Maize Biomass Research Articles

Impact of Commercial Organic Ameliorants on Nitrogen and Phosphorus Concentrations of Maize Biomass at Ninth Leaf and Silking Growth Stages

Impact of Commercial Organic Ameliorants on Nitrogen and Phosphorus Concentrations of Maize Biomass at Ninth Leaf and Silking Growth Stages

Inoculation with phosphate‐solubilizing bacteria alters microbial community and activates soil phosphorus supply to promote maize growth

AbstractPhosphorus (P) is one of the essential macronutrients for plants, but agricultural soil generally lacks available P. This study aims to ascertain the impact of phosphate‐solubilizing bacterial inoculation on the development of maize, soil characteristics, P fractions, and the microbial population in the soil. In this experiment, we explored the P solubilizing ability of P‐solubilizing bacteria through liquid culture. In a maize pot experiment, soil P fractions and maize growth were examined, and a metagenomic sequence was constructed to analyze the soil microbial community and gene abundances and to link their relationship. In the shaking flask culture experiment, it was found that the Burkholderia (XQP35) and Raoultella (SQP80) have a strong capability for calcium phosphate and calcium phytate. Compared with the blank control, the XQP35 and SQP80 treatments could improve maize biomass and the soil nutrient status. Moreover, SQP80 treatments increased the soil acid phosphatase activity. SQP80 inoculation dramatically decreased the variety of the soil microbial community and the abundance of Acidobacteria. We found that the different treatments had no significant effect on the number of genes but that the SQP80 treatments significantly increased the P‐cycling pathway gene family phoA and phoD compared with the CK treatment. Our results demonstrated that inoculation with XQP35 and SQP80 could dissolve varieties of insoluble P and, together with functional pathways of P‐cycling, promote the transformation of P fractions and ultimately increase soil available P content to promote the development of maize.

Beneficial Effects of Biochar Application with Nitrogen Fertilizer on Soil Nitrogen Retention, Absorption and Utilization in Maize Production

The irrational use of nitrogen (N) fertilizer has become a major threat to soil quality and food security, resulting in serious ecological and environmental problems. Holistic approaches to N fertilizer application are required to maintain a high N utilization efficiency (NUE) and sustainable agriculture development. Biochar is an efficient carbon-rich material for amending soil quality and promoting crop N uptake, but knowledge pertaining to the promoting effects of biochar application on N fertilizers is still limited. In this study, a field plot experiment was designed to detect the combined effects of biochar (0, 15 and 30 t ha−1) and N fertilizer (204, 240 and 276 kg N ha−1) on the soil nutrient levels, NUE, plant growth performance and crop production of maize. The results demonstrated that the combined application of N fertilizer and biochar can significantly decrease the soil pH and increase the contents of soil organic carbon, mineral N, available phosphorus and potassium. The crop N uptake and N content were largely promoted by the addition of N fertilizer and biochar, resulting in higher leaf photosynthetic efficiency, dry matter accumulation and grain yields. The highest yields (14,928 kg ha−1) were achieved using 276 kg N ha−1 N fertilizer in combination with 15 t ha−1 biochar, and the highest NUE value (46.3%) was reached with 204 kg N ha−1 N of fertilizer blended with 30 t ha−1 of biochar. According to structural equation modeling, the beneficial effects of N fertilizer and biochar on the plant biomass of maize were attributed to the direct effects related to soil chemical properties and plant growth parameters. In conclusion, N fertilizer combined with biochar application is an effective strategy to enhance the utilization of N fertilizer and crop production for maize by increasing soil fertility, improving plant crop uptake and promoting plant growth.

