Maize Biomass Research Articles

Dynamic simulation of photosynthate distribution parameters and biomass of summer maize under water stress

Dynamic simulation of photosynthate distribution parameters and biomass of summer maize under water stress

Combined effect of cover crops and bio-fertilizer on sustainable popcorn maize production.

Cover crops play an important role in low-input cropping systems, increasing the use of agro-ecosystem services. Due to the lack of information about the impact of cover crops and bio-fertilizers on popcorn maize (Zea mays everta Sturt.) growth and yield quality, especially the popping volume and nutritive quality, such as concentrations of protein and mineral elements, this research aimed to provide essential information. The interrelation between popcorn maize productivity and quality with important groups of soil microorganisms presents additional novelty. The results demonstrated that field pea is a beneficial cover crop, especially when combined with a bio-fertilizer, supporting the accumulation of maize biomass, chlorophyll, yield potential, and the concentrations of protein, Ca, Mg, Fe, and Zn. In addition, field pea residues promoted N-fixing bacteria, and the number of total microorganisms, especially actinomycetes and decomposing bacteria, which could promote nutrient uptake and grain quality. Residues of cover crop mixtures, common vetch + winter oats and field pea + winter oats, promoted the total number of microorganisms in the soil, and up to the end of vegetation, a greater number of decomposition and ammonification microorganisms were found, especially when the bio-fertilizer was applied, which consequently could support greater maize biomass. Popping volume, as a main trait of popcorn maize, had the highest value in the common vetch + winter oats variant, supporting again the statement that quality traits could be enhanced in sustainable production. Unlike living cover crops, mulch mainly affected soil microbial communities and promoted the development of actinomycetes and cellulolytic microorganisms during the growing season. The results of this research could contribute to the development of sustainable popcorn maize production for improved grain quality. They could also serve as a basis for isolating beneficial soil microorganisms to develop new bio-fertilizers that could improve maize production in synergy with cover crops.

Mixed cropping system of maize and bean as a local source of N-substances for the nutrition of farm animals

In this study, we investigated the quality of mixed cropping system (MCS) composed of maize and bean in comparison with maize grown as monoculture. Experimental stands were established using the precision vacuum seeding machine during a single crossing of the plot. Inter-row distance was 0.375 m, and regularly alternating experimental crops were maize (Zea mays L.) and common bean (Phaseolus vulgaris L.). Experimental variants included maize alone (M) in an amount of 80,000 seeds per hectare and maize (M-MCS) with bean (B-MCS) in a 1:1 ratio (80,000: 80,000 individuals) in MCS. Average yield of N-substances (t/ha) in the biomass obtained from individual variants was 2.36 t/ha in the pure maize culture and 3.09 t/ha in the mixed culture (by 30.9% more). The difference was statistically significant. On the other hand, differences in the content of N-substances (protein) were not found. Results of the experiment for the whole period from 2020–2022 also indicated that the presence of bean in the mixed crop statistically significantly increased contents of acid detergent fibre and crude fibre. On the other hand, compared with the biomass of maize monoculture, bean reduced contents of starch and lipids in the maize biomass. The measured results indicate that biomass from mixed cropping systems has a higher potential to fix more N than biomass from the maize monoculture which is important for digestibility of fodder in livestock production.

Facilitation between intercropped species increases micronutrient acquisition and controls rust disease on maize

