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Most farmers use urea as a nitrogen fertiliser to raise mustard (Brassica juncea L.), although its nitrogen (N) content is quickly lost due to its hygroscopic nature. Nitrogen loss in the form of nitrous oxide (N₂O) and nitrates (NO₃^–) has been causing low nitrogen fertiliser efficiency in vegetable cultivation. This investigation aims to assess the impact of urea fertiliser coated with biochar or activated charcoal on losses of N₂O and NO₃^– concentration in the soil during mustard production. The experiment used a randomised block design with five treatments of urea fertiliser coated with biochar/activated charcoal. The observed data included N₂O flux, nitrate, and ammonia content in soil and water. The results showed that urea fertiliser coated with activated charcoal from corn cobs tended to suppress N loss more effectively than urea coated with biochar or activated charcoal from coconut shells. Biochar and activated charcoal from coconut shells suppressed N-N₂O loss as much as 3.1% and 52.5% (7 days after planting (DAP)), respectively, and 68.7% and 71.6% (21 DAP), respectively. Biochar and activated charcoal from corn cob reduce N-N₂O loss by 46.5% and 66.5% (7 DAP), respectively, and by 70.7% and 77.8% (21 DAP). Urea-coated activated charcoal fertiliser increases mustard plant biomass and nitrogen uptake. Biochar and activated charcoal from coconut shells and corncobs increase nitrogen use efficiency by 5, 24, 6, and 17%, respectively. Biochar/activated charcoal coatings are a promising technology for boosting nitrogen use efficiency in vegetable crops, including mustard crops.

Biochar has demonstrated potential for stabilising high yields and sequestering carbon in dryland farmland, but it is unclear whether biochar affects the carbon sequestration capacity and carbon balance of annual farmland ecosystems. For this purpose, we conducted a plot control trial in salinised farmland in 2019–2021, where we set three treatments, control, and two biochar rates, 0 (CK), 15 (B15), and 30 t/ha (B30). The results showed that biochar application decreased soil organic carbon stocks in the early part of the experiment (first freeze and freeze period); these increased in the later part, and overall, the biochar treatments increased soil organic carbon storage by 3–6% compared with the control. Compared with the control (CK), biochar inhibited the total soil respiration rate and microbial respiration rate significantly (P < 0.05) during the crop growing period compared with the freeze-thaw period. After two years of freeze-thaw cycling, biochar application increased sunflower plant carbon sequestration and net primary productivity and suppressed total soil microbial respiration, thereby increasing net ecosystem productivity. Therefore, the application of biochar is conducive to carbon sequestration in farmland ecosystems and presents a carbon sink effect, thus being a good choice for improving the soil carbon pool and reducing emissions in the northern dry zone.

The effect of drought stress on carbon metabolism in the leaves and roots of bermudagrass was investigated. Plants established in PVC tubes suffered from three water treatments for 10 days. C138 and Tifway (drought-tolerant) were found to have lower relative electrical conductivity and higher water use efficiency than C32 (drought-sensitive) under moderate drought by increasing carotenoid and soluble sugar content and rapidly decreasing leaf starch content. The sucrose synthase activity of leaves and roots, acid invertase and neutral invertase activity of C32 roots substantially decreased under severe drought, resulting in a slow sucrose decomposition rate and significantly lower fructose and glucose contents than C138 and Tifway. The activities of four carbon metabolism enzymes and sucrose content in the leaves were greater than those in the roots, while the fructose and glucose contents were on the contrary, indicating that bermudagrass transported fructose and glucose obtained from sucrose decomposition from leaves to roots under drought to reduce roots damage. The path analysis indicated that leaves neutral invertase activity, and roots soluble sugar content might be the key parameter of carbon metabolism in bermudagrass under drought.

This paper studied the response of rice yield and soil nitrogen (N) cycling microorganisms to the combined application of animal slurry and mineral fertiliser. A pot experiment was conducted on typical yellow-brown paddy soil. There were five treatments: (1) CK – no N fertilisation; (2) S0 – mineral fertilisation; (3) S30 – 30% slurry with 70% mineral fertilisation; (4) S60 – 60% slurry with 40% mineral fertilisation; and (5) S100 – slurry application. Rice yield, yield components, and soil properties were investigated at harvest. The abundance of soil N cycle functional genes abundance was quantified via quantitative real-time PCR. The rice yield reached a high level when the proportion of slurry used to replace mineral fertiliser was 30–50%. The yield in response to mineral fertiliser (S0) was equivalent to that in response to no N fertilisation since the formation of effective panicles was inhibited. With the slurry replacement ratio increase, the available phosphorus and potassium contents in the soil improved, but the nitrate content decreased. Considering the entire soil N cycle, nitrogen-fixing microbes (nifH), ammonia-oxidising archaea (AOA amoA) and nitrite-reducing microbes (nirS and nirK) had greater abundances, reaching 108 copies. Compared with those in the S0 treatment, the abundances of most N cycle functional genes in the S30 treatment, except for napA, significantly increased from 31.2% to 100.9%, and the increase in the abundance of nirS and nosZ in the S100 treatment reached 4 times, which was obviously greater than that of the other genes. Correlation analysis revealed that high soil pH promoted N fixation and nitrification, while NH₄⁺-N had the opposite effect on N fixation and nitrification, and available phosphorus and potassium actively influenced denitrification. These results showed that a 30–50% slurry application ratio was recommended for rice, which was beneficial for maintaining high yields and high abundances of soil N cycle functional genes.