Effect of Combined Application of Vermicompost and NPS Fertilizer Rates on Growth, Yield and Yield Components of Maize (Zea mays L.) at Toke Kutaye District, Ethiopia

Maize is one of the major and important cereal crops in Western Shewa Zone, particularly, in the Toke Kutaye district. However, the yield of the crop is low mainly due to the low fertility status of the soils. Integrated use of vermicompost and NPS fertilizers is indispensable to improve this condition of the soil. In this context, a study was conducted in 2019/2020 to assess the effect of the combined use of vermicompost and NPS fertilizer on yield and yield components of maize. To achieve this objective field experiment was laid out in a randomized complete block design and replicated three times. The results of this study revealed that the current scenarios of maize production in Toke Kutaye district call for appropriate ways of adding nutrients to the soil to obtain optimum maize productivity. In response to this, the combined application of different rates of vermicompost and NPS fertilizer to soil significantly affected most parameters used for this investigation such as plant height, leaf number, leaf length, leaf area, stand count, ear length, and a number of ears per plant, thousand-grain weight, total above-ground dry biomass and grain yield of maize. Moreover, the combined form of NPS blended fertilizer and vermicompost was applied and the result revealed that the sole application of recommended NPS fertilizer and vermicompost increased maize yield by 52.27 and 55.72% over control treatments, respectively. Besides this, the combined use of vermicompost and NPS fertilizer by the rating of half of the recommended rate of both fertilizers increased maize yield by 60.05% over the control treatment. This indicates that the best option for soil fertility management is integrated soil fertility management that involves the combined use of vermicompost and NPS fertilizers as nutrient sources than the strategy of using organic or inorganic amendments alone. Then, it could be concluded that the use of blended NPS fertilizer at 50 kg ha-1with supplemental vermicompost at 5 t ha-1 to Jibat variety is the realistic approach to address the problem of low productivity of maize in the study area and other similar agroecology. Based on the findings and conclusions of this study it can be recommended that farmers in the study area should, therefore, be advised to use this variety and combined use of vermicompost and NPS fertilizer at a rate of 5 t ha-1 VC +50 kg ha-1 NPS for sustainable maize crop production tentatively. Nevertheless, further studies are needed to recommend agronomical optimum and to measure the long-term effects of the integrated soil fertility management techniques in more seasons, soil types and crop varieties before giving a conclusive recommendation.

Slow-Release Humic Acid-Based Zinc Fertilizers Improve Growth and Nutrition of Maize and Brachiaria Grass Successively Grown in Oxisols

Zinc (Zn) fertilization efficiency is often low in Oxisols due to the interaction of Zn with soil constituents and phosphorus (P). When Zn is supplied in soil fertilization as a complex via slow-release organomineral fertilizers (OMFs), it is less prone to react with soil constituents and P, thus increasing the efficiency of Zn supply to crops. However, obtaining effective synthesis routes for the production of enhanced-efficiency Zn-OMFs for Oxisols is still a challenge. In this study, we synthesized Zn-OMFs based on humic acid (HA) components in order to assess features concerning Zn complexation and release kinetics, as well as the agronomic performance of such products on biomass production, and Zn and P nutrition of maize and Brachiaria grass successively grown in two Oxisols with contrasting texture and soil organic matter (OM) content. Infrared analyses indicated that Zn was complexed in OMFs by sulfur and carbon groups, with kinetics studies showing that Zn is gradually released to soil from Zn-OMFs. Consequently, Zn diffusion and initial content in soil solution were reduced in Oxisols. At least one of the OMFs overperformed ZnSO4 in terms of maize biomass production and Zn shoot accumulation. Moreover, residual effects of OMFs were greater than those of ZnSO4 in Oxisols for Brachiaria grass cultivated after maize, with increases in biomass production and shoot Zn content varying depending on OMFs and Oxisol properties. A secondary effect of OMFs increasing P availability in the soil and P uptake by maize and Brachiaria grass plants was also noteworthy. Our findings showed that the overall agronomic performance was greater for OMFs when compared with ZnSO4, which is likely related to the slow release of nutrients by the synthetized OMFs due to Zn complexation by HA.

