N4 Treatment Research Articles

Effect of nitrogen fertilizer on the quality traits of Indica rice with different amylose contents.

Nitrogen is a key factor affecting the quality of rice. Studying the impact of nitrogen fertilizer on the taste, physicochemical properties, and starch structure of Indica rice with different amylose contents is of great significance for scientifically fertilizing and cultivating high-quality rice varieties for consumption. The results indicate that increasing nitrogen fertilizer application reduces the amylose content and increases the protein content, resulting in a decrease in taste quality. Simultaneously, it reduces the intergranular porosity of starch particles, improving the appearance and milling quality of rice. Compared to the N1 treatment (nitrogen fertilizer application rate of 90 kg ha-1), the taste of low-amylose rice (Yixiangyou 2115) and high-amylose rice (Byou 268) decreased by 14.24% and 19.79%, respectively, under N4 treatment (nitrogen fertilizer application rate of 270 kg ha-1). The effect of nitrogen fertilizer on low-amylose rice is mainly reflected in increased rice hardness, enthalpy value, and setback viscosity, resulting in a decline in taste. The effect of nitrogen fertilizer on high-amylose rice is mainly reflected in a decrease in peak viscosity, an increase in gelatinization temperature, and crystallinity under high nitrogen levels. Increasing nitrogen fertilizer application can improve the appearance and milling quality of rice, but it also leads to an increase in protein content, hardness, gelatinization enthalpy, decrease in breakdown value, and a decline in palatability. In practical production, different production measures should be taken according to different production goals. © 2024 Society of Chemical Industry.

Transcript Analysis Reveals Positive Regulation of CA12g04950 on Carotenoids of Pigment Pepper Fruit under Nitrogen Reduction

This study investigates the relationship between nitrogen fertilization and pepper fruit color by employing five different nitrogen treatments (N1: 750 kg/hm2, N2: 562.5 kg/hm2, N3: 375 kg/hm2, N4: 187.5, and N0: 0 kg/hm2). Fruits were harvested at 30 (S1: green ripening stage), 45 (S2: color transition stage), and 60 days (S3: red ripening stage) after flowering. Subsequently, pigment content, carotenoid component content, carotenoid enzyme activity, and transcriptome sequence were analyzed, and CA12g04950 function was validated through virus-induced gene silencing (VIGS). The results indicate that a reduction in nitrogen application led to an earlier onset of fruit color breakdown, and increased the contents of total carotenoid, capsanthin, phytoene and PSY (phytoene synthase) activity, LCYB (lycopene β-cyclase) activity and CCS (capsanthin/capsorubin synthase) activity. The analysis of different expression genes indicated that the most differently expressed genes were enriched in the N1 vs. N4 comparison, with 18 genes involved in carotenoid metabolism and 16 genes involved in nitrogen metabolism. Most DE genes were enriched in the pathways of photosynthesis, porphyrin, carotenoid biosynthesis, seleno-compounds, and nitrogen metabolism. There were numerous differential transcription factor families, including ERF, bHLH, MYB, C2H2, and NAC. Pearson correlation analysis revealed a significant positive correlation between CA12g04950 expression and 11 carotenoid genes in the N4 treatment. Subsequent silencing of CA12g04950 using VIGS resulted in delayed color ripening while a significant decrease in total carotenoid content and the expression levels of carotenoid genes. In conclusion, nitrogen reduction led to an increase in carotenoid content in pigment pepper fruits. Furthermore, under nitrogen reduction, CA12g04950 positively influenced the redness of the fruits.

Post-anthesis dry matter and nitrogen accumulation, partitioning, and translocation in maize under different nitrate-ammonium ratios in Northwestern China.

