Maize Monoculture Research Articles

The nutritional benefits of maize-soybean rotational systems in the North-Western Free State, South Africa

BackgroundMalnutrition is one of the major health concerns, particularly in the developing and under-developed world. In South Africa, maize is produced as a staple food and is the primary food for most of the country’s population. The North-Western Free State which forms part of the Nala municipality in the Lejweleputswa district of South Africa is a main producer of the country’s maize. However, the area is known for its sandy soil which contains little organic material, silt and clay. Maize in this area is normally grown in monoculture but with a focus on sustainable agriculture has recently incorporated soybean. As a means of fighting malnutrition, the objective of this study was to determine the influence that soybean incorporation as a rotation crop has on the nutritional value of maize.MethodsA trial was conducted on the farm Christinasrus in the North-Western Free State to compare the nutritional value of monoculture maize and maize in rotation with soybean over three consecutive seasons. Maize kernel samples were taken each season and its nutritional properties analyzed. Subsequent data were further analyzed using statistical analysis.ResultsResults showed that there was a seasonal effect on all nutritional properties with a general decrease in nutritional values in wetter years. Cropping systems had an effect on fibre content, with increased values observed in maize after soybean. In addition, there was a significant interaction between season and cropping systems on the total digestible nutritional value, with maize after soybean being more nutritious in wetter seasons.ConclusionResults suggest that maize in cropping systems with soybean has potential to be more nutritious while the soybean in the cropping system can act as a protein-rich companion, providing a more balanced diet for human consumption, thereby fighting malnutrition.

Shifting focus from external to in situ organic resources – The redesign of four tropical long-term experiments

Long-term experiments (LTEs) are critical for evaluating strategies that can maintain or increase crop yields, soil fertility and soil organic carbon (SOC), and help adapt to climate change. Yet, scientific knowledge is advancing and research questions are evolving. Therefore, it is important to review the objectives of LTEs over time. A change in their design may be necessary to keep the experimental treatments scientifically interesting, innovative, and relevant in the context of evolving agricultural challenges. Here, we describe the process of redesigning four LTEs in Kenya. These LTEs are unique in that they represent four different pedoclimatic conditions but with identical experimental treatments across sites. Initially, they focused on investigating how to maintain or increase SOC and maize yields over time by applying a combination of mineral nitrogen (N) and external organic resources. Specifically, the experimental treatments consisted of maize monoculture with different rates (1.2 and 4 t C ha−1 yr−1) and qualities of organic resources, either with or without mineral N fertilizer input. After about 20 years, it became clear that SOC was lost in most treatments. Therefore, continuing with the current experimental design was not an option. Taking advantage of the fact that the different former treatments led to different levels of soil degradation, we redesigned the LTEs to study the effectiveness of regenerative cropping strategies in rebuilding SOC and increasing crop yields starting from the different levels of soil degradation. The focus shifted from external to in situ organic inputs by increasing the root biomass of the cultivated crops. The newly established cropping system treatments are maize-legume rotation, maize-legume intercropping (double row configuration) and relay intercropping of maize with forage grass. A key finding from the previous phase of the experiments, namely, that external organic inputs with low C:N ratios are most efficient in building SOC, has been incorporated into the redesign. The relative contribution of external versus in situ organic resources is tested by splitting the cropping system treatments into those receiving either farmyard manure or green manure in the form of Tithonia diversifolia prunings and those receiving no external inputs. Split-plot treatments with and without mineral N were retained. The overall objective of studying mechanisms of tropical soil fertility maintenance and, more specifically, SOC formation, remained unchanged. However, the redesign aligned the LTEs with the current state of knowledge and pressing research questions, specifically focusing on the relative effectiveness of in-situ versus external organic inputs in SOC formation.