Genome of Paspalum vaginatum and the role of trehalose mediated autophagy in increasing maize biomass

A number of crop wild relatives can tolerate extreme stress to a degree outside the range observed in their domesticated relatives. However, it is unclear whether or how the molecular mechanisms employed by these species can be translated to domesticated crops. Paspalum (Paspalum vaginatum) is a self-incompatible and multiply stress-tolerant wild relative of maize and sorghum. Here, we describe the sequencing and pseudomolecule level assembly of a vegetatively propagated accession of P. vaginatum. Phylogenetic analysis based on 6,151 single-copy syntenic orthologues conserved in 6 related grass species places paspalum as an outgroup of the maize-sorghum clade. In parallel metabolic experiments, paspalum, but neither maize nor sorghum, exhibits a significant increase in trehalose when grown under nutrient-deficit conditions. Inducing trehalose accumulation in maize, imitating the metabolic phenotype of paspalum, results in autophagy dependent increases in biomass accumulation.

Improvement of water and crop productivity of silage maize by irrigation with different levels of recycled wastewater under conventional and zero tillage conditions

Although wastewater irrigation has a long history involving different stages of development, the future expectation to improve crop yield and water productivity in wastewater irrigation practices is still relevant. Therefore, the aim of this study is to evaluate water productivity, yield and crop quality of silage maize irrigated with different application levels (100%, 67%, and 33% of irrigation need) of recycled wastewater with three replicates in conventional tillage and zero tillage practices and comparing them with full fresh water irrigation. The results of two-year field studies showed that zero tillage resulted in saving 10.1% of irrigation water on average compared to conventional tillage and actual evapotranspiration in silage maize with zero tillage was 7.4% less. Biomass yield was the highest in full irrigation with wastewater under zero tillage. Zero tillage practice provided 12.0% and 13.2% higher water productivity(WP) and irrigation water productivity(WPirrig), respectively compared to conventional tillage. The WP was higher in treatments with wastewater with 100% and 67% irrigation levels, while the WPirrig was higher in treatment with wastewater with 67% irrigation level. While the crop total soluble solids, nutrients, crude protein, chlorophyll(SPAD), leaf area index and leaf relative water content (LRWC) values were higher in full irrigation with wastewater, acid and neutral detergent fibers and membrane damage was lower. Crude protein in zero tillage was lower than in conventional tillage, while SPAD and LRWC were higher. It could be concluded that wastewater can increase silage maize biomass yield and crop quality. This result may be more valuable in terms of both protecting scarce fresh water resources and contributing to the environment with waste disposal. Moreover, 67% irrigation treatment with wastewater can be preferred for the higher WP and WPirrig values, and zero tillage can be used as a practical treatment that contributes to the yield and water saving.

Nitrogen Promotes the Salt-Gathering Capacity of Suaeda salsa and Alleviates Nutrient Competition in the Intercropping of Suaeda salsa/Zea mays L.

Nitrogen accelerates salt accumulation in the root zone of an euhalophyte, which might be beneficial for inhibiting the salt damage and interspecific competition for nutrients of non-halophytes in intercropping. However, the variations in the effect of euhalophyte/non-halophyte intercropping with nitrogen supply are poorly understood. Here, we selected the euhalophyte Suaeda salsa (suaeda) and non-halophyte Zea mays L. (maize) as the research objects, setting up three cropping patterns in order to explore the influence of nitrogen application on the intercropping effect in the suaeda/maize intercropping. The results showed that the biomass of maize in the intercropping was significantly lower than that in the monoculture, while for suaeda, it was higher in the intercropping than that in the monoculture. The biomass of maize under NO3--N treatment performed significantly higher than that under no nitrogen treatment. Moreover, under suitable NO3--N treatment, more salt ions (Na+, K+) gathered around the roots of suaeda, which weakened the salt damage on maize growth. In the intercropping, the effect of NO3--N on the maize growth was enhanced when compared with the non-significant effect of NH4+-N, but a positive effect of NH4+-N on suaeda growth was found. Therefore, the disadvantage of maize growth in the intercropping suaeda/maize might be caused by interspecific competition to a certain extent, providing an effective means for the improvement of saline-alkali land by phytoremediation.

Effect of fertilizers enriched with bio-based carriers on selected growth parameters, grain yield and grain quality of maize (Zea mays L.)

