Maize Crop Residues Research Articles

Maize crop residue cover mapping using Sentinel-2 MSI data and random forest algorithms

The return of crop residues to cultivated fields has numerous agronomic and soil quality benefits and, therefore, the areal extent of crop residue cover (CRC) could provide a rapid measure of the sustainability of agricultural production systems in a region. Recognizing the limitations of traditional CRC methods, a new method is proposed for estimating the spatial and temporal distribution of maize residue cover (MRC) in the Jilin Province, NE China. The method used random forest (RF) algorithms, 13 tillage indices and 9 textural feature indicators derived from Sentinel-2 data. The tillage indices with the best predictive performance were STI and NDTI (R2 of 0.85 and 0.84, respectively). Among the texture features, the best-fitting was Band8AMean-5*5 (R2 of 0.56 and 0.54 for the line-transect and photographic methods, respectively). Based on MSE and InNodePurity, the optimal combination of RF algorithm for the line-transect method was STI, NDTI, NDI7, NDRI5, SRNDI, NDRI6, NDRI7 and Band3Mean-3*3. Likewise, the optimal combination of RF algorithm for the photographic method was STI, NDTI, NDI7, SRNDI, NDRI6, NDRI5, NDRI9 and Band3Mean-3*3. Regional distribution of MRC in the Jilin Province, estimated using the RF prediction model, was higher in the central and southeast sections than in the northwest. That distribution was in line with the spatial heterogeneity of maize yield in the region. These findings showed that the RF algorithm can be used to map regional MRC and, therefore, represents a useful tool for monitoring regional-scale adoption of conservation agricultural practices.

Soil hydro-physical variables and crop residues determinate runoff, soil loss, and glyphosate and AMPA concentration in the aqueous phase under simulated rainfall events.

Soil structural degradation and water erosion processes were observed even in no-tillage schemes in the Pampas region. Within these conservation systems, agrochemical application per hectare is one of the highest globally. Thus, this entails a serious risk of water contamination. The objectives of this study were to (1) test the hypothesis that the hydrological dynamics and sediment concentration related to surface runoff were conditioned by soil structure regardless of the presence of maize (Zea mays L.) crop residue and (2) assess the incidence of maize crop residue on glyphosate and aminomethylphosphonic acid (AMPA) concentration in runoff. The soil under study corresponded to Arroyo Dulce Series (Typic Argiudoll silty loam soil). Rain simulations were performed in the laboratory on undisturbed soil samples. Total runoff and infiltration rate were similar between treatments with C(+) and without C(-) maize crop residues (C(+) 1381.40mL and 14.27mm h-1, C(-): 1529.70mL and 21.67mm h-1). The C(-) treatments showed a higher sediment concentration than C(+) (1.58 and 0.42g 100mL-1, respectively). Glyphosate and AMPA average values in runoff were 15.9 and 33.9µg L-1. High variability of the hydro-physical properties and occurrence of soil structure, particularly platy ones, were detected. The hydrological variables were conditioned mainly by the occurrence of platy structures regardless of crop residue presence. Glyphosate concentration was increased in the first runoff event by the presence of corn residues, while AMPA concentrations were higher in the second runoff event in both residue treatments. In this study, maize residue on the soil surface protected the soil from sediment detachment but did not change runoff or infiltration. Thus, the implementation of agricultural management practices that promote vegetative residue cover has shown positive results to erosion.

Assessment of nutrient flows in maize-based farming system by smallholder farmers for sustainable production in Ikara, Kaduna State

Nutrient depletion is one of the major causes of decreased crop yield, and a threat to food security and sustainable crop production. NutMon- toolbox was used to determine nutrient flows and partial nutrient balances of maize-based smallholders’ farming system. Data was collected using structured questionnaire from 15 randomly selected farmers, with five farmers each in three villages. Composite soil samples were also taken from each of the three plots. At crop maturity, samples of crop products and residues were randomly taken from the selected fields. Nitrogen, P and K contents in soil and crop material was used to calculate nutrient flows and partial balances. Results obtained revealed that mineral fertilizer flow, averaged 349.20kg N yr-1 and 81.45kg K yr-1 and were lower than 376.65kg N yr-1 and 431.44kg K yr-1 organic input. However, phosphorus in mineral fertilizer (55.78kg P yr-1) was higher compared to phosphorus (51.06 kg P ha-1 yr-1) in organic input. Nitrogen, phosphorus and potassium for maize seeds and crop residue were all negative. The partial nutrient balances were positive 53.45kg N ha-1 yr-1 and 79.40kg K ha-1 but negative 1.10kg P ha-1 yr-1. Harvesting of crops for food, without incorporation of crop residue into the soil, were the most important sources of nutrient mining in smallholder production system. Integrated soil fertility management practices that favour the buildup of soil organic matter and use of animal manure should be encouraged through effective extension services at Ikara, Kaduna State, Nigeria.