A three-year field experiment was carried out to investigate the methane (CH₄) and nitrous oxide (N₂O) emissions and calculate the global warming potential (GWP) according to all energy input in response to the nitrogen (N) rate in the typical rice-wheat rotation system in Jiangsu, China. Four N treatments, including R220W180 (local practice), R220W140 (cutting 10% total N in wheat season), R180W180 (cutting 10% total N in rice season) and R180W140 (cutting 20% total N in rice and wheat seasons separately), were designed in the study. Results showed that annual CH₄ emission was decreased by 25.7% in response to cutting 20% N, which was ascribed to the 24.6% reduction of CH₄ emission in rice season (P < 0.05) compared to local practice. The mitigation of N₂O emissions in R220W140 and R180R180 treatments contributed to the 8.5% and 15.7% decrease in annual N₂O emission, which was the 23.5% decrease in cutting 20% N treatment compared to local practice, respectively. Specifically, under the same amount of N rate condition (10% N cutting), the transfer N from rice season (R220W140) to wheat season (R180W180) led to the 8.5% increase in N₂O emission (P < 0.05). In the end, the cutting of 20% N decreased GWP and yield-scale GWP by 19% and 17%, which mainly originated from CH₄ and N₂O emissions. However, cutting N did not significantly decrease grain yield (P > 0.05). These results suggested that the 180 kg N/ha for rice and 140 kg N/ha for wheat in one rotation season were the beneficial N rate to achieve the co-benefit of yield and GWP in the typical rice-wheat rotation system in Jiangsu, China.

In recent years, sulfur inputs into the soil have greatly diminished due to the significant decrease in SO₂ emissions. Plant nutrients, like sulfur, can be released by the mineralisation of soil organic matter (SOM), which is a complicated mixture of substances (or fractions) like glomalin-related soil protein (GRSP) and fulvic acids (FA), humic acids (HA), humic substances (HS) and others. GRSP, FA, HA, and HS content, as well as the content of mineral and organic fractions of sulfur, was determined in different mineral and organic fertiliser treatments of the long-term field experiment. Using these results, the sulfur content in GRSP was calculated based on the soil’s organic matter carbon and soil’s organic bound sulfur (C_SOM/S_ORG) ratio. Sulfur content in GRSP was 4.08–5.46 (easily extractable GRSP), 9.77–15.7 (difficultly extractable GRSP), and 13.9–21.1 (total GRSP) mg S/kg of soil. Overall, the application of the organic fertiliser caused an increase in S content bound to GRSP. A strong significant relationship was also observed between GRSP fractions and soil organic sulfur. A similar relationship was also observed for the HA and HS with organic sulfur.

Increased levels of the non-essential hazardous metalloid arsenic (As) in rice grains pose a threat to human health and the sustainability of the rice industry. In several counties, the average As contamination in polished rice has been detected to range from 0.002 to 0.39 mg/kg, which is above the safe limit of 1 mg/kg as recommended by the World Health Organisation. Beyond this limit, the digestive tract, circulatory system, skin, liver, kidney, nervous system and heart can be affected. Humans can develop cancer from consuming or inhaling As. In addition, long-term exposure to drinking water contaminated with arsenic has also been linked to a dose-response relationship with an increased risk of hypertension and diabetes mellitus. Rice has been shown to be an indirect source of arsenic accumulation in human bodies. Under flooded paddy soil, trivalent arsenate (AsIII) occupies 87–94% of the total As, while under non-flooded soil, pentavalent arsenate (AsV) predominates (73–96% of the total As). This review aims to provide a thorough and interdisciplinary understanding of the behaviour of As in the paddy soil and transportation to rice grain and further investigate efficient ways to limit arsenic contamination. Supplementation of soil with specific mineral nutrients such as iron (Fe), sulphur (S) and silicon (Si) can significantly decrease the arsenic accumulation in rice grain by minimising its uptake and translocation. The hydrogen bonding potentials of uronic acids, proteins and amino sugars on the extracellular surface of soil microorganisms facilitate the detoxification of arsenic species. Further, rice is absorbed less when exposed to aerobic water management practices than anaerobic ones since it reduces the build-up of As in rice, and the solution is immobilised as in the soil.