Low efficiency of nutrient use, especially nitrogen, from mineral fertilizers under the drought conditions is a worldwide problem in agriculture. Therefore, low-cost, and environmentally friendly technologies that improve the utilization of nutrients from applied fertilizers while increasing water availability to plants are urgently needed. The aim of our research was to prepare bio-based carriers composed from different ratios of natural hydroabsorbent (NHA), synthetic superabsorbent polymer (SAP), and zeolite. The commercial fertilizers (NP and NPK) were enriched with these carriers with subsequent determination of their ability to release nutrients and affect the growth of maize plants grown under drought conditions. The first (i) part of our experiment focused on the lab preparation of bio-based carriers followed by a testing of their abilities to release nitrogen into water in the lab conditions. The effect of selected carriers in the mixture with commercial fertilizers to the growth of maize were subsequently tested under the optimal and limited watering regime in the greenhouse pot experiment (ii). The control treatment (no fertilizer) and fertilization treatments were established, namely, single bio-based carrier (C2) and compound fertilizers (NP, NPK) and their mixture (C2-NP, C2-NPK). The effect of these fertilizers applied in two doses (at the level of 30 and 60 kg/ha N) on the yield and grain quality of maize (iii) was finally evaluated in a two-year field experiment (2020 – 2021). Based on the existing kinetic models, it was possible to the link nitrogen release to the structural variables of the composite carriers. A small volume of zeolite microparticles incorporated into the biopolymer network of the NHA and SAP carrier accelerated the nitrogen release in the lab experiment (i) and increased the maximum amount of released nitrogen in proportion to the zeolite content without significantly affecting the water-holding capacity. The results of the greenhouse pot experiment (ii) demonstrated that application of a bio-based carrier composed of 7 wt% SAP, 7 wt% zeolite and 86 wt% NHA in combination with NP and NPK fertilizers significantly increased chlorophyll content, the ability of maize plants to absorb radiation in photosystem II, and the weight of above-ground maize biomass under limited and optimal irrigation conditions. The C2-NPK increased grain weight, grain yield and protein content in the grain of maize under the field conditions (iii). Fertilizers enriched with bio-based carrier are a promising alternative to improve soil moisture and increase nutrient availability to plants grown not only in drought conditions.

Coupling of environmental factors and growth stages in simulation of maize biomass allocation

Coupling of environmental factors and growth stages in simulation of maize biomass allocation

Plants control the structure of mycorrhizal and pathogenic fungal communities in soil in a 50-year maize monoculture experiment

AimsSaprotrophic soil fungi participate in biomass mineralization, inhibit pathogen development and promote plant growth. Pathogens accumulate in soil and decrease crop yields. The structure of fungal communities is determined mainly by the organic matter content and pH of soil. Little is known about the influence of crop rotation and long-term monoculture on saprotrophic fungi that decompose plant roots and crop residues as sources of soil biomass.MethodsFungal communities that promote plant growth (arbuscular mycorrhizal fungi (AMF), yeasts, Trichoderma spp.), cellulolytic fungi and pathogenic species were analyzed in a 6-year crop rotation system (maize – spring barley – peas – winter rapeseed – winter wheat – sugar beets) and in 50-year maize monoculture. Fungal DNA was extracted from the rhizosphere and plant roots, and the ITS2 region of fungal rDNA was analyzed by high-throughput sequencing. In both treatments, weeds were controlled chemically (terbuthylazine + mesotrione + s-metolachlor) or mechanically.ResultsA total of 311 fungal species were identified. The biodiversity of soil fungi, in particular AMF and yeasts, was higher in monoculture than in crop rotation. Maize pathogens were more frequently identified in monoculture, whereas species of the genus Trichoderma were more prevalent in crop rotation. Herbicides clearly increased the abundance of cellulolytic fungi of the phyla Mucoromycota and Mortierellomycota, Mortierella spp. and Minimedusa polyspora. The abiotic properties of soil were affected by the cropping sequence. The content of organic carbon (Corg) and the availability of P and Mg decreased in monoculture. Maize yields were bound by a strong positive correlation with the availability of macronutrients and Corg in soil, as well as a weak positive correlation with the abundance of Trichoderma spp., Mucoromycota and Mortierellomycota.ConclusionsFungi exert a complex and ambiguous effect on maize biomass yields, whereas a decrease in the macronutrient content of soil in monoculture strongly decreases maize yields. In the long term, the cropping sequence considerably influences the structure of the soil microbiome which can be a reservoir of unique species and species that minimize the negative effects of monoculture in agroecosystems.Graphical