The Effects of Sunflower and Maize Crop Residue Extracts as a New Ingredient on the Quality Properties of Pork Liver Pâtés.

The present study aimed to evaluate the antioxidant capacity of ethanolic extracts from post-harvest sunflower and maize stalk residues, and their impact on the chemical composition, physicochemical parameters, lipid oxidative stability, microbiological properties, and sensory characteristics of pork liver pâtés over a 90-day storage period. Four formulations were prepared: a control group (CON), a batch with butylated hydroxytoluene as a synthetic antioxidant (BHT), 1% ethanolic extract from sunflower residues (SSRE), and 1% ethanolic extract from maize residues (MSRE). The MSRE had a higher total phenol content and showed better antioxidant activity relative to the SSRE (p < 0.01). The addition of SSRE decreased the lightness and increased the redness in the pork liver pâtés, with these pâtés showing the highest total color difference compared to the control (p < 0.01). The crop extracts increased the n-6 and total PUFA contents in pâtés and improved the PUFA/SFA ratio (p < 0.01). Formulations containing crop residue extracts showed higher TBARs and POV values than the control and BHT group (p < 0.01), indicating a pro-oxidant effect and accelerated lipid oxidation in pâtés during storage. As far as microbiological quality, the presence of crop residue extracts decreased the total viable count, lactic acid bacteria, and psychotropic aerobic bacteria (p < 0.01). The incorporation of crop extracts in the pork pâtés impaired their sensory quality, particularly color, odor, aroma, and flavor, and decreased their overall acceptability. These results indicated that, while the crop residue extracts were not as effective as synthetic antioxidants in preserving the lipid stability of pâtés, they demonstrated potential for enhancing the microbial quality of this type of meat product.

Growth, Productivity and Profitability of Direct Seeded Rice as Influenced by Maize Crop Residue Management Practices and Fertility Levels in Rice-Maize Sequence

Growth, Productivity and Profitability of Direct Seeded Rice as Influenced by Maize Crop Residue Management Practices and Fertility Levels in Rice-Maize Sequence

Utilization of Crop Residues and Solubilizing Bacteria to Enhance the Dissolution of Moroccan Phosphate Rock

Phosphorus is essential for plant growth, but its availability in soils is limited due to low solubility of phosphate compounds. This study evaluated the combined effects of crop residues (CR) and phosphate-solubilizing bacteria (PSB) on the dissolution of Moroccan phosphate rock. Pot experiments were conducted for 60 days using different doses of MPR (450 kg/ha, 300 kg/ha, and 150 kg/ha), rice and maize crop residues, and a PSB consortium from a rice paddy field. Parameters such as pH, bacterial count, and phosphorus content were measured. The pH increase was significantly higher under the T3 treatment (CR + PSB) with pH 8.26 to 8.58, followed by T1 (CR alone) with pH 7.73 to 8.1, T2 (PSB alone) with pH 7.4 to 7.91, and T0 (control) with pH 7.27 to 7.67. The number of PSB was highest under the T3 treatment (1238.5 x 10-6 to 2081.1 x 10-6 bacteria/g dry matter), followed by T1 (127.2 x 10-6 to 249.03 x 10-6 bacteria/g dry matter) and T2 with 1.7 x 10-6 to 44.6 x 10-6 bacteria/g dry matter, regardless of the MPR dose. Phosphorus solubilization was 35% to 62% with PSB alone (T2), 72% to 88.5% with CR alone (T1), and over 83.98% when both CR and PSB were combined (T3). This increase was more pronounced with higher MPR doses (300 to 450 kg/ha). Incorporating PSB and crop residues as biofertilizers is a viable strategy for enhancing phosphate rock dissolution and improving soil fertility in agricultural systems.