An appropriate supply of ammonium (NH4+) in addition to nitrate (NO3-) can greatly improve plant growth and promote maize productivity. However, knowledge gaps exist regarding the mechanisms by which different nitrogen (N) fertilizer sources affect the enzymatic activity of nitrogen metabolism and non-structural carbohydrates during the post-anthesis period. A field experiment across 3-year was carried out to explore the effects of four nitrateammonium ratio (NO3-/NH4+ = 1:0 (N1), 1:1 (N2), 1:3 (N3), and 3:1 (N4)) on postanthesis dry matter (DM) and N accumulation, partitioning, transportation, and grain yield in maize. NO3-/NH4+ ratio with 3:1 improved the enzymatic activity of N metabolism and non-structural carbohydrate accumulation, which strongly promoted the transfer of DM and N in vegetative organs to reproductive organs and improved the pre-anthesis DM and nitrogen translocation efficiency. The enzymatic activities of nitrate reductase, nitrite reductase, glutamine synthetase, glutamine oxoglutarate aminotransferase, and non-structural carbohydrate accumulation under N4 treatment were increased by 9.30%-32.82%, 13.19%-37.94%, 4.11%-16.00%, 11.19%-30.82%, and 14.89%-31.71% compared with the other treatments. Mixed NO3--N and NH4+-N increased the total DM accumulation at the anthesis and maturity stages, simultaneously decreasing the DM partitioning of stem, increasing total DM, DM translocation efficiency (DMtE), and contribution of pre-anthesis assimilates to the grain (CAPG) in 2015 and 2017, promoting the transfer of DM from stem to grain. Furthermore, the grain yield increased by 3.31%-9.94% (2015), 68.6%-26.30% (2016), and 8.292%-36.08% (2017) under the N4 treatment compared to the N1, N2, and N3 treatments. The study showed that a NO3-/NH4+ ratio of 3:1 is recommended for high-yield and sustainable maize management strategies in Northwestern China.

Improving the yield and nitrogen use efficiency of hybrid rice through rational use of controlled-release nitrogen fertilizer and urea topdressing.

Controlled-release fertilizers effectively improve crop yield and nitrogen use efficiency (NUE). However, their use increases the cost of crop production. Optimal management modes involving urea replacement with controlled-release N fertilizers to increase rice yield through enhanced NUE are not widely explored. Field experiments were conducted from 2017 to 2018 to determine the effects of different controlled-release N fertilizers combined with urea [urea-N (180kg ha-1, N1)]. We used controlled-release N (150kg ha-1, N2) as the base, and four controlled-release N and urea-N ratio treatments [(80%:0% (N3), 60%:20% (N4), 40%:40% (N5), or 20%:60% (N6) as the base with 20% urea-N as topdressing at the panicle initiation stage under 150kg ha-1] to study their impact on the grain yield and NUE of machine-transplanted rice. Grain yield and NUE were positively correlated with increases in photosynthetic production, flag leaf net photosynthetic rate (Pn), root activity, N transport, and grain-filling characteristics. The photosynthetic potential and population growth rate from the jointing to the full-heading stage, highly effective leaf area index (LAI) rate and Pn at the full-heading stage, root activity at 15d after the full-heading stage, and N transport in the leaves from the full-heading to mature stage were significantly increased by the N4 treatment, thereby increasing both grain yield and NUE. Furthermore, compared with the other N treatments, the N4 treatment promoted the mean filling rate of inferior grains, which is closely related to increased filled grains per spikelet and filled grains rate. These effects ultimately improved the grain yield (5.03-25.75%), N agronomic efficiency (NAE, 3.96-17.58%), and N partial factor productivity (NPP, 3.98-27.13%) under the N4 treatment. Thus, the N4 treatment with controlled-release N (60%) and urea-N (20%) as a base and urea-N (20%) as topdressing at the panicle-initiation stage proved effective in improving the grain yield and NUE of machine-transplanted hybrid indica rice. These findings offer a theoretical and practical basis for enhancing rice grain yield, NUE, and saving the cost of fertilizer.

Nitrogen Addition Affects Interannual Variation in Seed Production in a Tibetan Perennial Herb.

The variability observed in the annual seed production of perennial plants can be seen as an indication of changes in the allocation of resources between growth and reproduction, which can be attributed to fluctuations in the environment. However, a significant knowledge gap exists concerning the impacts of nitrogen addition on the interannual seed production patterns of perennial plants. We hypothesized that the addition of nitrogen would impact the annual variations in the seed production of perennial plants, ultimately affecting their overall reproductive efficiency. A multiyear field experiment was conducted to investigate the effects of varying nitrogen supply levels (e.g., 0, 4, and 8 kg N ha-1 yr-1 of N0, N4, and N8) on vegetative and floral traits, pollinator visitation rates, and seed traits over a period of four consecutive years. The results showed that the N0 treatment exhibited the highest levels of seed production and reproductive efficiency within the initial two years. In contrast, the N4 treatment displayed its highest level of performance in these metrics in the second and third years, whereas the N8 treatment showcased its most favorable outcomes in the third and fourth years. Similar patterns were found in the number of flowers per capitulum and the number of capitula per plant. There exists a positive correlation between aboveground biomass and several factors, including the number of flowers per capitulum, the number of capitula per plant, the volume of nectar per capitulum, and the seed production per plant. A positive correlation was found between pollinator visitation and the number of flowers per capitulum or the number of capitula per plant. This implies that the addition of N affected the maintenance of plant aboveground biomass, flower trait stability, pollinator visitation, and, subsequently, the frequency of seed production and reproductive efficiency. Our results suggest that augmenting the nitrogen content in the soil may have the capacity to modify the inherent variability in seed production that is observed across various years and enhance the effectiveness of reproductive processes. These findings have the potential to enhance our comprehension of the impact of nitrogen addition on the reproductive performance of perennial herbaceous plants and the underlying mechanisms of biodiversity in the context of global environmental changes.

