Impact of controlled release urea on maize yield and nitrogen use efficiency under different water conditions.
ABSTRACT: Controlled release urea (CRU) has been widely adopted to increase nitrogen (N) use efficiency and maize production, but the impacts can range widely depending on water availability in the soil. In an experiment using Zhengdan 958 (a popular summer maize hybrid), three levels of water treatments (adequate water condition [W3], which maintained soil moisture at about 75% ± 5% of the soil's field capacity; mild water stress [W2], which maintained moisture content at 55% ± 5% of field capacity; and severe water stress [W1], which had a moisture content of 35% ± 5% of field capacity) and four levels of controlled release urea fertilizer (N0, N1, N2 and N3 were 0, 105, 210 and 315 kg N ha-1, respectively) were compared in a rainout shelter system with soil. The results revealed that CRU had significant effects on maize yields and N use efficiencies under different water conditions. The mean yields increased with increasing water levels and showed significant differences. Under W1, the accumulation of dry matter and N were limited, and N internal efficiency (NIE) and the apparent recovery efficiency of applied N (REN) decreased with N increases; yields of N1, N2, and N3 were similar. Under W2, the dry matter and N accumulation, as well as the yield, showed an increasing trend with an increase in N application, and the NIE and REN of N3 showed no difference from N2. Under W3, yields of N2 and N3 were similar and they were significantly higher than that of N1, but the agronomic N use efficiency (ANUE), REN, and the physiological NUE (PNUE) of N2 were 54.2, 34.9, and 14.4% higher, respectively, than those of N3. N application beyond the optimal N rate did not consistently increase maize yield, and caused a decrease in N use efficiencies. Highest overall dry matter, N accumulation, and yields were observed with N3 under W2, and those showed no differences with N2 and N3 under W3. Under this experimental condition, the CRU of 210 kg ha-1 was optimized when soil moisture content was 75% ± 5% of field capacity, but an N rate of 315 kg ha-1 was superior when soil moisture content during the entire growing season was maintained at 55% ± 5% of field capacity.
Project description:Winter wheat is threatened by drought in the Huang-Huai-Hai Plain of China, thus, effective water-saving irrigation practices are urgently required to maintain its high winter wheat production. This study was conducted from 2012 to 2014 to determine how supplemental irrigation (SI) affected soil moisture, photosynthesis, and dry matter (DM) production of winter wheat by measuring the moisture in 0-20 cm (W2), 0-40 cm (W3), and 0-60 cm (W4) soil profiles. Rainfed (W0) and local SI practice (W1, irrigation with 60 mm each at jointing and anthesis) treatments were designed as controls. The irrigation amount for W3 was significantly lower than that for W1 and W4 but higher than that for W2. The soil relative water content (SRWC) in 0-40 cm soil profiles at jointing after SI for W3 was significantly lower than that for W1 and W4 but higher than that for W2. W3 exhibited lower SRWC in 100-140 and 60-140 cm soil profiles at anthesis after SI and at maturity, respectively, but higher root length density in 60-100 cm soil profiles than W1, W2 and W4. Compared with W1, W2 and W4, photosynthetic and transpiration rates and stomatal conductance of flag leaves for W3 were significantly greater during grain filling, particularly at the mid and later stages. The total DM at maturity, DM in grain and leaves, post-anthesis DM accumulation and its contribution to grain and grain filling duration were higher for W3. The 1000-grain weight, grain yield and water use efficiency for W3 were the highest. Therefore, treatment of increasing SRWC in the 0-40 cm soil profiles to 65% and 70% field capacities at jointing and anthesis (W3), respectively, created a suitable soil moisture environment for winter wheat production, which could be considered as a high yield and water-saving treatment in Huang-Huai-Hai Plain, China.