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

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

Suitability of maize crop residue fermented by Pleurotus ostreatus as feed for edible crickets: growth performance, micronutrient content, and iron bioavailability.

Small-scale farming of edible insects could help combat public health challenges such as protein energy malnutrition and anemia, but reliable low-cost feeds for insects are needed. In resource-limited contexts, where grains such as maize are prohibitively costly for use as insect feed, the feasibility of insect farming may depend on finding alternatives. Here, we explore the potential to modify plentiful maize crop residue with edible mushroom mycelium to generate a low-cost feed adjunct for the farmed two-spotted cricket, Gryllus bimaculatus. Mushroom farming, like insect agriculture, is versatile; it can yield nutritious food while increasing system circularity by utilizing lignocellulosic residues from row crops as inputs. Pleurotus ostreatus, is an edible basidiomycete capable of being cultivated on corn stover (Zea mays). Mushroom harvest results in abundant "spent" substrate, which we investigated as a candidate feed ingredient. We created six cricket feeds containing fermented Pleurotus substrate plus an unfermented control, measuring cricket mass, mortality, and maturation weekly to evaluate cricket growth performance impacts of both fungal fermentation duration and mushroom formation. Pasteurized corn stover was inoculated with P. ostreatus mycelium and fermented for 0, 2, 3, 4, or 8 weeks. Some 4 and 8-week substrates were induced to produce mushrooms through manipulations of temperature, humidity, and light conditions. Dried fermented stover (40%) was added to a 1:1 corn/soy grain mix and fed to crickets ad libitum for 44 days. The unfermented control group showed higher survivorship compared to several fermented diets. Control group mass yield was higher for 2 out of 6 fermented diets. Little variation in cricket iron content was observed via ICP-spectrometry across feeds, averaging 2.46 mg/100 g. To determine bioavailability, we conducted in vitro Caco-2 human colon epithelial cell absorption assays, showing that iron in crickets fed fruiting-induced substrates was more bioavailable than in unfruited groups. Despite more bioavailable iron in crickets reared on post-fruiting substrates, we conclude that Pleurotus-fermented stover is an unsuitable feed ingredient for G. bimaculatus due to high mortality, variability in growth responses within treatments, and low mass yield.

ANTIMICROBIAL ACTIVITY OF ETHANOLIC EXTRACTS FROM WHEAT, SUNFLOWER AND MAIZE CROP RESIDUES

Large quantities of agricultural residues are generated every year. Most of the crop-based residues are underutilized, mainly left to decay on the land or to be burnt, which can lead to an increase in a load of environmental pollution. Considering this, different strategies have been developed to use these renewable resources as raw materials for the production of bioactive compounds, their isolation and characterization, and potential application in a wide range of fields, particularly in the food industry as natural preservatives. In this study, the antibacterial efficacy of wheat, sunflower, and maize crop residue ethanolic extracts against six bacterial strains (Salmonella Typhimurium, Salmonella Enteritidis, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes and Yersinia enterocolitica) was evaluated by the broth microdilution method. Used extracts inhibited the growth of selected microorganisms with a minimal inhibitory concentration (MIC) of 320 μg/mL for most of the tested bacteria. L. monocytogenes showed a MIC value of 640 μg/mL for wheat ethanolic extract, and the MIC value of sunflower ethanolic extract for S. Typhimurium was 160 μg/mL. There were no minimum bactericidal concentration (MBC) values for any of the bacteria within the extract’s concentration ranges tested (≤ 2560 μg/mL). The results of the present study indicate that crop residue ethanolic extracts could exhibit bacteriostatic effect and therefore have the potential as natural additives in food preservation.

Organic Amendments Addition on Altering the Sorption, Vertical Movement and Leaching Behavior of Herbicides in Soil

