AGROENERGY EFFICIENCY OF IMPROVED TECHNOLOGIES FOR CREATION AND USE OF ALFALFA-CEREAL HAYMAKING IN THE NON-CHERNOZEM ZONE

On the basis of field experience in the creation of alfalfa-grass stands on sod-podzolic soil of the Non-Chernozem zone, a high agroenergetic efficiency of improved technologies has been established, including two zoned varieties of alfalfa changeable (Lugovaya 67 and Pastbishchnaya 88) in combination with agrotechnical methods (change in the composition of leguminous species in the previous period and pre-sowing inoculation of alfalfa seeds with complementary strains of Sinorhizobium meliloti). As a result of the application of the agro-energy method for assessing the production of exchangeable energy and total anthropogenic costs in uniform indicators according to the international SI system (GJ/ha), their payback was established — 8–11 times. This was achieved due to a high share of natural factors (88–91% of total costs), additional nitrogen input into the production process due to increased symbiotic fixation (141–171 kg/ha per year) and long-term use — for 7 years. The productivity of 1 hectare was 62–64 GJ/ha metabolic energy, the collection of protein was 956–1120 kg/ha, the saving of anthropogenic costs due to the exclusion of the use of nitrogen fertilizers was 17–21 GJ/ha.

Competition and Plant Trait Plasticity of Invasive (Wedelia trilobata) and Native Species (Wedelia chinensis, WC) under Nitrogen Enrichment and Flooding Condition

Nitrogen (N) is the important nutrition that regulatory plant functioning and environmental stability of invasive plant species under flooding (F) conditions. Little information clarifies the role of nitrogen enrichment and flooding on the invasive plant functional traits and competition with native competitors. Plant functional traits play an essential role in the successful growth of plants under different environmental conditions. Therefore, greenhouse pots experiment was conducted with invasive plant species (Wedelia trilobata, WT), and its native competitor (Wedelia chinensis, WC) in monoculture and cocultivation culture, along with flooding and nitrogen enrichment conditions. Considering the impact of flooding (F) and nitrogen (N) on an individual basis, the plant physiological traits of WC were nonsignificant compared to that of WT. However, in the combination of flooding × additional nitrogen (F.N, F.2N), plant physiological traits of WT were comparatively higher than those of WC, especially in cocultivation. In flooding × additional nitrogen (F.N and F.2N), better phenotypic plasticity at different plant traits makes WT more dominant in resource competition over WC. In conclusion, improved functional traits of WT under nitrogen enrichment and flooding conditions enhanced its competitiveness over native competitors.

CO-DIGESTION OF GREASY WASTE AND MBR SLUDGE USING BIO-AUGMENTED PSEUDOMONAS PUTIDA: EFFECT OF BUFFERING AGENTS

This study aims to investigate the bio-augmentation of Pseudomonas putida for initializing fat, oil,and grease (FOG) biodegradation in a co-digestion of the greasy waste and the membranebioreactor (MBR) excess sludge. The MBR sludge could be an additional nitrogen sourceconcurrently as a waste matrix fluidizer. Three rounds of a fed-batch of an HRT of 56-71 dayswere carried out. The first (B1) and second (B2) batches using phosphate (Na2HPO4) solution as abuffering system. It showed that the digesters with bio-augmented P. putida could remove moreFOG than that of the control. In the third batch (B3), the buffering solution was changed tobicarbonate (NaHCO3) with the interval bio-augmentation of P. putida in different doses; the 250ml (B3, T-250) and the 1000 ml (B3, T-1000) of P. putida culture every two weeks dosing. Thehighest FOG removal was found in both conditions with the removal efficiency of 79.77%. Thisstudy suggests that bicarbonate was a suitable buffer in the co-digestion process for the intervalbio-augmentation of P. putida. Moreover, it showed that a higher interval dose (B3, T-1000) of P.putida gave a more methane production rate of 981.08 ml/g TVS. d compared to the lower dose ofB3(T-250) with 353.75 ml/g TVS. d.

Activation of the symbiosis of free nitrogen-fixing bacteria with plants by an additional influx of photosynthesis products to the roots

An in vivo technology is proposed that enhances the export of assimilates from leaves to roots. The possibility of thus increasing the mass of the roots and the formation of additional nitrogen in the soil-plant system is shown.