Sustainable alternative to irrigated maize monoculture in a maize-dominated cropped area: Lessons learned from a system experiment

Maize is the most-produced food crop in the world and is grown in intensive rotations or in monoculture (continuous maize) systems. As maize production has expanded massively across the world, many concerns have emerged about its local environmental and other global impacts. Agronomists have designed innovative cropping systems and assessed them using system experiments to make arable systems more sustainable. However, knowledge is still lacking on the sustainability of innovative cropping systems compared to highly intensive systems such as irrigated maize-based monoculture. Here, we present the assessment results of a nine-year system experiment in Alsace, France, developed to compare an innovative system based on a diversified rotation and innovative management practices (three-year rotation of maize/soybean/winter wheat (plus a cover crop) combined with reduced tillage) with a continuous maize reference system. The results cover a six-year assessment period following an initial three-year design period. Classic criteria, such as profitability, workload, pesticide use, fossil energy consumption and nitrate leaching, were assessed along with other less studied criteria, such as pesticide leaching risk, soil structure, soil chemical quality and soil biological activity. Sustainability – which includes environmental, social and economic dimensions – was assessed with the MASC 2.0 method. Overall sustainability was substantially enhanced in the innovative system (5 out of 7 sustainability classes) in comparison with the low level of the reference system (2 out of 7). This was due to a clear improvement in the environmental performance (from 2 out of 5 to 5 out of 5) while social performance was high in both systems (4 out of 5) and economic performance was low (2 out of 5) due to very low contribution to economic development. Nevertheless, the innovative system had a major drawback: lower profitability, especially when scenarios included high maize prices. Furthermore, herbicide use on maize was higher in the innovative system than in the reference one. Avenues for progress, such as encouraging stakeholder participation at the assessment stage or additional innovations such as multiple cropping, are suggested.

Productivity of maize monoculture in long-term experience with fertilizers

Productivity of maize monoculture in long-term experience with fertilizers

Changes in Microbial Community and Activity of Chernozem Soil under Different Management Systems in a Long-Term Field Experiment in Hungary

The effects of intensive and reduced tillage, fertilization, and irrigation on soil chemical and microbiological parameters were studied in a long-term field experiment in Hungary. The treatments were plowing tillage, ripper tillage, strip tillage; control (without fertilization), NPK fertilization (N: 160 kg/ha; P: 26 kg/ha; K: 74 kg/ha); and non-irrigation and irrigation. Soil samples were collected through maize monoculture in the fall of 2021 in the 30th year of the experiment. The soil organic carbon, total nitrogen, soil microbial biomass (based on PLFA analysis), and soil enzyme activity were observed to be significantly high in the strip tillage plots, but were lower in the ripper tillage plots, and even lower in the plowing tillage plots. The fungal, arbuscular mycorrhiza fungal, and bacterial biomasses were significantly higher in the strip tillage and ripper tillage plots compared to the plowing tillage plots. The strip tillage treatment was found to be the most favorable cultivation method for improving the microbial biomass and activity of Chernozem soil, followed by the ripper tillage and plowing tillage treatments. The long-term use of chemical fertilizers greatly reduced the soil microbial biomass and negatively impacted the soil microbial community, leading to a decrease in fungi and Gram-negative bacteria. The ratio of cyclopropyl PLFA precursors to cyclopropyl PLFAs, as a “stress factor”, indicated the most stressful bacterial environment was that found in the fertilized, non-irrigated plowed soil.

Responses of labile organic carbon fractions and mineralized carbon to straw return combined with fertilizer application in the maize–Melilotus officinalis intercropping system