Project description:Water shortage threatens agricultural sustainability in China, effective water-saving technologies urgently need to be developed. In this study, five treatments were conducted: rainfed (W0), a local supplemental irrigation (SI) practice (W1), and three treatments in which soil water content was tested prior to SI, specifically at 0-20 (W2), 0-40 (W3) and 0-60 cm (W4) soil layers. Soil water consumption in W3 had no differ with W2 but was higher than W1 and W4. Crop evapotranspiration in W1, W3 and W4 treatments were higher than that in W2. W3 treatment had higher leaf area index than W1 and W4 at later grain filling stages. The mean photosynthetically active radiation capture ratio in W3, especially at 20, 40 and 60 cm plant heights, were significantly higher than those in W1, W2 and W4. The chlorophyll content index, actual photosynthetic activities, catalase and superoxide dismutase activities of flag leaves from W3 were the highest after the middle grain filling stages. W3 treatment obtained the highest grain yield (9169 kg ha-1) and water use efficiency (20.8 kg ha-1 mm-1) in the two seasons. These benefits likely accrued through created a suitable soil moisture environment in W3 treatment.
Project description:BACKGROUND:Water (W) and nitrogen (N) management generally cause regulations in the 2-acetyl-1-pyrroline (2AP) accumulation in fragrant rice; nevertheless, the feasibility of such management strategies at booting stage in improving 2AP accumulation has not been examined in details. METHODS:Field experiments were conducted in the early season (March-July) and repeated in the late season (July-November) in 2013. The treatments were applied urea (90?kg?ha-?1), calcium super phosphate (90?kg?ha-?1) and potassium chloride (195?kg?ha-?1) as basal fertilizer, and urea (65?kg?ha-?1) at tillering stage. Three N levels i.e., 0?kg?N?ha-?1 (N1), 30?kg?N?ha-?1 (N2), and 60?kg?N?ha-?1 (N3) and three water levels i.e., W1 treatment (well-watered treatment with water layer of 2-4?cm), W2 treatment (soil water potential was -?15?±?5?kPa), and W3 treatment (soil water potential was -?25?±?5?kPa) at booting stage was set up for three rice varieties i.e., Nongxiang 18, Yungengyou 14 and Basmati. The grain yield, head milled rice yield, 2AP contents and the biochemical parameters related to 2AP formation were investigated. RESULTS:Result indicated that W and N dynamics regulated the grain yield, head milled rice yield, and 2AP contents in brown rice across three varieties. The N2 and N3 treatment significantly increased the 2AP contents in brown rice by 9.54% and 11.95%, and 8.88% and 32.54% in the early and the late season, respectively; improved grain yield and head milled rice yield. The W3 treatment improved grain yield, head milled rice yield and 2AP content. Significant W and N interaction effect on 2AP content in brown rice was detected, where the W3?N3 treatment showed the strongest interaction regarding improvement of 2AP contents in brown rice. The 2AP accumulation and its related biochemical parameters and their relationships in different plant tissues at different growth stages under W and N treatments had also been assessed. The 2AP content, P5C content and DAO activity during grain filling periods was highly related to the 2AP content in brown rice. CONCLUSION:This study revealed that the 60?kg?N?ha-?1 coupled with -?25?±?5?kPa treatment showed the best positive effects on yield and aroma in fragrant rice, suggested that water and nitrogen management at booting stage can improve grain yield and fragrance in fragrant rice. However, further study to evaluate the metabolic and molecular basis of 2AP accumulation in fragrant rice is needed.
Project description:The main protease (Mpro) is the key enzyme of nCOVID-19 and plays a decisive role that makes it an attractive drug target. Multiple analysis of crystal structures reveals the presence of W1, W2, and W3 water locations in the active site pocket of Mpro; W1 and W2 are unstable and are weakly bonded with protein in comparison to W3 of Mpro-native. So, we adopt the water displacement method to occupy W1 or W2 sites by triggering HCQ or its analogs to inactivate the enzyme. Virtual screening is employed to find out best analogs of HCQ, molecular docking is used for water displacement from catalytic region of Mpro, and finally, MD simulations are conducted for validation of these findings. The docking study reveals that W1 and W2 are occupied by respective atoms of ZINC28706440 whereas W2 by HCQ and indacaterol. Finally, MD results demonstrate (i) HCQ occupies W1 and W2 positions, but its analogs (indacaterol and ZINC28706440) are inadequate to retain either W1 or W2 (ii) His41 and Asp187 are stabilized by W3 in Mpro-native and His41, Cys145 and HCQ by W7 in ZINC28706440, and W4, W5, and W6 make water mediated bridge between indacaterol with His41. The structural, dynamical, and thermodynamic (WFP and J value) profiling parameters suggest that W3, W4, and W7 are prominent in their corresponding positions in comparison with W5 and W6. The final results conclude that ZINC28706440 may act as a best analog of HCQ with acceptable physico-chemical and toxicological scores and may further be synthesized for experimental validation.