Herbicides are applied indiscriminately to achieve maximum weed control in agricultural production which might contaminate the food chain through the bio-augmentation of residue concentration in soil. One of the management suggested to overcome the herbicides contamination is treating with various organic amendments. Hence the laboratory column leaching and sorption experiments were conducted in Tamil Nadu Agricultural University (TNAU), Coimbatore to investigate the leaching behavior of herbicides viz., pendimethalin, atrazine and imazethapyr in soil as influenced by various organic amendments applied @ 5t/ha viz., FYM, vermicompost, composted coir pith, maize crop residue and biochar. Leaching experiment was conducted using PVC columns of 45 cm length and the sorption study was conducted using different concentrations of chosen herbicides as per OECD guidelines. Results showed that leaching and movement behavior of the studied herbicides in soil was modified by the applied organic amendments particularly the biochar and maize crop residue. Biochar treated soil retained 29.76, 40.20, and 38.07 percent of the applied pendimethalin, atrazine and imazethapyr respectively in surface 0-15 cm depth and reduced its movement to lower depths and to leachates. Herbicides adsorption was higher with biochar and is indicated by the Koc values of 225, 184 and 22 mg/L for pendimethalin, atrazine and imazethapyr respectively and was followed by the maize crop residue. It is concluded that the application of biochar @ 5t/ha as organic amendment is efficient in decreasing the herbicides movement viz., pendimethalin, atrazine and imazethapyr and modifying their sorption and leaching potential to groundwater.

Influence of residual maize crop residue management techniques and fertilizer levels on growth and productivity of zero till maize in rice-maize sequence

A field trial was conducted on a sandy clay loam soil during rabi seasons of 2020-21 and 2021-22 at the Agricultural College Farm, Bapatla to investigate the residual effect of maize crop residue management techniques and fertilizer levels on growth and productivity of zerotill maize in rice-maize sequence. The experiment was laid out in split-split plot design with four maize crop residue management practices (M1 : Exportation of maize stover, M2 : In-situ burning of maize stover (farmers practice), M3 : Mulching maize stover with rotary mulcher and M4 : Incorporation of maize stover with rotovator) as main plot treatments and three fertility levels (100% RDF, 75% RDF and 50% RDF) as sub plot treatments applied to kharif preceded rice and three fertility levels (100% RDF, 75% RDF and 50% RDF) as sub-sub plot levels applied to succeeding maize. Results revealed that incorporation of maize stover with rotovator (M4 ) applied to preceding rice significantly improved plant height (cm), days to 50% tasseling and 50% silking, cob length (cm), cob girth (cm), test weight (g) and grain yield of maize. Mean values for fertiliser levels revealed that plant height (cm), days to 50% tasseling and 50% silking, cob length (cm), cob girth (cm), test weight (g) and grain yield were registered with application of 100% RDF (S1 ) applied to preceding rice and application of 100% RDF applied to succeeding maize. Thus, incorporation of maize stover with rotovator (M4 ) along with application of 100 % RDF applied to preceding rice and application of 100% RDF (S1 ) to succeeding maize is an optimum and sustainable approach to enhance the growth and productivity of zero till maize in rice-maize system.

Effect of various Maize Crop Residue Management Practices and Fertility Levels on Physiological Growth Parameters of Direct Seeded Rice in Rice-maize Sequence

Effect of various Maize Crop Residue Management Practices and Fertility Levels on Physiological Growth Parameters of Direct Seeded Rice in Rice-maize Sequence

Effect of nitrogen doses and grass crop residue on common bean in no-tillage / Effect of nitrogen doses and grass crop residue on common bean in no-tillage

Nitrogen (N) is the most absorbed nutrient by the common bean, and the availability of this element changes according to the crop residues present on the soil surface. The aim of this study was to assess the effect of top-dressed doses of N and crop residue (maize alone, maize intercropped with brachiaria and brachiaria alone) on the performance of irrigated common bean. The experiment was conducted in a split-plot arrangement, where the plots consisted of residues of maize crop alone, maize intercropped with brachiaria, and brachiaria alone and the subplots consisted of doses of top-dressed N applied to common bean (0, 40, 80, 120, and 160 kg ha-1). Brachiaria alone and maize intercropped with brachiaria provided full coverage of the soil surface. The C/N ratio in the maize crop residue was higher than that in the brachiaria crop residue. This result characterizes maize as a material with slower and more gradual decomposition compared to brachiaria, which had a higher N content because it was desiccated at the time of its full vegetative vigor. Crop residue affected grain yield, particularly the cultivation on brachiaria alone. The maximum grain yield was achieved at an estimated dose of 136 kg ha-1 of N. These results demonstrate the effect of crop succession and nitrogen fertilization on the common bean agronomic performance in the no-tillage system, helping farmers and technicians in decision making.