The aim of this study was to evaluate the effects of continuous application of rice straw and biochar for 10 years on soil humus composition and structure in paddy soil. A 10-year field experiment was conducted in a paddy field and included three treatments: rice straw biochar (SC); rice straw (RS), no biochar or rice straw. The elemental analyser, Fourier transform infrared (FT-IR) spectrum, and three-dimensional excitation-emission matrix (3D EEM) fluorescence spectroscopy with fluorescence regional integration (FRI) analysis were used to study the soil humus composition and structure under different treatments. The results verified that the incorporation of rice straw and biochar significantly improved soil pH values and the soil organic carbon contents compared with the control. Rice straw significantly increased the contents of extractable humus, humic acid (HA) and fulvic acid in soil, while biochar only significantly affected HA and humic degree values. The molecular structure of HA affected by biochar is characterised by high humification and aromaticity, but rice straw increased the aliphaticity of the HA structure, as presented by elemental composition. Moreover, 3D EEM spectroscopy combined with FRI analysis showed that RS treatment formed soil humus had more aliphatic compounds, while SC treatment increased the aromatic components of humus. These results suggest that rice straw promotes the renewal of humus, and biochar enhances the humification degree of humus and the aromaticity of HA.

The improvement of rice production to meet food needs for the increasing population is a general problem faced in wetland development for agriculture. The use of industrial waste, such as coal fly ash (CFA), could effectively improve the soil properties of wetlands. In this study, CFA with an amount of 2% (weight/volume) or 240 g was added to 12 L of three different soils collected from the rice fields (peatland, swampland, and rainfed field) in a 15-L pot, and then incubated in the greenhouse for 15 days. The soil pH, concentrations of NH₄⁺-N, NO₃^–-N, exchangeable calcium (Ca) and magnesium (Mg) and available phosphorus in the soil were quantified following the completion of the incubation. Rice seedlings were planted in each pot, and after 90 days, the growth and yield variables were observed. The results showed that CFA application enhanced the concentrations of NH₄⁺-N, NO₃^–-N, and available phosphorus in peatland and swampland, the rice fields that contain high organic carbon (C), which ultimately leads to increasing rice growth and yield. The application of CFA to rice fields containing low organic carbon did not improve available nitrogen and phosphorus nor enhance the growth and yield of rice. Results of this study indicate an important role of soil organic C content in the rice fields in controlling the effect of CFA on nutrient availability, growth and yield of rice.

Due to its positive effects, mulching with organic matter is a popular soil conservation tool. However, opinions are divided on the effects of mulching on pests and pathogens. Our research aimed to investigate the effect of organic mulch on potato tuber damage caused by soil-dwelling pests and soil-borne pathogens. Therefore, mulching trials were carried out at four sites over six years, comparing the effects of straw, walnut leaves, mixed leaves, compost and two sowing methods (in soil, on soil surface, and under mulch). The total yield of the mulched plots was equal (2013, 2014) or significantly higher (2015, 2016, 2017, 2018) than the control, while the weight of damaged tubers did not increase. Total yield was higher in plots mulched with compost, walnut leaves and mixed leaves than in control and straw-mulched plots. The seeding method had no effect on yield or tuber damage for any of the cover crops. Mulching potatoes with organic matter, especially compost and leaves, is recommended, as their application positively affected yield but did not increase the number of damaged tubers. Sowing potatoes under mulch can reduce the digging work and cutting damage without reducing the yield.

Alfalfa (Medicago sativa L.) is a superior-quality perennial legume forage crop cultivated in China. However, fertiliser applications and the environmental factors affecting alfalfa yield and quality have not been well documented. In this study, we conducted a meta-analysis using a dataset from 105 studies published between 2003 and 2023 to explore the effects of fertiliser application and environmental factors on the yield and quality of alfalfa. The results showed that compared to the non-fertiliser control levels, fertiliser application increased alfalfa yield by 24.61% and improved the quality of alfalfa by increasing crude protein by 11.63% and decreasing acid detergent fibre by 7.69% and neutral detergent fibre by 6.76%. Alfalfa yield and the crude protein effect size increased with increasing altitude but decreased with increasing latitude based on fertiliser application. The acid detergent fibre and neutral detergent fibre effect size were positively correlated with mean annual temperature and mean annual precipitation. In conclusion, applying fertiliser is a productive approach to enhance the yield and grade of alfalfa, but environmental factors have an effect. This study provides comprehensive information on fertiliser applications and environmental factors that affect alfalfa yield and quality. These results provide insight into further improving alfalfa yield and quality and contribute to the development of alfalfa.