Context or ProblemGlobal food security is threatened by plant disease, and crop diversification often promotes productivity through reduced disease and facilitation for increased nutrient acquisition. However, whether such facilitation is a factor in disease resistance is unknown. Objective or Research QuestionInvestigate how crop diversity affects crop productivity and rust disease on maize, and whether competition or facilitation between crop species correspond with resistance. MethodsFive irrigated intercropping experiments with different fertilization and crop combinations were conducted at two sites for four years. Productivity (542 data points) and disease severity (27150 data points) of maize monoculture, maize - legume and maize - non-legume intercropping were compared. A meta-analysis of literature was performed to confirm the broader applicability of results from these field experiments. ResultsLegume-based intercropping increased the aboveground biomass of intercropped maize by 8% and grain yields by 10% in comparison to non-legume-based intercropping. Disease severity on maize intercropped with legumes was reduced by 45% and 48%, compared to monocultures of maize and maize intercropped with non-legumes, respectively. Moreover, as interactions among intercrops became more facilitative, the concentrations of zinc (Zn), copper (Cu) and iron (Fe) in maize increased, and these increases were highly correlated with decreasing disease severity. The global meta-analysis was consistent with our field experiments, as lower disease severity was associated with greater intensity of interspecific facilitation or with lower intensity of interspecific competition. Conclusions or SignificanceLower disease severity was closely related to enhanced acquisition of nutrients that can enhance the resistance to crop diseases, driven by stronger interspecific facilitative effects in intercropping systems. Facilitative effects on maize was increased by the identity of leguminous companion crop species, and was increased by sufficient irrigation, but reduced by applications of nitrogen and phosphorus fertilizers. ImplicationsOur findings identify a novel facilitative mechanism in general and advance the understanding of the facilitative mechanisms that underly disease control through crop diversification.

Pb-resistant Pantoea rwandensis promotes maize's growth by altering Pb accumulation in biomass and soil Pb immobilization.

In lead (Pb)-contaminated soil, inoculating phosphate-solubilizing bacteria (PSB) to reduce the phytoavailability of Pb and to change the soil nutrients is an important way to inhibit the Pb uptake by plants. In this study, we isolated the native Pb-resistant Pantoea rwandensis from a tailings site. We employed broth culture and pot experiments to investigate the effect of the inoculation of P. rwandensis on Pb immobilization in the soil, the soil nutrients, the microbial community, and Pb accumulation in the biomass of maize (Zea mays L.). The results showed that P. rwandensis not only tolerated Pb2+ but also dissolved Ca3(PO4)2 by secreting oxalic acid, tartaric acid, lactic acid, and acetic acid, which significantly increased the amount of dissolved P, up to 567.50 mg.L-1. In the pot experiment, the application of culture filtrate, an inoculation with P. rwandensis, or a mixture of culture filtrate and P. rwandensis increased the soil residual Pb by 49.57%, 89.81%, and 41.69%, respectively, compared to the control. Consequently, the increase in the residual Pb in the soil inhibited its uptake by maize, and an inoculation of P. rwandensis or a mixture of culture filtrate and P. rwandensis decreased the accumulation of Pb in the shoot biomass of maize by 61.65% and 72.48% and in the roots of maize by 26.00% and 39.59%, respectively. Meanwhile, P. rwandensis and the mixture of culture filtrate and P. rwandensis increased the shoot biomass of maize by 54.39% and 17.86% and the root biomass of maize by 108.77% and 17.86%, respectively. A P. rwandensis inoculation increased the biodiversity of the fungal community and the abundance of Proteobacteria, Mortierella, and Sphingomonas. Our results demonstrate that an inoculation with P. rwandensis could promote the transformation of Pb fractions and a functional change in the soil bacterial community, ultimately decreasing Pb accumulation in the biomass and promoting the development of maize.

Effects of agricultural management and of climate change on N2O emissions in an area of the Brazilian Cerrado: Measurements and simulations using the STICS soil-crop model