Effects of earthworm (Eisenia fetida) and arbuscular mycorrhizal fungi improving plant hormones and antioxidant enzymes under simulated acid rain stress

Acid rain is considered one of the three most serious environmental disasters worldwide, disrupting the normal physiological metabolism of plants and inhibiting their growth. Earthworms alleviate plant stress by regulating soil physical, chemical and biological characteristics, and mycorrhizal fungi can promote plant nutrient absorption and improve plant resistance via symbiosis with plants. We used Illumina high-throughput sequencing to conduct a relevant redundancy analysis (RDA) of soil microbial community structure and plant growth factors, and we constructed a structural equation model (SEM) for maize biomass and a biological index to study the mechanisms by which earthworms and mycorrhizal fungi affect maize stress resistance under simulated acid rain stress. The results showed that earthworms promoted the decomposition of soil organic matter; promoted the growth of the root system; and increased the hormone levels of gibberellin A3 (GA3), abscisic acid (ABA) and indole-3-acetic acid (IAA), ultimately improving the stress resistance of maize. Mycorrhizal fungi increased the relative abundance of plant growth-promoting rhizosphere bacteria, increased the levels of plant hormones and antioxidant enzymes, and improved the stress resistance of maize. Earthworms promoted infection by mycorrhizal fungi, and the interaction between earthworms and mycorrhizal fungi increased the root IAA content and the Shannon index of rhizosphere bacteria and alleviated the simulated acid rain stress of the aboveground part of the maize. This funding is crucial to understanding above- and belowground feedback in plant–soil systems under abiotic stress.

Anaerobic Fermentation of Silage from the Above-Ground Biomass of Jerusalem Artichoke (Helianthus tuberosus L.) and Maize (Zea mayse L.) as a New and Promising Input Raw Material for Biogas Production

Research of new input raw materials for biogas plants is a very actual topic. There are only a very few studies dealing with the possibility of using silage prepared from the above-ground parts of the Jerusalem artichoke (Helianthus tuberosus L.) and maize (Zea mayse L.) for methane production. This study deals with the determination of methane production and methane content in biogas during the fermentation of maize silage with dissimilar additions of the biomass of the Jerusalem artichoke (JA). Except for the effect of the JA’s addition on the yield of methane, we also studied its potential influence on the inhibition of the process of anaerobic digestion and the bacterial and methanogenic archaeal composition of anaerobic digestate. There were five model silages prepared; two of them contained only maize or JAs, and the remaining three were mixtures of maize and JA silages (30%wt; 50%wt and 70%wt). The fermentation tests showed that the JA addition (from 30 to 70%wt) resulted in the production of biogas decreasing, on average, by 15%. Based on the performed metagenomic analysis, we cannot confirm an essential influence of JA biomass addition on the composition of the community of microorganisms during fermentation.

In situ degradation of low-density polyethylene film in irrigation maize field: Thickness-dependent effect

Thickness of low-density polyethylene (LDPE) film might determine its mechanical strength, clean production and soil health. Yet, this issue is little understood. In situ aging effects were evaluated in LDPE films with the thickness of 0.006 mm, 0.008 mm, 0.010 mm and 0.015 mm in maize field. The data showed that maximum tensile force (TFmax), maximum tensile strength (TSmax) and elongation at break (EAB) were massively lowered with increasing thickness after aging. The greatest and lowest reduction magnitude of EAB was 27.6 % and 11.2 % in 0.006 mm and 0.015 mm films respectively. Also, the melting point (Tm) and crystallinity (Xc) under Differential Scanning Calorimeter (DSC) tended to decline with the increasing thickness. Moreover, the peak intensity of crystalline regions tended to transfer and concentrate on the amorphous regions, and such tendency became more pronounced in the thin films. Interestingly, there existed a pronounced distinct thickness-dependent effects on soil bulk density (SBD) and soil water-stable aggregate proportion. Thick plastic film mulching increased SBD but reduced the proportion of macroaggregates (mainly referred to 0.015 mm and 0.010 mm). In addition, thick film mulching slightly reduced the levels of soil organic carbon (SOC) and total nitrogen (TN), but significantly promoted the contents of soil labile C and N. Particularly, it significantly promoted above- & under-ground biomass of maize across two growing seasons (p < 0.05). To sum up, thickening LDPE film may act as a promising solution to improve LDPE film residue recycling, while benefiting for higher productivity. However, thick film mulching may cause a certain adverse impact on soil structure, and further investigations would be needed in the future.

