Weed species composition and diversity in maize as affected by tillage and fertilization in the Northern steppe of Ukraine

Topicality. In the current conditions in Ukraine, the issues of weed control in crops do not lose their relevance due to the negative processes caused by the aggravation of the economic situation, the rapid soaring prices on mineral fertilizers, machinery, fuels and lubricants, plant protection products, the replacement of energy-intensive traditional tillage systems with moldboardless and other resource-saving ones. Purpose. To study the influence of tillage and fertilizers on the weed infestation of agricultural crops in the link of the field grain-fallow-row crop rotation: winter wheat after maize (milk-wax ripeness) – grain peas – winter wheat in the Northern Steppe of Ukraine. Materials and Methods. Methods of tillage with applying mineral fertilizers under the primary tillage were tested. The field and statistical-mathematical methods were used in experimental studies. The number of weeds in crops was determined by the quantitative-weight method using square frames. Results. It was established that moldboardless tillage in the crop rotation link against the background of plowing under maize and harrowing with light harrows during the growing season leads in comparison with moldboard tillage to the following increase in weed infestation – on average for years of research: annual weeds during the growing season: in peas crops – by 40.6 (without fertilizers), 44.2 (with recommended dose) and 51.6 (with calculated dose) pcs/m2; before harvesting: by 22.7, 24.4 and 36.4 pcs/m2, respectively; in winter wheat crops after peas – by 0.5, 11.9 and 19.4 pcs/m2; 5.8, 8.4 and 6.7 pcs./m2, respectively; perennials in winter wheat crops after peas during the growing season: by 10.4, 9.1 and 10.9 pcs/m2; before harvesting: by 19.1, 18.3 and 20.0 pcs/m2, respectively. The application of mineral fertilizers increases germination of annual weed seeds. This was most clearly observed in winter wheat crops after maize of milk-wax ripeness. A tendency towards an increase in the air-dry weight of weeds under fertilization was revealed for all crops in the crop rotation link. Conclusions. Moldboardless tillage increases the number of weeds, but does not increase their air-dry weight, and decreases grain yield and quality. Mineral fertilizers applied in the experiment increase the air-dry weight of weeds and the number of their annual species. The species composition of weeds in the crops did not depend on the method of tillage. Key words: weeds, tillage, mineral fertilizers, winter wheat, peas

Short-term carbon, nitrogen and pH alterations in a hill-land Ultisol under maize silage relative to tillage method

Topicality. The productivity potential of maize determines the prospects of this crop in the grain balance of Ukraine. In the context of the crisis caused by the war and global climate change, which has a significant effect on crop production in the Steppe zone, the productivity of grain crops, including maize, is becoming increasingly unstable over the years, leading to a decline in the gross harvest of the crop. Given the changing weather conditions, in particular climate warming, substantiation, development and implementation of agrotechnical practices to mitigate the negative effects of drought, heat and soil moisture deficit is relevant. In the complex of zonal agrotechnical practices, the sowing dates of crops play an important role. Seed germination, timely emergence of seedlings, and optimal plant density depend on the sowing date. Early sowing in insufficiently warmed soil prolongs the sowing – germination period, or late sowing in excessively dry soil results in sparseness of seedlings and low grain productivity. Therefore, there is a requirement to create the most favourable conditions for the growth of maize plants, considering the biological characteristics and environmental requirements of hybrids, soil, climate and weather conditions. Purpose. Identification of the peculiarities of growth and development of maize plants and formation of maize grain yield depending on the sowing date of biotypes belonging to different maturity groups in the Northern Steppe of Ukraine. Materials and Methods. New maize hybrids of different ripeness groups DN Pulsatsiia, DN Atlant, DN Drah, DN Nazar were sown on the experimental plot of the Laboratory of Agricultural Resources of Maize and Sorghum at the SE Institute of Grain Crops of NAAS in three dates. The following research methods were used: laboratory and field methods for determining plant height, number of leaves per plant, individual plant productivity, grain moisture content; statistical method for performing correlation, analysis of variance and statistical evaluation of research results. Results. It was found that the highest grain yields were formed by the early ripening hybrid DN Pulsatsiia (10.27 t/ha), the mid-early hybrid DN Atlant (10.96 t/ha), the mid-ripening hybrid DN Drah (11.61 t/ha) and the mid-late hybrid DN Nazar (11.49 t/ha) at the early sowing date. Conclusions. In the growing season of 2021–2023, the highest grain yield was formed by maize hybrids of all maturity groups at early sowing date. Sowing corn both at the optimal and late time resulted in a decrease in grain yield in corn hybrids by an average of 4.5 and 13.1%, respectively, compared to the early time. Based on the experimental data, it was found that new maize hybrids DN Pulsatsiia, DN Atlant, DN Drah, DN Nazar form the highest grain yield in the Northern Steppe of Ukraine when they are sown on 14–25 April. Key words: maize, hybrid, sowing date, yield attributes, individual productivity of plants, grain yield

