Manured Plots Research Articles

Short‐term effects of a heavy dairy manure application on soil chemical and biological indicators in an irrigated semiarid cropping system

AbstractIntensive dairy production in southern Idaho is associated with the annual application of manure to croplands. However, a one‐time heavy application of manure could alternatively be used as a means to improve soil fertility and health for years or even decades, circumventing the need for frequent applications. To determine if this practice would negatively affect soil properties in the short term, we analyzed chemical and biological indicators of soil health for 2 years after dairy manure incorporation. Soil indicators measured were pH, electrical conductivity, extractable nitrogen (N) and phosphorus, total carbon (C) and N, enzyme activities, net N mineralization, soil organic C, soil protein, active C, ammonia oxidation potential, and particulate organic matter. Manure (with and without synthetic fertilizer) was found to significantly affect chemical and biological indicators in both topsoil (0–15 cm) and subsoil (15–30 cm), but the responses were greater in the subsoil. This can be attributed to the fact that manure was incorporated to approximately 30 cm via moldboard plow. All indicators responded positively to manure, except pH, which decreased slightly in the subsoil in the first year after application. Principal component analysis of chemical and biological indicators, across all years and depths, showed that the first two components explained 62% and 8.5% of the variance. While soil indicators were not adversely affected by manure, silage corn (Zea mays L.) yields in year 1 were significantly lower in manured plots, though in year 2, barley grain (Hordeum vulgare L.) yields were statistically similar among manure and fertilizer.

Morphological and Phenological Attributes of Chickpea (Cicer arietinum L.) Affected by Different Growing Conditions, Zeolite and Nitrogen Applications

The present study investigated the effects of two different zeolite applications and different nitrogen-based fertilizers on chickpea’s yield and yield components in dry and irrigated conditions. The field experiment was conducted during 2019 and 2020 in the experimental area of the Faculty of Agriculture, Eskisehir Osmangazi University, Eskisehir, Türkiye. The experimental design was a split-split plot with four replicates. The main plots were grown under dry-irrigated conditions. At the same time, subplots received zeolite applications (zeolite+- zeolite-), and sub-sub plots received nitrogen applications [control, traditional, chemical, farmyard manure, and Isabion, (an animal collagen-derived biostimulant)]. The experiment found that irrigation caused a delay in phenological characters but had a favorable impact on morphological characters and yield. The effect of zeolite applications was different in the first and second years of the experiments for the investigated characters. In the first year, the application of zeolite had a significant impact on grain yield, but there was no discernible effect in the second year. The experiment demonstrated that both chemical fertilizer and farmyard manure positively impacted phenological and morphological characteristics. In both years, the farmyard manure plots produced the highest grain yield. Farmers in Türkiye are advised to apply nitrogen to their crops as the profitability of chickpeas has risen in recent years. If the high cost of farmyard manure renders its use impracticable, farmers can opt for chemical fertilizer as an alternative.

Positive sweet corn response with selected climate‐smart agricultural practices

AbstractTo sustain agriculture for future generations and reduce the adverse impacts on soil health and the environment, there is a need to adopt sustainable and climate‐smart agricultural practices. A field experiment was conducted to study the effects of organic amendments (chicken and dairy manures and biochar) on the soil physicochemical properties, sweet corn (Zea mays) growth, and yield parameters at Prairie View A&M University, Texas. Two rates of biochar (2.5 and 5 t ha−1) and two types of manure (chicken and dairy) applied at three rates (0, 224, and 448 kg total N ha−1) were used in a factorial design with three replications. Plant height, period for each vegetative growth stage, leaf soil plant analysis development, time to reach 50% tasseling and 50% silking stage, cob length, cob diameter, sugar content, and biomass were measured. The results showed that plant biomass was significantly affected by biochar rate, while plant height, cob length, and cob diameter were significantly affected by manure rates. Sweet corn reached tasseling and silking stages earlier in chicken manure‐treated plots than the dairy manure plots. However, the sugar content was significantly affected by both biochar and manure rates. Furthermore, results revealed a strong positive correlation between plant height and cob length, diameter, and biomass; however, there was a negative correlation with tasseling and silking days. Soil phosphorus, total nitrogen, and potassium had a relatively positive correlation with plant growth parameters. Findings showed that different types and rates of amendments significantly influenced sweet corn growth parameters and soil nutrient status, highlighting the importance of adopting climate‐smart agricultural practices for improved crop yield and soil health.