AbstractMollisol is crucial for solving food security issues, but long‐term excessive application of chemical fertilizers has led to severe Mollisol degradation in Northeast China, especially a rapid decline in soil organic carbon (SOC). In context of the use of crop‐herbage intercropping and straw return as alternatives for some chemical fertilizers, it is important to understand how crop‐herbage intercropping and straw return combined with chemical fertilizers influence labile organic carbon (LOC) fractions that improve SOC. To address this, this study explored how the combined application of maize (Zea mays L.)–Melilotus officinalis intercropping, straw return, and chemical fertilizers affect LOC fractions and mineralized carbon (MC) from the perspective of physical property‐mediated pathways. Thus, a field experiment with six treatments was established in the Songnen Plain of Northeast China: (1) maize monoculture without chemical fertilizers and straw return (CK), (2) maize monoculture with chemical fertilizers and no straw return (CF), (3) maize monoculture with chemical fertilizers and straw return (CFS), (4) maize–M. officinalis intercropping and straw return combined with full application of chemical fertilizers (CFSM), (5) maize–M. officinalis intercropping and straw return combined with half application of chemical fertilizers (1/2CFSM), and (6) maize–M. officinalis intercropping and straw return without chemical fertilizers (SM). The CF and CFS groups had no effect on bulk density and porosity but reduced specific gravity. The CFSM group increased water contents, porosity, LOC fractions, SOC, MC, and CO2 release rate and decreased bulk density and specific gravity. Compared with the CF group, the 1/2CFSM group enhanced water contents, microbial biomass carbon, and water‐soluble organic carbon (WSOC) to 6.36%, 17.91%, and 11.6%, respectively. We found that maize–M. officinalis intercropping, straw return, and reducing chemical fertilizers application improved LOC fractions to increase SOC by positively affecting bulk density, specific gravity, and water contents. Further analysis indicated that WSOC was a key determinant of SOC and maize yields. These findings provide a strategy to increase SOC and rehabilitate degraded soils through crop‐herbage intercropping and straw return combined with reducing chemical fertilizers application, which will contribute to a sustainable and environmentally friendly agriculture.

Sustainability Assessment after Twenty Years of Sewage Sludge Application on Calcareous Soil Following N or P Criterion

Sewage sludge is a valuable source of nutrients when applied to the soil. Research on its agricultural use has been focused on chemical parameters to prevent heavy metal buildup. However, soil quality includes a wider spectrum of indicators. Our aim was to evaluate the impacts of sludge application on the biological and physical soil properties of calcareous soil when sludge is applied in maize monoculture using fertilization dosage criteria determined by N input or soil P thresholds. A control based on mineral fertilization was also included. After 20 years, no differences were found in the biological indicators: earthworm and soil oribatid mite abundances. Five oribatid species were identified, but three predominated: Acrotritia ardua americana, Oribatula (Zygoribatula) excavata and Tectocepheus sarekensis. The latter two showed a maximum number of individuals five months after maize stalks were buried in soil, independent of fertilization treatment. Sludge significantly increased water-stable aggregates (up to 30%), but there was no difference in macroporosity (apparent pore diameter > 30 μm). Under irrigated calcareous soil, sewage sludge applied as fertilizer is a sustainable option, independent of the threshold criterion (N or P) used. Nevertheless, as the P threshold criterion allows for reduced P inputs, it is more sustainable over the long term.

Optimizing row combinations of an intercrop of maize with cabbage

In order to explore the optimum row combinations of an intercrop of maize with cabbage, 11 treatments for different intercropping rows of two crops were conducted from 2010 to 2016. The intercrop made intercropped maize yield raise and intercropped cabbage yield lower compared with their respective monocultures. Intercropped maize and cabbage interacted with each other, which could be presented by the regression equations between YIR, income and LER, and the number of intercropping rows of both maize and cabbage. Although the positive effect of intercropped maize could not offset negative effect of intercropped cabbage in the same intercropping rows, the advantage of the intercrop appealed when intercropping strip of cabbage was 1–3 rows more than that of maize. Income of cabbage monoculture was higher than that of maize monoculture and the intercrop. LER of the intercrop was relatively low with a maximum of 1.08. There was possibility that LER was ≥1 when the intercropping strip of cabbage was ≥ 4 rows. M4||C7 is recommended for an optimum combination of this intercrop based on the highest average LER value, and the opportunity for farmers to plant and harvest these rows with machinery.