Project description:Water shortages and nitrogen (N) fertilizer overuse limit japonica rice production in Northeastern China. The interactions between water-saving irrigation and nitrogen management on rice root and shoot growth is still our research focus. Here, japonica rice (DN425) was subjected to the irrigation methods W1 (flooding irrigation), W2 [mild alternate wetting and drying irrigation (AWD); −10 kPa], W3 (severe AWD; −30 kPa), and different N fertilizer ratios were applied in different growth stages, namely, N1 (6:3:1:0), N2 (5:3:1:1), and N3 (4:3:2:1). From jointing to full heading stages, the highest photosynthate production capacity and root activity were obtained under W1N2. AWD markedly affected the root system and resulted in root senescence at later growth stages. Grain yield and N utilization efficiency were closely and positively correlated with the relative water content, crop growth rate (CGR), leaf area duration (LAD), the increase rate of root length density, root surface area density, and root volume density (RVD) from the jointing to full heading stages. This positive correlation was also observed in the increased rate of root bleeding sap (RBS) under W1N2 and CGR under W2N3. From full heading to maturity stages, N2 could promote root growth, LAD, and CGR under AWD to a greater extent than those under the other treatments. Water use efficiency (WUE) and N uptake efficiency (NUpE) were both negatively associated with the decreased rate of RVD, root dry weight (RDW), and RBS. They were closely and positively correlated with the increased rate of RDW and CGR. Our results suggested that W2N2 treatment delayed root senescence, maintained leaf photosynthesis, optimized the crop growth rate from full heading to maturity stages, and improved grain yield. The optimal grain yield, WUE, and NUpE were achieved at the irrigation water amount and topdressing fertilizer ratio of 41.40–50.34 × 102 and 31.20–34.83 kg ha–1, respectively.
Project description:Methane and carbon dioxide are one of the most important greenhouse gases and significant components of the carbon cycle. Biogeochemical methane transformation may occur even in the extreme conditions of deep subsurface ecosystems. This study presents methane-related biological processes in saline sediments of the Miocene Wieliczka Formation, Poland. Rock samples (W2, W3, and W4) differed in lithology (clayey salt with veins of fibrous salt and lenses of gypsum and anhydrite; siltstone and sandstone; siltstone with veins of fibrous salt and lenses of anhydrite) and the accompanying salt type (spiza salts or green salt). Microbial communities present in the Miocene strata were studied using activity measurements and high throughput sequencing. Biological activity (i.e., carbon dioxide and methane production or methane oxidation) occurred in all of the studied clayey salt and siltstone samples but mainly under water-saturated conditions. Microcosm studies performed at elevated moisture created more convenient conditions for the activity of both methanogenic and methanotrophic microorganisms than the intact sediments. This points to the fact that water activity is an important factor regulating microbial activity in saline subsurface sediments. Generally, respiration was higher in anaerobic conditions and ranged from 36 ± 2 (W2<sub>200%t.w.c</sub>) to 48 ± 4 (W3<sub>200%t.w.c</sub>) nmol CO<sub>2</sub> gdw<sup>-1</sup> day<sup>-1</sup>. Methanogenic activity was the highest in siltstone and sandstone (W3, 0.025 ± 0.018 nmol CH<sub>4</sub> gdw<sup>-1</sup> day<sup>-1</sup>), while aerobic methanotrophic activity was the highest in siltstone with salt and anhydrite (W4, 220 ± 66 nmol CH<sub>4</sub> gdw<sup>-1</sup> day<sup>-1</sup>). The relative abundance of CH<sub>4</sub>-utilizing microorganisms (<i>Methylomicrobium</i>, <i>Methylomonas</i>, <i>Methylocystis</i>) constituted 0.7-3.6% of all taxa. Methanogens were represented by <i>Methanobacterium</i> (0.01-0.5%). The methane-related microbes were accompanied by a significant number of unclassified microorganisms (3-64%) and those of the <i>Bacillus</i> genus (4.5-91%). The stable isotope composition of the CO<sub>2</sub> and CH<sub>4</sub> trapped in the sediments suggests that methane oxidation could have influenced δ<sup>13</sup>C<sub>CH4</sub>, especially in W3 and W4.