Fate of fluoroquinolones associated with antimicrobial resistance in circular periurban agriculture

Animal antibiotic use contributes to antimicrobial resistance (AMR) in humans. While animal manure benefits soil fertility, it also acts as hotspot for antibiotic residues, antibiotic-resistant bacteria, and their genes. Amending soils with poultry litter is recognized as “magic” among horticulture farmers and it remains a common practice globally. However, this poses a risk especially in countries where prophylactic use of antibiotics is allowed. In Argentina, fluoroquinolones are used in this way besides being listed as essential medicines and classified as “watch” by the World Health Organization. Antibiotic selective pressure can favour AMR in the environment but the fate of antibiotic residues and AMR dissemination from these practices remains poorly understood. Our research addresses this gap with a biological model tracing fluoroquinolones from poultry to soil to lettuce and tracking anthropogenic AMR with the proposed biomarker genes sul1 and intI1. Fresh poultry litter was stored for six months before application in a horticulture field experiment. The experiment included control and manured plots where lettuce was cultivated till harvest. Enrofloxacin concentration was 7.3 μg/kg in fresh poultry litter, while its metabolite ciprofloxacin was 39.22 μg/kg after storage. Although no fluoroquinolones were detected in soils, lettuce from manured plots contained enrofloxacin and ciprofloxacin at 14.97 and 9.77 μg/kg, respectively, providing evidence of fluoroquinolone bioaccumulation in plants. Abundance of sul1 and intI1 in poultry litter was not affected by storage. Manured soils showed better soil quality than controls, but sul1 gene abundance was 1.6 times higher, reaching 7.61 Log sul1/g soil. A less sensitive, but significant effect was registered for intI1. These findings show that static storage is insufficient to stop the transmission of antibiotics and AMR biomarkers from poultry to horticulture. Amending soil with industrial poultry litter contributes to pollution with these emergent contaminants and risks human antibiotic exposure through fresh vegetables.

Integrating NDVI and agronomic data to optimize the variable-rate nitrogen fertilization

The success of Variable Rate Application (VRA) techniques is closely linked to the algorithm used to calculate the different fertilizer rates. In this study, we proposed an algorithm based on the integration between some estimated agronomic inputs and crop radiometric data acquired by using a multispectral sensor. Generally, VRA algorithms are evaluated by comparing the yields, but they can often be affected by factors acting in the final phase of the crop cycle and not dependent on the fertilization treatments. Therefore, we decided to compare our algorithm (ALG) versus the traditional application of fertilizer (TRD) by evaluating the crop growth 1.5 months after the fertilization time. The algorithm was tested on a sorghum crop under organic farming, managed with or without manure. The saving of N obtained with ALG was equal to 14 and 5 kg ha− 1 (-14 and − 10% for the non-manure and fertilized treatments, respectively). The NDVI values acquired after fertilization showed a remarkable reduction of relative standard deviation for ALG system (from 22 to 9% and from 34 to 14% for manured and not manured, respectively), which was not found for TRD system (from 16 to 17% and from 29 to 18% for manured and not manured, respectively). The above ground biomass produced was statistically equivalent for the two systems in the manured plots and significant higher for ALG in not-manured plots (+ 0.74 t ha− 1 of dm, equal to + 23%). Finally, the indices calculated to evaluate the Nitrogen Use Efficiency (NUE) were consistently better in the ALG theses.