Compared to solely mineral fertiliser application, organic fertiliser substitution has been demonstrated to be effective in enhancing nitrogen cycling in cropland, but the relevant research based on grassland is still insufficient. A field experiment was carried out in the grasslands of northern China to examine the impact of mineral/organic fertilisation on soil organic nitrogen fractions, activities of soil N-hydrolysing enzymes and their interrelationships. The results showed that the active soil organic nitrogen pool (hydrolysable NH₄⁺-N + amino sugar-N + amino acid N) increased significantly after fertilisation, and organic fertiliser combined with mineral fertiliser addition showed the best promotion effect. N-acetyl-β-d-glucosaminidase, protease and urease activities are also significantly affected by fertilisation. The findings of our study indicate that the combination of mineral fertiliser and organic fertiliser shows a higher potential in improving the active soil organic nitrogen supply. This approach seems to be a viable agronomic strategy for augmenting soil nitrogen supply and ensuring the stability of the soil nitrogen pool in the semi-arid steppe region of northern China.

The impact of precipitations and air temperatures on winter wheat yields was evaluated in a 34-year long- term field trial with mineral and organic fertilization established at two experimental sites with different soil-climatic conditions: Ivanovice na Hané with well fertile soils (degraded Chernozem), higher average year temperatures and lower precipitations; Lukavec situated in Bohemian-Moravian highlands with less fertile soils (Cambisol), lower temperatures and higher precipitations. At both sites, a significant positive effect of used fertilizers was noted from the dose of 80 kg N/ha; the best yields were generally obtained at 120 kg N/ha and 160 kg N/ha. The wheat yields at the Ivanovice site were negatively affected by the decrease of precipitations, namely in more fertilized treatments, particularly farmyard manure + mineral nitrogen, from the dose of 80 kg N/ha. A different trend was obtained at the Lukavec site where better winter wheat yields were obtained under lower precipitations. The air temperatures played a positive role at the Lukavec site, but no significant effect of temperature was observed at the Ivanovice site. The less productive areas in highlands can become more interesting for agriculture production with changing climate. However, the soils generally having lower quality and nutrient content can be a limiting factor for obtaining high yields.

In the current studies, heavy metal tolerance level, accumulation efficiency and sexual reproduction were determined in Viola × wittrockiana, a non-metallophytic ornamental cultivar in comparison to V. tricolor, a metallophyte, after zinc (Zn) or lead (Pb) treatment (0, 10, 100 and 1 000 ppm) in pot experiments. The seed germination frequency that was not reduced in comparison to the control, the effective Zn absorption from the soil and exclusion strategy for Pb, as well as the regular sexual reproduction of V. × wittrockiana treated with heavy metals all indicate the tolerance of this plant to heavy metals. The lack of a seed set under experimental conditions of V. × wittrockiana was due to the absence of pollinators, rather than the negative impact of heavy metals, as pollen viability and ovule development were normal under the treatments. The results indicate that V. × wittrockiana represents similar tolerance to Viola metallophytes and could be considered as a good material for the reclamation of polluted areas. The exceptional tolerance to heavy metals, the ability to initiate new generations in heavy-metal-burdened soil, which are additionally coupled with the unique beauty, make the garden pansy a good candidate to be potentially used in the future for phytoremediation purposes.

In this experiment, we investigated the effects of drought combined with exogenous silicon (Si) and potassium application on super sweet corn growth and development. Drought stress caused decreases in the stem diameter, leaf area, cob length, cob diameter, 100 seed weight, seed number, cob yield, biologic yield, and relative water content (RWC), but proline content and catalase activity were higher under drought stress conditions. The results of a two-year experiment showed that potassium sulfate application and foliar application significantly increased RWC in drought stress conditions, and the highest increase was related to treatment with potassium sulfate in an amount of 25 kg/ha. Under normal irrigation conditions, with 25 kg of potassium sulfate per ha and Si foliar application, the maximum cob diameter (5.85 cm) was observed. Si application did not significantly affect proline content under normal irrigation conditions but increased proline content under drought stress. The highest proline content (10.77 mmol/g fresh weight) was recorded in the Si application using 25 kg of potassium sulfate per ha under drought stress conditions. Also, applying potassium sulfate with silicone foliar spraying had no significant effect on biologic yield under normal irrigation conditions. However, under drought stress treatments, biologic yield increased by applying 15 and 25 kg/ha of potassium sulfate and Si foliar spraying. In summary, applying potassium sulfate and exogenous Si can enhance the antioxidant system of the plant, promote the RWC, thus improving biologic and cob yield, and enhance the drought resistance of super sweet corn.