Effect of LMWOAs on Maize Remediation of Cadmium and Plumbum Pollution in Farmland

Plant extraction is a thorough remediation method to remove heavy metals from soil. Chelating agents can enhance the extraction effect of heavy metals from soil by plants. In this study, low molecular weight organic acids (LMWOAs), such as citric acid (CA), tartaric acid (TA) and polyaspartate (PASP), were added to the farmland soil contaminated with Cd and Pb and combined with corn to enhance the absorption and extraction of Cadmium (Cd) and Plumbum (Pb). The effects of LMWOAs on the growth and yield of maize, Cd and Pb concentrations in each part of maize, rhizosphere soil pH, total cadmium and lead content and DTPA-Cd and Pb concentrations were studied. The enrichment, transport and extraction ability of maize were analyzed, and calcium chloride (CaCl2) was compared. The results showed that: (1) Exogenous LMWOAs increased the biomass and yield of maize compared with no material added (CK), and CA increased the yield of maize by 6.33%. (2) Exogenous LMWOAs promoted the uptake of Cd and Pb in all parts of maize, and the distribution of Cd and Pb in all organs was as follows: straws &gt; roots &gt; maize cobs &gt; kernels and roots &gt; straws &gt; maize cobs &gt; kernels. The Cd and Pb concentrations in maize kernels were in line with GB 13078-2017 in China, which could be used as feed maize. (3) Exogenous LMWOAs enhanced the enrichment of Cd and Pb in maize straws and roots. PASP had a good enrichment effect on Cd and Pb. CA and CaCl2 could enhance the transport capacity of Cd and Pb from maize roots to straw. (4) Compared with CK, the total amount of Cd and Pb in rhizosphere soil decreased by 6.93–26.99% and 2.74–6.79%, respectively. LMWOAs could promote the concentration of DTPA-Cd and Pb in rhizosphere soil, and PASP had the most significant increase in DTPA-Cd and Pb in rhizosphere soil. Compared with CK, the soil pH value decreased by 0.03–0.14 units. LMWOAs can enhance the removal of heavy metals from maize, and PASP has the most significant comprehensive effect.

Rapeseed-maize double-cropping with high biomass and high economic benefits is a soil environment-friendly forage production mode in the Yangtze River Basin

The problem of the large area of winter abandoned fields in the Yangtze River Basin (YRB) has gotten worse. Moreover, there was no suitable annual forage crop planting pattern to fulfilling the annual forage needs of livestock and poultry production in the YRB region. Utilizing the abandoned field to develop high-quality and efficient forage crop planting patterns is significant. Herein as a first-time study, two growing seasons of five different double-cropping modes field experiments were performed with ryegrass-maize (RM), hairy vetch-maize (HM), rapeseed-maize (BM), milk vetch-maize (MM), and abandoned-maize (AM) to study their effects on forage production, soil properties, latter maize performance, and economic benefits. Rapeseed-maize double-cropping mode achieved the maximum annual biomass yield (37.0 Mg ha−1) and net profit value (33563 CNY ha−1), which is the most productive among the five double-cropping modes. The soil available phosphorus content after planting rapeseed was significantly higher than other modes, which was 65.6%, 37.0%, 1.5%, and 12.2% higher than abandoned field, ryegrass, hairy vetch, and milk vetch, respectively. There was a non-significant difference in soil penetration resistance (PR) between after planting rapeseed, hairy vetch, and milk vetch at the soil depth of 5–27.5 cm; whereas, the PR was reduced by 24.7% and 34.8% after planting rapeseed compared to abandoned field and planting ryegrass, respectively. Compared to the abandoned field, planting hairy vetch and milk vetch showed highly significant effects on suppression of weeds biomass and density in maize field followed by rapeseed, while planting ryegrass significantly increased the weeds biomass and density by 61.6% and 62.3%, respectively. The principal component analysis results indicated that the PR was negatively correlated to the soil fertility and maize growth traits, while positively correlated with weeds occurrence. Besides, the root activity, and root, shoot biomass of maize were significantly positively correlated with the soil fertility after harvesting winter crops. Therefore, rapeseed-maize double-cropping may be a productive pattern to promote annual forage production and enhance the agricultural economy in the Yangtze River Basin region.