Effect of hand-hoe based conservation agriculture on soil fertility and maize yield in selected smallholder areas in Zimbabwe

The use of green manure legumes (GLM) as cover crops in rotation with maize has the potential to enhance maize yields. The objectives of this study were to determine the effect of GML - maize rotation system on (i) maize growth and yield and, (ii) weed infestation levels. The two year (2007/8 and 2008/9 seasons) rotation system consisted of five GML cover crops, viz. mucuna, lablab, sunhemp, cowpea and butterfly pea followed by maize. GML biomass ranged between 0.8 and 13.6 Mg ha-1, while nitrogen (N) content ranged between 10 and 279 kg N ha-1. Maize grain yield following GML ranged between 2.6 and 10.59 Mg ha-1. In 2007/8 season cowpea, mucuna, lablab and sunhemp plots had a lower weed dry matter (5.30, 11.97, 5.83 and 21.03 g m-2, respectively) than the control (+N) (49.47 g m-2). In 2008/9 season, at 6 - 8 WAP, control (+N) had a higher weed dry matter than the other treatments, except of butterfly pea. The dominant weed species were Mexican ricardia (Ricardia brasiliensis), Yellow nutsedge (Cyperus esculentus), Guinea-fowl grass (Rottbollia cochinchinesis), Witch weed (Striga asiatica), Bermuda grass and Cynodon species. Green manure legume fallows can increase maize grain yield significantly and suppress the weed population as compared to natural fallow. However, maximizing biomass production and N accumulation is critical in order to reap the benefits of green manure. Hence, integrating GML into the existing cropping system will require that appropriate timing for planting GML be well established. Key words: Green manure legume, maize, rotation, weed infestation.

Several tillage methods were compared in different regions of Iran such as: Isfahan(central), Shiraz (south west), Mashhad(North east) and Hamedan(west). In Isfahan (central), seven different tillage methods were compared during four years. In Hamedan, four different tillage methods were studied for fall wheat within 3 years. In Mashhad, four different tillage depths and four different moisture contents were compared over 3 years. In Shiraz, seven different tillage methods on wheat yield were compared in 4 years. A national study on possibility to use surface tillage in irrigated wheat land compared to conventional method using moldboard plow was conducted in six different regions (Shiraz, Mashhad, Eastern Azarbayjan, Karaj, Golestan, and Khuzistan) for five years. Varied tillage methods have shown different yield but statistically was not significant. No till (direct drilling) and minimum tillage indicated significantly lower yield therefore could not be recommended as a favorite system for wheat production. Chisel plowing (reduced tillage system) has shown promising performance and can be recommended due to higher field efficiency. Chisel plow (in spring) + disk + leveler in fall noted to be a substitute for moldboard plows because of higher coefficient of harvest and field efficiency. In terms of deep tillage, subsoiling to the depth of 35 cm plus moldboard plow had the highest yield and the effective treatment for reducing CI by 12.8 % and increasing yield by 3.8 %. The moldboard plowing (conventional method) had the lowest yield. Due to high cost, energy consumption and statistically no significant difference between treatments, subsoiling for wheat production would not be recommended. Maximum grain yield was obtained at 10 to 15 % moisture content and tillage depth of 10-15 cm (Mashhad). Optimum moisture content for tillage in Zarghan and Darab areas was 15 - 18 % and 13 -15 % respectively. However water irrigation methods must be study in detail in order to reduce water consumption. Shallow tillage noted as a good substitute for moldboard plowing because of lower energy consumptions and time saving. The suitable moisture content for surface tillage (disking) is about 10-15 %. The effect of year was significant on different regions due to rainfall variation, temperature differences, and soil nutrition changes over the years. It was proved that for shallow tillage, crop residue is the main problem which planter must be modified with a sharp furrow opener. It is also recommended after each three years of surface tillage a moldboard plow or deep tillage operations can be used for weed control.

