Maize Fertilizer Research Articles

Optimizing nitrogen fertilization in maize: the impact of nitrification inhibitors, phosphorus application, and microbial interactions on enhancing nutrient efficiency and crop performance.

Despite the essential role of nitrogen fertilizers in achieving high crop yields, current application practices often exhibit low efficiency. Optimizing nitrogen (N) fertilization in agriculture is, therefore, critical for enhancing crop productivity while ensuring sustainable food production. This study investigates the effects of nitrification inhibitors (Nis) such as Dimethyl Pyrazole Phosphate (DMPP) and Dimethyl Pyrazole Fulvic Acid (DMPFA), plant growth-promoting bacteria inoculation, and phosphorus (P) application on the soil-plant-microbe system in maize. DMPFA is an organic nitrification inhibitor that combines DMP and fulvic acid for the benefits of both compounds as a chelator. A comprehensive rhizobox experiment was conducted, employing varying levels of P, inoculant types, and Nis, to analyze the influence of these factors on various soil properties, maize fitness, and phenotypic traits, including root architecture and exudate profile. Additionally, the experiment examined the effects of treatments on the bacterial and fungal communities within the rhizosphere and maize roots. Our results showed that the use of Nis improved plant nutrition and biomass. For example, the use of DMPFA as a nitrification inhibitor significantly improved phosphorus use efficiency by up to 29%, increased P content to 37%, and raised P concentration in the shoot by 26%, compared to traditional ammonium treatments. The microbial communities inhabiting maize rhizosphere and roots were also highly influenced by the different treatments. Among them, the N treatment was the major driver in shaping bacterial and fungal communities in both plant compartments. Notably, Nis reduced significantly the abundance of bacterial groups involved in the nitrification process. Moreover, we observed that each experimental treatment employed in this investigation could select, promote, or reduce specific groups of beneficial or detrimental soil microorganisms. Overall, our results highlight the intricate interplay between soil amendments, microbial communities, and plant nutrient dynamics, suggesting that Nis, particularly DMPFA, could be pivotal in bolstering agricultural sustainability by optimizing nutrient utilization.

Potential of cattle urine as an alternative fertilizer for maize (Zea mays L.) production in Ethiopia

Maize productivity has been increasing through the years due to increased use of inorganic fertilizers. However, the price and environmental impact has brought lack of interest among the farmers. Thus, this study was aimed at evaluating the growth, yield and nitrogen use efficiency (NUE) of maize varieties under cattle urine application. The field experiment was conducted in randomized complete block design with three replications. The experiment consisted of four treatments viz. control, 100 and 50 % cattle urine and recommended dose of inorganic fertilizer. The results demonstrated a comparable growth and grain yield increment due to 100 % cattle urine and recommended dose of inorganic fertilizer. The difference between the two varieties in growth, yield and related traits, and NUE indices due to fertilizer applications was insignificant. The leaf area of maize nourished with 100, 50 % cattle urine and recommended dose of inorganic fertilizer increased by 11.15, 9.73 and 9.78 folds, respectively, in two months period relative to the controls. Fertilized plants had significantly (p < 0.05) higher grain yield (GY). The use of 100, 50 % cattle urine and inorganic fertilizers resulted in 526.76, 326.12, 542.91 % and 47.83, 36.03, 49.78 % increment in average GY and aboveground biomass, respectively, compared to controls. Similarly, plants fertilized with 50 % cattle urine showed an average GY reduction of 39.87 and 38.10 % compared to the recommended dose of inorganic fertilizer and 100 % cattle urine, respectively. The use of 50 % cattle urine produced significantly higher NUE, N agronomic efficiency (NAE), N recovery efficiency (NRE) and internal efficiency (IE). Higher GY kg-1 of N applied was obtained from cattle urine applications. In a nutshell, the results confirmed the potential of cattle urine as an alternative to inorganic fertilizers in maize production. However, further studies on optimization of the cattle urine rate and scale up works are recommended.

