Optimal instar and method of meta-tolyl-N-methyl-carbamate application for killing Aphrophora costalis Matsumura

For determining the effects of meta-tolyl-N-methylcarbamate (MTMC, metolcarb) on Aphrophora costalis Matsumura (ACM) and the migration and leaching law of MTMC in soil, the thin-layer chromatography method was used. The characteristics of migration and leaching of MTMC in the dark brown soils, and the most critical influences such as soil type, pH, and amount of water were considered to evaluate the impact of leaching rate. The results showed that 25% MTMC diluted 1,000 times was most effective in controlling ACM, with a mortality reaching 87.8% by root irrigation, and a mortality of up to 94.4% by root burial. For dark brown soil, clay minerals are primarily quartz, as well as small amounts of agalmatolite, mica, and kaolinite. Adsorption of MTMC by dark brown soil begins within 2 h, which increases rapidly in capacity before 16 h, and tends to balance with a decrease in the gradient concentration after 16 h. The desorption capacity of MTMC exhibits a gradual increase within 2 h, showing a maximum around 12 μg·g-1, which tends to stabilize after 12 h. MTMC has moderate mobility in dark brown soil. This research has important practical significance for controlling tree diseases and insect pests and protecting the environment.

Responses of Arbuscular Mycorrhizal Fungi Diversity and Community to 41-Year Rotation Fertilization in Brown Soil Region of Northeast China

Arbuscular mycorrhizal fungi (AMF) play vital roles in the growth and development of plants, ecosystem sustainability, and stability in agroecosystem, such as transporting nutrients to host plants, improving soil physical structure, and enhancing the stress resistance of host plants. However, the effects of fertilization on AMF diversity and community in brown soil areas are still unclear. The purpose of this study is to explore changes in AMF diversity and community structures and finding out the factors that influenced the changes after 41 years of fertilization in brown soil. Samples were collected from five treatments of the long-term fertilization experiment in June 2019, including CK (no fertilizer), N (mineral nitrogen fertilizer), NP (mineral nitrogen and phosphate fertilizer), M (pig manure), and MNP (pig manure, mineral nitrogen, and phosphate fertilizer). Illumina HiSeq sequencing was used to determine AMF diversity and community structure. The relationship between AMF communities in soil and roots and environmental factors was analyzed by redundancy analysis. The results showed that the soil nutrient content of manure treatments was generally higher than that of chemical fertilizer treatments and no fertilizer treatment. Long-term fertilization increased AMF spore density, which increased with the increase of soil fertility. The moderate content of soil available phosphorus was beneficial to the colonization of AMF. AMF diversity in soil decreased with soil fertility, but AMF diversity in roots was influenced only by soil nitrate–nitrogen and pH. Glomus was the dominant genus in both soil and root samples. AMF community structure in soil and roots had a different response to long-term fertilization. Application of manure had a greater impact on AMF community structure in soil, whereas application of exogenous phosphate fertilizer had a greater impact on that in roots. Soil ammonium nitrogen, nitrate–nitrogen, total nitrogen, organic carbon, total potassium, and available potassium were the most important factors that influenced taxa of AMF in soil, whereas soil ammonium nitrogen, nitrate–nitrogen, total nitrogen, organic carbon, total potassium, available potassium, available phosphorus, and plant phosphorus and potassium content were the most important factors influencing taxa of AMF in maize roots under long-term fertilization in brown soil.

Prediction of sediment transport capacity based on slope gradients and flow discharge

Sediment transport capacity (Tc) is an essential parameter in the establishment of the slope soil erosion model. Slope type is an important crucial factor affecting sediment transport capacity of overland flow, and vegetation can effectively inhibit soil loss. Two new formulae of sediment transport capacity (Tc) are proposed of brown soil slope and vegetation slope in this study and evaluate the influence of slope gradient (S) and flow discharge (Q) on sediment transport capacity of different slope types. Laboratory experiments conducted using four flow discharges (0.35, 0.45, 0.55, and 0.65 L s-1), four slope gradients (3, 6, 9, and 12°), and two kinds of underlying surface (Brown soil slope, Vegetation slope). The soil particle size range is 0.05–0.5mm. The vegetation stems were 2mm in diameter and randomly arranged. The results show that the sediment transport capacity was positively correlated with the flow discharge and slope gradient. The vegetation slope’s average sediment transport capacity is 11.80% higher than the brown soil slope that same discharge and slope gradient conditions. The sensitivity of sediment transport capacity to flow discharge on brown soil slope is higher than that of slope gradient. The sensitivity of sediment transport capacity of vegetation slope to slope gradient is more heightened than flow discharge. The sediment transport capacity was well predicted by discharge and slope gradient on brown soil slope (R2 = 0.982) and vegetation slope (R2 = 0.993). This method is helpful to promote the study of the sediment transport process on overland flow.

