Soil Spraying Greening Project Construction Plan

     Soil Spraying Greening Features:

Soil Spraying Greening, an innovative green technology introduced to China from Japan in the late 1990s, involves thoroughly mixing grass seeds, fertilizers, water retention agents, soil, organic matter, and stabilizers, then uniformly spraying the mixture at a designed thickness onto the engineering slopes requiring protection to achieve a landscape that resembles natural greening.

Section II: Selection of Soil Spraying Methods:

Based on local temperature, rainfall, slope gradient, rock fissures, rock hardness, and plant selection, the "Metal Mesh Laying Project + Vegetation Matrix Spraying Project" is adopted to enhance the connectivity between the growth base and the slope, depending on the differences in site conditions. The choice of suitable grass species and their proportions, along with the growth environment for green plants and the dual function of promoting the growth of target tree species, ensures the effectiveness and quality. The soil spraying material includes plant seeds, organic nutrient soil, soil conditioners, stabilizers, microbial agents, and fertilizers. Soil spraying is carried out using a 12m3 air compressor and machinery, as well as mixers.

Section 3: Selection of Construction Duration

Based on the characteristics of the engineering climate, the construction period is from March to June, with optimal construction periods in February and September to October. Generally suitable periods are from November to January of the following year. Therefore, different seed mix ratios and construction methods are selected according to the climate characteristics of various construction phases to ensure the greening effect.

Section 4: Spraying Greening Project Construction Preparation

(One) Requirements for Spray Seeding Materials

Plant Seed Materials: Seed quality assessment: The target community is the shrub community in the ecological protection design principle for highway embankments. According to design requirements and varying local seasonal and soil conditions, indigenous plant species are used in combination with green, exotic plant seeds during winter. Mixed sowing is conducted with seeds of deep-rooted, grape-like, drought-resistant, poor soil-tolerant, and highly adaptable pioneer grasses and target tree species. The appropriate plant seeds and their ratios are selected to achieve a year-round green landscape effect. Before sowing, the germination rate of bulk seeds is tested, and seed quantities are calculated based on actual area and conditions to ensure effectiveness and quality.

(a) The main types of plant seeds provided according to design specifications are as follows:

Herbs: ryegrass, tall fescue, white clover,波斯菊,毛苕子, Bermuda grass, white clover.

(2) Shrubs: Pyracantha fortunea, Lespedeza, Parrotia, Phaseolus, Magnolia denudata, Ligustrum quihoui, Wisteria floribunda.

(3) Ya Jiu Mu: Fragrant Acacia, Alnus. (Used when the slope ratio is greater than 1:1.)

Mixed planting of plant seeds according to different seasons, adjusting the amount of each seed, sowing rate, and substrate mixing method for each construction period; the sowing rate per square meter is 20-30 grams; herbs account for 6%, shrubs for 94%.

(b) Key physiological characteristics of plant seeds:

(1) Tall Fescue: Highly cold-resistant. Suitable for growth in various soil conditions and adapts well to different site conditions.

(2) White clover: Tolerant to barrenness and strong cold resistance. It can grow in acidic soil under shade, with a dense root system that benefits soil formation.

(3) White clover: Grows rapidly in poor soil, performs better in moist conditions, but has poor drought and heat resistance, weak root-holding capacity, and is prone to soil slippage on steep slopes.

Dog's Tooth Vine: Highly tolerant of extreme heat and drought. Grows well on coastlines and sandy soils, but does not tolerate shade and has poor cold resistance.

Mulan of Many Flowers: Grows well in barren and arid lands, can also develop normally in poor soil quality, heat-resistant, but poor cold and acid tolerance; rapid initial growth, strong self-seeding ability.

(6) Amorpha fruticosa: Tolerant of poor soil and drought, with strong root stability, consistent germination and growth, high reliability, moderate shade tolerance, heat resistance, and easy compatibility with herbaceous plants. It can grow normally on steep slopes and rocky mountains, though its initial growth is relatively slow.

(7) Ryegrass: Capable of growth in barren areas and under shaded conditions, it has moderate wear resistance, adapts to a wide range of soils, and grows rapidly in slightly acidic, moderately fertile soil. It has poor cold, heat, and drought resistance, with annual ryegrass only suitable for growth in the same year.