Time Matters: A Short-Term Longitudinal Analysis of Conservation Agriculture and Its Impact on Soil Health

Conservation agriculture is seen as a potential solution to modern farming challenges. This paper elucidates its immediate impact by investigating the short-term dynamics of soil health, including the biological constituents, following the implementation of conservation agriculture. We hypothesised that implementing conservation agriculture would lead to changes in soil health. However, these changes will vary across the physical, chemical, and biological properties of the soil, given that each of these components is likely differently influenced by conservation agriculture. The study site was a multi-year trial in Ottosdal (South Africa) with different crop production systems, including maize monoculture, conservation agriculture (rotation of maize, sunflower, and cover crops), and an uncultivated grassland, which served as a natural reference system. Appropriate statistical methods were used to analyse soil health parameters and their interactions from samples collected during the three consecutive summer growing seasons. The study revealed significant soil health dynamics between the cultivated and uncultivated systems. Total available P, organic matter content, and microbial biomass were key indicators of soil health over the 3 years. Crop sequence influenced these dynamics, while a shift from abiotic to biotic factors was observed as primary system differentiators. Notably, crop rotation and soil structure significantly influenced soil microbial communities. These findings provide valuable insights into the interactions between soils and biota and the resulting effects on soil health dynamics. However, further research is required to fully elucidate the mechanisms involved and optimise sustainable farming practices for diverse environmental contexts.

Keanekaragaman dan komposisi spesies laba-laba predator dan parasitoid Hymenoptera pada tanaman jagung dengan dan tanpa refugia pada musim yang berbeda

Tanaman refugia merupakan tanaman yang berperan penting dalam konservasi musuh alami. Tanaman refugia berguna untuk menjadi tempat berlindung dan menyediakan inang/mangsa bagi musuh alami terutama dari golongan parasitoid dan predator. Tujuan dari penelitian ini untuk mengetahui pengaruh refugia dan perbedaan musim tanam terhadap keanekaragaman dan komposisi spesies musuh alami (khususnya laba-laba predator dan parasitoid Hymenoptera) pada pertanaman jagung. Penelitian lapangan dilaksanakan pada dua musim berbeda, yaitu musim kemarau (bulan April hingga Juli 2022) dan musim hujan (bulan September hingga Desember 2022) di Desa Tumpang, Kabupaten Malang. Lahan untuk penelitian dikelompokkan menjadi empat area berbeda, dengan setiap area ditentukan dua plot pengamatan (berukuran 40 m × 50 m) terdiri atas lahan jagung monokultur (plot kontrol) dan lahan jagung dengan tanaman refugia (plot perlakuan). Pengambilan sampel dilakukan menggunakan perangkap jebak (untuk laba-laba predator) dan perangkap kuning (untuk parasitoid Hymenoptera). Pemasangan perangkap dilakukan 1 × 24 jam dan dilakukan pada umur jagung 2, 4, 6, 8, 10 dan 12 minggu setelah tanam (MST). Hasil penelitian selama dua musim tanam jagung diperoleh keanekaragaman laba-laba predator berjumlah 626 individu terdiri atas 7 famili, dan 40 morfospesies, sedangkan parasitoid Hymenoptera berjumlah 787 individu yang terdiri atas 5 famili, dan 63 morfospesies. Berdasarkan analisis generalized linier models (GLM), diperoleh hasil bahwa penanaman refugia tidak memengaruhi keanekaragaman musuh alami, namun berpengaruh terhadap komposisi spesies laba-laba predator. Perbedaan musim tanam berpengaruh terhadap keanekaragaman dan komposisi spesies laba-laba predator dan parasitoid Hymenoptera.