If appropriately applied, tillage can positively affect the crop’s yield by enhancing the soil’s physical properties. Fertilisation also has beneficial effects on yield if applied at efficient rates by increasing available-to-uptake nutrients and improving soil’s chemical properties. A field experiment was carried out in Debrecen, Hungary, to evaluate the individual and the interaction effects of these 2 factors on sunflower and sweet corn. The cultivation methods applied were ploughing (C1), direct drilling (C2) and deep loosening (C3). In addition, 3 fertilisation rates were applied to each cultivation system: F1 (control, no fertilisation); F2 (100 : 50 : 70) kg NPK/ha and F3 (150 : 100 : 120) kg NPK/ha in a randomised complete block design (RCBD) with 4 replicates. Our results showed that fertilisation did not affect the yield of sweet corn measurably. However, C1 resulted in the highest yield, whereas C2 and C3 resulted in relatively similar yields. In sunflowers, the yields of both C1 and C2 were higher than that of C3. No significant differences were recorded between C1 and C2. The yields of both F2 and F3 were higher than the yield of F1. The differences between F2 and F3 were insignificant. It could be concluded that the cultivation method is a determining factor in the yield of sweet corn. The effects of both fertilisation and cultivation treatments were more detectable in sunflowers. The differences between the two fertilisation rates (F2 and F3) were insignificant in both species, indicating that the extra fertilisation levels might be unnecessary.

Plant-based indicators of water status, such as midday stem water potential (Ψ_stem) and leaf stomatal conductance (g_s), are used to optimise irrigation scheduling in horticultural crops because they integrate the effect of soil and climatic conditions and the internal physiological constraints. The use of these indicators relies on experimentally acquired thresholds that relate the value of the indicator to negative effects on yield. In five irrigation treatments, we monitored yield, fruit size and the courses of Ψ_stem and g_s throughout four consecutive growing seasons. We found that Ψ_stem was more sensitive to irrigation treatment than g_s. Both indicators increased with available soil water content (ASWC) and decreased with evaporative demands of the atmosphere (ET_C). On a seasonal basis, crop load had a stronger impact on g_s than Ψ_stem. In summary, our study explored the effect of environmental conditions and crop load on plant-based indicators of tree water status and can be useful for establishing thresholds for irrigation scheduling in apple tree orchards.

However, its underlying mechanism remains largely undetermined. In this work, we examined the impacts of the continuous application of pig manure fertiliser for 10 years on wheat yield in the calcaric fluvisol soil with a texture of sandy loam, and the relationship between soil microbial community composition and soil properties was also analysed. The wheat yield, yield components and wheat biomass were analysed by collected aboveground part. Soil nutrient, enzymatic activity and microorganism compositions were analysed by collected soil samples at the filling stage. The results showed that long-term application of pig manure fertiliser could remarkably increase wheat yield by improving soil nutrient availability, enzyme activities, and microbial composition. Moreover, soil pH, nitrogen content, dehydrogenase and urease were closely related to the soil microbial diversity. In conclusions, the long-term application of pig manure in combination with term mineral fertiliser could optimise microbial community composition by regulating the interaction between microbial species and enhancing soil enzyme activity and soil fertility, leading to increased wheat yield.

Soil macroarthropods, as a component of the soil community, directly feel the impact of land use changes. Not only the density but understanding the soil macroarthropods distribution pattern will help in providing an insight into the quality of soil health. The sampling process was carried out using the pitfall trap methods on the forest, logged forest areas, mixed gardens, and monoculture gardens in the tropical rainforest of Bukit Pinang-Pinang Padang, Indonesia. The results showed that the forest as a natural habitat supported the density of soil macroarthropods among other land use types. The density in the forest, logged forest area, mixed garden, and monoculture garden sequentially is about 20.29, 13.18, 15.2 and 12.21 indv/m2. The presence frequency high value of soil macroarthropods was found in the forest, and for some soil macroarthropods, such as Hymenoptera, Diptera, and Araneits, the importance value increases when their habitat is disturbed. The fertile soil in intensive monoculture gardens does not support the individuals’ total number, types, and density of soil macroarthropods. On the other side, the dominant soil macroarthropods prefer disturbed soil conditions and will decrease their presence frequency if chemical compounds are introduced into the soil. Land use change in the Bukit Pinang-Pinang tropical rainforest area causes changes in the distribution pattern of soil macroarthropods. The changing tendency of distribution patterns in fragmented habitats is due to nutrient availability, limited resources and land treatment. Habitat fragmentation affects not only the abundance and density of individuals and types of soil macroarthropods but also the distribution pattern, which not only threatens their existence and the environment but also has the potential to regenerate.

