Nitrogen Use Efficiency In Maize Research Articles

Effects of Different Doses of Nitrogen on Growth and Nitrogen Use Efficiency of Maize (Zea mays L.) in Berekum Municipality of Ghana

Background: Adequate and balanced use of plant nutrients could increase crop performance and reduce adverse environmental effects. Farmers in Berekum have little information on the specific rate of nutrient, especially nitrogen application for hybrid and open pollinated maize varieties. Methods: A field experiment was carried out in Berekum Municipality of Ghana to determine the effects of different doses of N fertilizer (0, 90, 120 and 150 kg N ha-1) on growth and nitrogen use efficiency (NUE) of Pannar 12 (hybrid) and Omankwa (open-pollinated) maize varieties. The experiment was conducted in a factorial randomized block design and replicated thrice. Result: Experimental results revealed that incremental doses of nitrogen significantly impacted vegetative growth and NUE of maize. The studies indicated that the growth response in terms of plant height, number of leaves per plant and stem diameter of Omankwa was better than that of Pannar 12. It was found that in the main cropping period of 2019, the maximum NUE of 14.58 kg/kg was gained when Pannar 12 was grown with 150 kg N ha-1, while the highest NUE (15.91 kg/kg) was recorded when Omankwa was grown with 90 kg N ha-1. In the minor season of 2019, NUE was highest (13.54 kg/kg) when Pannar 12 was grown with 150 kg N ha-1, while application of 120 kg N ha-1 to Omankwa resulted in the highest NUE (10.85 kg/kg). The studies indicated that application of nitrogen at 90, 120 and 150 kg N ha-1 improved NUE in maize. However, NUE was optimized in Pannar 12 due to application of 150 kg N ha-1, while application of 90 kg N ha-1 was enough to optimize NUE in Omankwa.

Nitrogen source affects in‐season nitrogen availability more than nitrification inhibitor and herbicide in a fine‐textured soil

AbstractNitrogen (N) fertilizer management continues to be challenging due to potential nitrogen losses under variable weather conditions. This study aimed to evaluate the performance of nitrification inhibitors, nitrogen sources, and herbicides on in‐season nitrogen availability and agronomic indicators. A 2 site‐year field experiment was conducted in silty‐clay loam soil in the maize (Zea mays L.) phase of a maize–soybean rotation in Central Nebraska. The study included two herbicide treatments (Acuron and Resicore) and four nitrogen treatments: (1) anhydrous ammonia with a nitrification inhibitor, (2) anhydrous ammonia without a nitrification inhibitor, (3) urea with a nitrification inhibitor, and (4) urea without a nitrification inhibitor. Nitrogen sources had a more significant effect on NH4+‐N retention (300%–340% higher in anhydrous ammonia vs. urea) than nitrification inhibitors (14%–50% higher with inhibitor vs. without inhibitor) and herbicides. Similarly, nitrogen sources significantly affected NO3−‐N formation (58%–64% lower in anhydrous ammonia vs. urea) compared with nitrification inhibitors (7%–27% lower with inhibitor vs. without inhibitor) and herbicides. Nitrification inhibitors did not affect agronomic indicators. However, anhydrous ammonia increased grain yield by 1.1 Mg ha−1, partial factor productivity by 6 kg grain kg−1 N, agronomic efficiency by 5.5 kg grain kg−1 N, aboveground biomass N‐uptake by 34 kg N ha−1, grain N‐uptake by 15 kg N ha−1, nitrogen recovery efficiency by 33%, and residual total inorganic N by 6–40 kg N ha−1 compared to urea. These findings suggest that using the right fertilizer source, followed by nitrification inhibitor and herbicide, can be an effective strategy for conserving nitrogen and improving nitrogen use efficiency in maize.

Does biochar improve nitrogen use efficiency in maize?