Further investigation into the impact of manuring on stable carbon (δ13C) and nitrogen isotope (δ15N) values in pulses: a four-year experiment examining Celtic bean (Vicia faba)

Plant stable carbon (δ13C) and nitrogen (δ15N) isotope values can be used to directly investigate crop husbandry practices such as manuring; a key variable in understanding the scale and intensity of past farming practices. We present new results from a four-year experiment examining the impact of manuring on the δ13C and δ15N values of a heritage cultivar of the broad or faba bean (Vicia faba), the ‘Celtic black broad bean’. This paper builds upon our previous pilot study (Treasure ER, Church MJ, Gröcke DR (2016) The influence of manuring on stable isotopes (δ13C and δ15N) in Celtic bean (Vicia faba L.): archaeobotanical and palaeodietary implications. Archaeol Anthropol 8:555–562. https://doi.org/10.1007/s12520-015-0243-6). Our results indicate that manuring increased δ15N values in beans, with a mean value of 0.5 ± 0.4‰ in control samples compared to a mean value of 2.1 ± 1.3‰ in the most intensively manured plots. It was not always possible to distinguish between an unmanured and manured crop on the basis of δ15N values, although manured crops consistently exhibited larger variation in δ15N. Bean δ13C values show no clear relationship with manuring, although large variability (> 3‰) was found within crops cultivated under the same conditions. Manuring also increased plant biomass production, seed-size and the bean per plant ratio. Overall, we suggest that high δ15N values (> 1.5‰) in archaeobotanical remains of pulses can be attributed to small-scale, intensive cultivation that is typical of gardens where manuring rates are very intensive.

Effects of cultural practices on weed community and seedbank dynamics in a potato rotation

ContextStagnant yields and declining soil health are common characteristics of high-intensity, low-residue cropping systems, such as potato, particularly in northeastern North America. Incorporating cultural practices including cover cropping and manure application is a way to combat declines in agroecosystem health and potato productivity. However, manure application and the use of cover crops may exacerbate weed issues through seedbank additions. ObjectiveThis study was aimed at investigating how the cultural practices of cover cropping and manure application and their associated management activities can alter weed community dynamics and weed seedbank composition in a northeastern North American potato rotation. MethodsThe study evaluated the use of eight cover crop mixtures—annual and perennial grasses and legumes—grown over two years with/without manure added in year one of the rotation. It also examined the effects of the cover crop mixtures and the presence/absence of manure on the weed community and on seedbank dynamics within a three-year potato rotation between 2019 and 2021. ResultsIn year one of the study and directly after application, manure plots had greater weed seedbank density and species richness; however, this did not result in greater in-season weed biomass. Manure application resulted in a gradual decline in weed seedbank density over time regardless of cover crop treatment. Further, manure application increased the in-season competitive ability of cover crops, resulting in greater weed suppression per unit of cover crop biomass. In contrast, in the absence of manure, weed seedbank density remained largely unchanged through time regardless of cover crop treatment. We found that management practices associated with annual and perennial cover crops had distinct ecological filtering effects throughout the rotation on the weed community and prevented the dominance of any particular species. ConclusionTogether, our results demonstrate that combining the cultural practices of annual or perennial cover cropping and manure application contributes to weed suppression and should be considered an important component of sustainable potato production.

Effects of Biochar and Cattle Manure under Different Tillage Management on Soil Properties and Crop Growth in Croatia