Intercropping regulates plant- and microbe-derived carbon accumulation by influencing soil physicochemical and microbial physiological properties

Intercropping can increase soil carbon (C) sequestration and utilization by planting a variety of plants on a same land. However, the main plant and microbial-driven pathways leading to the increased C sequestration in intercropping soils are rarely studied. Therefore, it is important to reveal the distinct contributions of plant- and microbe-derived C to soil organic C (SOC) for understanding the regulation of intercropping in global C storage. Herein, two widely accepted sets of bio-markers, namely, amino sugars and lignin phenols, were employed to compare the distribution of plant- and microbe-derived C as well as their contributions to SOC in maize monoculture and intercropping systems, based on a field experiment established in 2013; meanwhile, the associations of soil physicochemical properties and microbial physiological traits with plant- and microbe-derived residues were disclosed via correlation and model analysis. Compared with the monoculture, maize intercropping significantly increased soil amino sugar and microbial necromass C contents as well as their contributions to SOC in maize mature stage; maize inter-planted with gingelly or soybean significantly increased these variables in the elongation stage; meanwhile, maize inter-planted with gingelly significantly increased soil lignin phenol content and its contribution to SOC in the mature stage. In all treatments and growth stages, microbial necromass C contributed more to SOC than lignin phenols, and fungal necromass C contributed more to SOC than bacterial necromass. The contribution of microbial necromass C to SOC was mainly influenced by amino sugar content, microbial C use efficiency, dissolved organic C content, and microbial biomass C content. The contribution of plant-derived C to SOC was mainly influenced by lignin phenol content, pH, and NH4+-N content. These results demonstrate the distinct regulations of maize intercropping on plant- and microbe-derived C to soil C pool by influencing soil physicochemical properties and microbial physiological traits, and meanwhile, highlight the potential of intercropping in global C storage.

Effects of soil physicochemical environment on the plasticity of root growth and land productivity in maize soybean relay strip intercropping system.

Soil is a key foundation of crop root growth. There are interactions between root system and soil in multiple ways. The present study aimed to further explore the response of root distribution and morphology to soil physical and chemical environment under maize (Zea mays L.) soybean (Glycine Max L. Merr.) relay strip intercropping (MS) An experiment was carried out aiming to examine the effects of nitrogen (N) applications and interspecific distances on root system and soil environment in MS. The two N application levels, referred to as no N application (NN) and conventional N application (CN), were paired with different interspecific distances: 30, 45 and 60 cm (MS30, MS45 and MS60) and 100 cm of monoculture maize and soybean (MM/SS100). The results demonstrated that MS45 increased the distribution of soil aggregates (> 2 mm) near the crop roots and maize soil nutrients status, which increased by 20.3% and 15.6%. Meanwhile, MS reduced soil bulk density, increased soil porosity and improved soil oxygen content. Optimization of the soil environment facilitated root growth. The MS45 achieved a better result on root distribution and morphology than the other configuration and also increased land productivity. Relay intercropped soybean with maize in interspecific row spacing of 45 cm, improved soil physicochemical environment, reshaped root architecture and optimized root spatial distribution of crops to achieve greater land productivity. © 2024 Society of Chemical Industry.

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.

Control of western corn rootworm with entomopathogenic nematodes in maize monoculture

Control of western corn rootworm with entomopathogenic nematodes in maize monoculture

旱作条件下大豆玉米复合种植系统水分利用特征和生产力的比较研究

Quantitative investigation of the utilization characteristics of precipitation resources and the production capacity of the intercropping production system under the soybean maize intercropping mode in northern China is of great significance for improving the resource utilization rate of dryland agriculture and regional sustainable development. This study adopted a completely randomized block design, and six planting modes were set up: soybean monoculture, maize monoculture, and four soybean maize intercropping modes. Plant height and grain yield data were observed, and precipitation resource utilization efficiency was calculated. Based on the FAO-56 recommended crop coefficients, the crop coefficients were corrected according to the actual growth of crops in the experimental area; combined with meteorological data, the crop water demand under different planting modes was estimated based on the Penman-Monteith principle. The results showed that crops' daily growth water demand under different planting modes was generally deficient in water in the early and middle stages of growth, and surplus in the later stages. Compared with the monoculture mode, there were significant differences in precipitation resource utilization efficiency under different intercropping modes (P < 0.05), with soybeans reduced by 67.50% ~ 89.56%, and corn reduced by 43.99% ~ 61.05%. Based on the semi-humid and semi-arid area of the eastern Loess Plateau, an appropriate irrigation system needs to be designated for soybean and corn intercropping systems in the early and middle stages of crop growth. Under a certain proportion of water resource supply, different modes have different water resource utilization efficiency and final production capacity for the intercropping system.