The article presents the results of research on the impact of different chemical protection systems on the phytosanitary condition of maize agrocenoses under the conditions of the Right-Bank Forest-Steppe of Ukraine. During 2023–2025, the effectiveness of herbicidal, insecticidal, and fungicidal crop protection systems was assessed based on weed infestation levels, population density of key pests, and the incidence and development of diseases. It was established that the combined application of soil and post-emergence herbicides (Akris + Stellar Plus) ensured a significant reduction in weed infestation (down to 3.5–8.2 plants/ m2), with a technical efficiency reaching 95.3%. The analysis of weed species composition in maize crops revealed that annual weeds accounted for 85.6% of the total infestation. Among them, spring annual species were predominant, comprising 74.6% of the weed community. Perennial weeds such as field sow-thistle (Sonchus arvensis L.), field bindweed (Convolvulus arvensis L.), and couch grass (Elytrigia repens L.) represented 1.4% of the overall weed population. The dominant weed species in maize fields were Amaranthus retroflexus (35.6%), Chenopodium album (22.3%), Setaria glauca (17.0%), and Elytrigia repens (8.2%) Among the harmful species, the greatest threat to maize crops was posed by wireworm larvae (Elateridae) and the European corn borer (Ostrinia nubilalis Hbn.), which exhibited high levels of harmfulness. The intensity of maize damage by these pests was strongly influenced by hydrothermal conditions. In years with excessive soil moisture (May 2025 — 64.6 mm of precipitation), seedling damage by wireworms exceeded 10–15%, whereas in drier periods (May 2023–2024), the damage level decreased but remained within the economic threshold. The highest harmfulness of the corn borer was recorded in 2024–2025, when crop infestation levels ranged between 22.0–40.0%, which was associated with excessive rainfall in June. Con- versely, a sharp rise in temperature in July 2024 led to a decrease in pest population density and damage intensity. The application of the insecticide Ampligo (0.2 L/ha) at the BBCH 18–19 stage proved to be an effective measure for controlling both soil-dwelling and stem-boring pests, reducing their harmfulness by 25–35%. The use of the fungicide Abacus (1.5 L/ha) significantly reduced the development and spread of helminthosporium and fusarium diseases of maize, providing reliable protection during critical stages of organogenesis. The fungicide contributed to a marked decrease in leaf and ear infection rates, which posi- tively affected the preservation of the photosynthetic potential of plants. The obtained results confirm the expediency of using Abacus within the maize protection system against a complex of fungal pathogens. Thus, the integrated application of herbicides, insecticides, and fungicides in maize protection systems con- sidering the biological characteristics of phytophages, weed species composition, and prevailing weather conditions ensures stable control of major harmful organisms and promotes the maintenance of agroeco- logical balance within the agrocenosis.

Axle load and tillage effects on crop yields on a Mollic Ochraqualf in Northwest Ohio

Four nitrogen fertilizer regimes were superimposed on a tillage trial on a sandy Avalon soil at Dundee in 1985 in order to investigate whether the rate and time of N fertilizer application influenced the poor early-season growth and reduced yields found to occur in the treatments receiving least tillage. The tillage treatments were conventional tillage, chisel plough followed by off-set disc, chisel plough alone and no-till, each split for rate (50 or 200 kg N ha-1) and time (all N at planting, or split applications at planting and 6 weeks later) of N application. Both tillage method and rate of N application significantly influenced maize grain yield, plant stand and leaf N content, but time of N application appeared to have no significant effect on any of the parameters measured. Regression analysis of leaf N content at ear initiation, silking and early dent stage with grain yield indicated that the latter was most strongly correlated with N nutrition at silking.