Field efficacy of selected insecticides and botanicals against fall armyworm in maize

In Bangladesh's northern and western regions, where maize (Zea mays L.) crops were already under threat from other pressures, particularly those brought on by climate change, the invasion of the fall armyworm [Spodoptera frugiperda (J.E. Smith); FAW] has compounded yield losses. From the present study, it was observed that application of the synthetic insecticides Ripcord 10 EC (Cypermethrin), Karate 2.5 EC (Lamda Cyhalothrin), Nitro 505 EC (Chlorpyrifos 50% + Cypermethrin 5%), Virtako 40 WG (Thiamethoxam 20% + Chlorantraniliprole 20%) and Neem Seed kernel Extract (Azadirachtin) compared to the untreated control, was effective and dramatically enhanced FAW larval mortality, decreased leaf degradation, and boosted biomass in maize. In the first round of spraying, both stay living larvae were identified on plants treated with Ripcord 10 EC (Cypermethrin), and in the second round of spraying; no live larvae were found on plants treated with Karate 2.5 EC (Lamda Cyhalothrin). After the third round of spraying, below one larva was found on all treated plants. The most effective synthetic pesticides are therefore recommended Ripcord 10 EC (Cypermethrin) and Karate 2.5 EC (Lamda Cyhalothrin) for the control of FAW in maize which will be planted in November-December in Bangladesh.

Effect of soil supplementation with mineral-organic mixtures on the amount of maize biomass and the mobility of trace elements in soil

The application of calcium fertilisers and organic fertilisers or materials is an alternative allowing to reduce soil acidification and increase the organic matter content. Under Polish conditions, where soils belonging to the agronomic category of light and acidic soils predominate, such an approach can bring measurable benefits in improving physical, chemical, and biological properties of soils. However, it should be noted that until now these treatments have usually been applied separately; therefore, the aim of this study was to determine the effect of the combined application of calcium carbonate fertiliser with leonardite (CaLO) and with poultry litter (CaPL) on the amount of maize biomass, the content of trace elements in the biomass, and selected soil properties, including the mobility of trace elements in soil. The study was conducted as a pot experiment. The experimental design included 4 treatments: soil with no fertilisers (Control), soil with mineral fertilisers (NPKS), and soil with mineral fertilisers and the addition of a mixture of CaCO3 and leonardite (NPKS+CaLO) as well as CaCO3 and poultry litter (NPKS+CaPL). The study showed a substantial increase in the amount of mainly aboveground parts of maize biomass after applying mixtures of CaCO3 and organic materials. Despite the lack of significant differences, the relative increase in the chlorophyll a content in NPKS+CaLO and NPKS+CaPL treatments was over 7 % compared to NPKS treatment. The obtained results are inconclusive as to the effect of the applied mixtures on the trace element content in maize biomass. Soil supplementation with CaLO mixture significantly reduced cadmium, copper, and lead contents in maize aboveground parts, while the zinc content was higher compared to the NPKS-fertilised treatment. Soil supplementation with CaPL mixture decreased the zinc content in maize aboveground parts, while the cadmium, copper, and lead contents were higher compared to the NPKS-fertilised treatment. Soil pH significantly improved after applying CaLO and CaPL mixtures. Soil supplementation with CaLO and CaPL was vital for reducing the content of water-soluble forms of Cd and Zn, while for Pb and Cu, we observed an increase in these forms of trace elements in the soil. The treatments with CaLO and CaPL had lower content of NH4EDTA-extracted elements compared to the control.