Potato Yield Gaps in North Korea and Strategies to Close the Gaps

Potato has become one of the staple crops to improve food security in North Korea since the late 1990s. However, the potato yield has been stagnated around 11–12 t ha−1 for several decades, and a food shortage is still a primary issue in North Korea. Yield gap analyses were carried out using the SUBSTOR-potato model to quantify the potato yield gaps and explore the potential ways to close the yield gaps in two different cropping seasons in North Korea (early- and main-season potatoes). Yield gaps were estimated to be around 80% for both early- and main-season potatoes. Early-season potato yield was substantially determined by water or nitrogen supplies, depending on the year’s weather condition (i.e., with or without spring drought). Irrigation during the vegetative stage could effectively reduce the year-to-year variation in yield as well as the yield gap (+7.0 t ha−1, +66.1%). Meanwhile, additional nitrogen fertilizer in the early-season potatoes was less effective compared to that in the main-season potatoes. For the main-season potatoes, where precipitation was sufficient, the primary limiting factor of yield was nitrogen supply. Since heavy rainfall aggravated nitrogen leaching, additional nitrogen fertilizer is recommended as a top dressing rather than a basal dressing. Additional top dressing at 50 days after planting with the current amount of nitrogen fertilizer was expected to increase the main-season potato yield by 42.0 t ha−1 (+191.4%). This study highlights that the primary limiting factor of potato yield may differ between the cropping seasons. Therefore, our findings suggest that different agronomic strategies should be applied for different cropping seasons to improve potato production in North Korea, where agronomic resources are limited.

Surface Current Improvement of Magnesium-Doped Hexagonal Boron Nitride Monolayer by Additional Nitrogen Gas Flow

Hexagonal boron nitride (h-BN) is the most well-known wide band gap two-dimensional (2D) material (> 6 eV). To achieve its applications in optoelectronic devices, the conductance of h-BN must be implemented to the extent that it can be fabricated into a p–n junction. Here, we demonstrate a method to improve the surface current of p-type h-BN monolayer by introducing additional nitrogen gas flow during growth. First-principles calculations were conducted to show that nitrogen atmosphere can promote the formation of boron vacancy, making a low barrier site for Mg doping incorporation. Magnesium-doped h-BN monolayer was achieved using a low pressure chemical vapor deposition method under N2 flux. The surface current has been enhanced by three times up to 16 μA under 4 V external voltage. This approach provides potential applications of controllable conductive h-BN film for two-dimensional optoelectronic devices.

Increasing Chitinase Activity of Serratia marcescens PT-6 through Optimization of Medium Composition

Chitin hydrolysate is one of the value added product derived from shrimp shell waste. Production of chitin hydrolysate using biological process offers an environmental friendly method compared to chemical process. Serratia marcescens PT-6, a gram negative chitinolytic bacterium isolated from shrimp pond sediment, shows good activity in hydrolyzing chitin. This study aimed to improve the chitinase activity of S. marcescens PT-6 culture by optimizing the component of chitin-containing medium (additional nitrogen source, additional carbon source, and colloidal chitin). The optimization of chitinase by S. marcescens PT-6 culture was done using one variable at a time method. The sequence of the research were to optimize 1) the type of additional carbon source (glucose, lactose, sucrose, and starch), 2) the type of additional nitrogen source (yeast extract, peptone, ammonium sulphate, and ammonium chloride), 3) the concentration of colloidal chitin (0.5; 1; 1.5; 2; and 2.5%), and 4) the concentration of the additional carbon and nitrogen source. The culture of S. marcescens PT-6 was incubated in colloidal chitin medium at 30 oC and chitinase activity from culture supernatant was analyzed. The results showed that starch gave the highest chitinase activity compare to other carbon source, meanwhile yeast extract was chosen as the best nitrogen source among others. The combination of 1.5% colloidal chitin with 0.5% starch and 0.1% yeast extract in medium increased the chitinase activity of S. marcescens PT-6 to 0.021 U/ml. These results indicated that an appropriate medium composition could increase the chitinase activity produced by S. marcescens PT-6 culture.

The effect of the term of mulching and herbicides spraying on ‘Foxtrot’ tulip flowering and bulbs yield

The experiment studied the effect of various mulching terms of ‘Foxtrot’ tulips with wheat straw in combination with spraying of plantations with herbicides using various doses and different amounts of working liquid. The mulch was laid out just after planting and after the soil had frozen. The experiment included combinations, in which the mulch was left until the end of the growing season or removed in spring. Spraying with single (linuron 675 g·ha–1 + lenacyl 1000 g·ha–1) or double herbicide dose (linuron 1350 g·ha–1 + lenacyl 2000 g·ha–1) was made before covering the soil with mulch and also on mulch – two weeks after planting the bulbs, or in the spring after thawing the soil. Volumes of 300 dm3 and 600 dm3 of working liquid were used for spraying. Tulips covered with mulch bloomed 2–3 days later and formed longer shoots as compared to non-mulched ones. The highest yield of marketable bulbs and the first-selection ones was obtained from tulips mulched immediately after planting and sprayed 2 weeks later with herbicides used in a single dose of 600 dm3 of a working liquid. Mulching of tulips after soil freezing and removal of mulch in spring adversely affects the number and weight of commercial bulbs. The lowest yield was obtained in combinations, in which the mulch was not used. The use of additional nitrogen fertilization before laying out the mulch did not affect the yield of tulips. Herbicides can be used both before mulching and after covering the plantation with mulch. It is not necessary to increase the dose of the agent and the amount of water.