THE IMPACT OF PLANTAIN (Musa paradisiaca L.) PEEL LIQUID ORGANIC FERTILIZER ON THE GROWTH OF PAKCOY (Brassica rapa L.)

Plantain peels are an underutilized waste product that is often discarded without being processed, resulting in an unpleasant odor in the surrounding environment. However, plantain peels are rich in nutrients that can benefit plant growth, making them a potential ingredient in liquid organic fertilizers. This study aimed to investigate the growth response of pakcoy plants when treated with POC (plantain peel organic fertilizer). A complete randomized design (CRD) was used with five treatments and four replications in each treatment, including a control group (N0) and four POC treatments (N1-N4) with varying concentrations (50-125 ml). The results showed that plantain peel POC had a significant effect on plant height growth, number of leaves, and fresh weight in the N4 treatment, which had the highest concentration of 125 ml plantain peel POC.

Effects of optimized nitrogen fertilizer management on the yield, nitrogen uptake, and ammonia volatilization of direct-seeded rice.

Direct-seeded rice has been developed rapidly because of labor savings. Changes in rice cultivation methods put forward new requirements for nitrogen (N) fertilizer management practices. Field experiments with five different fertilizer ratios of basal, tillering and panicle fertilizer, namely N1 (10:0:0), N2 (6:2:2), N3 (4:3:3), N4 (2:4:4) and N5 (0:5:5), were conducted to investigate the effects of different N fertilizer management practices on yield formation, N uptakes, and ammonia (NH3 ) volatilization from paddy fields in direct-seeded rice. The results showed that the N4 treatment improved grain yield by 5.1% while decreasing NH3 volatilization by 20.4% compared with that of conventional fertilizer treatment (N2). The panicle number per unit area was the key factor to determine the yield of direct-seeded rice (72%). Excessive N application of basal fertilizer (N1) reduced seedling emergence, N use efficiency, and yield by 45.3%, 160.6%, and 6.9% respectively and increased NH3 volatilization by 28.1% compared with that of the N4 treatment. Removal of basal N fertilizer (N5) N reduced spike number and yield by 13.0% and 6.9% respectively, minimizing NH3 volatilization while affecting the construction of high-yielding populations compared with that of the N4 treatment. Optimized N fertilizer management achieved delayed senescence (maintenance of higher leaf Soil Plant Analysis Development meter values in late reproduction), higher canopy photoassimilation (suitable leaf area), higher N fertilizer use efficiency, and less N loss (lower cumulative NH3 volatilization). © 2023 Society of Chemical Industry.

Effect of Nitrogen Schedule and Weed Management Practices on Yield Attributing Characters and Yield of Transplanted Hybrid Rice (Oryza sativa L.)

The experiment conducted during kharif season of 2018-19 and 2019-20 at student instructional farm of Chandra Shekhar Azad University of Agriculture and Technology Kanpur, to study on productivity and resource use efficiency of transplanted hybrid rice in relation to weed management and nitrogen application. The experiment was laid out in split-plot design keeping nutrient management practices, viz. N1-150 kg Nitrogen ha-1; 3 equal split application at transplanting, 25 and 45 DAT, N2-150 kg nitrogen ha-1; 4 equal split application at transplanting ,25, 45 and 60 DAT, N3-180 kg nitrogen ha-1; 3 equal Split application at transplanting ,25 and 45 DAT. N4-180 kg nitrogen ha-1; 4 equal Split application at transplanting, 25, 45 and 60 DAT in main plots, and weed management practices, viz. W1- Un-weeded (weedy check), W2– Two hand weeding at 20 and 40 DAT, W3– Anilophos @ 0.40 kg a.i. ha-1 fb weeding by cono-weeder at 30 DAT, W4-Pretilachlor @ 0.75 kg a.i. ha-1 fb weeding by cono-weeder at 30 DAT, W5- Anilophos @ 0.40 kg a.i. ha-1 fb fenoxaprop-ethyl @ 80 g a.i. ha-1 at 25-30 DAT and W6- Pretilachlor @0.75kg a.i ha-1 fb fenoxaprop-ethyl @ 80g a.i. ha-1 at 25-30 DAT in sub plots with three replications. Significantly higher yield attributes and yield (62.14 q/ha) were found under N4 treatment than others and was comparable with N1. Similarly, highest yield attributing characters and grain yield (67.84 q/ha) of hybrid rice was noticed with W2 treatment.