Soil-plant simulation models have been ever more used as predictive tools to evaluate productivity and environmental impacts of agriculture practices. The aims of this work were to evaluate the STICS model’s capacity of simulate the emissions of nitrous oxide (N2O) under different management systems. And, to predict, by applying the calibrated and validated STICS model, the N2O emissions, under different management systems, in the edaphoclimatic conditions of the Brazilian Cerrado. The study was conducted in a long-term experiment at Embrapa Cerrados, located in Planaltina/DF, Brazil. The experiment started in 1995. The following land use systems were evaluated: CT - conventional tillage with disc harrow, and biannual grass/legume rotation; NT1 - No-tillage, with biannual crop rotation – soybean/sorghum; NT2 - No-tillage, with biannual crop rotation – maize/pigeon pea.Closed static chambers and gas sample analysis by gas chromatography were used to measure N2O fluxes. The model was calibrated with the data measured in the CT and NT1 treatments. The attributes used in the calibration were: growth, development and yield of crops and N2O fluxes. To test the model, data from the NT2 treatment was used. Data for all treatments were collected at the same time. After calibration and validation, the STICS model was used to predict the effects of soil management systems, conventional (CT) and no-tillage (NT) on greenhouse gas emissions and on grain and biomass crops production. The simulation was made for the period from 2021 to 2070. The STICS model performed well at simulation of the following parameters: N2O emissions, soil water dynamics, soil temperature; and leaf area, aerial biomass and grain yield of soybean and maize. The performance of the model was good for the conventional soil management system as well as in the no-tillage system. Based on the predicted increase in temperature for the period 2021–2070, we can conclude from the data generated through the STICS model that there is strong evidence that grain yield and total aerial biomass of plants will decrease. The data show that there is a rising tendency in N2O emissions over the simulated period. This is expected to occur for the two soil management systems studied (NT and CT). We believe this increase in emissions along the years is related to temperature increase and to the reduction of crop cycle.

Earthworms facilitate stabilization of both more-available maize biomass and more-recalcitrant maize biochar on mineral particles in an agricultural soil

Agricultural soils have lost enormous amounts of soil organic matter (SOM) as the result of conventional agriculture. Nowadays, returning plant biomass in the form of crop residues is used as an efficient strategy to increase the amount of SOM. In addition, earthworms help increase the SOM content by transforming OM into stable forms. There is, however, limited information on how earthworms transform and stabilize various forms of crop residues and what the potential feedbacks on soil quality are. In a five-month laboratory manipulation experiment, we added maize biomass and/or biochar to a temperate agricultural soil both in the presence and absence of earthworms and carried out physical fractionation to analyse the stabilization of OM either as aggregate-occluded particulate OM (oPOM) or mineral-associated OM (MAOM).We show that the combination of maize biomass, maize biochar and earthworms proved to be highly efficient in increasing the OM content in agricultural soils and that earthworms can simultaneously enhance both OM decomposition and stabilization. In the absence of earthworms, the OM was stabilized more in the oPOM fraction, suggesting that both maize substrates acted as aggregation agents. In the presence of earthworms, however, maize substrates were stabilized more in the MAOM fraction, either through direct sorption as plant-derived substrates or as microbial necromass, suggesting that earthworms facilitate stabilization of both more-available maize biomass and more-recalcitrant maize biochar on mineral particles. We provide evidence that plant-derived rather than microbial-derived MAOM is present in the earthworm-affected agricultural soil and is thus important in increasing the SOM content and stability.

Addition of organic amendments derived from invasive apple snails alleviated soil acidification, improved soil nitrogen and phosphorus effectiveness, microbial growth and maize yield in South China

Pomacea canaliculata (apple snail) is an invasive agricultural pest posing serious threats to aquatic crop production and wetland ecosystem function in Asia. The shell of P. canaliculata is composed of calcium carbonate (CaCO3), while its soft tissue is protein-rich (carbon (C) and nitrogen (N) sources). Thus, P. canaliculata has the potential to be used as a source of organic soil amendments. Here, we evaluated the effectiveness of snail derivatives (powder, including shells and soft tissues of the snails) as organic soil amendments to improve the productivity of an acidic dryland soil in South China. Snail powder (SP) was incorporated into the soil at application rates of 0–50 g kg−1, followed by planting of maize. Our results showed that SP addition significantly increased soil pH (up to 7.25–7.95), alleviated soil acidification. Moreover, SP addition improved soil N, phosphorus (P) effectiveness, and dissolved organic carbon (DOC) content, increasing biomass of actinobacteria and arbuscular mycorrhizal fungi (AMF) to stimulate microbial growth. Notably, SP addition increased height (up to 42.4 %), biomass (up to 117.6 %) and yield (up to 118.9 %) of maize, with 10 g kg−1 SP optimal for plant productivity. However, the optimal application rate and buffer time for field application of SP warrant further study. Our findings demonstrate the potential of SP resource utilization for acidic soil remediation and the invasive snail P. canaliculata control.