Project description:Faced with the scarcity of water resource and irrational fertilizer use, it is highly important to supply plants with water and fertilizer at desiderated stages to improve yield with high water use efficiency (WUE). A pot experiment was conducted to investigate the effects of growth stage-specific water deficiency and potassium (K) fertilization on tomato yield and WUE. The entire growing season of tomato was divided into 5 stages: vegetative growth stage (VG), flowering and fruit setting stage (FS), early fruit growth stage (FG), fruit development stage (FD) and fruit maturity stage (FM). Three soil moisture (W) and three K fertilization levels were set up. W levels included W1, W2 and W3, indicating that soil water was maintained at 60-70% field capacity, 70-80% field capacity, and 80-90% field capacity, respectively. K levels included K1, K2 and K3, indicating that 0 g K2O per kg soil, 0.46 g K2O per kg soil and 0.92 g K2O per kg soil was applied. All combinations of the three W and three K levels were solely imposed at each of the five growth stages, for other four stages, plants were watered to 80-90% field capacity without K fertilizer (W3K1). The permanent W3K1 over the entire growth stage was taken as control (CK). The results showed that W deficiency imposed at all stages significantly affected tomato yield (P<0.01), except for VG stage in which W deficiency did not cause yield loss. K fertilization level during FS or FM stage had a significant effect on yield (P<0.01). A significant interaction effect of W and K on yield was only observed during FM stage. For WUE, significant effect of W deficiency at FS, FD and FM stages were observed, and a significant effect of K levels at FS, FD and FM stages was observed. Specifically, K fertilization was necessary during specific growth stage of tomato (i.e. FS and FM). During FS stage, even if a sufficient water supply seems necessary, a deficit irrigation with K fertilization could be applied as K fertilization could alleviate the negative effect of soil water deficit, however, excess of K fertilization during FM stage should be avoided to maintain tomato yield and WUE.
Project description:<h4>Introduction</h4>Since May 2017, all cigarettes and roll-your-own (RYO) tobacco in the United Kingdom must be sold in standardized packs with pictorial warnings displaying, for the first time, a stop-smoking website.<h4>Aims and methods</h4>Data come from three waves of a longitudinal online survey with smokers and ex-smokers conducted pre- and post-standardized packaging, with Wave 1 (W1) in April-May 2016, Wave 2 (W2) in September-November 2017, and Wave 3 (W3) in May-July 2019. Only smokers are included in the analysis: W1 (N = 6233), W2 (N = 3629), and W3 (N = 2412). We explored any change in citing warnings on packs as a source of information about a stop-smoking website, and whether citing warnings as a source was associated with use of a stop-smoking website. As the warnings, and therefore the stop-smoking website, are larger on RYO packs than on cigarette packs due to the larger pack size, we explored differences in awareness of a stop-smoking website among exclusive cigarette smokers (W1 = 3142, W2 = 1884, W3 = 1247) and exclusive RYO smokers (W1 = 2046, W2 = 1119, W3 = 814).<h4>Results</h4>Among smokers recalling seeing information about a stop-smoking website, citing warnings as a source increased between waves (W1 = 14.0%, W2 = 24.2%, W3 = 25.1%) and was associated with having visited a stop-smoking website (odds ratio = 11.81, 95% confidence interval 8.47-16.46). Citing warnings as a source of a stop-smoking website increased among exclusive RYO smokers at each wave (W1 = 15.5%, W2 = 26.3%, W3 = 32.1%), while for exclusive cigarette smokers it only increased at W2 (W1 = 10.5%, W2 = 22.4%, W3 = 19.9%).<h4>Conclusions</h4>Warnings are an important source of cessation resource information. Making this information more prominent may help sustain awareness.<h4>Implications</h4>The findings support the inclusion of a stop-smoking website on warnings as awareness among smokers increased and citing warnings as a source of information about a stop-smoking website was associated with having visited a stop-smoking website. We also explored whether the stop-smoking website on warnings on RYO packs, which is larger than on cigarette packs as a function of the larger size of RYO packs, would have any impact on awareness of this information. That exclusive RYO smokers were more likely than exclusive cigarette smokers to notice a stop-smoking website on warnings suggests that this information should be more prominent.