Optimizing Nitrogen Fertilization and Variety for Millet Grain Yield and Biomass Accumulation in Dry Regions

Meeting foxtail millet (Setaria italica L.) (FM) production targets of high grain yield requires appropriate genotype selection and nitrogen (N) fertilization. However, high input costs and low crop yields are the major concerns for FM production systems, particularly in dry regions. To reduce the production costs without sacrificing yield, we assumed that N fertilization would increase the grain yield of FM varieties by improving reproductive organ biomass accumulation. To test this hypothesis, a two-year (2017 and 2018) field investigation in a randomized complete block design with split plot arrangement and three replicates was carried out on FM varieties, namely, V1 (Zhangzagu 8; hybrid) and V2 (Bagu 214; common) to ascertain the effects of five N levels (N1—15; N2—61; N3—108; N4—155; N5—201 kg N ha−1) on biomass accumulation and grain yield at different growth stages. Results showed that the V1 variety had a 34.8% and 28.5% higher grain yield compared to V2 treatment in both years, respectively. The interaction between variety and nitrogen was also significant. The combination of V1 and N4 produced a higher grain yield in both years. This increase in V1 grain yield was supported by the evidence of greater reproductive organ biomass formation, with a 113 and 120 kg ha−1 higher-than-average rate of biomass accumulation in both years, respectively. Among N rates, the N4 level resulted in a higher grain yield (3226 kg ha−1) and (3437 kg ha−1) compared with other N rates in the 2017 and 2018 growing seasons. This higher yield under N4 treatment was confirmed by a higher reproductive organ biomass accumulation at various growth phases, with 138 kg ha−1 and 124 kg ha−1 in 2017 and 2018, respectively. We also noticed that further increases in nitrogen levels did not increase FM grain yield. Conclusively, these data display the significance of proper FM production management techniques. Growing the varieties Zhangzagu 8 at 155 kg N ha-1 fertilization and Bagu 214 at 108 kg N ha−1 fertilization could be promising options to achieve higher grain yield.

Drip Fertigation with Relatively Low Water and N Input Achieved Higher Grain Yield of Maize by Improving Pre- and Post-Silking Dry Matter Accumulation

Appropriate irrigation and nitrogen (N) management strategies are necessary to achieve a sustainable yield of maize with relatively low water and N inputs. Here, a 2-year field experiment with two irrigation methods (drip irrigation and flood irrigation) and five N application rates (0, 225, 300, 375, and 450 kg N ha−1) was conducted to evaluate maize yield and water and N use efficiency in the North China Plain (NCP). Compared with flood fertigation (FF), drip fertigation (DF) improved the soil water content (SWC) in the 0 to 40 cm soil layer and maintained a greater soil mineral N content (Nmin) of that soil layer. This resulted in increased soil Nmin in the 0 to 40 cm soil layer for the 375 kg ha−1 (N3) under DF compared with the 450 kg N ha−1 (N4) treatment under FF during both pre- and post-silking of maize. The maize crop accumulated greater N at both pre- and post-silking compared using N3 under DF compared to N4 under FF. Greater pre-silking N accumulation increased both leaf area and plant growth rate, leading to more dry matter (DM) accumulation and develop more kernels, while sufficient post-silking N accumulation maintained high leaf area to produce more DM post-silking and promote maize ability to support grain filling. As a result, maximum maize yield (10.4 Mg ha−1) was achieved due to increased kernel number and kernel weight for N3 (375 kg N ha−1) under DF with a 20% reduction in N fertilizer input compared with the N4 (450 kg N ha−1) treatment under FF. Due to greater grain yield and N uptake and less water consumption, the agronomic N efficiency (AEN), N partial factor productivity (PFPN), water use efficiency (WUE) and net income for the N3 treatment under DF increased by 30.4%, 28.6%, 58.3% and 11.0% averaged over two years, respectively, compared to the N4 treatment under FF. Therefore, drip fertilization could improve maize grain yield with a relatively lower water consumption and N application rate compared with flood irrigation with higher N fertilization, as well as increase the economic benefits.