Opening up the subsoil: Subsoiling and bio-subsoilers to remediate subsoil compaction in three fodder crop rotations on a sandy loam soil

The intensification of modern arable farming has brought on a steady increase of the risk of soil compaction, while simultaneously pushing the impact deeper into the soil profile. In the subsoil, outside the reach of regular tillage operation, it can become exceedingly difficult to deal with compacted layers. Commonly, farmers turn towards mechanical remediation strategies, like subsoiling, to deal with this issue. However, the numerous drawbacks that come with these operations have prompted the search for more sustainable alternatives, like bio-subsoilers, which are deep-rooting plant species with the capacity to penetrate compacted subsoil layers. This study aimed at investigating both mechanical and biological remediation strategies in a side-by-side comparison. The effectiveness of subsoiling and the use of two deep rooting (cover) crops (i.e. alfalfa and fodder radish) as remediation measures to alleviate subsoil compaction was assessed in terms of soil quality indicators, like penetration resistance, bulk density, porosity, plant available water capacity, air capacity and air permeability at 35 and 45 cm depth, and the above- and belowground growth of the main crop. In addition, a combination of both subsoiling and use of deep rooting (cover) crops was included to evaluate the potential role of the latter in protecting the mechanically loosened subsoil from recompaction. This complex comparison was done in three distinct maize-based fodder crop rotations (rotation 1: maize monoculture; rotation 2: maize/winter cereal rotation with fodder radish as cover crop after winter cereal; rotation 3: maize/winter cereal/alfalfa rotation). The study field (sandy loam soil) was selected based on the presence of a highly compacted layer at the interface between topsoil and subsoil (30–50 cm). The experiment demonstrated that subsoiling is an effective remediation measure to disrupt heavily compacted layers in the upper-subsoil, at least in the short-term. The crop response was however highly variable and only positive when the opportunity of reaching the subsoil proved to be advantageous for the crop (i.e. dry season). Besides its high degree of variability between years, the effects also proved to be very short-lived under a standard arable fodder crop rotation. Including deep rooting (cover) crops, like fodder radish and alfalfa, and limiting the initial subsoil disruption helped to partially stabilize the disrupted subsoil and reduce recompaction. Fodder radish and alfalfa penetrated the compacted subsoil without previous disruption by subsoiling. However, this did not lead to a significant improvement of the measured soil physical parameters.

Effect of Reduced Nitrogen Fertilization on the Chemical and Biological Traits of Soils under Maize Crops

The European Commission’s “Farm to Folk” strategy recommends reducing fertilizers by at least 20% by 2030. In this context, the aim of this study was to verify whether a 20 and 40% reduction of nitrogen (N) fertilization rate will be sufficient to maintain soil chemical features, fertility, and yields in monoculture maize cultivation in the no-tillage (NT) system versus the traditional plowing (PL) system. We also examined which tillage system (PL, NT) allows the reduction of fertilization while maintaining good yields of the tested soils. Two fields (10 ha each) were established for PL and NT maize cultivation, and soils (0–20 cm) were sampled twice per year—before maize sowing and after maize harvesting. A broad range of chemical and biological parameters were monitored (i.e., pH, forms of nitrogen, phosphorus and carbon, content of selected macronutrients and humic substances, and respiration activity). It was concluded that the 20% reduction in N fertilization (after 4 years of use) did not have an adverse effect on the soil’s chemical and biological features, which mainly depended on the season of the year. The maize yield seemed to be higher in the PL system, which was mostly the result of the tillage system rather than the N dose. The study will be continued in the next vegetation season to further verify our findings, especially with regard to the maize tillage system and yields.