Pre Extension Demonstration of Soil Test Crop Response Based Recommended Phosphorus Fertilizer for Maize in Bako Tibe and Gobu Sayo Districts of Western Oromia, Ethiopia

Pre-extension demonstration of soil test crop response based phosphorus fertilizer recommendation for maize was conducted in Bako Tibe and Gobu Sayo districts with the objective of participatory demonstration of soil test crop response based phosphorus recommendation under farmers’ condition in 2022 cropping season. Two treatments were applied (T&amp;lt;sub&amp;gt;1&amp;lt;/sub&amp;gt;) blanket Recommendation (T&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;) Soil Test crop response based recommended phosphorus fertilizer with improved maize (BH-661) variety. The trial was conducted on eleven farmers’ fields which were used as replications. Plot size for each treatment was 10m x 20m with the spacing of 35cm and 75cm between plants and rows respectively using seed rate of 25 kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; and with recommended optimum N-fertilizer rate of 110 kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. In each PAs, one FREG unit comprising of 20 farmers were established. About 185 (139 male and 46 female) participants were take part on field visit based training held during physiological maturity of maize. The average total biomass with soil test crop response based Recommended phosphorus fertilizer was 32,385 kgha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; while blanket recommendation was 27,730 kgha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. Again the average grain yield for STCRBPR was 7,205kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt; while blanket recommendation was 4,641kg ha&amp;lt;sup&amp;gt;-1&amp;lt;/sup&amp;gt;. Similarly, the results of the economic analysis indicated that the use of p-fertilizer based on soil test crop response and the blanket suggestion with MRR 500.93% could yield net returns of 188,029.36 and 119348 ETB per hectare, respectively. As a result, the suggested phosphorus fertilizer based on soil test crop response should be expanded/scaled up to include additional maize producer farmers in the region and surrounding districts.

Unraveling the advantages of site-specific nutrient management in maize (Zea mays L.) for enhancing the growth and productivity under varied plant populations in the hot and moist sub-humid region of Odisha

In developing countries like India, a cereal-based cropping system is one of the important practices, having a significant role in food security and the country’s economy. Among the cereal crops cultivated in India, maize is one among them having a huge market demand, and yield potential and can perform under various agroclimatic conditions. In the cultivation of cereal crops like maize, input optimization and intensification of farming by altering plant population are highly essential for agricultural sustainability as well as crop productivity. Nutrients can be efficiently applied through site site-specific approach by using a decision support system, namely, Nutrient Expert (NE) rather application of a recommended dose for an agroclimatic region. Considering the above fact, the research was carried out in the rabi season of 2022-2023 at the Post Graduate Research Farm ofCenturion University of Technology and Management (23?38' N latitude and 87?42' E longitude) in Odisha. The experiment was laid out in a split-plot design with different spacings and NE-based nutrient recommendations. The main factor consisted of 3 different spacings and 4 different nutrient recommendations were considered in sub-plots. The recommended dose of fertilizer for maize was 120-60-60 kg ha-1 of N: P2O5:K2O respectively. The results of the experiment revealed that the highest plant height (249 cm), dry matter accumulation (1556 g m-2), leaf area (5674 cm2 plant-1), grain yield (6362 kg ha-1), and stover yield (9334 kg ha-1) were obtained in 60 cm × 15 cm spacing. The NE-based nutrient management for a target yield for 10 t ha-1 recorded the highest values in terms of growth attributes, yield attributes, and yield of maize. The experiment concluded that providing fertilizers through NE-based nutrient recommendation for a target yield of 10 t ha-1 with a spacing of 60 cm × 15cm can be considered for obtaining better growth, yield attributes, and yield of maize.

Assessment of Endogenous Soil Fertility to Update Fertilization of Maize (Zea mays L) Crops in the Savannah Region of Togo