Project description:OBJECTIVE:Adolescent driving while alcohol/drug impaired (DWI) and parental monitoring knowledge may have notable interplay. However, the magnitude and direction of causality are unclear. This study examined possible reciprocal associations among adolescents between DWI and parental monitoring knowledge. METHODS:The data were from waves 1, 2, and 3 (W1, W2, and W3) of the NEXT Generation Health Study, with longitudinal assessment of a nationally representative sample of 10th graders starting in 2009-2010 (n = 2,525 at W1) and analyzed in 2014. Those who had obtained an independent/unsupervised driving license were included for the analysis. Autoregressive cross-lagged path analysis was used to examine potential reciprocal associations between DWI and parental monitoring knowledge of both mothers and fathers, controlling for potential confounders. RESULTS:Stability of fathers' and mothers' monitoring knowledge across 3 consecutive interview waves was identified. W1 monitoring knowledge of both fathers and mothers was prospectively associated with DWI at W2 but not for W2 with W3. A significant negative association between adolescent DWI at W2 and mothers' monitoring knowledge at W3 was found but not between W1 and W2. None of the associations between DWI and fathers' monitoring knowledge from W1 to W2 or from W2 to W3 were significant. CONCLUSIONS:Early (10th grade) parental monitoring knowledge may predict lower adolescent self-reported DWI in 11th grade. More notably, adolescent DWI did not seem to increase parental monitoring knowledge. Future interventions are needed to improve parental monitoring knowledge and enhance awareness of the DWI risk in their adolescent novice drivers.
Project description:The major changes in hormone levels that occur through the menstrual cycle have been postulated to affect the expression of hormone-regulated and proliferation-associated genes (PAGs) in premenopausal ER+ breast cancer. Whilst previous studies have demonstrated differences in gene expression, here, we investigated if there are within patient changes in the expression of oestrogen- and progesterone-regulated genes (ERGs and PRGs) and PAGs in ER+ breast cancer during the menstrual cycle. Samples from 96 patients in two independent prospective studies of the effect of menstrual cycle on ER+ breast cancer were used. Plasma hormone measurements were used to assign tumours to one of three pre-defined menstrual cycle windows: W1 (days 27-35 and 1-6; low oestradiol and low progesterone), W2 (days 7-16; high oestradiol and low progesterone) and W3 (days 17-26; intermediate oestradiol and high progesterone). RNA expression of 50 genes, including 27 ERGs, 11 putative PRGs and seven PAGs was measured. The AvERG (geomean of <i>PGR</i>, <i>GREB1</i>, <i>TFF1</i> and <i>PDZK1</i>) was used as a composite measure of ERG expression and showed significant changes between the three windows of the menstrual cycle increasing over 2.2-fold between W1 and W2 and decreasing between W2 and W3 and between W3 and W1. Proliferation gene expression also varied significantly, following the same pattern of changes as ERG expression, but the changes were of lower magnitude (1.4-fold increase between W1 and W2). Significant changes in the expression of eight individual ERGs, including <i>GREB1</i>, <i>PGR</i> and <i>TFF1</i>, and two PAGs were observed between W1 and either W2 or W3 with all genes showing higher levels in W2 or W3 (1.3-2.4-fold; FDR 0.016-0.05). The AvProg, a composite measure of PRG expression, increased significantly (1.5-fold) in W3 compared to W1 or W2 but no significant changes were observed for individual PRGs. In conclusion, we observed significant changes in ERG, PRG and PAG expression in ER+ breast tumours during the menstrual cycle that may affect the assessment and interpretation of prominent biomarkers (e.g. PgR) and commonly used multigene prognostic signatures in premenopausal ER+ breast cancer.