Effects of tillage on the appropriate fertilizer N applications needed to achieve maximal grain yield are poorly denned. The study objective was determination of relative corn grain yield response to N application rate for four tillage practices: no‐tillage (NT), ridge tillage (RT), fall chisel plowing (CP) and fall moldboard plowing (MP). Maize (Zea mays L.) grain yield and N accumulation were monitored over a 6 year period with the same tillage treatment and the same fertilizer N rate applied each year to each plot. Two hybrids, differing in relative maturity rating, were planted each year. Fertilizer N rates ranged from 10 to 190 kg ha−1 and consisted of 10 kg ha−1 of liquid starter N applied at planting with varying amounts of fall applied anhydrous ammonia. With only starter fertilizer, grain yields increased with tillage intensity in the order NT ≤ RT ≤ CP ≤ MP. With ≥ 55 kg total applied Nha−1, 6 year average grain yields were unaffected by tillage. Total N removed in grain annually with only starter fertilizer ranged from 25–85 kg ha−1 Maximal amounts of N removed, about 145 kg N ha−1, occurred with 100–145 kg applied N ha−1 for all tillage treatments under the more favorable climatic conditions. Several interactions affecting grain yield appear climatically sensitive with exception of tillage by fertilizer N interactions. Because of variability in climate, planting dates varied by almost 4 weeks. Relative yield loss due to planting delay were Fertilizer N (mean change ≅−124 –−275 kg ha−1 day−1) > Starter N only and MP (mean ≅− 259 kg ha−1 day−1) > other tillages in general. Yield loss due to delayed planting ranged from 0.0–275 kg ha−1 day−1. Grain yield gains due to early spring soil temperatures were 16.0–21.8 kg ha−1 index‐degree−1 with MP tillage and averaged 2.7– 16.7 kg ha−1 index‐degree−1 more than those of other tillage‐hybrid combinations.

Tillage method scan have a drastic impact on soil quality, and the effects may be cumulative overtime. Therefore, soil analyses were done in 1987 to quantify effects of three tillage methods on soil quality following 25 years of continuous coin (Zea mays) cultivation on two well drained soils at South Charleston and Wooster in central Ohio. Crosby soil at South Charleston is classified fine, mixed, mesic Aeric Ochraqualf, and Wooster silt loam at Wooster is a fine loamy, mixed, mesic. Typic Fragiudalf. The three tillage methods were plow till (PT) involving moldboard plowing in the fall, minimum till (MT) involving chisel plowing in the fall, and no till (NT) involving direct sowing in the residue of the previous crop. Soil samples were taken for 0–60 cm depth using a truck-mounted core sampler, with separate for row zone (RZ) and traffic zone (TZ) cores taken for assessment of soil physical properties. Soil chemical analyses were done on samples composited by mixing equal proportions of soil from RZ and TZ. Soil physical properties were measured for the surface 0–10 cm and 10–20 cm depths, while chemical properties were measured for 0–60 cm depth in 10 cm depth increments. There were significant differences in bulk density (ρb) between RZ and TZ. The ρb of 0–10cm depth in TZ was more than RZ by 0.7% for NT, 6.6% for MT, and 8.0% for PT. There were no significant differences in pρof 0–10cm layer due to tillage. Differences in moisture retention among tillage methods woe not statistically significant. Both initial and equilibrium infiltration rate (ic) in the RZ were in the order of NT > PT > MT. The ic did not differ among treatments. For the South Charleston site, soil pH was not significantly affected by the tillage treatments. Soil pH of the 10–50 cm layer of the Wooster site was, however, lower in NT than PT treatment. The 10–50 cm layer of the Wooster site also had lower concentrations of Ca2+, Mg2+ and K+ in NT than PT. Trends in SOC content and Bray-P were in the order of NT □ MT □ PT for the top 0–20 cm layer, and PT □ MT □ NT for 30–50 cm layer. Exchangeable Mg+ content was significantly affected by tillage, and mean contents of Mg+ were in the order of PT = MT > NT. The data support the conclusion that 25 years of no-till with continuous corn had no deleterious effect on either soil physical or chemical quality.

The integration of various sustainable management techniques in cropping systems can potentially reduce agro-environmental problems, but may warrant a new approach to weed management, due to changes in weed communities. A 3-yr experiment was conducted to determine the effects and interactions of tillage (moldboard plow or chisel plow), weed control method (chemical or mechanical), and nutrient source (mineral fertilizers or liquid hog manure supplemented with mineral fertilizers) on crops and weeds in a corn (Zea mays L.)–soybean (Glycine max (L.) Merr.) rotation on two soils (a Sainte-Rosalie clay and a Duravin clay loam, Orthic Gleysols), at Saint-Hyacinthe, Québec. In most cases, weed density and biomass were more important with mechanical than with chemical control. Nutrient source did not affect weed density, but weed biomass was higher in the manure than the mineral treatment in 1997. Weed populations on both soils were greater with chisel plow tillage combined with mechanical weed control. The presence of crop residues in chisel plow systems may have hindered the efficacy of mechanical weed control operations, particularly when corn was the previous crop. Soybean populations, mid-season biomass and yields were reduced in chisel plow compared with moldboard plow tillage. Corn populations and mid-season biomass were not affected by any of the factors, whereas corn yields showed variable responses over the years. Efficacy of mechanical weed control would need to be enhanced or complemented with other weed control methods, in order to reduce the risks of weed infestations and lower crop yields, particularly in conservation tillage systems. Liquid hog manure would have little effect on weed populations, but would need to be adequately balanced in order to ensure proper crop nutrition and optimum yields. Key words: Chisel plow tillage, mechanical weed control, liquid hog manure, conservation tillage