Optimization Of Population And Concentration Of Liquid Organik Fertilizer On Growth And Production Of Sweet Corn (Zea mays saccharata Strut)

: Sweet corn (Zea mays saccharata Strut) is a weel-known horticultural commodity and has been cultivated in various processed forms. Marked demand for sweet corn continues to increased, so market needs continue to grow and need to be maximized. This study aims to determine population optimization and concentration of liquid Organic fertilizer on the growth and production of sweet corn (Zea mays saccharata Strut). This study used a Factorial Randomized Block Design with 3 replications and consited of 2 factors. The first factor is population difference, P1:population 62,000 plant per hectare, P2: population 83,333 plant per hectare, P3:125,000 plant per hectare, while the second factor is concentration of liquid organic fertilizer, N1:without POC, N2:POC 45 ml/L, N3:POC 90 ml/L, N4:POC 135 ml/L. Differences in population significanly affected the parameters of plant height 42 DAP, stemp diameter 42 DAP, lenght of cob, diameter of cob, weight of cob. The best treatment of was obtained in the P1 treatment, which was 62,000 plant per hectare. NASA POC concentration significantly affected all parameters. The best treatment was obtained in the N4 treatment with a concentration ot 135 ml/L. The interaction between population differences and NASA POC concentration had a significant effect on the parameters of plant height at 42 DAP.

ENHANCEMENT OF GROWTH AND YIELD QUALITY OF ONION PLANT VIA FOLIAR APPLICATION OF BIO-STIMULANTS UNDER DIFFERENT NITROGEN SOURCES

There are environmental hazards of synthetic nitrogen fertilizers, however, there is a general tendency to raise the yield and quality of strategic crops in Egypt i.e., onion plant. Also, a little is known about the joint effects of different nitrogen sources as soil addition plus foliar spraying with bio-stimulants on onion plants. Thus, this research paper aims to assess the possibility of using compost as a partial substitute for synthetic nitrogen fertilizer with onion plants sprayed with some bio stimulants. During two successive seasons (2020/2021 and 2021/2022), a field trial was performed aiming to evaluate the effect of nitrogen recommended dose (NRD) via different nitrogen sources i.e., plant compost (2.0 %N), ammonium sulphate (21.0%N), urea (46.5%N) and ammonium nitrate (33.5%N) and some bio stimulates on onion plant and some soil properties. The nitrogen treatments [N1:40% of NRD as plant compost +20% of NRD as ammonium sulphate + 20% of NRD as urea+20% of NRD as ammonium nitrate, N2:100% of NRD as ammonium sulphate, N3:100% of NRD as urea and N4:100% of NRD as ammonium nitrate] represented the main plots, while foliar application of bio-stimulants represented the sub main plots, where the foliar application treatments were F1: without (control), F2: liquorice extract (7.50 gL-1); F3: garlic extract (350.0 ml L-1) and F4: yeast extract (7.5 gL-1).The findings indicate that onion plants grown under N1 treatment had growth, yield and quality traits better than the corresponding onion plants grown under other nitrogen treatments, where N2 treatment came in the second order and N3 treatment came in the third order, while N4 treatment came in the last order. Regarding foliar application, the plants sprayed with garlic extract (F3) had the highest values of studied traits followed by that sprayed with liquorice extract (F2) then that spayed with yeast extract (F4) and lately that grown without bio stimulants (F1). Generally, the best performance of onion plants was recorded under N fertilization of 40% of NRD as plant compost + 20 % of NRD as ammonium sulphate + 20 % of NRD as urea+ 20 % of NRD as ammonium nitrate and spraying, simultaneously, with garlic extract. Also, all studied soil properties like soil EC, pH, Om and available N differed due to all studied treatments. Thus, it can be confirmed the possibility of using plant compost as a partial substitute for mineral N fertilizer with onion plants sprayed with some bio stimulants.

Optimal management of nitrogen fertilizer in the main rice crop and its carrying-over effect on ratoon rice under mechanized cultivation in Southeast China