A study was conducted at the University of Venda Experimental Farm, Limpopo province, South Africa to determine the effects of tillage and mulching on selected soil properties, and yield of sunflower (Helianthus annuus L.). The experiment was laid out in a split plot design with three replications during the 2018/19 and 2019/20 cropping seasons. Treatments consisted of conventional tillage (CT) and minimum tillage (MT) and three levels of avocado leaf mulch (0, 6 and 12 t/ha). Bulk density (BD), aggregate stability (AS), infiltration rate (IR), soil water content (SWC) and grain yield were determined. Tillage had no significant effect on BD in either season but influenced SWC and sunflower grain yield. CT recorded a significantly higher AS than MT during 2018/19 cropping season. Tillage × mulch interaction was significant during 2018/19 season with CT at 12 t/ha mulch recording higher AS than the MT. IR was significantly influenced by tillage × mulch interaction in both seasons with MT recording higher IR than the CT during 2018/19. Avocado mulch had no significant effect on sunflower grain yield in either season but influenced SWC in 2019/20 season. It was concluded that avocado mulch could be a relevant component of conservation agriculture but long-term studies are needed to validate the benefits observed in this study.

Crop residue management and water saving are the two major issues for the sustainability of the rice-wheat cropping system. Therefore, a two-year field experiment was conducted in a split-plot design to study the combined effect of three rice residues (residue incorporation (RI), residue standing (RS) and residue removal (RR) and two wheat residue incorporation (WI) and residue removal (WR) management in main plots and two irrigation regimes, i.e., flood (F) and surface drip (SD) in subplots on the growth and water productivity of direct seeded rice (DSR). During both years, RI-WI resulted in significantly higher plant height (PH), leaf area index (LAI) and dry matter accumulation (DMA) than in other residue management treatments. Drip irrigation significantly increased PH, LAI, DMA grain yield, straw, and biological yield, along with a 9.6% irrigation water savings over flood irrigation. During both years, grain yield, straw and biological yield of DSR were significantly higher in RI-WI than in RR-WR and RR-WI. RI-WI had significantly greater apparent water productivity (AWP) and actual water productivity (RWP) of DSR. Drip irrigation had significantly higher AWP and RWP during both years than flood irrigation except RWP during 2017. Transpiration efficiency (TE) in rice residue incorporation was significantly higher than in rice residue standing and removal. During both years, the TE of drip irrigation was also significantly higher than flood irrigation. So, incorporating rice and wheat residues along with drip irrigation improves crop growth and water productivity.

The information on the behaviour of potassium (K+) in tropical paddy rice soils, which is important for a better understanding of the plant availability of K+ is still very limited. We compared the quantity-intensity (Q/I) relationships for K+ under conventional tillage and no-tillage systems in tropical paddy fields in the absence and presence of K+ fertiliser in the addition of nitrogen. The results showed that the values of the activity ratio for K (ARK) and potential buffering capacities (PBCK) in the no-tillage rice field were respectively 16% and 33% higher than that in the conventional tillage field. With the addition of K fertiliser, the value of exchangeable K in equilibrium (ΔK0) in the no-tillage paddy field was 67.9% greater than that in the conventional tillage field. This indicates that K fertilisation is more efficient when applied on a no-tillage paddy field. When the K fertiliser was added (49.8 kg K/ha), the application of N fertiliser at the rate of 115 and 184 kg N/ha resulted in a higher ARK value than that at the rate of 46 kg N/ha. This suggests that the simultaneous application of K and N fertiliser was able to increase exchangeable K in the soil. The application of no-tillage increased of the dry grain yield of rice (about 10%) compared with the application of conventional tillage. Meanwhile, there were significant relationships between the rice yield with the ARK and ΔK0. Moreover, the ARK was significantly correlated with K-uptake.