Sunlight and soil biota accelerate decomposition of crop residues in the Argentine Pampas

The benefits of maintaining soil organic matter in agroecosystems have long been recognized, although there are many open questions with respect to the controls on crop residue decomposition and the consequences for carbon and nutrient cycling. The large extension of intensively cropped agriculture in the Argentine Pampas of soybean, sunflower, wheat, and maize motivates the need for a broader understanding of these controls. In modern no-till agriculture, post-harvest crop residues may remain upright as standing or on the soil surface for extended periods of time; nevertheless, the effects of sunlight exposure and its interaction with soil biota on decomposition of crop residues have not been evaluated. We established a manipulative experiment using soybean, sunflower, wheat and maize crop residues with treatments of full or attenuated sunlight exposure and presence or absence of soil biota. Species identity was significant in determining rates of leaf residue decomposition with mass loss of soybean ≥ sunflower > wheat ≥ maize. Sunlight exposure significantly accelerated decomposition of leaf residues in the absence of soil biota, while soil biota significantly contributed to increased leaf residue decomposition with and without sunlight exposure. In contrast, stem residue decomposition was modest under all conditions and differences in decomposition were determined by species identity. Surface area for leaf and stem residues across species was the strongest litter quality predictor for the variation in crop residue decomposition. Our results suggest that sunlight exposure, duration of fallow period with or without rotation or cover crops, and the proportion of leaves vs. stems in crop residues interacting with soil biota may be fundamental elements in determining carbon turnover in these intensively cropped agroecosystems. There would be great value in incorporating the impacts of sunlight exposure and unexplored aspects of crop residue quality in models for sustainable agriculture in the region and globally.

Yield and nutrient concentrations of organic cherry tomatoes and legumes grown in intercropping systems in rotation with maize

ABSTRACT This study evaluated the productivity and nutrient concentrations of organic cherry tomatoes and leguminous green manures grown in intercropping systems in rotation with maize. The experimental design was a complete randomised block design with five replications and eight treatments, as follows: monocrop of cherry tomato adding residual maize crop residue (straw) as a mulch (control), monocrop of cherry tomato without the addition of maize crop residue (control), cherry tomatoes intercropped with jack bean, sun hemp, dwarf velvet bean, mung bean, white lupin or cowpea bean grown as green manures. In this production system, which was evaluated between 2011 and 2013, maize was cultivated from January to April, and the cherry tomatoes, with or without leguminous green manures, were grown from May/July to November/December. The number and weight of total and marketable fruits of tomatoes were 70% – 88% higher in 2011 than in 2012 and the number of damaged fruits was 12% lower in 2011 than in 2012. In 2011, the weights of total and marketable fruits in the intercropping treatment with white lupin were lower than that in the controls and in the intercropping treatments with dwarf velvet and cowpea bean. The white lupin and sun hemp green manures produced the highest biomass dry weight, followed by the jack bean, cowpea bean, mung bean and dwarf velvet bean. The different treatments had no effect on the yield of the maize.

Incorporation of maize crop residue maintains soybean yield through the stimulation of nitrogen fixation rather than residue-derived nitrogen in Mollisols

Crop residue amendment to soil is recommended as an effective management practice to return nutrients, especially in the maize-soybean rotation system where large amounts of maize residues are produced. Quantifying the utilisation of maize-residue N by the subsequent soybean crop is essential for optimising the N fertilisation strategy for sustainable production. However, whether and how maize residue amendment alters N acquisition in soybean plants are largely unknown. It was hypothesised that maize residue would supply N and enhance N2 fixation to meet the N requirements of subsequent soybeans. Three treatments, namely: 1) chemical fertiliser (55.2, 35.2 and 22.4 kg ha−1 of N, P and K, respectively), 2) maize residue (8 t ha−1), and 3) non-fertiliser were applied in a maize-soybean rotation system in a Mollisol soil. It was demonstrated that soybean seed yield in the maize-residue treatment was the same as that in the chemical fertiliser treatment, with 2.9 vs. 3.2 t ha−1 in 2014, 2.7 vs. 2.6 t ha−1 in 2016, and 3.0 vs. 3.1 t ha−1 in 2018. A follow-up pot experiment using 15N-labelled residue indicated that the residue-derived N accounted for 0.5 % of the total N in soybean seeds and the proportion of symbiotically fixed N reached 82 %. The amount of fixed N during the pod-filling period in the residue treatment was 0.66 g plant-1, which was 49 % and 41 % higher than those in the chemical fertiliser and non-fertiliser treatments, respectively. The stimulation of N2 fixation was associated with an increase in fixed N per nodule and the enrichment of diazotrophs in the rhizosphere of soybean. With maize residue amendment, the increased N2-fixing capability of nodules during the reproductive period, rather than residue-derived N, fulfilled the N demand for maintaining seed yield of soybean. In the maize-soybean rotation system, maize residue amendment would facilitate the N2 fixation to partly substitute for N fertiliser for soybean production in Mollisols.