Sphingomonas sp. Hbc-6 alters physiological metabolism and recruits beneficial rhizosphere bacteria to improve plant growth and drought tolerance.

Drought poses a serious threat to plant growth. Plant growth-promoting bacteria (PGPB) have great potential to improve plant nutrition, yield, and drought tolerance. Sphingomonas is an important microbiota genus that is extensively distributed in the plant or rhizosphere. However, the knowledge of its plant growth-promoting function in dry regions is extremely limited. In this study, we investigated the effects of PGPB Sphingomonas sp. Hbc-6 on maize under normal conditions and drought stress. We found that Hbc-6 increased the biomass of maize under normal conditions and drought stress. For instance, the root fresh weight and shoot dry weight of inoculated maize increased by 39.1% and 34.8% respectively compared with non-inoculated plant, while they increased by 61.3% and 96.3% respectively under drought conditions. Hbc-6 also promoted seed germination, maintained stomatal morphology and increased chlorophyll content so as to enhance photosynthesis of plants. Hbc-6 increased antioxidant enzyme (catalase, superoxide, peroxidase) activities and osmoregulation substances (proline, soluble sugar) and up-regulated the level of beneficial metabolites (resveratrol, etc.). Moreover, Hbc-6 reshaped the maize rhizosphere bacterial community, increased its richness and diversity, and made the rhizosphere bacterial community more complex to resist stress; Hbc-6 could also recruit more potentially rhizosphere beneficial bacteria which might promote plant growth together with Hbc-6 both under normal and drought stress. In short, Hbc-6 increased maize biomass and drought tolerance through the above ways. Our findings lay a foundation for exploring the complex mechanisms of interactions between Sphingomonas and plants, and it is important that Sphingomonas sp. Hbc-6 can be used as a potential biofertilizer in agricultural production, which will assist finding new solutions for improving the growth and yield of crops in arid areas.

Appropriate bandwidth achieves a high yield by reducing maize intraspecific competition in additive maize–soybean strip intercropping

Maize–soybean strip intercropping can effectively alleviate arable land competition, improve land output, and be conducive to the sustainable development. The key to achieve these advantages is to stabilize the maize yield. Suitable narrow row spacing could maximize the benefit of maize–soybean strip intercropping, and an increasing bandwidth with suitable narrow row spacing is beneficial to the mechanized production of soybean. In practice, to ensure the maize yield in additive maize strip intercropping, maize plant spacing decreases and intraspecific competition intensifies as the bandwidth increases. However, interspecific interactions have been the primary focus of studies because of the better rhizosphere nitrogen fixation ability of soybean and the activation of maize rhizosphere nutrients. Therefore, it is particularly urgent to identify the trade-offs between intraspecific competition and interspecific interactions in maize and the regulatory effects on maize yield. Field experiments were conducted from 2017 to 2020 to analyze the results of interindividual competition in maize and interactions with soybeans under different bandwidths. It was found that maize biomass and yield at the maturity stage decreased by 8.0% and 6.4%; 20.5% and 19.4%; and 28.7% and 44.1% from 2 m to 2.8 m, respectively, but the biomass proportion in ears showed no significant difference. Intraspecific competition of maize was weakened by special promotion in intercropping, but stable yield was achieved only at 2 m. In response to suitable competition, maize roots can flourish only on the basis of ensuring aboveground biomass. The results revealed that the primary negative determinant of maize yield was intraspecific aboveground competition and strengthening intraspecific competition reduced biomass accumulation without altering the allocation ratio to the ear. We concluded that maize yield was guaranteed at 2 m due to the special strip planting design compensated for the enhanced intraspecific competition of maize aboveground parts in the additive maize–soybean strip intercropping system.