The negative environmental impact of conventional agriculture threatens agroecosystem stability and food security. Therefore, searching for optimal soil management practices is crucial for maintaining and improving soil functions. This work aims to determine the impact of conventional and conservation tillage on Stagnosols in a semi-humid environment in Marija Magdalena (Croatia) during 2021 and 2022. Under each tillage treatment, subplots were biochar, cattle manure, and control (split-plot design). The conservation tillage exhibits lower compaction in addition to conventional tillage. In 2021, at 0–15 cm and 15–30 cm depths, control plots had the highest bulk density (BD), while biochar plots had the lowest. In 2022, biochar and manure treatments under conventional tillage had significantly higher BD than those under conservation tillage. Penetration resistance did not exceed 2 MPa in all treatments. Soil water content was high in conservation treatments at 0–15 cm. Water-stable aggregates were higher in biochar and manure plots under both tillage treatments. Maize yield was higher in conservation treatments in 2021 and in conventional during 2022. Manure and biochar in the conventional system showed a better impact on grain yields than under conservation. Conservation tillage in rain-fed farming maintains crop yields and reduces soil compaction.

The determination of grain yield, yield components, and macro nutrient content of corn (Zea Mays L.) by different agricultural practices

A field experiment was conducted to determine the impacts of some treatments on grain yield, yield components (cob length, cob diameter, grain weight), and macro nutrient content of corn (Zea mays L.). During the study, tobacco waste compost (50 t ha-1), poultry manure (4 t ha-1), bio-humus (10 t ha-1) and NPK (0.3 t ha-1) were applied. The experiment was established with a randomized complete block design with four replications in Izmir, Türkiye. According to the two years average values; cob length varied from 18.84 to 22.35 cm, cob diameter from 4.38 to 5.05 cm, grain weight from 1704 to 2529 g, grain yield from 14.48 to 19.88 t ha-1 by the treatments. The greatest average yield values were obtained under tobacco waste compost (19.88 t ha-1) and poultry manure (19.64 t ha-1) plots over the control. All yield components were significantly affected the treatments. Macro nutrient contents of corn grain were found statistically significant by the treatments as compared with control. Total N, P, K, Ca, and Mg content of grain varied between 1.25-1.64%, 0.044-0.087%, 2103-3559 ppm, 25.83-571.88 ppm, 127.57-469.93 ppm, respectively. As a conclusion, all treatments increased the yield components and macro nutrient content of corn with similar effects; on the other hand, poultry manure and tobacco waste compost were the most effective materials on all parameters. Moreover, the positive and significant correlations were found among first and second year parameters.

Soil Organic and Enzymatic Properties as Influenced by Green Manuring and Establishment Methods in Rice-rice system

The field study was conducted during kharif and rabi seasons of 2016-17, 2017-18 and 2018-19 at Instructional Farm of College of Agriculture, Odisha University of Agriculture and Technology, Bhubaneswar to evaluate the effect of green manuring and establishment methods on growth parameters of rice-rice system. The experimental site was sandy loam in texture, slightly acidic in reaction, low in available nitrogen (198 kg/ha), medium in available phosphorus (18 kg/ha), potassium (193 kg/ha), OC (0.51%) with EC (0.20 dS/m). The rice varieties “Swarna sub-I” and “Lalat” were grown in kharif and rabi seasons, respectively. The experiment was designed with two groups of treatments, one without green manuring and the other with green manuring with Sesbania aculeata in main plot along with sequence of three establishment methods namely, Puddled Transplanted Rice (PTR), Non Puddled Transplanted Rice (NPTR) and Direct Seeded Rice (DSR) making it a total of nine establishment methods i.e PTR-PTR, PTR-NPTR, PTR-DSR, NPTR-PTR, NPTR-NPTR, NPTR-DSR, DSR-PTR, DSR-NPTR, DSR-DSR as sub plots in kharif and rabi seasons. From the above experiment, it is observed that the soil organic carbon in green manured plots were superior with respect to soil biological properties as it realized higher soil organic carbon (0.51%), microbial biomass carbon (246.29 μg C/g soil), microbial biomass nitrogen (83.5 μg N/g soil). The enzymatic activities of the soil were also enhanced with green manuring recording higher dehydrogenase and phosphatase activity of 226.40 mg TPF/g soil/24 hrs and 352.81 mg p-nitrophenol/kg soil/1hr respectively, at 0-15 cm after 3 years of rice-rice system. Among the establishment methods, DSR-DSR method of establishment recorded higher soil organic carbon, microbial biomass carbon and microbial biomass nitrogen of 0.58%, 251.33 μg C/g soil and 89.36 μg N/g soil respectively. Similarly, the dehydrogenase and alkaline phosphatase activities were also enhanced under DSR-DSR method of establishment recording 242.60 mg TPF/g soil/24 hrs and 381.90 mg p-nitrophenol/kg soil/1hr respectively, after 3 years of rice-rice system.