The diagnosis of soil fertility is a prerequisite for the formulation of balanced and site-specific fertilizer recommendations. Macro elements (nitrogen – N, phosphorous – P and potassium – K) based nutrient omission trials were conducted in the districts of Oti, Tandjoare, Tone and Kpendjal of the Savannah region. The objective was to assess endogenous soil fertility under maize cropping to further develop updated site-specifique fertilization schemes for the crop. A total of twenty-five producers were selected in the region (eight in Tandjoare, seven in Tone, five in Oti and five in Kpendjal) for the study in a paticipatory approach. The approach was participatory in order to involve the end user in the exercise. A randomized complete block design was adopted with five fertilization treatments including N0P0K0 (T1), N0P60K70 (T2), N120P0K70 (T3), N120P60K0 (T4) and N120P60K70 (T5) kg ha-1 for the trial. The unit plot size was 100 m2 (10 m x10 m). Grain yield, yield response to nutrients and Agronomic Efficiency (AE) were determined. Genstat Edition 12th was used to discriminate means.The average yields were 0.56, 0.83, 3.18, 3.44 and 4.57 Mg ha-1 respectively for T1, T2, T3, T4 and T5 in Tandjoare, 0.32, 0.52, 1.06, 2.39 and 3.02 Mg ha-1 respectively for T1, T2, T3, T4 and T5 in Tône, 1.01, 1.35, 2.56, 3.16 and 4.39 Mg ha-1 respectively for T1, T2, T3, T4 and T5 in Oti and 0.39, 0.75, 1.54, 2.33 and 3.31 Mg ha-1 respectively for T1, T2, T3, T4 and T5 in Kpendjal. The ranking of yield data by fertilizer treatment indicates that all three macronutrients (N, P and K) are required for maize production in the Savannah region, with a priority ranking of N&gt;P&gt;K. The results also showed that the best Agronomic Efficiency is obtained when all macronutrients are supplied in all four districts. The results of this diagnostic will be used as a basis for formulating balanced, site-specific fertilizer recommendations for intelligent, environmentally-friendly agriculture.

Acidification prior to drying of digestate solids affects nutrient uptake and fertilizer value when applied to maize

Acidification has proven effective in minimizing NH3 emissions during the drying of digestate bio-solids, but its impact on soil nutrient dynamics and plant growth is less understood. This study aimed to assess the nitrogen and phosphorus efficiency of acidified-dried digestate solids as starter fertilizer for maize through a pot experiment and a soil incubation study. Two types of digestates (MDS and SDS) and two acidifying agents (concentrated H2SO4 and alum) were used. Drying significantly lowered the nitrogen fertilizer replacement value (N-FRV) from 42% in untreated to 12% in the dried material, reducing maize biomass and N uptake by 34% and 54%, respectively. The decline mitigated by acidification, which doubled N-FRV to 28%. Drying enhanced maize P uptake by 25%, indicating dried MDS as an effective P fertilizer (P-FRV of 82%). However, alum negated the drying benefits for P uptake, aligning it with raw MDS levels. The SDS treatments showed no significant effects on maize growth or nutrient uptake, though dried SDS indicated a high N mineralization potential, N-FRV and P-FRV remained around 33% and 26%, respectively. The study concludes that H2SO4-acidified dried MDS could serves as a suitable starter fertilizer with balanced N and high P availability, supporting early maize development. Alum may serve to preserve N value while reducing P solubility to prevent runoff. Dried SDS is less effective as a mineral fertilizer replacement, better suited for sustaining soil organic N and P levels.

Soil amendment and N fertilization strategies to improve C sequestration and storage in soil aggregates

AbstractManagement can affect soil quality through changes in carbon (C) stock, especially in protected C fractions of soil aggregates. Soil aggregation and C sequestration may be improved with soil correction (liming and gypsum) and nitrogen (N) fertilization, but it is not clear how these factors might interact to affect humic substances. The objective of the study was to evaluate the effects of calcium (Ca), magnesium (Mg), and N fertilizatilizer amendments on the accumulation of C, N, and humic substances in soil aggregates from an Oxisoil in Brazil. The production system was no‐till soybean [Gycine max (L.) Merr] double‐cropped with maize (Zea mays L.) and intercropped with forage grass since 2016. Treatments were no amendment, lime only, and lime + phosphogypsum, factorially arranged with and without annual N fertilization of maize. Soil was collected at 0–10, 10–20, 20–40, and 40–60 cm 6 years after initiation of the experiment. The combination of lime, gypsum, and N led to 13% greater total C stock and 20% greater total N stock within the 0–60 cm soil profile than the control. Levels of fulvic acid (FA) and humic acid (HA) were similar among aggregate classes, but humin was greatest in larger aggregates. Liming plus N decreased FA and HA, but gypsum application mitigated this negative effect. Application of limestone, gypsum, and N increased humin, mainly in the soil surface (0–10 cm). Soil C storage and stabilization was enhanced in large soil aggregates with the combined use of lime, gypsum, and N fertilization in humid tropical soils.