AbstractBiochar is promoted as a means of improving soil fertility. Yet, few experiments have investigated its potential to improve nitrogen (N) use efficiency for high‐yielding maize production in the U.S. Midwest. We tested the hypothesis that biochar application increases inorganic soil N availability during maize growth, leading to higher grain yields and N recovery efficiency while reducing the risk of N leaching following harvest. Four N fertilizer rates (0, 90, 179, and 269 kg ha−1 as urea ammonium nitrate [UAN] solution) were applied with or without biochar (10 Mg ha−1) before planting in a two‐year field study. Inorganic soil N concentration was measured during the growing season (0–15 cm), and deep soil cores were obtained following harvest (0–90 cm). Results show that biochar did not affect maize yield, crop N uptake, or N recovery efficiency (by the difference method) across N rates, and there was no biochar by N rate interaction. While biochar lowered soil inorganic N concentrations on several sampling dates, this did not translate into seasonal differences in cumulative soil N availability, although grain yields in the unfertilized control were ~10% lower with biochar, suggesting net N immobilization. Biochar partially reduced the risk of N leaching following harvest by decreasing soil N concentrations at 30–60 cm, but mean concentrations for 0–90 cm were not different. Compared to previous work highlighting the benefits of biochar in arid climates with low soil fertility, we found no evidence of increased crop yield, NRE, or reduced risk of N leaching on Mollisols in a temperate climate.

ZmNRT1.1B (ZmNPF6.6) determines nitrogen use efficiency via regulation of nitrate transport and signalling in maize.

Nitrate (NO3 - ) is crucial for optimal plant growth and development and often limits crop productivity under low availability. In comparison with model plant Arabidopsis, the molecular mechanisms underlying NO3 - acquisition and utilization remain largely unclear in maize. In particular, only a few genes have been exploited to improve nitrogen use efficiency (NUE). Here, we demonstrated that NO3 - -inducible ZmNRT1.1B (ZmNPF6.6) positively regulated NO3 - -dependent growth and NUE in maize. We showed that the tandem duplicated proteoform ZmNRT1.1C is irrelevant to maize seedling growth under NO3 - supply; however, the loss of function of ZmNRT1.1B significantly weakened plant growth under adequate NO3 - supply under both hydroponic and field conditions. The 15 N-labelled NO3 - absorption assay indicated that ZmNRT1.1B mediated the high-affinity NO3 - -transport and root-to-shoot NO3 - translocation. Transcriptome analysis further showed, upon NO3 - supply, ZmNRT1.1B promotes cytoplasmic-to-nuclear shuttling of ZmNLP3.1 (ZmNLP8), which co-regulates the expression of genes involved in NO3 - response, cytokinin biosynthesis and carbon metabolism. Remarkably, overexpression of ZmNRT1.1B in modern maize hybrids improved grain yield under N-limiting fields. Taken together, our study revealed a crucial role of ZmNRT1.1B in high-affinity NO3 - transport and signalling and offers valuable genetic resource for breeding N use efficient high-yield cultivars.

Plastic film mulching and biochar amendment enhance maize yield and nitrogen fertilizer use efficiency by reducing gaseous nitrogen losses

Simultaneously increasing the crop yield and nitrogen use efficiency in maize is challenging. Efficient management strategies such as plastic film mulching or biochar amendment are recognized as potential methods for overcoming this problem. However, no comprehensive studies have quantified how the addition of biochar combined with plastic film mulching might affect the crop productivity and N flow in agroecosystems. Therefore, we conducted a field experiment from 2018 to 2021 in the Loess Plateau region of China to evaluate the effects of adding biochar at two rates under traditional planting without mulching and plastic film mulched farmland (CK: no mulch or biochar; CKL: 4.5 t ha –1 biochar with no mulch; CKH: 9.0 t ha –1 biochar with no mulch; PM: plastic film mulch with no biochar; PML: plastic film mulch with 4.5 t ha –1 biochar; and PMH: plastic film mulch with 9.0 t ha –1 biochar) on the soil mineral nitrogen residual quantity (NO 3 – -N and NH 4 + -N), gaseous nitrogen loss (N 2 O and NH 3 ), maize yield, and nitrogen use efficiency (NUE) in an agroecosystem. The results showed that plastic film mulching plus biochar amendment increased the maize yield by 13.9–45.1% and NUE by 12.1–74.8%, reduced the soil residual mineral nitrogen in the 0–200 cm soil layer at the maturity stage, and effectively decreased ammonia volatilization. Plastic film mulching increased the N 2 O flux by 12.1–26.9%, whereas biochar amendment decreased the N 2 O flux by 7.9–26.0%. Adding biochar at 9.0 t ha –1 (N 2 O: 14.9–29.1%; NH 3 : 16.4–28.6%) was more effective at reducing the N 2 O flux and NH 3 volatilization than adding biochar at 4.5 t ha –1 (N 2 O: 6.9–13.7%; NH 3 : 3.0–16.0%). Among all of the treatments, plastic film mulching combined with biochar at 9.0 t ha –1 was most effective at increasing the maize yield and NUE, as well as decreasing ineffective N losses (gaseous N loss and N leaching), thereby reducing the risk of nitrogen losses from farmland. Mainly because the mulching measures and biochar amendment significantly promoted the growth of maize and the absorption of soil nitrogen. This soil management practice can achieve sustainable high yields with high efficiency in the Loess Plateau and regions with similar agroecosystems. • Biochar amendment reduced N 2 O and NH 3 flux. • Addition of 9.0 t ha –1 biochar more effective at inhibiting ineffective N loss. • Plastic film mulch and biochar improved maize yield and nitrogen use efficiency. • Plastic film mulch plus 9.0 t ha –1 biochar suitable for use in semi-arid regions.

