN3 treatments were 58.73 mg·kg-1, 83.3%, 94.20 mg·kg-1, 94.6%, 104.46 mg·kg-1 and 96.3%, respectively. The FA mineralization release for NAM treatments were higher by 2.83-9.19 mg·kg-1 than that of MU treatment. The results of path analysis showed that NAM addition weakened the direct effect of soil NH4+-N pool on NO3--N pool but enhanced the indirect effects of FN pool on NO3--N pool through affecting NH4+-N pool. The wheat grain yields of the MUN1, MUN2 and MUN3 treatments were significantly higher by 31.6%, 21.5% and 22.9% than that of MU treatment. Nitrogen use efficiencies were increased by 8.1%, 13.5% and 3.1%, respectively. In summary, through double regulation for N release and transformation in soil, NAM delayed the appearance time of soil NH4+-N peak and retarded its transformation into NO3--N, and increased the roles of MBN and FN in supplying N, thereby increased crop yield and N-fertilizer use efficiency.

[Effects of different low limits of irrigation on nutrients, enzyme activity and glomalin-rela-ted soil protein in soil aggregates of drip irrigation under plastic film.] / è†œä¸‹æ»´çŒä¸åŒçŒæ°´æŽ§åˆ¶ä¸‹é™å¯¹è®¾æ–½åœŸå£¤å›¢èšä½“å »åˆ†ã€é ¶æ´»æ€§å’Œçƒå›Šéœ‰ç´ å«é‡çš„å½±å“.

Irrigation is the main source of soil water in greenhouse. There is a lack of understanding on the effects of drip irrigation under the plastic film on the distribution characteristics of soil nutrients, enzyme activity and glomalin-related soil protein (GRSP) in soil aggregates. The effects of different irrigation low limits (20 kPa, D20; 30 kPa, D30; 40 kPa, D40) on soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), urease activity, invertase activity and GRSP in soil aggregates were investigated under the greenhouse with the continuously six years' irrigation. The results showed that compared with D20 and D40 treatments, D30 treatment significantly decreased the proportion of micro-aggregate (<0.25 mm), increased the proportion of macro-aggregate (>0.25 mm), and improved the mean mass diameter (MWD) by 26.4% and 13.4%, respectively. The concentrations of SOC, TN, TP and GRSP were relatively higher in 2-1 mm, 1-0.25 mm, and <0.053 mm aggregates. About 46.5% of SOC, 53.3% of TN and 37.7% of TP were distributed in the 1-0.25 mm aggregates. The urease and invertase activities were increased with the decreases in the size of aggregates, which were significantly increased in D30 and D40 treatments. The 1-0.25 mm aggregates had highest contributions to enzyme activities, with 38.7% of urease and 41.2% of invertase in bulk soil. Results from the correlation analysis showed that MWD was highly positively correlated with GRSP, SOC and urease activity, and the concentration of GRSP was highly positively correlated with SOC and urease activity. Therefore, the irrigation low limits of 30 kPa promoted soil aggregate stability and protection of soil aggregates to nutrients, enzyme activities and GRSP in greenhouse.

[Effects of nitrogen additions on soil hydrolase and oxidase activities in Pinus elliottii plantations.] / æ°®æ·»åŠ å¯¹æ¹¿åœ°æ¾æž—åœŸå£¤æ°´è§£é ¶å’Œæ°§åŒ–é ¶æ´»æ€§çš„å½±å“.

We evaluated responses of hydrolase and oxidase activities in a subtropical Pinus elliottii plantation through a nitrogen (N) addition field experiment (dosage level: 0, 40, 120 kg N·hm-2·a-1). The results showed that N additions significantly decreased the carbon, nitrogen and phosphorus related hydrolase and oxidase activities. The activities of ß-1,4-glucosidase (BG), cellobiohydrolase (CBH), ß-1,4-N-acetylglucosaminidase (NAG) and peroxidase (PER) activities were decreased by 16.5%-51.1% due to N additions, and the decrease was more remarkable in the higher N addition treatment. The activities of α-1,4-glucosidase (aG), ß-1,4-xylosidase (BX), acid phosphatase (AP) and phenol oxidase (PPO) were decreased by 14.5%-38.6% by N additions, however, there was no significant difference among the different N addition treatments. Soil enzyme activities varied obviously in different seasons. The activities of BG, NAG, BX, CBH, AP and PPO were in the order of March > June > October, and aG and PER activities were in the order of October > March > June. Most of the soil hydrolase and oxidase activities were positively correlated with soil pH, but negatively with NO3--N content. It indicated that N additions inhibited soil hydrolase and oxidase activities by reducing soil pH and increasing soil nitrification. N additions inhibited the soil organic matter mineralization and turnover in the subtropical area, and the effects were obvious with the increasing dosage of N additions.

Degradation Ability of Modified Polyvinyl Alcohol Film for Coating of Fertilizer.

Using outdoor exposure and cinnamon soil incubation test, by quality changes, infrared spectroscopy and electron microscopic scanning technology, to research the degradation ability of self-developed coated fertilizer films. The results of outdoor exposure and cinnamon soil incubation test showed that all films had certain degradation ability, and the degradation rate increased with the increase of time. Under two kinds of test conditions, the highest degradation rate could reach above 35%. The degradation ability of film citric acid/ PVA was much stronger than epoxy resin/PVA. The degradation ability of citric acid/PVA/diatomite composite film materials was further enhanced because of the addition of diatomite. The epoxy resin/PVA composite film materials, although they had certain degradability, compared to the contrast, the difference was not significant, and adding diatomite can't obviously increase the degradation rate. The results of IR spectroscopy showed that some major functional groups, such as C==O, C==C, ==C--H would be reduced after degradation, and the transmission rate also increased, which showed that the degradation of composite film materials must be happened Scanning electron microscopy showed that the surface becomes rough and uneven, and it also meant the films have some degradation. The results of IR spectroscopy and scanning electron microscopy were consistent with the results of quality change test, and could more objectively represent the degradability of film material. Modified film materials can effectively control nutrient release without causing harm to the soil environment, so it is suitable for the film materials of coated fertilizer.