This study attempted to clarify the carrying-over effect of different nitrogen treatments applied to the main crop on the crop population growth and yield formation of ratoon rice under mechanized cultivation in Southeast China. Based on the constant total nitrogen application amounts (225.00 kg ha−1) in the main crop, an experiment with different ratios of basal and topdressing nitrogen fertilizer (the ratio of basal fertilizer:primary tillering fertilizer:secondary tillering fertilizer:booting fertilizer at 3:1:2:4 (N1), 3:2:1:4 (N2), 3:3:0:4 (N3), and 4:3:0:3 (N4), respectively, and a control without nitrogen treatment (N0)) was set up across two consecutive years in field using hybrid rice variety Yongyou 1540 as the test materials. The results showed that the total tiller number and effective tillering percentage increased in the main crop under the N1 treatment, more nitrogen fertilizer applied in late growth stage of the main crop, and its effective tillering percentage of the main crop was the highest at up to 70.18%, which was 9.15% higher than that of conventional fertilization treatment (N4), more nitrogen fertilizer applied in early growth stage of the main crop. The same tendency was observed in leaf area index (LAI) value of the main crop and its subsequent ratoon rice, which were 16.52 and 29.87% higher, respectively, in the N1 treatment than that in the N4 treatment at the full heading stage. The same was true in the case of the transport rates of stem and sheath dry mater and the canopy light interception rates in both the main and its ratoon crops. The transport rate of stem and sheath in main crop rice under N1 treatment increased by 50.57% compared with N4 treatment. The canopy light interception rate of N1 treatment increased by 5.07% compared with N4 treatment at the full heading stage of the ratoon crop. Therefore, the total actual yield was the highest in the main and its ratoon crops under N1 treatment, averaging 17 351.23 kg ha−1 in two-year trials, which was 23.00% higher than that in the conventional fertilization treatment (N4). The results showed that appropriate nitrogen treatment was able to produce a good crop stand in the main crop, which was essential for producing a good ratoon crop population and high yield especially under mechanized cultivation with low stubble height of the main crop. The study suggested that shifting the proper nitrogen application amounts to the late growth stage of the main crop, such as N1 treatment, not only had a higher productive effect on ensuring the yield of the main crop, but also had a positive effect on the axillary bud sprouts from the stubbles for ratoon rice, resulting in an increased percentage of productive panicles and achieving the goal of one planting with two good harvests under the conditions of our study.

PRODUCTIVE BEHAVIOR OF Dactylopius coccus Costa ON TWO CONFINED Opuntia ficus-indica (L.) Mill CULTIVARS

Recently, the commercial breeding of Dactylopius coccus in confined environments has been developed not to depend on seasonal production and ensure the supply chain. Previous studies have shown the technical viability of their breeding of i Opuntia in a repository also called "Nopaloteca". However, considering the genetic diversity of Opuntia in each region, it is necessary to evaluate alternative cultivars to maximize the efficiency of that production system. The evaluated cultivars were Esmeralda and Villanueva (Opuntia ficus-indica (L.) Mill.). Four height levels (m) within the “Nopaloteca” (N1: 0.5; N2: 1.0; N3: 1.5 and N4: 2.0) and two harvest indices (pre and post oviposition) were evaluated regarding their effects on the carminic acid concentration (CAC, %) and fresh weight (FW, g) of D. Coccus. The results showed no significant difference in the CAC of the D. coccus colonies in both cultivars (18 %); however, the highest FW was reached in the cv. Esmeralda with 6.3 g per cladode (p ≤ 0.05). The highest CAC was found in the N4 treatment (2.0 m) with 18.6 % (p ≤ 0.05); while the highest average FW values (p ≤ 0.05) were in the intermediate levels of the N2 (1.0 m) and N3 (1.5 m) treatments, with 6.4 and 6.1 g per cladode, each. The post oviposition phase harvest of D. coccus resulted in a higher CAC concentration (20.4 %); meanwhile, in the pre-oviposition phase, 15.6 % was harvested (p ≤ 0.05). Due to the productivity and quality obtained, the Esmeralda cultivar could be used as an alternative host for the intensive breeding of D. coccus in confinement, in north-central Mexico.

Impact of Nisin in Combination with Sodium Benzoate and Calcium Carbonate on the Bacterial and Yeast Population of Coconut Neera (Coconut Inflorescence sap)

A natural sap from mature coconut palm known as coconut neera is enriched with essential minerals and vitamins. Rapid microbial fermentation affects neera processing industries because it spoils the physicochemical properties. There are various methods in preservation that extend the shelf life of coconut neera. The addition of nisin is one of the methods which protect neera against fermentation. Therefore, the study is focused to identify the effective combination of nisin (50 ppm) with preservatives like sodium benzoate (500, and 1000 ppm), and calcium carbonate (2500, and 3000 ppm) at two different combinations in neera. At the end of 21 d, 3000 ppm calcium carbonate with 50 ppm nisin in N4 treatment had an effective reduction of 120 × 105 CFU/ml and 143 × 102 CFU/ml for total bacteria and total yeast count. The reduced microbial survival resulted in the pH of 10.45 ± 0.05, total soluble solids of 15.43 ± 0.12 °Brix, and total acidity of 1.11 ± 0.04 mg/ L, at this combination. The treatment of nisin with 3000 ppm calcium carbonate demonstrated the high red fluorescence bacterial cells than the treatment of nisin with 1000 ppm sodium benzoate. Additionally, the microorganisms in N4 treatment precipitated 65.34% Ca2+ from 79.96% in XRF intensity analysis. The synergistic effect of nisin and calcium carbonate explored their antimicrobial activity against the heterogeneous microbial population in coconut neera. The concentration of 3000 ppm calcium carbonate and nisin 50 ppm preserves the physicochemical and sensory qualities, up to 21 d at 4°C, and offer hope for the industrial-scale implementation.