Remote sensing for detecting freshly manured fields

The application of manure on fields during the rainy season can pollute the environment by leaching nitrates into nearby bodies of water. To reduce and prevent this problem, closed periods are declared to stop the use of manure as a fertilizer during these seasons. However, compliance is difficult to verify due to the impracticality of monitoring all the fields in a region or country through on-site or satellite surveys. To address this problem, a method to automatically monitor freshly manured fields using machine learning and satellite imagery is proposed. This paper evaluates the Sentinel-2 (S2) satellite bands as well as 51 of the most common vegetation indices (VI) found in the literature for precision agriculture through experiments based on several feature selection methods. To train the models, a new dataset of freshly manured plots verified by on-site investigations is generated and made publicly available for future research. The proposed method is able to fully detect all freshly manured plots in the test dataset obtaining an F1-Score close to 90% of the tested area.

The effect of using fresh farmyard manure (animal manure) on the severity of Fusarium verticilioides in soil, root, stem, and kernels as well as lodging and borer incidence of maize plants.

Fusarium verticillioides, an important maize pathogen, produce fumonisins, causes stalk rot and consequentially reduce crop growth and yield. Therefore, herein we aimed to evaluate the potential use of two farmyard soil organic manures, i.e., fresh (5-6 days old) and stored (5-6 months old) organic manure, to manage F. verticillioides infections as well as borer incidence and lodging in maize plants. After 30, 60, and 90 days of sowing, samples of soil, roots, and stems were collected to isolate F. verticillioides. Moreover, we estimated ear and kernel rot induced by F. verticillioides at the final harvest. Fresh organic manure treatment increased infection rates of F. verticillioides in soil, roots, stem and kernels compared to the control treatment. In contrast, stored organic manure plots treatments decrease F. verticillioides frequency. At 90 days after sowing, stored organic manure suppressed the survival of F. verticillioides, which reduced the F. verticillioides incidence percent. These results were similar to the effect of herbicides-and insecticide-treated plots demonstrated, which show a significant decrease in F. verticillioides incidence rates. Mycological analysis on symptomless kernels revealed a higher % of pathogen infection in opened husks variety (Balady) than closed husks variety (SC10). Compared with stored organic manure, the stem borer incidence and lodging percentage were the highest in fresh organic manure plots. Finally, these results demonstrated that storing organic manure within five to six months as farmyard manure led to high-temperature centigrade within organic manure, thereby destroying spores of F. verticillioides, whereas fresh organic manure did not.

Leaching of Sulfadiazine and Florfenicol in an Entisol of a Chicken-Raising Orchard: Impact of Manure-Derived Dissolved Organic Matter

