Yinghua LUO, Shanmin QU, Xiangping LIU, Chenghao JIN

College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing 163319, China

Abstract At present, the development and function research of lawn has become diversified, and the application of lawn has been extended from outdoor to indoor environment. The indoor lawn has functions of absorbing toxic and harmful gases, releasing oxygen, increasing air humidity and regulating temperature. It can effectively improve the indoor air quality of northern areas, purify and beautify the home environment. This paper elaborated the purpose and significance of the application of new indoor lawn, the establishment methods of the indoor lawn, and the application design of the indoor lawn landscape.

Key words Northern areas of China, Indoor lawn, Environmental protection

1 Introduction

With the social and economic development, people’s quality of life has been continuously improved, and their working and living environment has changed from survival to health, energy conservation and environmental protection. Now, people pay more and more attention to the low-carbon and environmental protection of working and living environment, and the indoor air quality safety is also receiving more and more attention. Especially, in the northern areas of China, the cold period nearly spans a half year. Thus, heating is very important. Modern heating in the living room mainly adopts geothermal heating, which often leads to the closed state inside the living room, accordingly leading to the situation that indoor air is too dry and the relative humidity of the living room is seriously insufficient. These greatly reduce the comfort level of people’s indoor life, and often cause the occurrence of a large number of rhinitis patients in the northern winter, seriously influencing the daily life of people in northern areas. Therefore, in order to improve the comfortable indoor living and working environment, people often use plants to regulate the indoor air quality and humidity. As new environment-friendly material, the indoor lawn landscape has functions of adsorbing dust in the air, absorbing toxic and harmful gases, releasing oxygen, and increasing air humidity and regulating the indoor temperature[1]. Therefore, the application of lawn is gradually extending from the outside to the purification and beautification of the indoor environment in the northern areas.

2 Purpose and significance of indoor lawn landscape application

In recent years, with the continuous improvement of people’s living standards, the pursuit of higher quality of life and mental enjoyment has gradually been introduced to people’s daily life. However, the increasing deterioration of environmental pollution has brought serious threats to people’s physical and mental health. Environmental pollution has become a common concern and a problem that needs to be solved urgently. It has been found that the lawn has played an important role in improving the environment. The artificial indoor lawn landscape has the functions of regulating indoor air humidity and absorbing toxic and harmful gases in the air[2]. The photosynthesis of the indoor lawn can make the indoor air fresher, and the photosynthetic rate is higher than that of the potted flowers, thus the indoor lawn has a significant effect on improving the indoor air quality in the northern areas of China[3]. Indoor lawn refers to the lawn using the lawn the main raw material to improve the indoor living environment and give people a natural beauty. It refers to the herbaceous plant community with certain landscape effects and ecological effects grown under artificial cultivation conditions[4].

3 Analysis on current situations of indoor lawn landscape application

The development of indoor lawns is a new and emerging industry[3]. In China, the development of indoor miniature lawn landscape is still in its infancy. Because the design of indoor lawn landscape has high design requirement, and the indoor environment does not have sufficient sunshine and space like outdoor. What’s more, it has other series of limitations such as grass selection, and substrate selection. The positive significance of indoor lawns for living room air has been confirmed by experts. According to the findings of Tuyaetal.[5], a certain number of indoor small lawn has the effect of increasing indoor humidity by about 50%, reducing airborne bacteria by more than 90%, and reducing airborne formaldehyde by 0.53 mg/m3within 24 h. Through comparative experiments, Chen Jing studied the humidity, formaldehyde and bacteria content of the simulated lawn on the simulated space, and test results showed that the formaldehyde concentration dropped from the initial 0.75 mg/m3to 0.17 mg/m3after 24 h, and the bacteria in the air declined by more than 90%, the indoor air humidity is increased by about 45%[6]. These research findings could provide a theoretical basis for the development and promotion of indoor small lawn application and the further improvement of the living environment.

4 Specific application of indoor lawn landscape

In China, the research on application of indoor lawn started late, and there are few research data on indoor lawn. According to the current development of lawn industry in China, we made a preliminary discussion on the development of new lawn in the northern areas of China, and selected the optimum conditions for establishment of indoor lawn, in hope of laying a foundation for the research and development of indoor lawn in the future.