Effect of Ridge–Furrow with Plastic Film Mulching System and Different Nitrogen Fertilization Rates on Lodging Resistance of Spring Maize in Loess Plateau China

The ridge–furrow with plastic film mulching (RF) system has been widely adopted in rain-fed crop planting due to its potential to enhance crop yield and water use efficiency. However, the impact of the RF system on maize lodging resistance, particularly when nitrogen fertilizer is applied, remains uncertain. Therefore, a two-year field experiment was carried out with two planting systems (FP: flat planting and RF) and two nitrogen application rates (N180: 180 kg·N ha−1 and N300: 300 kg·N ha−1) to assess the risk of lodging in maize. The results showed that compared to FP, RF resulted in a significant increase of 78.7% in lodging rate. In addition, the lodging rate increased by 22.6% with increasing nitrogen fertilizer application. The lignin content increased by 43.4%, while the stalk bending strength rose by 42.5%, under RF compared to the FP system. These improvements in the mechanical properties of maize stalks contributed to the improved lodging resistance index of RF, which was found to be approximately 21.3% higher than that of FP. In addition, high nitrogen application rates increased the risk of lodging for different planting patterns over two years. In conclusion, fertilization of spring maize with 300 kg·N ha−1 under the RF system led to higher yields but increased lodging rates. The risk of lodging should be considered when planting maize under the RF system. The results of this study can provide scientific basis and technical support for the optimization of rain-fed maize cultivation measures in the Loess Plateau.

Effects of different tillage practices and cropping systems on soil fertility and soil properties in maize

Effects of different tillage practices and cropping systems on soil fertility and soil properties in maize

Sustainable management strategies for balancing crop yield, water use efficiency and greenhouse gas emissions

CONTEXTTo ensure food security in the face of climate change, it is crucial to use effective agricultural management practices that produce the triangular win-win for water, crops, and environments. OBJECTIVEThis study aimed to explore the sustainable management measures for balancing crop yield, water use efficiency (WUE) and greenhouse gas (GHG) emissions in China during 1981–2020. METHODSThe study selected the Beijing-Tianjin-Hebei (BTH) region of China as the research area, where there were sharp contradictions among water shortage, food security and polluted environment. Four irrigation treatments and four fertilization treatments were set referring to the local cultivated experiences. The daily dynamic changes in crop yield, WUE and GHG emissions were simulated by optimized Agricultural Production Systems sIMulator (APSIM) model. RESULTS AND CONCLUSIONSThe irrigations had positive impacts on crop yield and WUE in BTH region. The irrigation amount's rise caused a gradual augmentation in the total yield of winter wheat and summer maize from 1981 to 2020.The highest total yield was achieved under W4 irrigation treatment (320 mm water for winter wheat and 60 mm water for summer maize), with an annual mean of 24,579.2 kg·ha−1. The annual average WUE under the W3 irrigation treatment (240 mm water for winter wheat) was the highest, with an average of 13.9 kg·ha−1·mm−1. However, extensive fertilization exacerbated soil GHG emissions. The soil GHG emissions were found to be significant increase as the input amount of fertilization. The FI fertilization measure (no fertilization) was assessed to have the least impact on the environment, with an average GHG emissions of 0.4 Mg·CO2-eq·ha−1. The optimal goals of high yield, high WUE and low GHG emissions were achieved by choosing effective combination practices of water and nitrogen management. Overall, the W3 irrigation and F3 fertilization (180 kg/ha fertilizer for winter wheat and 120 kg/ha fertilizer for summer maize.) treatments had the maximum water-fertilizer production indexes in the BTH region. SIGNIFICANCEThis study highlights the importance of agricultural management measures for guaranteeing food security and environmental sustainability at the same time under climate change.

Phytin recovered from grain distillation can serve as a phosphorus fertilizer for maize and soybean

AbstractPhosphorus (P) recovery from waste streams can increase food system P use efficiency while simultaneousl mitigating point source P losses. Phytin is a P‐rich waste product generated from maize grain biorefineries, largely located in the US Midwest. However, since the majority of P in phytin is organic, phytin‐P is likely to have limited crop availability in soil following application, as it must first be mineralized to orthophosphate‐P by soil phosphatases. To evaluate the fertilizer potential of phytin recovered from a maize wet milling plant and test hypothesized mechanisms of P mineralization, a five‐step gradient of phytin substitution for monoammonium phosphate (MAP) (0%, 25%, 50%, 75%, and 100% substitution) was evaluated for maize (Zea mays L.) and soybean (Glycine max L.) growth in a P‐deficient Aquic Argiudoll. Irrespective of crop species, aboveground biomass at end of vegetative growth (VT stage) was similar for up to 75% phytin substitution as MAP, but was 21% lower for maize and 49% for soybean when phytin was fully substituted for MAP. Soil microbial biomass carbon (C), nitrogen (N), and P, as well as activities of phosphomonoesterase and phosphodiesterase were invariant across the phytin substitution gradient, suggesting negligible mineralization of phytin P. Full substitution of MAP with phytin lowered soil microbial biomass C:N by 121% for maize and by 153% for soybean, and soil phosphatase activities per unit microbial biomass C were 24% higher under soybean. Our results indicate that phytin can be partially substituted for highly water‐soluble P fertilizers for the two major crop species of the US Midwest in which phytin waste generation is co‐located.