THP9 enhances seed protein content and nitrogen-use efficiency in maize.

Teosinte, the wild ancestor of maize (Zea mays subsp. mays), has three times the seed protein content of most modern inbreds and hybrids, but the mechanisms that are responsible for this trait are unknown1,2. Here we use trio binning to create a contiguous haplotype DNA sequence of a teosinte (Zea mays subsp. parviglumis) and, through map-based cloning, identify a major high-protein quantitative trait locus, TEOSINTE HIGH PROTEIN 9 (THP9), on chromosome 9. THP9 encodes an asparagine synthetase 4 enzyme that is highly expressed in teosinte, but not in the B73 inbred, in which a deletion in the tenth intron of THP9-B73 causes incorrect splicing of THP9-B73 transcripts. Transgenic expression of THP9-teosinte in B73 significantly increased the seed protein content. Introgression of THP9-teosinte into modern maize inbreds and hybrids greatly enhanced the accumulation of free amino acids, especially asparagine, throughout the plant, and increased seed protein content without affecting yield. THP9-teosinte seems to increase nitrogen-use efficiency, which is important for promoting a high yield under low-nitrogen conditions.

Nitrogen-Use Efficiency in Maize (Zea mays L.) on Fluvisol Soils in Afgoi District, Southern Somalia

In this study, an experiment was conducted to determine the best rate of nitrogen fertilization on maize grain yields and interaction of nitrogen levels and application methods of nitrogen on growth and yield of maize.
 For this purpose, the maize experiment was designed in the experimental farm of Somali Ministry of Agriculture, in Afgoi, Lower Shabelle, Somalia in 2017 spring and autumn. The treatments consisted of eight rates (0 kg N ha-1; 25 kg N ha-1; 50 kg N ha-1; 75 kg N ha-1; 100 kg N ha-1; 125 kg N ha-1; 150 kg N ha-1 and 175 kg N ha-1.) Nitrogen and three applying methods (broadcasting, row placement, and hill placement). The layout of the experiment was designed in Randomized Complete Block Design with three replications. A total of 9 parameters viz. plant height (cm), number of cobs plant-1, cob length (cm), cob weight (gr), 1000 grain weight (gr), stover yield (t ha-1), grain yield (t ha-1), biological yield (t ha-1) and harvest index (%), were collected. The collected data were analyzed statistically and means were adjudged by Duncan's Multiple Range Test at 1 and 5% level of probability.
 Both in the spring season and In the autumn season, according to the nitrogen rates, the result showed that there was significantly different in all characters among the different application rates of nitrogen the maximum stover yield was recorded in 100 kg N ha-1 while the maximum grain yield was noted from 100 kg N ha-1. Both in the spring season and In the autumn season in the methods of application, there was no significant variation in all parameters measured but the interaction effect was significantly different among the treatments, the maximum stover yield and grain yield were recorded in 100 kg N ha-1 and hill placement. Thus, applying 100 kg N ha-1 and the method of row placement is promising to increase the maize yield and the study is required to be repeated for one more season.