4.1 Selection and performance comparison of indoor lawn grass speciesIn northern areas, indoor lawn grasses should select variety that has uniform color, beautiful appearance, long green period, low and tidy plants, and strong resistance to pests and diseases. The main types of lawn grasses in the northern areas of China are cold-season lawn grass species, which are characterized by cold tolerance and long green period. There are two growth peak periods of spring and autumn in the year, and the growth is slow and dormancy occurs in summer[2]. Commonly used cold-season lawn grasses mainly include: hundreds of varieties of more than 40 species, such as Poa Linn., Festuca Linn., Lolium Linn., Agrostis Linn., Bromus Linn. and Bromus Linn.[7]. PerennialLoliumperenneL. and hardFestucaL. have higher color and texture;FestucaelataKeng ex E. Alexeev, perennialLoliumperenneL. have high density and good integrity; hardFestucaL. andFestucarubraL. have strong disease resistance but weak heat resistance; perennialLoliumperenneL. is the easiest to form lawn. Generally, it is possible to consider mixed planting, such as Poa Linn.,FestucaelataKeng ex E. Alexeev. and perennialLoliumperenneL.[2]In northern areas, the common varieties of lawn grasses include Poa Linn.,FestucarubraL., Festuca elata Keng ex E. Alexeev., Carex heterostachya Bge., and perennialLoliumperenneL.

4.2 Establishment of lawn

4.2.1Soilless culture substrate. Simply speaking, the soilless culture substrate is the use of nutrient solutions and solid matrices to provide the necessary water, nutrients, oxygen and temperature for plant growth and development[4]. The ideal soilless culture substrate should have reasonable physical and chemical indicators, stable chemical properties, near-neutral pH, and have no toxic substances. The advantages of soilless cultivation include high yield, good quality, water saving, fertilizer saving, labor saving, less pests and diseases, no obstacle of continuous cropping, thus it is an effective way to achieve modernization and green production of mass production. For the convenience of management, most of the indoor lawns are planted through soilless cultivation. The soilless culture substrate is characterized by short pinging time, easy access to matrix materials, low management cost, no weeds, light weight, cleanliness, easy processing and redesign[2]. The soilless culture substrate generally adopts substrate mixed in a certain proportion to form a matrix. For example, the inorganic matrix adopts river sand, vermiculite, slag, etc., and the organic substrate adopts fermented cotton stalk, mushroom slag, fermented corn stalk, fermented maize cob, andetc. Usually, the matrix formula mainly adopts maize stalk∶vermiculite∶river sand=5∶3∶2, cotton stalk∶vermiculite∶river sand=5∶3∶2, maize talk∶slag∶river sand=5∶3∶2, and cotton stalk∶slag∶river sand=5∶3∶2,etc.[4].

4.2.2Supply of water and nutrient solution. The indoor lawn planting can not lack the supply of irrigation and supply of nutrient solution. Combined with the characteristics and requirements of indoor lawn planting, it is possible to use environmental small pipes for water and nutrient solution supply[2]. In order to maintain the appearance, the small pipes should be designed in the lower part of the substrate when making the base. The roots of the lawn grass should be in the matrix inside the pipe to maintain the good growth of the lawn grasses. The water supply system adopts the tidal method water pump design. When the water pump starts, the water level remains in a saturated state and will not spill over from the fixed holes, so that the soilless substrate absorbs the nutrient solution and gives the lawn sufficient nutrition. When the pump stops, the water level will slowly drop, so that it will keep a good gas permeability. Nutrient solution is the key to soilless cultivation. The preparation of nutrient solution should take into account the purity and cost of chemical reagents. The method of preparation is to first dispense the mother liquor (stock solution) and then dilute it. In this manner, it can save the container and facilitate the storage.

4.2.3Design of the "indoor lawn creative landscape". Depending on the size of the indoor space and the location, it is recommended to design indoor creative landscape lawns with different sizes, such as wavy lawns, down-grade lawns, and rain-drop lawns. It can also be designed as a retractable lawn landscape according to the size of the field. It can be made into a lawn landscape that can be moved at any time. It can also be designed into any creative mosaic lawn block according to the different seasons, so as to achieve the rationality of indoor layout[7]. How to use the indoor lawn design in a more scientific and reasonable manner, bring the greatest benefits to the people, and maximize the function of the lawn has become the primary problem of the current grass science workers.

5 Prospects

In northern areas of China, the new indoor lawn landscape has the functions of absorbing dust and generating oxygen, purifying indoor air, beautifying the environment, and also can effectively regulate the humidity and temperature in winter, bringing a healthy and environmentally friendly natural environment to mod-ern living, making people forget the fatigue of work, the sorrow of life, but providing the desire to yearn for a new life. However, the research and application of new indoor lawn in the northern areas are still in the infancy, and a complete set of indoor lawn cultivation and maintenance mode has not been established yet. Indoor lawn is different from ordinary outdoor lawn. It is necessary to consider that indoor lawn grows on a special substrate. For non-professional ordinary families, planting indoor lawn will face long-term planting and possible lawn pruning problems, lawn diseases and maintenance and management problems. As a result, the promotion and utilization of the new indoor lawn landscape have not formed a certain commercial scale in northern areas of China, and has not been widely promoted by the public. Therefore, the research on application of new indoor lawn landscape is expected to provide a new direction for the application of lawn grasses, and lay a certain foundation for the market development of lawn products.