The aim of this study was to determine the heavy metals concentrations in soil, inflorescences of Brassica napus and rapeseed honey sampled from some regions of north-eastern Bulgaria. Thirteen locations were selected for experimental studies. The soils, plants and honeys samples were taken from conventional beekeeping areas away from major industrial pollutants. The median amounts of elements in the soil samples (mg/kg DW) are 1.1246 for Fe(s), 0.7048 for Al(s), 0.5636 for Pb(s), 0.1658 for Cu(s) and 0.0148 for Zn(s). The median amounts of heavy metals measured in the inflorescences of Brassica napus (mg/ kg DW) are 5.5430 for Fe(p), 2.9095 for Zn(p), 1.3225 for Pb(p), 0.2593 for Cu(p) and 0.2105 for Al(p). The median heavy metals concentrations in  tested honey (mg/kg DW) are 1.0026 for Fe(h), 0.1849 for Al(h), 0.1832 for Pb(h), 0.1250 for Zn(h), 0.0702 for. Cu(h). The relationship between the heavy metal in soil, plants and honey was investigated using the Spearman’s rank correlation coefficient. Significant differences in the concentrations of Fe(s), Al(s) and Pb(s) in soils, Fe(p) and Zn(p) in the plant samples, Fe(h) in honey samples from the different locations were found. The heavy metal content tested in honey did not pose a risk to human health.

The soil seed bank, as a potential source of ground vegetation renewal, plays an important role in the natural recovery and succession of vegetation as well as in the construction of ecosystems. To clarify the characteristics of the soil seed bank of Achnatherum inebrians and its relationship with the aboveground vegetation, the soil seed bank density, species composition and aboveground vegetation of three different grassland types, namely, desert, steppe and meadow, were investigated by means of field survey sampling and indoor germination experiments. The results showed that the seed bank densities of the three habitats were ranked as desert (1 422.22 seeds/m²), steppe (2 077.78 seeds/m²) and meadow (3 722.22 seeds/m²). The numbers of species were 16, 11 and 17, respectively. With respect to the vertical allocation, the soil seed banks in each habitat were shallow, and the seeds were mainly concentrated in the soil surface layer (0–5 cm). The species richness of the soil seed banks in the three habitats was higher than that of the aboveground vegetation, but there were some differences in richness, evenness and dominance. The species richness and diversity of soil seed banks and aboveground vegetation in meadow habitats were higher than those in desert and steppe habitats, indicating that the soil seed banks and aboveground vegetation in meadow habitats had higher stability. There was a significant positive correlation between the density of temporary soil seed banks and the density of aboveground plant communities in grassland habitats. The results may provide some reference for the prevention and control of Achnatherum inebrians in the three habitats.

A greenhouse study was conducted to test the effects of low herbicide dose exposure on different crops measuring visible damages, plant height, leaf area, and dry matter. Seven crops were tested: lettuce (Lactuca sativa L.) cv. Novosadska majska maslena, oil pumpkin (Cucurbita maxima Duch) cv. Olivija, oilseed rape (Brassica napus L.) cv. NS Ras, pepper (Capsicum annuum L.) cv. Kurtovska kapija, soybean (Glycine max (L.) Merr) cv. ZP Laura, sunflower (Helianthus annuus L.) cv. NS Kruna, and tomato (Solanum lycopersicum L.) cv. Dunavski Rubin. Herbicide dicamba in the range of 0.14 to 1 155.6 g a.i. (active ingredient)/ha inhibited biomass, height, leaf area, and visual injury of all crops, while glyphosate doses from 0.48 to 3 840 g a.i./ha also reduced the growth of all tested species. A rate of 116 g a.i./ha mesotrione was needed to reach 80% visual injury in oilseed rape, while the same effects on lettuce only required 1.8 g a.i./ha of mesotrione. Tomato and oil pumpkin were also sensitive to low mesotrione doses, where only 1.3 g and 0.5 g a.i./ha of mesotrione was needed for 80% of biomass reduction, respectively. Lettuce was the most sensitive crop of all tested species; biomass was reduced by 80% by dicamba, glyphosate, mesotrione, and nicosulfuron at the low rates of 33 g a.i./ha, 19 g a.i./ha, 1.25 g a.i./ha, and 2.7 g a.i./ha, respectively. Among all herbicides, visible injuries were detected in dicamba at the lowest rates. Soybean was the most tolerant of glyphosate, mesotrione, and nicosulfuron. Based on the available literature and obtained results, herbicide off-target movement must be mitigated to maximise herbicide efficacy and decrease the negative influence on susceptible plants and the environment.

The present study compares the six crop residue management techniques in main plots (since 2008) and three split nitrogen (N) levels, i.e., 75, 100 and 125 kg N/ha in subplots for rice crops for two years, i.e., 2019 and 2020, in sandy loam soil under field conditions. This experiment evaluated the long-term effect on rice productivity, soil organic carbon content and nutrient requirement in rice-wheat cropping system. The results revealed that different crop residue management practices and N levels significantly influenced rice growth, yield and yield attributes and improved nutrient uptake by grain and straw. Maximum grain yields of 20.8% and 17.8% higher over the conventional (no straw) treatment during 2019 and 2020, respectively, were recorded where the rice and wheat residue was retained or incorporated. The rice grain yield without residue responded significantly up to 125 kg N/ha. Whereas, with rice and wheat residue, rice grain yield did not respond to the application of N beyond 75 kg N/ha during both years.