Maize yield as affected by the interaction of fertilizer nitrogen and phosphorus in the Guinea savanna of Nigeria

The soils of the Nigeria savannas are particularly low in nitrogen (N) and phosphorus (P) and negatively affects maize productivity. The main objective of the study was to evaluate the interactive effect of N and P fertilizers on maize growth, grain yield, nitrogen uptake and N use efficiency. Field experiments were conducted during the 2015 and 2016 cropping seasons at Iburu in southern Guinea and Zaria in northern Guinea savanna zones of Nigeria. The treatments consisted of three levels of nitrogen (0, 60, and 120 kg N ha−1) and three levels of phosphorus (0, 13, and 26 kg P ha−1). The experimental design consisted of three replications in a split-plot design, with N as the main plot and P as the subplot. Our results show that the response of maize to N depends on the application of P. Higher yields were obtained with the combined application of 120 kg N ha−1 and 26 kg P ha−1 in both locations. With no P applied, plant N uptake (PNU) was greater at N rate of 120 kg ha−1 at Iburu while in Zaria, it increases with increase in N from 0 to 60 kg ha−1. When P was applied at 13 kg ha−1, the PNU increased by 52 and 66% at Iburu while in Zaria the increases were 51 and 57% each with N application of 60 and 120 kg ha−1, respectively, compared with zero N rate. The values for N recovery efficiency (NRE) and agronomic efficiency (AE) were lower for N rate of 120 than for 60 kg ha−1 irrespective of P application rate at both locations. The N utilization efficiency (NUTE) however was higher at 120 N kg ha−1 under 26 kg P ha−1across locations. It can be concluded from these results that in low fertile soils environments such as the Nigeria savannas, N fertilizer should be applied along with P fertilizer for optimum growth, grain yield and nitrogen use efficiency of maize.

Crop performance and nitrogen use-efficiency in maize under conservation agriculture coupled with sub-surface drip fertigation

A field experiment was conducted in maize under medium-term conservation agriculture (CA) based maizewheat system at BISA-CIMMYT, Ladhowal, Punjab during kharif 2019 to assess the effect of CA+ practices (CA with sub-surface drip irrigation) with variable N doses on maize. The CA+ treatments were residue retained (WR) permanent bed (PB) with sub-surface drip fertigation (PB-SSD): without N (N0), 120 kg N/ha,150 kg N/ha applied in 4-equal (Eq) and differential splits (Df); CA alone treatment includ PB furrow irrigation with 120 kg N/ha (PBWRFurrow- N120); conventional tillage (CT) involved furrow irrigation with 120 kg N/ha (CTWOR-Furrow-N120) and other treatments were residue removed (WOR) PB: PBWOR-without N (N0), with 120 kg N/ha, and 150 kg N/ha applied in four Eq-splits and Df-splits. The findings of the present experiment showed that the numerical value of yield attributing characters were higher under CA+ plots as compared to CA alone (PBWR-Furrow-N120) and CT (CTWOR-Furrow-N120). Biological yield of maize was significantly higher in all CA+ plots as compared to CA alone and CT plots. Highest biological yield was recorded under PBWR-SSD-N150 Df (23.45 t/ha). Highest no. of cobs (72800/ha), no. of grains/cob (605) and cob length (22.61cm) along with dry matter resulted highest biological yield in PBWR-SSD-N150 plots. The grain N content remained statistically similar across all the N management plots, but in case of total N uptake, PBWR-SSD-N150 Df (CA+) plots dominated due to higher biomass. Besides, CA+ based PBWR-SSD-N120 (average of Df and Eq) registered 23-24% higher total N uptake than CA alone (PBWRFurrow- N120) and conventional (CTWOR-Furrow-N120) plots. Improved agronomic N use-efficiency was also recorded under CA+ plots as compared to CA alone (36.4 kg/kg N) and CT (36.7 kg/kg N) plots.

Effects of combined nitrification inhibitors on soil nitrification, maize yield and nitrogen use efficiency in three agricultural soils