Influence of copper microelement on productivity and fruit quality of the innab plant in macrofertilizer backgraund

On Absheron gray-brown soils, studies were carried out using various doses of copper microelement against the background of macrofertilizers on the productivity and quality of innab fruits. The results of laboratory analyses showed that Absheron's gray-brown soils are poorly provided with forms of nitrogen, phosphorus and copper microelement and potassium medium. The microelement copper was carried out under the innab culture against a background N100P40K70 in 3 doses. The results of the studies showed that the highest productivity increase (3.2 s/ha or 11.2%) and fruit quality (vitamin "C" 635mg/%, sugar 32.5%, acidity 0.57% and microelement content: Cu-28.3-Zn-30.5.0mg/kg,) the innab plant is observed in the version with copper application at the rate of 2.0 kg per ha. Key words:macrofertilizer, microelement, gray-brown soil, innab, productivity, quality

Environmental Behaviors of Procymidone in Different Types of Chinese Soil

Procymidone is a widely used fungicide in the prevention and treatment of fungal diseases on many crops in China. Part of the procymidone will enter the soil during the application process. Procymidone may exhibit environmental behavior diversity in different soils. Therefore, it is extremely important to clarify the environmental behavior of procymidone in soil for its environmental safety evaluation. Here, the degradation, adsorption, and mobility behaviors of procymidone in four typical types of Chinese soil were investigated for the first time. The half-lives of procymidone in the soils ranged from 14.3 d to 24.1 d. The degradation rates of procymidone in the soils were promoted by organic matter content, moisture content, and microorganisms. Furthermore, the degradation of procymidone on the soil surface was promoted by light. The desorption rates of procymidone in laterite soil, yellow brown soil, black soil, and chestnut soil were 27.52 ± 0.85%, 16.22 ± 0.78%, 13.67 ± 1.29%, and 7.62 ± 0.06%, respectively, which were contrary to the adsorption ability. The mobility order of procymidone in the soils was: laterite soil > yellow brown soil > black soil > chestnut soil, with the Rf values of 0.28, 0.22, 0.18, and 0.16, respectively. Three degradation products of procymidone were identified by liquid chromatography coupled with quadrupole/time-of-flight mass spectrometry, and the degradation pathway of procymidone in the soil was speculated. The results will provide a theoretical basis for the removal of procymidone in the soil environment.

Environmental assessment of the use of the herbicide Lumax

The sensitivity of agricultural crops to the Lumax herbicide, consisting of three active agents C-metolachlor, terbutylazine and mesotrione, the duration of their action in meadow-brown soil, and the aftereffect of the herbicide on the plants of the crop rotation were determined. The study was conducted in the conditions of the greenhouse in the Primorsky Territory in 2019 and 2020. The herbicide Lumax was used on experimental plots before corn germination at doses of 4.0 l/ha (recommended) and 8.0 l/ha (twice the recommended). In the autumn of 2019 and in the spring of 2020, samples of meadow-brown soil were taken from the experimental plots and from the control (without herbicides) from the depth of the arable layer containing 3.5% humus. The samples were used to establish the duration of the action of active agents and the aftereffect of the herbicide Lumax. Prior to this, plants indicating residual amounts of the chemical in meadow-brown soil were preselected. The doses of the herbicide which reduce the above-ground mass of the test plant by 50% were calculated, as well as its maximum permissible concentration in the soil. It was determined that by the end of the growing season, 0.7–3.0% of the active agent of the herbicide Lumax is retained in meadow-brown soil at a rate of application of 4.0 l/ha, and 0.6–3.9% – at a rate of 8.0 l/ha. By the beginning of the next field season, the preparation applied at the recommended rate completely decomposed, while when it was applied at a double rate of the recommended rate, 0.8–1.7% of the herbicide remained. Eight months after the application at a rate of 4.0 l/ha, the herbicide Lumax is safe for subsequent crops of the crop rotation. In case of overdose or double application (8.0 l/ ha), it can have an aftereffect on sensitive crops. The crops that are highly sensitive to the Lumax preparation were identified: cabbage, radish, rapeseed, beetroot, tomatoes, cucumber and rice; sensitive: wheat, buckwheat and soybean; relatively resistant: oats and barley. A safe consumption rate of the Lumax herbicide (4.0 l/ha) for subsequent crops of the crop rotation was established.

Impact of manure and biochar additions on annual crop growth, nutrient uptake, and fate of 15N-labelled fertilizer in two contrasting temperate prairie soils after four years

Liquid hog manure (LHM) and solid cattle manure (SCM) co-applied with biochar could beneficially influence soil nitrogen (N) and phosphorus dynamics. A split-plot design was used at two sites (Brown and Black) in Saskatchewan to assess LHM and SCM (100 kg N ha-1) applied alone or in combination with biochars (8 Mg carbon ha-1) produced using slow or fast pyrolysis. Crop growth and nutrient uptake, along with fertilizer 15N recovery were followed over four years in a cereal-oilseed rotation. Crop growth on the Brown soil was more responsive to the treatments than the Black soil, reflecting lower fertility of the Brown soil. The manure and biochar, applied alone or in combination, had little impact on available soil phosphorus. Manure and biochar effects on crop growth and nutrient uptake were attributed to temporal effects on soil N immobilization-mineralization influencing plant available soil N. A negative impact of the fast pyrolysis biochar on growth and plant uptake was observed and attributable to its greater labile-carbon content, which likely promoted soil N immobilization. Synergism observed between SCM and the slow pyrolysis biochar may reflect enhanced net SCM-N mineralization and increased water-holding capacity. The majority (55-80%) of plant 15N recovery occurred during the first year, with 86% of fertilizer 15N conserved within the soil-plant system after four years. Greater (40%) plant 15N recovery without biochar addition, coupled with increased (38%) soil 15N recovery with added biochar, suggests biochar-related immobilization and/or sorption in the biochar-amended soils.