Antibiotic pollution from manured farmland soils is a major public concern, and their potential interaction with manure particles and/or manure–dissolved organic matter (DOM) often complicates their leaching behaviour. This study investigated the leaching of sulfadiazine (SDZ) and florfenicol (FFC) with manure-DOM in undisturbed field lysimeters and repacked soil columns under natural and simulated rainfall conditions. The results showed that manure-DOM reduced SDZ mass flux, but soil hydrological processes and heavy rainfall events led to accelerated leaching. FFC was more prone to leaching in a manured plot (0.48 µg m−2 h−1) compared to the control (0.12 µg m−2 h−1), suggesting DOM facilitated transport of FFC in the field lysimeter study via cotransport mechanisms favored by abundant macropores in the study site. In contrast, SDZ and FFC mobility were reduced in repacked soil columns under manure-DOM conditions, suggesting complexation and adsorption in matrix pores. Two kinetic site models and two-site nonequilibrium adsorption models revealed the existence of nonequilibrium conditions and kinetic sorption processes in the repacked column. FFC exhibited lower leaching potential compared to SDZ in both the repacked column and natural field conditions. Redundancy analyses revealed that FFC had a close relationship with humic-like components (C1 and C3), but SDZ was more related to the protein-like components (C2) of DOM. The presence of manure-DOM may decrease the ecological risks of highly mobile antibiotics under matrix flow through complexations and adsorption. However, a similar scenario in macroporous flow under heavy rainfalls may lead to accelerated leaching.

Evaluation of the role of common vetch (Vicia sativa L.) green manure in crop rotations

Common vetch (Vicia sativa L.) is an annual legume, grown as green manure provide rapid soil cover, can increase soil moisture and organic matter content and reduce soil erosion during fall. During the fallow period, legumes grown as catch crops are known by releasing large amounts of mineral nitrogen (N) for the subsequent crop. By taking advantage of these benefits, it is possible to increase the yield of the next crop in an environmentally friendly and sustainable way. The goal of this study was to determine the value of common vetch as a green manure, considering its effect on soil conditions and the yield of next crops. We examined three different common vetch seed rate as a green manure in a crop rotation with triticale, oat and corn. Next to the green manured treatments, we used fertilized and bare fallow control treatment for comparison. In our study we evaluated the aboveground biomass weight of spring vetch green manure and its effect on the moisture content of the soil. We examined the green manure’s effect on the next crops plant height and yield. We found that the moisture content of the green manured plots was significantly higher during summer drought. On the green manured plots, 37.9% higher triticale yield, 50% higher oat yield and 44% higher corn yield were measured compared to the control plots. The insertion of spring vetch green manuring into crop rotations could be a good alternative to sustainable nutrient replenishment methods. It can be used to reduce the input needs of farming, reduce carbon footprint, contribute to the protection of soils and increase the organic matter content of the soil.

How do tanniferous forages influence soil processes in forage cropping systems?

AbstractNitrogen‐fixing legumes such as alfalfa (Medicago sativa L.) and sainfoin (Onobrychis viciifolia Scop.) may benefit agricultural systems. In addition to quality forage, both legumes contain secondary metabolites that play important roles in agroecological systems. Alfalfa contains triterpenes (saponins), and sainfoin contains phenolic compounds (tannins). Terpenes and phenolics can influence soil nutrient dynamics by inhibiting microbial activity, which could slow nitrogen mineralization and minimize nitrogen losses. However, research evaluating their influence in the soil has largely come from silviculture or laboratory studies. Therefore, we initiated a field study in Lewiston, UT, assessing how alfalfa and sainfoin influence soil characteristics. The randomized split‐plot block design had three replicates and included a fertilized bale‐and‐remove system, a green manure system (leaving mown plant forage in the field), and a no‐fertilizer bale‐and‐remove system. We measured saponin and condensed tannin (CT) concentrations in alfalfa and sainfoin, respectively, forage biomass, and soil characteristics [e.g., ammonium (NH4), nitrate (NO3), dehydrogenase, organic C, soil respiration, etc.]. Green manure plots showed greater microbial respiration (p = .02), microbial biomass (p < .01), and readily mineralized carbon (p = .04) than other systems. Forage biomass was greater in sainfoin than in alfalfa (p < .001), whereas soil NO3 was greater in alfalfa than in sainfoin (p < .01). The soil NO3 differences could be explained by the inhibition of mineralization by CT in sainfoin compared with the saponins in alfalfa. Planting forages containing tannins may reduce nitrogen losses, thereby enhancing agricultural sustainability.