Cost Reduction Economical Drip Layout for Enhancing Productivity, Profitability and Soil Fertility in Maize and Cotton under Semi-arid Condition

Background: Single economical cost reducing drip lay out for major annual crops with paired row geometry is an alternate solution to overcome constraints faced by the farmers and increase the income. Further to achieve high crop production and sustainable agricultural development, it is necessary to compare the effects of different dripline spacings and fertilization rates on maize and seed cotton yield. Methods: A field experiment was carried out at Agricultural Engineering College and Research Institute, Tiruchirappalli to evaluate the suitability of single economical drip layout and to optimize the fertilizer level in modified geometries as well as to assess the impact of geometries in water and productivity of maize and cotton. Result: The results revealed that, the economics was in favor with 1.20 m lateral spacing and application of 100% recommended N and K through drip fertigation and P as soil application (L2F2) having higher gross return, net return and BCR in maize and cotton. 1.2 m spacing between two laterals with 4Iph emitter at 0.6 m interval with recommended dose of 100% N and K trough fertigation and P as soil application is recommended to achieve higher productivity and monetary return form cotton and maize.

Assessment of soil microbial diversity and soil enzyme activities under inorganic input sources on maize and rice ecosystems

BackgroundTo increase crop productivity, modern agricultural practices comprises fertilizers, algaecides, herbicides and fungicides. ObjectiveThe purpose of this study was to evaluate the effects of soil microbial population and soil enzyme activity by the use of fertilizer in maize and inorganic input in the rice ecosystem. MethodsA field experiment (2021 to 2023) was carried out using synthetic fertilizer doses with maize crops followed by rice crops using inorganic inputs. Soil microbial population and enzyme activities were examined. ResultsMaize field experiment revealed that the plots treated with 75 % Standardized Dose of Fertilizer (SDF) of NPK had the highest populations of diazotrophs (124 × 105cfu / g), Phosphobacteria (66.33 × 105cfu / g), and Azospirillum (0.409 × 105 MPN / g) than 100 % and 150 % SDF of NPK. The soil enzyme activity was higher in the unfertilized control plot than fertilized plot. These experimental results revealed that a low amount of fertilizer and no fertilizers favour the growth of soil microorganisms and soil enzyme activities, respectively. Followed by the rice field experiment, revealed that the soil microbial population was decreased by the application of inorganic inputs viz., fertilizer, algaecide, herbicide and fungicide. However, the maximum soil microbial population was found in algaecide application followed by herbicide and fungicide. ConclusionThe field experiment concluded that soil microbial population and enzyme activity were affected by inorganic amendments. Less inorganic fertilizers and no fertilizers improve soil microbial activities and soil enzyme activities.

Heat stress and sexual reproduction in maize: unveiling the most pivotal factors and the greatest opportunities.

The escalation in the intensity, frequency, and duration of high-temperature (HT) stress is currently unparalleled, which aggravates the challenges for crop production. Yet, the stage-dependent responses of reproductive organs to HT stress at the morphological, physiological, and molecular levels remain inadequately explored in pivotal staple crops. This review synthesized current knowledge regarding the mechanisms by which HT stress induces abnormalities and aberrations in reproductive growth and development, as well as by which it alters the morphology and function of florets, flowering patterns, and the processes of pollination and fertilization in maize (Zea mays L.). We identified the stage-specific sensitivities to HT stress and accurately defined the sensitive period from a time scale of days to hours. The microspore tetrad phase of pollen development and anthesis (especially shortly after pollination) are most sensitive to HT stress, and even brief temperature spikes during these stages can lead to significant kernel loss. The impetuses behind the heat-induced impairments in seed set are closely related to carbon, reactive oxygen species, phytohormone signals, ion (e.g. Ca2+) homeostasis, plasma membrane structure and function, and others. Recent advances in understanding the genetic mechanisms underlying HT stress responses during maize sexual reproduction have been systematically summarized.