Metabolic Response of ‘Topaz’ Apple Fruit to Minimal Application of Nitrogen during Cell Enlargement Stage

Nitrogen is an integral element of foliar sprays during apple fruit formation. However, in red cultivars, the application may have adverse effects on color in the second stage of fruit development. The effect of a low-dose foliar application of urea was monitored on ‘Topaz’ apple pomometric (fruit mass, firmness, total solids, starch content, skin color) and biochemical traits (primary metabolites, phenolic compounds, and assimilatory pigments). Three applications (17 July, 27 July, and 18 August) of two different urea doses (N1 = 1.4 kg N ha−1; N4 = 4 kg N ha−1) and control (N0, only sprayed with water) were used. Low doses of urea did not affect flesh firmness, total soluble, solid, and starch content, but individual fruit mass was significantly higher in N1 treatment compared to the other two treatments. Significantly lower a* parameters and a lower content of anthocyanins were measured on apples subject to N4 treatment. Many secondary metabolites (phenolic acids, flavan-3-ols, flavonols, and chalcones) were also negatively affected by low-dose urea application. Conversely, urea treatments significantly increased total assimilatory pigments in apple skin. Even minor levels of nitrogen, applied directly on the leaf at later stages of red apple fruit development, negatively altered color traits and the composition of metabolites.

Effects of nitrogen application rate and hill density on rice yield and nitrogen utilization in sodic saline–alkaline paddy fields

Soil salinity and alkalinity can inhibit crop growth and reduce yield, and this has become a global environmental concern. Combined changes in nitrogen (N) application and hill density can improve rice yields in sodic saline–alkaline paddy fields and protect the environment. We investigated the interactive effects of N application rate and hill density on rice yield and N accumulation, translocation and utilization in two field experiments during 2018 and 2019 in sodic saline–alkaline paddy fields. Five N application rates (0 (control), 90, 120, 150, and 180 kg N ha–1 (N0–N4), respectively) and three hill densities (achieved by altering the distance between hills, in rows spaced 30 cm apart: 16.5 cm (D1), 13.3 cm (D2) and 10 cm (D3)) were utilized in a split-plot design with three replicates. Nitrogen application rate and hill density significantly affected grain yield. The mathematical model of quadratic saturated D-optimal design showed that with an N application rate in the range of 0–180 kg N ha–1, the highest yield was obtained at 142.61 kg N ha–1 which matched with a planting density of 33.3×104 ha–1. Higher grain yield was mainly attributed to the increase in panicles m–2. Nitrogen application rate and hill density significantly affected N accumulation in the aboveground parts of rice plants and showed a highly significant positive correlation with grain yield at maturity. From full heading to maturity, the average N loss rate of the aboveground parts of rice plants in N4 was 70.21% higher than that of N3. This is one of the reasons why the yield of N4 treatment is lower than that of the N3 treatment. Nitrogen accumulation rates in the aboveground parts under treatment N3 (150 kg N ha–1) were 81.68 and 106.07% higher in 2018 and 2019, respectively, than those in the control. The N translocation and N translocation contribution rates increased with the increase in the N application rate and hill density, whereas N productivity of dry matter and grain first increased and then decreased with the increase in N application rate and hill density. Agronomic N-use efficiency decreased with an increase in N application rate, whereas hill density did not significantly affect it. Nitrogen productivity of dry matter and grain, and agronomic N-use efficiency, were negatively correlated with grain yield. Thus, rice yield in sodic saline–alkaline paddy fields can be improved by combined changes in the N application rate and hill density to promote aboveground N accumulation. Our study provides novel evidence regarding optimal N application rates and hill densities for sodic saline–alkaline rice paddies.