Application of nitrification inhibitors (NIs) with nitrogen (N) fertilizer is one of the most efficient ways to improve nitrogen use efficiency (NUE). To fully understand the efficiency of NIs with N fertilizer on soil nitrification, yield and NUE of maize (Zea mays L.), an outdoor pot experiment with different NIs in three soils with different pH was conducted. Five treatments were established: no fertilizer (Control); ammonium sulfate (AS); ammonium sulfate + 3, 4-dimethyl-pyrazolate phosphate (DMPP) (AD); ammonium sulfate + nitrogen protectant (N-GD) (AN); ammonium sulfate + 3, 4-dimethyl-pyrazolate phosphate + nitrogen protectant (ADN). The results showed that NIs treatments (AD, AN and ADN) significantly reduced soil nitrification in the brown and red soil, especially in AD and ADN, which decreased apparent nitrification rate by 28% - 44% (P < 0.05). All NIs treatments significantly increased yield and NUE of maize in three soils, especially ADN in the cinnamon soil and AD in the red soil were more efficiency, which significantly increased maize yield and apparent nitrogen recovery by 5.07 and 6.81 times, 4.39 and 8.16 times, respectively. No significant difference on maize yield was found in the brown soil, but AN significantly increased apparent nitrogen recovery by 70%. Given that the effect of NIs on both soil nitrification and NUE of maize, DMPP+N-GD was more efficient in the cinnamon soil, while N-GD and DMPP was the most efficiency in the brown and red soil, respectively. In addition, soil pH and soil organic matter play important role in the efficiency of NIs.

A response surface methodology approach to improve nitrogen use efficiency in maize by an optimal mycorrhiza-to-Bacillus co-inoculation rate.

Co-inoculation of arbuscular mycorrhizal fungi (AMF) and bacteria can synergically and potentially increase nitrogen use efficiency (NUE) in plants, thus, reducing nitrogen (N) fertilizers use and their environmental impact. However, limited research is available on AMF-bacteria interaction, and the definition of synergisms or antagonistic effects is unexplored. In this study, we adopted a response surface methodology (RSM) to assess the optimal combination of AMF (Rhizoglomus irregulare and Funneliformis mosseae) and Bacillus megaterium (a PGPR—plant growth promoting rhizobacteria) formulations to maximize agronomical and chemical parameters linked to N utilization in maize (Zea mays L.). The fitted mathematical models, and also 3D response surface and contour plots, allowed us to determine the optimal AMF and bacterial doses, which are approximately accorded to 2.1 kg ha–1 of both formulations. These levels provided the maximum values of SPAD, aspartate, and glutamate. On the contrary, agronomic parameters were not affected, except for the nitrogen harvest index (NHI), which was slightly affected (p-value of < 0.10) and indicated a higher N accumulation in grain following inoculation with 4.1 and 0.1 kg ha–1 of AMF and B. megaterium, respectively. Nonetheless, the identification of the saddle points for asparagine and the tendency to differently allocate N when AMF or PGPR were used alone, pointed out the complexity of microorganism interaction and suggests the need for further investigations aimed at unraveling the mechanisms underlying this symbiosis.

Yield and Nitrogen Use Efficiency of Maize (Zea mays L.) Following the Application of Various Nitrogen Sources under Rainfed Conditions in the Bono Region of Ghana

Background: Poor soil fertility management in Ghana has necessitated the need to investigate the appropriate source of nitrogen which enhances nitrogen use efficiency and improves maize productivity under rainfed condition. Methods: The experiment consisted of five treatments; control (no fertilizer), NPK 15-15-15 (90 kg N ha-1), urea (90 kg N ha-1), poultry manure (4.2 tons ha-1) and combination of NPK 15-15-15 and poultry manure (½NPK 15-15-15 + ½ poultry manure). Randomized complete block design was the experimental design used for the experiment with three replications. Result: The greatest grain yield (5,551 kg ha-1) and biomass yield (14,296 kg ha-1) for the major rainy season were recorded by the combined application of NPK 15-15-15 and Poultry manure treatment, while the highest grain yield (3,507 kg ha-1) and biomass yield (7,976 kg ha-1) was recorded by NPK 15-15-15 treatment during the minor rainy season.

Effects of Nitrogen Application Rates and Irrigation Regimes on Root Growth and Nitrogen-Use Efficiency of Maize under Alternate Partial Root-Zone Irrigation