Maize yields from manure and mineral fertilizers in the 100‐year‐old Knorr–Holden Plot

AbstractIt takes years, if not decades, before measurable changes in crop productivity and soil properties due to management practices can be detected. The objective of this experiment was to evaluate the effects of long‐term cattle manure and inorganic fertilizer applications on irrigated continuous maize grain yield, yield stability and reliability, nitrogen use efficiency (NUE), and soil properties. The experiment was conducted at the Knorr–Holden Plot in Scottsbluff, NE, from 1912–2012. Maize received no fertilizer in the first 30 yr of the experiment, and yields declined as nutrient supply from the native prairie was used. In 1942–1952, there were two cattle manure rates (0 and 27 kg ha–1 yr–1), and yield significantly increased in the manure treatment. In 1953, second replication and six inorganic N treatments were added effectively, making the study a randomized complete block with manure as the main and inorganic N as subplot factor with two replications. Linear regression of yield against years in manured plots had similar slopes across N rates. There was a gradual increase in slope with increasing N rates in non‐manured plots. Yield response to inorganic N rates in the non‐manured plot had a significantly greater slope but lower intercepts than the manured plot. Manure provided greater yield stability and reliability and significantly increased soil organic matter, nitrate‐N, and P accumulation in soil. Optimized manure and inorganic fertilizer N management are necessary to provide a stable and reliable yield and help establish an economically and environmentally sustainable maize production system.

Effects of different tillage and fertilization management practices on soil organic carbon and aggregates under the rice–wheat rotation system

Studying the impact of tillage and fertilization on soil organic carbon (SOC) content and aggregate is essential to define better strategies for improving soil structure and SOC sequestration. A field experiment was conducted for 9 years to investigate effects of different tillage and fertilization management practices on SOC and its active fractions [labile organic carbon (LOC), dissolved organic carbon (DOC) and microbial biomass carbon (MBC)] within the bulk soil and in soil aggregates under rice (Oryza sativa L.)–wheat (Triticum aestivum L.)-based cropping systems. Five treatments were included: conventional tillage with no fertilizer (CT), conventional tillage with chemical fertilizer (CTFR), reduced tillage with chemical fertilizer (RTFR), conventional tillage with organic manure (CTOM), and reduced tillage with organic manure (RTOM). The results showed that the organic manured plots (CTOM and RTOM) significantly increased the concentrations of SOC and active carbon fractions (LOC, DOC and MBC) within the bulk soil and soil macroaggregates, and increased the mass proportion of macroaggregates (>250 μm) compared with chemical fertilizer treatments (CTFR and RTFR) or CT. The highest SOC concentration and macroaggregates (>250 μm) were observed in CTOM. The increased SOC, especially active carbon fractions, was mainly concentrated in soil macroaggregates (>250 μm). Soil aggregates were dominated by macroaggregates (>250 μm), which had higher MBC and lower PAOC (the percentage of slow plus passive carbon fractions) after 9 years of RTOM treatment than after CT or CRFR treatment. The results indicated that RTOM played a positive role in promoting the formation of the soil macroaggregate structure. By studying the responses of SOC and water-stable aggregate contents to different tillage and fertilization managements, the continual application of organic manure may be feasible and the periodic organic manure addition may be combined with reduced tillage practice to produce an integrated soil management strategy for the paddy–upland rotation region in Middle China.

Impact of crop rotation and fertlilizers (chemical, organic and bio) on diseases and yield of maize (Zea mays) in Far North Cameroon