Pyrolyzed and unpyrolyzed residues enhance maize yield under varying rates of application and fertilization regimes.

Biochar is increasingly gaining popularity due to its extensive recommendation as a potential solution for addressing the concerns of food security and climate change in agroecosystems, with biochar application for increased carbon sequestration, enhanced soil fertility, improved soil health, and increased crop yield and quality. There have been multiple studies on crop yield utilizing various biochar types and application amounts; however, none have focused on the influence of diverse biochar types at various pyrolysis temperatures with different application amounts and the integration of fertilizer regimes in maize crops. Therefore, a two-year factorial field experiment was designed in a temperate Himalayan region of India (THRI) to evaluate the residual effect of different biochar on maize yield under different pyrolysis temperatures, various application rates and fertilizer regimes. The study included three factors viz., amendment type (factor 1), rate of application (factor 2) and fertilizer regime (factor 3). Amendment type included 7 treatments: No biochar- control (A1), apple biochar @ 400°C pyrolysis temperature (A2), apple biochar @ 600°C pyrolysis temperature (A3), apple residue biomass (A4), dal weed biochar @ 400°C pyrolysis temperature (A5), dal weed biochar @ 600°C pyrolysis temperatures (A6), and dal weed residue biomass (A7). The rate of application included 3 levels: Low (L- 1 t ha-1), medium (M- 2 t ha-1), and high (H- 3 t ha-1). At the same time, the fertilizer regimes included 2 treatments: No fertilizer (N) and recommended dose of fertilizer (F). The results revealed that among the various amendment type, rate of application and fertilizer regimes, the A3 amendment, H rate of application and F fertilizer regime gave the best maize growth and productivity outcome. Results revealed that among the different pyrolyzed residues used, the A3 amendment had the highest plant height (293.87 cm), most kernels cob-1 (535.75), highest soil plant analysis development (SPAD) value (58.10), greatest cob length (27.36 cm), maximum cob girth (18.18 cm), highest grain cob yield (1.40 Mg ha-1), highest grain yield (4.78 Mg ha-1), higher test weight (305.42 gm), and highest stover yield (2.50 Mg ha-1). The maximum dry weight in maize and the number of cobs plant-1 were recorded with amendments A4 (14.11 Mg ha-1) and A6 (1.77), respectively. The comparatively 2nd year of biochar application than the 1st year, the H level of the rate of application than the L rate and the application and integration of the recommended dose of fertilizer in maize results in significantly higher values of growth and productivity in maize. Overall, these findings suggest that the apple biochar @ 600°C pyrolysis temperature (A3) at a high application rate with the addition of the recommended dose of fertilizer is the optimal biochar for enhancing the growth and productivity of maize in the THRI.

Maize residue input rather than cover cropping influenced N2O emissions and soil–crop N dynamics during the intercrop and cash crop periods

The well-known benefits of cover cropping for mitigating climate change and improving soil quality could be threatened by increased greenhouse gas emissions. Therefore, such practices could have negative consequences in the context of global climate change. The present year-long field experiment, carried out under irrigated semiarid conditions, evaluated the effect of returning maize crop residues at two topsoil input levels in combination with bare fallow, a cereal (barley, Hordeum vulgare L.) and a legume (vetch, Vicia sativa L.) as cover crops as part of an annual cover crop–cash crop (maize, Zea mays L.) rotation. In addition, control plots, without the addition of nitrogen fertilizer (either in the previous cropping season or during the experiment), were established following the same experimental design in order to assess the carry-over impact of residual nitrogen from prior crops. Nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) fluxes were measured together with soil mineral nitrogen and crop yields and nitrogen use efficiency. The significant effect of maize residue input on N2O emissions during the cover crop phase (this was 43% greater for the lower maize residue input than for the higher) was offset after subsequent maize fertilization (there was a 170% increase following the higher maize residue input compared to the lower). Although no differences in soil mineral nitrogen content were reported between treatments before maize fertilization, N2O emissions were 72% higher on the fertilized plots than on the control plots. Before maize fertilization, N2O emissions were increased by the incorporation of cover crop residues and soil rewetting after irrigation, with the highest N2O fluxes being reported for the cereal crop. Cumulative CO2 fluxes were higher in the plots with cover crops (cereal and legume) than in bare fallow plots, while CH4 sink was not affected by cover cropping or maize residue input. The grain yield penalty for maize production (a 7% decrease) with the legume cover crop on the nitrogen fertilized plots (the opposite of what was observed in the control area) highlights the need for an accurate estimation of the nitrogen supply from the mineralization of legume residues. Overall, cover crop and maize residue input did not have any significant effect on annual cumulative N2O emissions, so the positive effects of these practices should be considered to recommend them under semiarid conditions for climate change mitigation and adaptation.