Root growth and its adaptation are quite important for efficient use of water and nutrients. The present study investigated the effects of alternate partial root-zone irrigation (APRI) coupled with nitrogen application on root growth and nitrogen-use efficiency (NUE) of maize (Zea mays L.). Treatments (conducted at Wuwei City, northwest China) included APRI with controlled irrigation at 45%, 65%, and 80% of field capacity (FC) (W1, W2, and W3, respectively) coupled with nitrogen application rate of 100, 200, and 300 kg N ha−1 (N1, N2, and N3, respectively). The study found a significant interaction effect of irrigation regimes and nitrogen application rates on maize root growth and NUE. Compared with N2, N3 did not increase the length, surface area, weight, and volume of roots at the filling and maturity stages under W2, while it did under W3, which suggests that increasing nitrogen application rates did not compensate for the adverse effect of drought on root growth. In addition, NUE positively correlated with these root morphological parameters but negatively with the root-to-shoot ratio at the filling and maturity stages. The W2N2 treatment with moderate soil moisture and relatively high soil nitrate-nitrogen promoted total root growth and deeper roots and optimized vertical root distribution, with a low root-to-shoot ratio, resulting in the greatest NUE. These results suggest that moderately controlled irrigation (W2) combined with a reasonable nitrogen rate (N2) improves root growth and optimizes root distribution, resulting in a high NUE in maize under alternate partial root-zone irrigation.

RZWQM2 Simulated Drip Fertigation Management to Improve Water and Nitrogen Use Efficiency of Maize in a Solar Greenhouse

The drip fertigation technique is a modern, efficient irrigation method to alleviate water scarcity and fertilizer surpluses in crop production, while the precise quantification of water and fertilizer inputs is difficult for drip fertigation systems. A field experiment of maize (Zea mays L.) in a solar greenhouse was conducted to meet different combinations of four irrigation rates (I125, I100, I75 and I50) and three nitrogen (N) fertilizer rates (N125, N100 and N75) under surface drip fertigation (SDF) systems. The Root Zone Water Quality Model (RZWQM2) was used to assess the response of soil volumetric water content (VWC), leaf area index (LAI), plant height and maize yield to different SDF managements. The model was calibrated by the I100N100 scenario and validated by the remaining five scenarios (i.e., I125N100, I75N100, I50N100, I100N125 and I100N75). The predictions of VWC, LAI and plant height were satisfactory, with relative root mean square errors (RRMSE) &lt; 9.8%, the percent errors (PBIAS) within ±6%, indexes of agreement (IoA) &gt; 0.85 and determination of coefficients (R2) &gt; 0.71, and the relative errors (RE) of simulated yields were in the range of 1.5–7.2%. The simulation results showed that both irrigation and fertilization had multiple effects on water and N stresses. The calibrated model was subsequently used to explore the optimal SDF scenarios for maximizing yield, water use efficiency (WUE) or nitrogen use efficiency (NUE). Among the SDF managements of 21 irrigation rates × 31 N fertilizer rates, the optimal SDF scenarios were I120N130 for max yield (10516 kg/ha), I50N70 for max WUE (47.3 kg/(ha·mm)) and I125N75 for max NUE (30.2 kg/kg), respectively. The results demonstrated that the RZWQM2 was a promising tool for evaluating the effects of SDF management and achieving optimal water and N inputs.

Nitrogen accumulation and nitrogen substitution effect of maize under straw returning with continuous cropping

<p id="C3">Crop straw resources in Northeast China are rich, but burning and discarding are serious, and nutrient utilization rate is very low. We explored the feasibility of the substitution of straw returning to nitrogen fertilizer and its effects on nitrogen accumulation under continuous cropping in cold region. A frame culture and continuous positioning experiment was carried out in the experimental site of Northeast Agricultural University from 2017 to 2019, with ¹⁵N labeled urea. A three-factor split-plot design was adopted in this experiment, the main plot was straw returning method with no straw returning (S0) and straw returning (S1), and the sub-plot was nitrogen application levels with 0 (N0), 175 (N1), and 350 (N2) kg hm^-2. Two application methods were set for each fertilizer application amount, one ratio of base fertilizer and top dressing applied was 1:1, and the other ratio of base fertilizer and top dressing applied was 1:0. The results were as follows: When the straw returning amount was 12 t hm^-2, the returning straw could replace 36.8 kg hm^-2 pure nitrogen. The average amount of maize straw was 46.50 million tons in Heilongjiang Province from 2017 to 2019, and straw returning could replace 142,700 tons pure nitrogen. The replace amount of pure nitrogen in the ratio of base fertilizer and top dressing (1:1) was 26.88% higher than that in 1:0. Straw returning was negatively correlated with nitrogen use efficiency in maize. The average nitrogen use efficiency of maize in S0 treatment was 6.09% higher than S1 treatment, and the yield of S1 treatment was 4.66% higher than S0 treatment when the urea application amount was 350 kg hm^-2 (161 kg hm^-2 pure nitrogen). The highest yield of maize was 268.22 g frame^-1 in the treatment of straw returning and topdressing with commonly fertilizer applied in local agriculture. In conclusion, the nitrogen substitution effect was remarkable under maize straw returning in Northeast China. Long-term combined application of crop straw and nitrogen fertilizer significantly improved the biomass, yield, and nitrogen accumulation of maize, which was a cultivation mode for increasing yield and efficiency of maize in Northeast China.