The effects of potato drip irrigation on soil nitrogen dynamics and potato yield was studied in small-plot field trials. The trials were evaluated at during three experimental times seasons (2016-2018). Four variants of irrigation were determined, ie non-irrigated, 60, 65 and 70 ASWC (Available Soil Water Capacity). At the same time, two pre-planting fertilization dates were set at a maximum of 120 kg N/ha a in divided i.e. 60 kg N/ha before planting and 60 kg N/ha by fertigation during vegetation. Pre-planting crop fertilization or in-season fertigation did not have any significant effect on the potato yields of most variants. In all studied parameters, the positive beneficial effect of irrigation was recorded and compared to the non-irrigated control. The mitigation of drought stress in plants during the growing season is the most important advantage of irrigation. In the trials, on average across all years and varieties, the yield of the irrigated variant increased by 41 % compared to the non-irrigated variant. Maintaining optimal soil moisture has a favourable effect use of applied fertilizers. The highest mineral nitrogen content in the soil was recorded for the variant without irrigation. Considering the increased use of nitrogen fertilizers, the subsurface drip line appeared to be optimal for the creation of suitable conditions for nitrogen availability to plants in the root zone.

A ¹⁵N-labelling technique was carried out to investigate the effect of wheat straw co-application with Bacillus nealsonii, Cohnella, and Paenibacillus lautus on N uptake and assimilation in Diospyros lotus. Wheat straw combined with Bacillus increased the plant height, biomass accumulation, photosynthetic capacity, and uptake of ¹⁵N by roots, with ¹⁵N accumulating mainly in leaves of D. lotus. The NO₃^–-N content in roots and leaves were decreased by wheat straw co-application with Bacillus, whereas NH₄⁺-N, soluble protein, and total N contents were increased. Wheat straw addition promoted the activities of nitrate reductase, glutamine synthase and glutamate synthase in roots rather than in leaves. These N assimilation enzymatic activities, and glutamic-oxaloacetic transaminase and glutamic pyruvic transaminase activities were markedly increased by wheat straw combined with Bacillus. Moreover, the combined application of wheat straw and Bacillus, particularly B. nealsonii, improved the N use efficiency. These findings suggest that the combined application of wheat straw and Bacillus improved D. lotus growth by increasing N uptake, metabolism, and utilisation efficiency.

The ability to adapt, survive, and compete with weeds of transgenic plants is the necessary evaluation content to release transgenic lines in target regions. We compared weediness and agronomic traits of transgenic maize lines G1F-8 and G1F-19 carrying the mcry1F gene with their near-isogenic maize inbred line Zheng 58 in the wasteland and cultivated field under natural conditions for two consecutive years. The results showed that there was no significant difference identified in the species, quantity, and relative coverage ratio (RCR) of weeds between fields with G1F-8, G1F-19, and Zheng 58, regardless of the sowing pattern in the wasteland. Compared with the vigour of weeds, none of G1F-8, G1F-19, and Zheng 58 showed survival advantages, and all showed weak growth potential with no final grain yield. Meanwhile, no volunteer seedlings were found upon investigation in the following year. The simulated seed overwintering experiment in the wasteland further showed that the three kinds of maize could not germinate in the second year. In cultivated land, G1F-8 and G1F-19 had the same growth stages, plant height, and RCR as Zheng 58 throughout two years. In conclusion, the transgenic lines G1F-8 and G1F-19 exhibited no adaptability risk in Gongzhuling, Jilin, China.

Water and nutrient use efficiencies are important adaptive features of plants in arid and semi-arid environments. In this study, water, nitrogen (N), and phosphorus (P) use efficiencies of Stipa purpurea Griesb., an endemic and dominant grass species, were investigated in the alpine steppe along precipitation gradients on the Tibetan Plateau. The leaf N content of S. purpurea increased along the precipitation gradient, but leaf P decreased, whereas carbon (C) remained unchanged. Leaf δ¹³C (water use efficiency, WUE) and C : N ratio (N use efficiency, NUE) decreased with increasing precipitation. But leaf C : P (P use efficiency, PUE) and N : P ratios increased with increasing precipitation. A trade-off was found between WUE and PUE but not between WUE and NUE. The changes in leaf traits were associated with changes in soil water, organic C, total N and P. These findings offer insights into understanding alpine plant water and nutrient use strategies along a precipitation gradient, as well as facilitate the prediction of alpine ecosystem responses to precipitation changes.