Enhancing leaf area index and biomass estimation in maize with feature augmentation from unmanned aerial vehicle-based nadir and cross-circling oblique photography

Rapid and accurate estimation of plant phenotypes plays a vital role in effective breeding and management of maize crops. Unmanned aerial vehicle (UAV) platforms are emerging as a valuable tool in the assessment of crop phenotypes, offering a promising avenue to enhance the accuracy and efficiency of phenotypic analysis. This study executed two UAV photography methods to acquire aerial images for the estimation of leaf area index (LAI) and above-ground biomass (AGB) in summer maize. Nadir photography was implemented to obtain data from three sources including multi-spectral (MS), RGB, and thermal infrared (TIR) sensors. Additionally, RGB imaging-based cross-circling oblique (CCO) photography was implemented to obtain accurate 3D point cloud data. The nadir photography data was processed to generate orthomosaic image and extract features including vegetation index, canopy cover, canopy height, canopy temperature, and textural information. Features including canopy occupation volume, plant area index, canopy cover, and canopy height were extracted from the CCO photography-derived point cloud data. Furthermore, a data augmentation method, called linear regression-based feature augmentation (LRFA), was proposed for augmenting features extracted from nadir and CCO photography. The results showed that the introduction of CCO photography improved the accuracy of LAI and AGB estimation during the big trumpet stage and LAI estimation during the milk stage compared to the integrated multi-source nadir photography data. Notably, the LRFA derived features outperformed raw features in the majority of modeling scenarios, with the random forest achieved an average accuracy (R2) improvement of 6.1% for LAI estimation and 3.7% for AGB estimation. This study highlights the significance of combining different photography technologies and feature augmentation method for estimating maize phenotypes, providing novel opportunities for crop growth monitoring in modern agriculture.

Maize-soybean intercropping improved maize growth traits by increasing soil nutrients and reducing plant pathogen abundance

IntroductionMaize (Zea mays L.)–soybean (Glycine max L.) intercropping has been widely utilized in agricultural production due to its effectiveness in improving crop yield and nutrient use efficiency. However, the responses of maize rhizosphere microbial communities and the plant pathogen relative abundance to maize growth traits in maize-soybean intercropping systems with different chemical nitrogen fertilizer application rates remain unclear.MethodsIn this study, a field experiment was conducted, and the bacterial and fungal communities of maize rhizosphere soils in maize-soybean intercropping systems treated with different N fertilization rates were investigated using Illumina NovaSeq sequencing. Maize growth traits, soil physicochemical properties and soil enzyme activities were also examined.Results and discussion:We found that intercropping and N fertilizer treatments strongly influenced soil microbial diversity, structure and function. The PLSPM (partial least squares path modeling) confirmed that soil nutrients directly positively affected maize biomass and that intercropping practices indirectly positively affected maize biomass via soil nutrients, especially NH4+-N. Intercropping agronomic approaches also improved maize growth traits by reducing the plant pathogen abundance, and the relative abundance of the plant pathogen Trichothecium roseum significantly decreased with intercropping treatments compared to monocropping treatments. These results confirmed the benefits of maize-soybean intercropping treatments for agricultural production.