The agronomic and economic viability of innovative cropping systems to reduce Fusarium head blight and related mycotoxins in wheat

CONTEXTThe effective control of Fusarium head blight (FHB) in wheat, mainly caused by the toxigenic fungus Fusarium graminearum, has a significant impact on food safety worldwide. As maize is one of the main hosts of F. graminearum, the risk of infection by this plant pathogen is highest when wheat is grown after maize and infected crop residues are not buried through ploughing. OBJECTIVESThis study aimed to investigate the agronomic and economic viability of two innovative cropping systems with the goal to reduce the risk of FHB and mycotoxins in subsequent wheat. These systems were maize-intercropping and cover cropping with different plant species before the wheat growing season under reduced tillage practices. METHODSFor the maize-intercropping study, red clover, sudangrass, phacelia, white mustard and Indian mustard were used as intercrops with grain maize and compared with a sole maize crop in a grain maize-winter wheat rotation under no-tillage or reduced tillage. For the cover cropping study, white mustard, Indian mustard and winter pea were used as interval cover crops in a silage maize-spring wheat rotation under no-tillage and compared with treatments without a cover crop, i.e. herbicide or plough applied after silage maize. The incidence of Fusarium head blight causing species and the accumulation of mycotoxins in grains of wheat as well as the crop yield were monitored. In addition, an economic assessment was conducted by calculating the receipts, operating costs and gross margin for each cropping system. RESULTS AND CONCLUSIONSGrowing intercrops with maize or interval cover crops in a maize-wheat rotation under reduced tillage decreased mycotoxins in wheat while maintaining wheat yield. The use of white mustard or Indian mustard as intercrops reduced deoxynivalenol in winter wheat by up to 52% compared with maize grown as a sole crop. The use of white mustard, Indian mustard or winter pea as interval cover crops also reduced deoxynivalenol and improved yield in spring wheat by up to 85% and 25%, respectively. Remarkably, the toxin reduction through these cover crops was comparable with that obtained by ploughing. However, due to increased operating costs, we observed economic trade-offs in these innovative cropping systems, i.e. 7–25% reduced gross margin over the entire rotation. SIGNIFICANCEBoth cereal growers and consumers can benefit from the recommended practices, which considerably lower the risk of mycotoxin contamination in harvest products while maintaining crop yield. To address the economic trade-offs, policy makers should support innovation in cropping systems, enhancing food safety while also ensuring the economic viability of cereal production systems.

ENERGY AND ECOLOGICAL ANALYSIS OF THE LIFE CYCLE OF ENERGY USE OF MAIZE CROP RESIDUES

Maize crop residues have significant energy potential in Ukraine. The purpose of this work is to analyze the energy and environmental efficiency of thermal energy production from corn residues, taking into account the sustainability criteria. The task of the work is to quantitatively calculate energy and environmental efficiency indicators and compare them with values that meet the criteria of sustainable development. Using the life cycle assessment methodology, the cases of using bales, pellets and briquettes from plant biomass as fuel in a boiler with a capacity of 500 kW were considered. The calculation of the energy conversion factor and reduction of greenhouse gas emissions has been performed. It is shown that at distances of transportation of finished biofuel not exceeding 150 km, energy indicators (energy yield coefficient, specific cumulative energy demand) are within the recommended values corresponding to sustainable development. The distribution of primary energy consumption of fossil fuels by stages of the life cycle of thermal energy production from maize crop residues is shown. Reductions of greenhouse gas emissions from the introduction of heat production technologies from maize crop residues meet the new requirements of the European Parliament and of the Council Directive on the promotion of the use of energy from renewable sources on the use of renewable energy sources. It is shown that in general the production of pellets and briquettes from corn residues is energetically inexpedient when transporting biomass at a distance that meets the criteria of sustainable development.