NITROGEN SOURCE DOES NOT CHANGE THE MORPHOPHYSIOLOGICAL CHARACTERISTICS OF MAIZE ON A CLAY SOIL

This study aimed to evaluate the effect of different nitrogen fertilizer sources and rates on the morphophysiological characteristics and nitrogen use efficiency of maize. The experiment was set in Campos Novos, Santa Catarina State, Brazil, during the 2016/2017 and 2017/2018 growing seasons. The experimental design was a randomized block with treatments arranged in split plots. Four nitrogen sources were evaluated in the main plots: conventional urea, protected urea, nitrification inhibitor-treated urea, and urease inhibitor-treated urea. Four nitrogen rates were assessed in the split plots: 0 (control), 140, 280, and 420 kg N ha−1. Nitrogen source did not affect ear height, leaf area index, stem diameter, or number of senescent leaves. Increments in nitrogen rate increased plant height, ear height, stem diameter, and grain nitrogen content but decreased nitrogen use efficiency. Stabilized (nitrification/urease inhibitor-treated) or protected N sources did not influence morphophysiological characteristics or improve nitrogen use efficiency of maize compared with conventional urea.

Exploring the synergism between surface liming and nitrogen fertilization in no‐till system

AbstractSurface liming to correct soil acidity may have limited effectiveness in subsurface layers in no‐till systems (NTS). The possibility of downward movement may be increased when liming is combined with fertilization with urea (ammoniacal N), as NO3– formed by nitrification of NH4+ can form ion pairs with exchangeable Ca2+ and Mg2+. Liming can also increase the nitrogen use efficiency (NUE) of crops and reduce dependence on soil N. In this work, we investigated the effects of surface application of lime under NTS and N topdressing on soil chemical properties and the nutrition, productivity, and NUE of maize (Zea mays L.) and upland rice (Oryza sativa L.). The treatments comprised four lime rates applied superficially (0, 1,500, 3,000, and 6,000 kg ha–1), and absence (–N) or presence of N fertilization (+N) as urea by topdressing. The treatments were applied during two agricultural years (2011/2012 and 2012/2013), with maize in the first crop season and upland rice in the second crop season. At 18 mo after liming, the application of 6,000 kg lime ha–1 significantly improved the chemical attributes of the soil (pH, soil organic matter (SOM), K, Ca2+, Mg2+, and base saturation [BS]). The application of urea increased the mobility of Ca2+ and Mg2+ to greater depths. The combination of 3,000 kg lime ha–1 with N fertilization synergistically increased the nutrition (N, P, and S), grain yield, and N‐related efficiency indexes in the maize and upland rice crops.

Strip deep rotary tillage combined with controlled-release urea improves the grain yield and nitrogen use efficiency of maize in the North China Plain

Inappropriate tillage practices and nitrogen (N) management have become seriously limitations for maize (Zea mays L.) yield and N use efficiency (NUE) in the North China Plain (NCP). In the current study, we examined the effects of strip deep rotary tillage (ST) combined with controlled-release (CR) urea on maize yield and NUE, and determined the physiological factors involved in yield formation and N accumulation during a 2-year field experiment. Compared with conventional rotary tillage (RT) and no-tillage (NT), ST increased the soil water content and soil mineral N content (Nmin) in the 20–40 cm soil layer due to reduction by 10.5 and 13.7% in the soil bulk density in the 0–40 cm soil layer, respectively. Compared with the values obtained by common urea (CU) fertilization, CR increased the Nmin in the 0–40 cm soil layers by 12.4 and 10.3% at the silking and maturity stages, respectively. As a result, root length and total N accumulation were enhanced under ST and CR urea, which promoted greater leaf area and dry matter (particularly at post-silking), eventually increasing the 1 000-kernel weight of maize. Thus, ST increased the maize yield by 8.3 and 11.0% compared with RT and NT, respectively, whereas CR urea increased maize yield by 8.9% above the values obtained under CU. Because of greater grain yield and N accumulation, ST combined with CR urea improved the NUE substantially. These results show that ST coupled with CR urea is an effective practice to further increase maize yield and NUE by improving soil properties and N supply, so it should be considered for sustainable maize production in the NCP (and other similar areas worldwide).