Identification of QTNs, QTN-by-environment interactions for plant height and ear height in maize multi-environment GWAS

Plant height (PH) and ear height (EH) are important traits associated with biomass, lodging resistance, and grain yield in maize. There were strong effects of genotype x environment interaction (GEI) on plant height and ear height of maize. In this study, 203 maize inbred lines were grown at five locations across China’s Spring and Summer corn belts, and plant height (PH) and ear height (EH) phenotype data were collected and grouped using GGE biplot. Five locations fell into two distinct groups (or mega environments) that coincide with two corn ecological zones called Summer Corn Belt and Spring Corn Belt. In total, 73,174 SNPs collected using GBS sequencing platform were used as genotype data and a recently released multi-environment GWAS software package IIIVmrMLM was employed to identify QTNs and QTN x environment (corn belt) interaction (QEIs); 12 and 11 statistically significant QEIs for PH and EH were detected respectively and their phenotypic effects were further partitioned into Add*E and Dom*E components. There were 28 and 25 corn-belt-specific QTNs for PH and EH identified, respectively. The result shows that there are a large number of genetic loci underlying the PH and EH GEIs and IIIVmrMLM is a powerful tool in discovering QTNs that have significant QTN-by-Environment interaction. PH and EH candidate genes were annotated based on transcriptomic analysis and haplotype analysis. EH related-QEI S10_135 (Zm00001d025947, saur76, small auxin up RNA76) and PH related-QEI S4_4 (Zm00001d049692, mads32, encoding MADS-transcription factor 32), and corn-belt specific QTNs including S10_4 (Zm00001d023333, sdg127, set domain gene127) and S7_1 (Zm00001d018614, GLR3.4, and glutamate receptor 3.4 or Zm00001d018616, DDRGK domain-containing protein) were reported, and the relationship among GEIs, QEIs and phenotypic plasticity and their biological and breeding implications were discussed.

Contrasting impacts of plastic film mulching and nitrogen fertilization on soil organic matter turnover

Plastic film mulching and nitrogen (N) fertilization are two important field management practices used to increase crop yields in rain-fed agriculture in arid and semi-arid areas. These two practices, however, can have opposing effects on soil organic carbon (SOC) stock and turnover. To clarify and analyze the combined effects of these practices, we conducted a 7-year continuous maize cultivation experiment with four treatments: (1) no plastic film mulching without N fertilization (Control), (2) plastic film mulching without N fertilization (PFM), (3) N fertilization without plastic film mulching (N), and (4) plastic film mulching with N fertilization (PFM + N). The 13C natural abundance of in the light and heavy fractions of organic carbon (LFOC and HFOC) was used to differentiate “old” (>7 years) and “new” (<7 years) C in the soil after C3 to C4 vegetation change. PFM increased soil temperature and moisture content over 7 years and led to a 150 % and 108 % increase in the above-ground and root biomass of maize, respectively. Hot and wet conditions under PFM accelerated the decomposition of both labile C (i.e., LFOC) and persistent C (i.e., HFOC), as measured by CO2 efflux from the soil. PFM decreased the LFOC and HFOC pools due to the fast decomposition of “old” C and inadequate stabilization of “new” C. Furthermore, PFM accelerated HFOC decomposition to a greater extent than that of LFOC. The Q10 values of SOC decomposition remained similar both in the presence and absence of PFM. Nitrogen fertilization increased the aboveground and root biomass of maize by 54 % and 40 %, respectively. In the control soil, microorganisms decomposed organic N owing to limited availability of mineral N and in the absence of any from replenishment by fertilizer N. Thus, the increase in LFOC content under N fertilization, was primarily attributed to the reduced decomposition of “old” C. The use of N fertilization produced a similar HFOC content as that of the control soil, while also accelerating the decomposition of “old” C and promoting the stabilization of “new” C, resulting in a faster turnover rate. Consequently, the impact of N fertilization on SOC turnover was negligible owing to the contrasting effects on LFOC and HFOC. The application of N fertilization resulted in a reduction of the Q10 value as compared to control. The combination of PFM and N fertilization accelerated the decomposition of HFOC and SOC, while having absent effect on SOC, labile C and persistent C contents. This indicates that 7 years weren’t long enough to trigger a response to the combination of PFM and N fertilization from SOC and HFOC contents. In summary, PFM led to a decline in the SOC content by accelerating the decomposition of both LFOC and HFOC. Conversely, N fertilization maintained SOC content by inhibiting LFOC decomposition and enhancing HFOC decomposition.