This study provides a comprehensive analysis of global scientific data concerning the impact of segetal phytobiota as one of the key factors of ecological risks in agrobiocenoses, particularly under climate change conditions, which act as a powerful abiotic stress fac­tor. In this study, weeds are considered as indicators of disturbances in the functioning of agroecosystems and soil degradation. It has been established that the level of weed infestation can serve as a marker of the adaptive potential of agrophytocenoses to abiotic stresses. Modern scientific studies on the influence of key environmental factors under climate change conditions such as temperature stresses, droughts, excessive moisture, decreased soil fertility, humifica­tion loss, and soil microbiota imbalance on the struc­ ture and dynamics of agrophytocenoses are analyzed. Special attention is paid to changes in the species composition of weeds, particularly the spread of in­ vasive and adventive species, which confirm high ecological plasticity, competitiveness, and ability to form dominant groups even under intense anthropogenic influence. The authors developed a fivelevel scoring scale for assessing ecological risks in agrophytocenoses based on their weed infestation level — from minimal (1 point) to high (5 points). This approach allows for assessing the level of ecological risks in an agrocenosis and rationally planning measures to control its phytosanitary state. It is shown that the level of eco­logical risk in crop fields is determined by the degree of agrocenosis weed infestation. It is proven that the reduction of ecological risk during ontogenesis is achieved through the application of agrotechnolo­ gies that regulate the level of weed infestation in agrocenoses and influence their development. The data obtained by the authors confirm that a reduction in ecological risk in agrocenoses is possible through timely ecological monitoring and the implementa­ tion of a complex of preventive, agrotechnical, and protective measures that promote increased adaptive resistance of agrophytocenoses and regulate their phytosanitary state. It has been established that the high ecological plasticity and adaptive properties of segetal vegetation contribute to the formation of zones within agrophytocenoses where weeds displace cultivated species, promoting the spread of herbicideresistant populations. Such processes create ecological risks due to threats to biodiversity and a decrease in the ecological stability of agroecosystems

This work was excuted during seasons 2018/2019, and 2019/2020, in Tayba Block-the Sudan - Gezira central clay plains, to evaluate the field operation performance of four land preparation methods using three tillage equipment: chisel plow "intensive tillage", disc harrow "medium tillage", ridger "minimum or reduced tillage" and no tillage machine. An overall operation index is estimated from four measured machine operating characteristics. Diagnosis of land preparation methods was made using analytical hierarchy method for weight assignment for assignment of relative weights for the operating parameters, and compromise programming technique for ranking of tillage methods. The experiment was conducted as a factorial experiment with RCBD, the LSD test at 1%and 5 % was used to compare between means. Results indicate that no significant differences (P<0.05) in field efficiency between Chisel plow and ridger and harrow showed the least efficiency value. There is significant differences in fuel consumption rate between all treatments with highest consumption is by Chisel plow and lowest is by ridger. The significantly highest rear wheel slippage is attained by ridger while there is no significant differences in that resulted from chisel or disc harrow. The significantly highest field capacity (P<0.05) is attained by ridger followed by harrow and then chisel plow. The analytical hierarchy procedure ranked the machines operation indicators in descending order by weight values of 1.02, 0.62, 0.29 and 0.12 for. Multi-criteria analysis by compromise programming technique results in overall indices of tillage equipments: ridger, chisel plow, disc harrow in descending values of 67.53, 61.00, and 57.29 respectively. The overall performance index (OPI) for the operation of the agricultural equipment could be used to take the tillage decision-making process by selecting the most effective machinery to give optimum seed bed with minimum energy input. However, it is not possible to calculate the overall index for no tillage method because without using a machine there is no fuel consumption, no field efficiency, no field capacity, and no wheel slippage. This imply that for heavy clay soils of Gezira Scheme and in other similar environments it is recommended to use reduced tillage "ridging only" as the most technically feasible tillage method, other wise use chisel plowing if funds are available.

Influence of tillage methods and soil crust breakers on cotton seedling emergence in silty-loam soil