Influence of Biodegradable Polymer Coated Urea on Nitrogen Uptake and Utilization of Maize (Zea mays L)

Controlled release nitrogen fertilizers could be an excellent management approach for improving nitrogen fertilizer efficiency. The present study aimed to investigate the effect of coated urea fertilizers to increase nitrogen uptake and utilization of maize. The nitrogen use efficiency of maize from various biodegradable polymer-coated urea fertilizers, such as palm stearin coated urea (PSCU), pine oleoresin coated urea (POCU), and humic acid coated urea (HACU), was determined in a pot culture experiment conducted at the Department of Soil Science and Agricultural Chemistry, Tamil Nadu Agricultural University, Coimbatore, during 2021. The coating materials have been coated on urea with different coating thicknesses, viz., PSCU - 5, 10, 15%, POCU – 2, 4, 6%, and HACU - 5, 10, 15%. Among all the treatments, T11: HACU 15% produced highest grain yield (72.0g plant-1) followed by T7: POCU 4% (69.7 g plant-1) and T4: PSCU 10% (69.0g plant-1). In terms of dry matter production, T10: PSCU 10% produced maximum dry matter (186.5g plant-1), followed by T11: HACU 15% (186.2 g plant-1), and T7: POCU 4% (185.3g plant-1). The nitrogen uptake by the maize plant was higher in T7: POCU 4 % (1.62g plant-1), followed by T11: HACU 15% (1.59 g plant-1) and T4: PSCU 10% (1.59g plant-1). Irrespective of treatments, the highest nitrogen utilization by the maize crop was found in T7: POCU 4% (73.9%) followed by T4: PSCU 10% (71.1%) and T11: HACU 15% (70.9%) treatments. When compared to uncoated urea fertilizer, all coated urea fertilizers outperformed uncoated urea fertilizer in terms of grain yield, dry matter accumulation, and nitrogen uptake. To improve the nitrogen use efficiency, coated urea fertilizers prove to be a promising alternative to uncoated urea fertilizers.

Responses of shoot biomass accumulation, distribution, and nitrogen use efficiency of maize to nitrogen application rates under waterlogging

Waterlogging (WL) during the early growing stage is one of the most important environmental factors limiting maize (Zea mays L.) production. The application of nitrogen (N) fertilizer is important to maintain normal plant growth and defense against abiotic stresses. However, the effects of N fertilization on biomass accumulation and partitioning, as well as N utilization in maize under WL stress remains unclear. Thus, we conducted a two-year field experiment at Jingzhou City, Central China to investigate the effects of varying N fertilizer application rates (0, 90, 180, 270, and 360 kg N ha−1) on shoot biomass accumulation and its distribution, N uptake, and N use efficiency in maize under well-watered (WW) conditions throughout the maize growing season and WL for 6 d at the sixth leaf stage. Compared to the WW condition, WL significantly reduced shoot biomass, N accumulation, harvest index, N harvest index, nitrate reductase activity, N use efficiency, and N partial factor productivity at all N application rates. Moreover, these parameters (excluding N partial factor productivity) increased with increasing N application rates (up to 360 kg N ha−1) under WL, suggesting that a high N rate (such as 360 kg N ha−1) could improve the accumulation and distribution of shoot biomass and N utilization of waterlogged maize. The enhanced shoot biomass, nitrate reductase activity, N accumulation, and N use efficiency were related to increased root biomass and root length density at higher N treatments under WL. In addition, compared with other N treatments, 360 kg N ha−1 resulted in a better proportion of biomass distribution in the kernel and improved transfer of biomass from the vegetative organs to grain under WL, which accounted for the enhanced harvest index. Therefore, an appropriate increase in the nitrogen application rates (up to 360 kg N ha−1) helped to improve biomass accumulation in the shoot and its transfer to the grain, together with N use efficiency in maize under early (sixth leaf)-stage waterlogging.