Soil Tillage and Cropping System Effects on the Physical-Hydric Properties of a Soil under No-Tillage

A no-tillage system (NT) is an alternative to replace soil management with intense soil tillage and degradation. Our objective was to evaluate the physical–hydric properties of soil under NT for four years after undergoing 13 years of minimum (4NTM) and conventional tillage (4NTC) with reference to continuous NT for 17 years (17NT). The soil bulk density, porosity, storage capacities of water and air, visual evaluation of soil structure (VESS), and saturated hydraulic conductivity were determined. The root dry biomass of soybean, maize, and palisade grass was also measured. NT during four years established after receiving 13 years of tillage did not significantly affect soil properties compared to 17NT, which means that four years of NT reached structural stability similar to continuous 17NT. The VESS scores were less sensitive to identifying soil compaction. Crops have no significative influence on soil properties, but the roots of maize seem to be less sensitive to soil compaction, which is important considering it is in a crop rotation system. The treatments (soil tillage and crop rotation) presented soil compaction below a 10 cm depth, and to our loamy textural class soil, a Bd &gt; 1.60 Mg m−3 restricted soil aeration due to macroporosity &lt; 0.10 m3 m−3.

Role of humic acids-based fertilisers and nitrogen fertilisers in regulation macroelement content in maize biomass

Role of humic acids-based fertilisers and nitrogen fertilisers in regulation macroelement content in maize biomass

Potassium and Brackish Water Irrigation Influence Electrical Conductivity, Potassium Dynamic, and Maize Yield in Coastal Saline Soil

ABSTRACT Brackish water irrigation builds up salinity in the root zone of crops resulting in osmotic stress, nutritional imbalance, and specific ion effect. The development of agro-technology to ameliorate the adverse effects of salt stress has received considerable attention. In this pot culture experiment, we used two types of irrigation water (SW0- normal water, EC- 0.5 dS m−1 and SW1-brackish water, EC- 4 dS m−1), two sources of potassium (K) fertilizers (F1-KCl and F2-K2SO4) and three doses of K (K1–0, K2–30, K3–60 mg kg−1) to study the effect of brackish water irrigation and K on soil saturated paste electrical conductivity (ECe), K dynamic and maize biomass yield in saline soil. The ECe in SW1 was increased significantly (P < .001) by 182% over SW0 but decreased with K application. The SW1 treatment significantly increased the release of non-exch.K by 27% over SW0 at 21 DASE (the day after seedling emergence). The addition of K3 significantly increased the water-soluble K (ws.K), exchangeable K (exch.K) and non-exch.K by 54, 93, and 9%, respectively over K1. The SW1K3 treatment significantly reduced ECe and increased maize biomass yield (24%) over SW1K1. The outcome of the study suggested that SW1 with K3 supports maize production in saline soil during winter.

Impact of microplastic particle size on physiological and biochemical properties and rhizosphere metabolism of Zea mays L.: Comparison in different soil types

The effect of microplastics (MPs) on plant growth has received increasing attention. However, whether soil texture and MPs size influence the toxicological effects of MPs on plants is unknown. To address this knowledge gap, two soils with different physical structures (lime concretion black and silty loam soils) were selected to explore the potential toxicity of MPs of different particle sizes to maize growth. The results showed that, in both soils, the harm caused by small MPs on maize growth was greater than that caused by large MPs. Low MPs concentrations had no significant effect on maize growth between two soil types; however, when exposed to a concentration of 1 % large MPs, the dry biomass of maize was promoted in lime concretion black soil but inhibited in silty loam soil. All MPs-exposed treatments resulted in a high level of superoxide anions in maize roots, resulting in an increase in the root aerenchyma area and reducing the metabolic activity of maize roots. Metabolomics showed that MPs exposure affected multiple amino acid metabolic pathways, including phenylalanine and tyrosine metabolism, and inhibited lignin biosynthesis in roots. This study provides a theoretical basis for a more comprehensive assessment of the effect of MPs pollution on agricultural production.