Many fertilizers are used in the Far North of Cameroon for maize production. The aim of this work was to reveal diseases and yield performance of maize in response to different fertilizers during two years (2018 and 2019). CMS 9015 maize variety was used. Three sites were selected. In the site of Kongola (crop rotation), the experimental design was in completely randomized blocks consisting of four treatments: Control (To); Bio fertilizer (Myc); mineral fertilizer (EM); organic fertilizer (EO) with three replications.Two other sites were used and where fertilizers have been used for more than 5 years. At the Meskine site, the fertilizer used was mineral (Urea 46% and NPK 23-10-5) and in Pitoaré, organic manure (cow dung, chicken dropping) was used as fertilizer. Mycorrhizae used were Glomus sp and Gigaspora sp. Several diseases were identified. Fungal diseases such as the leaf gray spot (Cercospora zeae), corn leaf blight (Helmintosporum turcicum) and physoderma brown sport (Physoderma maydis) were observed during the two years in the organic manure plots in Pitoare site. One viral disease, maize streak, was observed in all plots with higher incidence and severity during the two years (100 and 50 respectively).The gray spot was not influenced the yield, whereas maize streak caused adecrease of yield when the infection attack was early.Corn leaf blight and physoderma brown spot were fungal diseases with highest incidence (more than 70%) during the two seasons. The highest yield was obtained in EO treatment (9.3 t/ha) at Pitoare in 2019 growing season and the lowest was obtained in the mycorhizal plot (1.05 tonnes/ha) in 2018. Fetilizers reduce development of maize diseases when there are used in rotational cropping system than in a continuous system than in continuous system. Keywords: Zea mays, fertilizers, diseases, rotation, incidence, severity, yield.

Nitrogen turnover and N2O production in incubated soils after receiving field applications of liquid manure and nitrification inhibitors

Applying abundant manure to soils can accelerate nitrogen (N) transformations and nitrous oxide (N2O) emissions. We conducted a laboratory incubation to examine the turnover of labile N in manured soils. Soils were collected from agricultural fields that had recently received spring-injected liquid dairy manure with or without admixing nitrification inhibitors. Bands and interbands of the manure plots were incubated separately. Time courses of ammonium (NH4+) and nitrate (NO3−) were used to derive and contrast zero-, first-, and second-order kinetics models. We found that nitrification rates were consistently better represented by first-order kinetics (k1). Furthermore, across all evaluated soils, the dependency of nitrification rate (k1 of NH4+) on initial NH4+ concentration was modelled by Michaelis–Menten kinetics reasonably well, with an affinity (Km) of 63 mg N·kg−1 soil (R2 = 0.82). Compared with the manure interbands, the initially NH4-enriched bands had a much faster nitrification rate, with half-life for NH4+ of only 4 d and rapid k1 (0.186 versus 0.011 d−1). Soil N substrate and k1 exerted control on N2O production. Nitrous oxide production increased linearly with both measured NH4+ intensity (R2 = 0.47) and modelled k1–NH4+ (R2 = 0.48). Conversely, N2O production increased non-linearly with NO3− intensity (R2 = 0.68), where high NO3− caused a saturation plateau with a threshold of 96 mg N·kg−1·d−1 — beyond which no additional N2O was produced. During peak N transformations, measured N2O-N flux was 1.4% ± 0.3% of the inorganic N undergoing nitrification. Heavily manured soils exhibited augmented N turnover that increased N2O fluxes, but inhibitors reduced these emissions by half.

Uticaj meliorativnih mera na produktivnost lucerke na kiselom zemljištu tipa vertisol

Alfalfa is the most important forage legume in our agroecological conditions for feeding cattle. In the area of Jablanica district, alfalfa occupies a considerable place in the total plant production. The restrictive factor in the establishment and short durability of alfalfa stand is the low pH of arable agricultural soil. Within the three-year field trial on Vertisol soil type (pH in KCl 4.9), from 2016 to 2018, alfalfa plot yield has been analyzed with different fertilization variants. The research results indicate that alfalfa provides a significantly higher yield on the plot where amelioration measures were applied, through the application of limestone and manure, with the addition of mineral fertilizer. A barely lower yield was achieved on the calcified and manured plot, while the lowest yield was on the control plot, where a generous amount of mineral fertilizer was added, which is a common practice of agricultural producers in the area of Jablanica district.