Changes in physico-chemical properties of paddy soil due to water and fertilizer management

Soil physico-chemical properties are an important phenomenon for sustainable crop production and maintenance of optimum soil health. Hence, a laboratory measurement was conducted with soil samples of three years long experimental field of the Department of Soil Science, Bangladesh Agricultural University, Mymensingh to assess the changes in five selected soil physico-chemical properties viz. soil texture, bulk density, soil pH, total nitrogen and organic matter. The experiment was laid out in a split plot design with two water regimes (continuous flooding and alternate wetting & drying) in the main plots and five fertilizer treatments (N0 - control, N1- 140 kg N/ha as PU, N2- 104 kg N/ha as USG (2× 1.8 g/ 4 hills), N3 - 5 t CD + PU @ 140 kg N /ha on IPNS basis and N4- 5 t CD + USG (2× 1.8 g/ 4 hills @ 104 kg N/ha)) in the subplots under rice-rice cropping pattern with three replications. After three years, soil samples were collected at 0-5 and 5-10 cm soil depths for measuring bulk density and at 0-10 cm depth for other soil properties and analyzed. Results found that % sand, % silt, % clay, bulk density and soil pH was not changed significantly compared to initial status. Percentage of total nitrogen and organic matter was significantly affected by irrigation and fertilization. Total nitrogen (%) was higher in AWD whereas organic matter (%) was higher in CF practice. The highest total nitrogen (%) and organic matter (%) was found in N4 treatment in which USG was applied in combination with cowdung as organic manure. It can be suggested that N4 treatment was formed good combination for sustaining chemical properties of soil. Further long- term experimentation will be needed to know the changes in soil properties for sustainable crop production and improving soil health.
 Asian Australas. J. Biosci. Biotechnol. 2020, 5 (2), 65-71

Effects of long-term fertilization on soil ammonia-oxidizing microorganisms

Long-term fertilization can change the supply of soil carbon and nitrogen (N), with consequences on the abundance and community structure of soil microorganisms. Based on the long-term fertilization positioning experiment station of brown earth, we analyzed the dynamics of soil ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) under different fertilization treatments, including no fertilization (CK), low level of inorganic N fertilizer (N2), high level of inorganic N fertilizer (N4), and organic manure combined with inorganic N fertilizer (M2N2), aiming to provide a basis for microbiological mechanism of soil N transformation and improvement of soil fertility. The results showed that the ratio of AOA to AOB abundance was 2.28-61.95 under different fertilization treatments. Compared with that in CK, the AOA abundance was reduced by 1.6%-13.6% after long-term fertilization. The abundance of AOB in N4 treatment decreased first and then increased with soil depths, but with contrary results in other treatments. The Shannon diversity index (H), evenness index (J), and Simpson index (S) of AOB were higher than those of AOA. The AOB diversity was increased at 0-20 cm soil layer in M2N2 treatment, while that of AOA was decreased. Soil AOB clustered with soil depths, and neither AOA nor AOB community clustered with fertilization treatments. In summary, long-term fertilization altered the composition of AOA and AOB. AOA was sensitive to environment, whereas AOB was more abundant and stable.

Effects of nitrate nitrogen supply on the growth, photosynthetic characteristics and 15N absorption, utilization of Malus hupehensis seedlings.

To explore the effects of different nitrate nitrogen levels (N0, N1, N2, N3 and N4 were equivalent to 0, 2.5, 5, 10, 20 mmol·L-115NO3- -N, respectively) on the growth, photosynthetic characteristics and 15N absorption, utilization and distribution, Malus hupehensis seedlings were grown in cultural liquid Hoagland by using the 15N-labeled tracer method. The results showed that the leaf chlorophyll content, leaf area and dry mass in different organs were the highest in N2 treatment. With the increase of 15NO3- -N application rates, the leaf net photosynthetic rate (Pn)significantly increased but tended to decease when the 15NO3--N concentration exceeded N2 treatment. In the 20th day after treatment, the root activity, root length, root surface area and number of tips of seedlings in N2 treatment were significantly higher than those in the other treatments. The distribution ratio of 15N in different organs was significantly different among those treatments. The relatively balanced distribution ratio of 15N appeared in N2 treatment, which the 15N utilization rate also reached relatively higher level. The total N content and 15N absorption of seedlings increased at low 15NO3--N concentration, reached the highest value in N2 treatment with 103.77 and 21.57 mg, and then deceased at high 15NO3--N concentration. At the 12th day after treatment, the leaf nitrate reductase (NR) activity was the highest in N2 treatment and the lowest in N4 treatment. The leaf nitrate reductase (NR) activity deceased by 84.9% in N4 treatment compared with N2 treatment at the 16th day after treatment. Our findings indicated that the photosynthesis and absorption of nitrate nitrogen were inhibited under low 15NO3--N stress, and the assimilation of nitrate nitrogen and root growth were restrained under too much higher 15NO3--N level, which was not good for the growth, nitrogen absorption and utilization of apple seedlings. The appropriate nitrogen level could promote plant growth, enhance the photosynthesis and also increase the absorption, utilization and distribution of nitrogen.