Effect of Legumes Intercropped with Maize on Biomass Yield and Subsequent Biogas Production

The presented study deals with the use of legumes intercropped with maize for the production of biogas from silage. The main goal was to find out whether silages made from mixed cultures can be used in biogas production and how the use of such silages affects qualitative and quantitative parameters of the fermentation process compared with the pure maize silage. Variants prepared were pure cultures of maize, bean, lupin, and white sweet clover. In addition, mixed cultures were prepared of maize and individual legumes. Measured values showed that in terms of dry matter (DM) yield, mixed culture silages are almost of the same or even better quality than silage made from the maize monosubstrate. Compared with the maize monoculture silage, the presence of white lupine, white sweet clover, and broad bean in silages statistically significantly increased the content of DM, ash, and acid detergent fiber (by more than 5%). Bean and lupine in mixed silages with maize significantly increased the content of lipids (on average by more than 1.2%). Legumes in silages were significantly decreasing contents of neutral detergent fiber, crude protein, and starch. Production of biogas from silages of maize monosubstrates and mixed substrates of maize with white lupin, maize with white sweet clover, and maize with broad bean was directly proportional to the content of CAR and starch in these substrates. A perspective variant was the mixed substrate of maize and sweet clover from which biogas production was only 6% lower than that from conventional maize silage. The highest yield was recorded in the maize monosubstrate (0.923 m3/kgVS). Variants of mixed substrates had a yield ranging from 0.804 to 0.840 m3/kgVS.

Stability of soil bacteria in undisturbed soil and continuous maize cultivation in Northern Thailand.

Rotational shifting cultivation (RSC) in Northern Thailand serves the dual purpose of ensuring food security and meeting economic goals through maize cultivation. However, the research question remains: Does the dynamics of soil bacterial communities differ between maize monoculture and RSC fields with continuous fallow throughout the season? Therefore, the objective of this study was to investigate and compare the variation of soil bacterial communities in maize monoculture and fallow RSC fields. A continuous 5-year fallow field (undisturbed soil; CF-5Y) and a continuous 5-year maize cultivation field (M-5Y) in Mae Chaem District, Chiang Mai Province, Northern Thailand, were selected due to their similarities in microclimate, topography, and the 5-year duration of different field activities. Over the span of a year, we collected soil samples from the surface layer (0-2 cm depth) at both sites. These collections occurred at 3-month intervals, starting from March 2022 (summer season) and followed by June (rainy season), September (rainy season), December (winter season), and March 2023 (summer season). Soil bacterial diversity and composition were analyzed using 16S rRNA gene-based metagenomic analysis. The results found that undisturbed soil over a 5-year period exhibited more stability in the richness and diversity of bacteria across seasons compared with M-5Y. Notably, fertilizer application and tillage practices in M-5Y can enhance both the diversity and richness of soil bacteria. In terms of bacterial abundance, Proteobacteria prevailed in CF-5Y, while Actinobacteria dominated in M-5Y. At the genus level, Candidatus Udaeobacter dominated during the summer and winter seasons in both CF-5Y and M-5Y sites. Interestingly, during the rainy season, the dominant genus shifted to Bacillus in both CF-5Y and M-5Y fields. The soil bacterial community in M-5Y was strongly influenced by organic matter (OM) and organic carbon (OC). In contrast, in CF-5Y, there was no correlation between soil properties and the soil bacterial community, likely due to the lower variation in soil properties across seasons. β-Glucosidase was the dominant enzyme in both CF-5Y and M-5Y sites, and it showed a positive correlation with OM and OC. Further studies should continue to investigate soil bacteria dynamics, considering the changes in land management practices.