Struvite/biochar composites as recovered phosphorus fertilizers from domestic sewage sludge increased biomass and nutrient uptake of maize

Global mines of phosphates, which are a main source for the manufacturing of phosphorus (P)-fertilizers, are running out. To solve this problem, the recovery of P by struvite (NH4MgPO4·6H2O) precipitation as a slow-release P-fertilizer (SRPF) has been a growing interest of recent research. This study aimed to assess the effect of struvite/biochar composites as SRPFs on the growth yield, nutrient uptake responses of maize in two soils (with different amounts of calcium carbonate equivalent), and calculation of P use efficiency indices. The greenhouse experiment was designed with six P fertilizer treatments, i.e. triple super-phosphate (TSP), four types of struvite/biochar composites (S/G0, S/G25, S/G50, and S/G75), and control (no P fertilizer applied) with three replication. Results showed that struvite/biochar composite with high amounts of biochar i.e. S/G75 is the best treatment for improving biomass’s of maize (63 and 39%), plant height (25 and 16%), SPAD value (31 and 26%) compared to control and TSP in soil-1 with the low amount of calcium carbonate equivalent, respectively. Applying S/G75, S/G50, S/G25, and S/G0 composites, and TSP concentration of P increased by 2, 1.85, 1.76, 1.73, and 1.34 times over control in soils, respectively. Using of composites significantly influenced P uptake, and recovery efficiency of P by plants, while the S/G75 composite was showed superior to other P-fertilizers. Overall, the struvite/biochar composites showed great potential as efficient SRPF for enhanced maize growth, and the presence of biochar in struvite composite with high amount (S/G75) increased the efficiency of fertilization in calcareous soil.

The Potential of Bioaugmentation-Assisted Phytoremediation Derived Maize Biomass for the Production of Biomethane via Anaerobic Digestion.

Anthropogenic behaviors are causing the severe build-up of heavy metal (HM) pollutants in the environment, particularly in soils. Amongst a diversity of remediation technologies, phytoremediation is an environmentally friendly technology that, when coupling tolerant plants to selected rhizospheric microorganisms, can greatly stimulate HM decontamination of soils. Maize (Zea mays) is a plant with the reported capacity for HM exclusion from contaminated soil but also has energetic importance. In this study, Zea mays was coupled with Rhizophagus irregularis, an arbuscular mycorrhizal fungus (AMF), and Cupriavidus sp. strain 1C2, a plant growth-promoting rhizobacteria (PGPR), as a remediation approach to remove Cd and Zn from an industrial contaminated soil (1.2 mg Cd kg-1 and 599 mg Zn kg-1) and generate plant biomass, by contrast to the conservative development of the plant in an agricultural (with no metal pollution) soil. Biomass production and metal accumulation by Z. mays were monitored, and an increase in plant yield of ca. 9% was observed after development in the contaminated soil compared to the soil without metal contamination, while the plants removed ca. 0.77% and 0.13% of the Cd and Zn initially present in the soil. The resulting biomass (roots, stems, and cobs) was used for biogas generation in several biomethane (BMP) assays to evaluate the potential end purpose of the phytoremediation-resulting biomass. It was perceptible that the HMs existent in the industrial soil did not hinder the anaerobic biodegradation of the biomass, being registered biomethane production yields of ca. 183 and 178 mL of CH4 g-1 VS of the complete plant grown in non-contaminated and contaminated soils, respectively. The generation of biomethane from HM-polluted soils' phytoremediation-derived maize biomass represents thus a promising possibility to be a counterpart to biogas production in an increasingly challenging status of renewable energy necessities.