Microbial activity effect on aggregate stability after residue addition in a Mollisol and a Vertisol in the Pampas, Argentina

Crop residue addition to the soil promotes an increase in microbial activity and, as a consequence, may improve soil aggregate stability. However, this effect may be different in soils with contrasting aggregation agents. The aim of this study was to evaluate, in an incubation experiment, the role of microbial activity on soil aggregate stability after crop residue addition in two soils with contrasting clay mineralogy. Soybean and maize crop residues were added with three different frequencies on a Mollisol and a Vertisol, which were incubated during a 120-days period. It was studied the dynamics of soil aggregate stability after application of a fast wetting (MWDfw), slow wetting (MWDsw) and stirring after prewetting treatment (MWDst) which evaluates three different breakdown mechanism, i.e., slacking, microcracking and mechanical breakdown, respectively. Microbial activity dynamic was evaluated through measurements of soil respiration rate, microbial biomass-C (MBC) and hot-water extractable carbohydrate-C (HWEC). The Vertisol showed higher resistance to slaking (59% higher) but lower resistance to mechanical breakdown (92% lower) and microcracking (102% lower) than the Mollisol, with a scarce effect of residue quality and addition frequency. The discrete changes recorded in MWDfw throughout the experiment, were positively associated with changes in cumulative respiration (P < 0.001), MBC (P < 0.05) y HWEC (P < 0.05) in the Mollisol, and only with changes in MBC in the Vertisol (P < 0.05). Also, the small changes in MWDst were weakly and positively associated (P < 0.05) with changes in cumulative respiration in the Mollisol but not in the Vertisol. However, changes in MWDsw were closely associated with changes in cumulative soil respiration rate (P < 0.0001) and MBC (P < 0.001) in both soils, and with HWEC only in the Mollisol (P < 0.0001), with a higher effect on these variables than the other aggregate stability test. However, while in the Vertisol the increase in MWDsw as a function of cumulative soil respiration was lineal, in the Mollisol it was detected an evident increase in MWDsw up to a threshold of 500 μg C-CO2 g soil−1 of cumulative soil respiration. Similarly, changes in MWDsw associated with changes in MBC were higher in the Mollisol than in the Vertisol (i.e. 0.018 v. 0.004 mm of MWDsw per unit of MBC). Thus, this research added new evidence about the contrasting role of transitory aggregation agents that are provided by microbial activity on aggregate stability in two contrasting soils such as a Mollisol and a Vertisol.

Contribution of above- versus belowground C inputs of maize to soil organic carbon: Conclusions from a 13C/12C-resolved resampling campaign of Belgian croplands after two decades

The few available studies on maize biomass in soil of field experiments have shown that belowground maize biomass resides more than twice as long as aboveground residues. Our principal objective was to investigate the effect of maize crop residue incorporation on the long-term dynamics of soil organic carbon (SOC) for a selection of croplands with sandy to sandy loam texture in Flanders, Belgium. After a period of more than 20 years, we resampled 31 and 29 parcels that had either silage maize (MS, only belowground biomass input) or grain maize (MG, both above- and belowground biomass input) dominated crop rotations. Changes in maize-derived SOC (Cmaize) of MS and MG systems between 1993 and 2018 were evaluated by detecting SOC content and its δ13C value. In addition, a 140-day incubation experiment (at 20.5 °C) was carried out to compare the stability of Cmaize and the related nitrogen (N) mineralization between the MG and MS fields. After two decades, δ13C raised 2.4 and 2.6‰, while Cmaize increased 1.6 and 2.2 g kg−1 in MS and MG systems, respectively. The estimated average humification coefficient over this period of maize-C was 0.11 for the MS system, about twice as that of the MG system (0.06). This reconfirms findings of stronger contribution of belowground biomass versus aboveground residues to stabilized SOC pools over the medium to long term. By the end of the incubation, on average 10.4% and 11.6% of Cmaize had been decomposed in the MS and MG soils, respectively. These Cmaize mineralization rates were statistically equal for the two systems, which indicates that mainly belowground biomass remained in the soils. Also, net N mineralization was indifferent to the crop rotations (MS: 58.8 mg N kg−1 and MG: 52.6 mg N kg−1). To reconcile the two main observations in this study, we hypothesize that the lower preservation of shoot-C could be manifested on a shorter term. Detailed research is needed to determine the time scale of increased stabilization of root-C versus shoot-C under field conditions.