Effects of Nitrogen Reduction at Different Growth Stages on Maize Water and Nitrogen Utilization under Shallow Buried Drip Fertigated Irrigation

A field experiment of drip fertigated nitrogen reduction was set up in a typical Maize planting area in the Xiliao River Basin in 2018 and 2019. Different phased nitrogen reductions were set up under shallow buried drip irrigation during the growth period to explore ways to improve nitrogen use efficiency (NUE) by understanding the Maize regulation of nitrogen absorption and utilization. The recommended nitrogen application in the early stage (Nopt, total nitrogen 240 kg·hm−2) had the highest grain nitrogen uptake and total nitrogen uptake, followed by nitrogen reduction before the maximum canopy mulching (Nde-I, total nitrogen 180 kg·hm−2), nitrogen reduction after the maximum canopy mulching (Nde-II, total nitrogen 180 kg·hm−2) and no nitrogen application (N0). Without nitrogen application, the leaves were thin, green and yellow. The total nitrogen uptake was 38.54~41.31% lower than the recommended nitrogen application in the early stage. When nitrogen fertilizer was reduced in the maximum canopy mulching, grain nitrogen absorption was affected. Grain nitrogen absorption fell by 15.07% to 17.51% when nitrogen was reduced in the maximum canopy mulching compared to the recommended nitrogen application. The harvest index of nitrogen reduction before the maximum canopy coverage was 9.65~11.52% higher than that in the later stage, indicating that the nitrogen absorption between Maize grain, stem, and leaf was better regulated. Maize evapotranspiration water consumption was reduced throughout the growth cycle when nitrogen was reduced at various stages. Nitrogen reduction before maximum canopy mulching boosted water use efficiency (WUE) by 3.44% to 6.12% compared to the recommended nitrogen application in the early stage. The nitrogen fertilizer agronomic efficiency increased by 11.17% to 13.87%. The nitrogen use efficiency rose by 10.99~3.15% (5.24~6.60 percentage points). A total of 25% of nitrogen fertilizer was saved with the yield declining by only about 5%, resulting in increased NUE while maintaining the yield stability. Under shallow buried drip fertigated irrigation, the appropriate reduction in nitrogen fertilizer during the period from Maize sowing to the maximum canopy development ensured the nitrogen supply during tasseling–silking stage and filling stage, which can be used as a regulation method and a way to improve the Maize fertilizer use efficiency.

A P-type pentatricopeptide repeat protein ZmRF5 promotes 5' region partial cleavages of atp6c transcripts to restore the fertility of CMS-C maize by recruiting a splicing factor.

A fast evolution within mitochondria genome(s) often generates discords between nuclear and mitochondria, which is manifested as cytoplasmic male sterility (CMS) and fertility restoration (Rf) system. The maize CMS-C trait is regulated by the chimeric mitochondrial gene, atp6c, and can be recovered by the restorer gene ZmRf5. Through positional cloning in this study, we identified the nuclear restorer gene, ZmRf5, which encodes a P-type pentatricopeptide repeat (PPR) family protein. The over-expression of ZmRf5 brought back the fertility to CMS-C plants, whereas its genomic editing by CRISPR/Cas9 induced abortive pollens in the restorer line. ZmRF5 is sorted to mitochondria, and recruited RS31A, a splicing factor, through MORF8 to form a cleaving/restoring complex, which promoted the cleaving of the CMS-associated transcripts atp6c by shifting the major cleavage site from 480th nt to 344 th nt for fast degradation, and preserved just right amount of atp6c RNA for protein translation, providing adequate ATP6C to assembly complex V, thus restoring male fertility. Interestingly, ATP6C in the sterile line CMo17A, with similar cytology and physiology changes to YU87-1A, was accumulated much less than it in NMo17B, exhibiting a contrary trend in the YU87-1 nuclear genome previously reported, and was restored to normal level in the presence of ZmRF5. Collectively these findings unveil a new molecular mechanism underlying fertility restoration by which ZmRF5 cooperates with MORF8 and RS31A to restore CMS-C fertility in maize, complemented and perfected the sterility mechanism, and enrich the perspectives on communications between nucleus and mitochondria.