Bi‐directional hoeing in maize

AbstractThe weed control efficacy (WCE) of mechanical weeding in the inter‐row area in conventional cropping systems can achieve more than 90%. Despite the use of special intra‐row tools (e.g., finger weeders), only a WCE of 65%–75% can currently be realized in the intra‐row area. To close the gap between inter‐row and intra‐row WCE, in this study, a new approach for high‐efficacy precise mechanical weeding is presented. By using a GPS‐based pneumatic precision seeder (Kverneland GEOseed), a square crop seeding pattern of 37.5 cm × 37.5 cm was established in maize to enable post‐emergence hoeing lengthwise and transverse to the sowing direction. Thus, the treated area by the hoeing blades is postulated to increase, resulting in higher WCE. For this, six field experiments were conducted in South‐Western Germany in 2021 and 2022. Goosefoot blades and no‐till sweeps were guided automatically using a camera for row detection and a hydraulic side‐shift control for the hoe. This bi‐directional treatment was compared to an herbicide application and to hoeing treatments only along and transverse to the sowing direction. The bi‐directional hoeing treatment increased the WCE compared to hoeing along the crop rows on average from 80% to 95% and was not significantly different from the herbicide applications in 2022. Precise sowing in combination with hoeing along and transverse the crop rows resulted in 5.3% crop losses compared to 2.2% for hoeing only along the sowing direction by using only 15 cm wide goosefoot blades, while in the herbicide treatment and the untreated control no crop losses were detected. While maize biomass was not significantly different from the herbicide treatment in most cases over both years, in 2022, even the grain yield of the bi‐directional hoeing treatment with goosefoot blades (7.8 Mg ha−1) was statistically equal to the herbicide treatment (6.9 Mg ha−1). This study demonstrates the great potential of bi‐directional hoeing as an effective alternative to chemical weed control in row crops such as maize, sunflower and sugar beet.

Cultivation of Crops in Strip-Till Technology and Microgranulated Fertilisers Containing a Gelling Agent as a Farming Response to Climate Change

Climatic and soil conditions are changing in response to the increasing human impact. This requires the introduction of low-cost, low-emission, but effective technologies in the field cultivation of crops, in turn requiring and justifying research in this area. In laboratory tests and field studies, the production and environmental effects of strip-till and the application of microgranular fertilisers with a gelling component were determined (and, in particular, their use in combination as a plant cultivation technology). These effects were measured in terms of soil properties, the biomass production, and the yields of maize (Zea mays L.), spring barley (Hordeum vulgare L.), and winter rape (Brassica napus L.). Fertiliser microgranules with a gelling agent absorbed water in the amount of 118.6–124.7% of fertiliser mass and increased the volumetric moisture content of the soil in the layer in which they were applied (0–7.5 cm) by 3.0–3.9 percentage points compared to the soil moisture without fertiliser. Strip tillage with the application of fertilisers with a gelling agent significantly increased the amount of water in the soil during the sowing period for winter and spring plants and reduced the CO2 emissions from the soil relative to the conventional tillage without microgranular fertiliser. The biomass of maize, spring barley, and winter rape before flowering, as well as the yields of these plants, were higher when cultivated using strip-till and fertilisers with gelling agents than when ploughed with a mouldboard plough without the use of microgranulated fertilisers. This technology also increased the number of microorganisms, including bacteria, actinobacteria, and filamentous fungi in the soil after harvesting compared to the unfertilised, ploughed soil. Strip tillage and microgranulated fertilisers containing a gelling agent can thus reduce the environmental pressure exerted by agriculture and reduce the risk of climate change, as well as being a way of adapting agriculture to climate change.