Efficacy of growth regulators for maize fields

At the current stage of agricultural development, it is paramount to introduce advanced technologies for maize cultivation. Special attention is required for the use of modern growth regulators in order to ensure stable increase in grain production. To protect maize from stress factors emerging in unfavorable meteorological conditions of the steppe zone (such as drought, high temperatures, negative impacts of pesticides, diseases, etc.), increasing attention is given to the application such physiologically active compounds as plant-growth regulators (PGRs). The experimental studies were carried out in 2021–2023 on the experimental field of the Dnipro State Agrarian-Economic University. The objective of the study was to identify the efficacies of the plant-growth regulators used in different doses on maize. The highest efficacy in the technology of maize cultivation was achieved by treating the maize plants with humates during the phase of 3–5 leaves. This treatment promoted a stable tendency towards growth, resulting in 5–7 cm increase in height (2.1–2.8%), 5–6% increase in leaf surface area, and increases in yield structure (13.6 cm in the cob length (5.1%), 18 grains (3.9%) in cob grain filling, and 29 g (9.1%) in mass of 1,000 grains), compared with the control without growth regulators. Somewhat lower efficiency according to all the aforementioned parameters was demonstrated by coating of seeds. Treatment of the seeds with growth regulators and microbial fertilizers in the phase of 3–5 leaves resulted in 7.3% to 18.7% increase in the yield, indicating their high efficacy, especially in unfavorable weather conditions. Therefore, the greatest gains in the grain yield was seen after using humate 400 g/ha + polyethylene glycol 360 g/ha – 1.08 t/ha; humate 800 g/ha + polyethylene glycol 240 g/ha – 1.19 t/ha; sodium metasilicate 600 g/ha – 1.23 t/ha; Pakt 500 g/ha – 1.23 t/ha; and Peram 100 mL/ha + Vympel PGR 500 g/ha – 1.12 t/ha. That is, of the sixty seven tested combinations of physiologically active compounds, no variant produced a grain-yield increase lower than 0.5 t/ha, and the variants with foliar feeding of the maize demonstrated no clear upward tendency in the yield after the PGRs had been introduced in doses above the norms. Studies of efficiency of the growth regulators and microbial fertilizers for maize confirmed that achievement of maximum grain yield is possible only by optimizing the vital factors at all stages of organogenesis of maize. When climatic elements develop with various amplitudes during a vegetative period, effectiveness of preparations is determined by their ability to enhance tolerance to the environmental stressors.

Study of Genotypic and Phenotypic Correlation and Path Analysis Under Potassium Fertilization in Maize (Zea mays)

During the autumn season of 2018, a field experiment was carried out. The study’s goal was to evaluate phenotypic and genotypic correlation as well as path coefficient analysis under varied degrees of potassium fertilization. The study included nine different maize genotypes. Planted with three levels of potassium fertilization (75, 100, and 125 K2SO4 Kg Hectare-1). The split plot arrangement was done according to RCBD with three replications. The most important findings were summarized as follows: The genetic analysis revealed that genotypes differed significantly in all analyzed variables under the three levels of potassium fertilization. The grain yield genetically, phenotypically, and positively correlated with plant height, leaf area index, number of rows per ear, number of grain in a row and weight of 300 grain. The trait of a number of grains in a row showed genetic, phenotypic, and significant correlation with the three levels of potassium fertilization and the highest reached 0.95 and 0.89 respectively at the third level. Path analysis showed that the direct effects for a Leaf area index, number of rows per ear, Number of grains per row and weight of 300 grain were negative at the first level of potassium and highly positive at the other two levels. the direct selection for a number of rows per ear and Number of grains per row will incredibly effective in enhancing yield. However, the highest indirect effect for Number of grains per row was through plant height (1.76) at the first levels of potassium fertilization.