Please select the most similar patent number from A, B, C and D. Which number is?
A method of cultivating a plant employing a small-quantity medium comprises: performing ground treatment; boring a hole in the ground; filling a medium in the hole; and sowing a seed or transplanting a seedling to cultivate a plant. After the hole has been bored, a plastic cloth or a seedling pot is provided inside the hole to hold the medium, such that the plant can be removed from the hole along with the medium later to obtain an independently-growing plant. Placing a medium in soil in a natural environment to cultivate a plant enables an environmental temperature of the soil to be effectively employed to perform cultivation, and ensures that the medium does not lose a large amount of water while completely isolating the plant from soil pests.
A: A soilless culture medium for succulents, comprising the following raw materials by volume: 25%-50% of peat soil, 25%-40% of worm cast, 20%-35% of carbonized rice husk, and 5%-20% of honeycomb briquette slag. The medium has an appropriate material ratio, low costs, proper air porosity and water-holding capacity, large total porosity, and small bulk density, and is particularly suitable for cultivation of succulents. An economical and environment-friendly culture medium for succulents is obtained by reducing the amount of the peat soil in the medium. The medium can be used as an ideal soilless culture medium for succulents.
B: Disclosed are a shallow and narrow riverway ecological management system based on an artificial ecological island and a construction method therefor. A plurality of artificial ecological islands are constructed in a riverway, a submerged plant planting blanket is laid on a riverbed of the riverway, and an aeration device is provided; wherein an island body of the artificial ecological island is an annular body that is hollow in the middle portion, water flow channels and supporting portions are arranged at intervals and in a staggered manner at the bottom of the annular body, and water flow is filtered and purified by means of a filter material matrix filled in the annular body; an aeration point is provided at the hollow position of the annular body, and air is pumped into a water body in the portion, so that the content of dissolved oxygen in the water body can be increased and the water quality can be improved; emergent plants and floating-leaved plants are planted on biological matrix soil layers at the upper half portion and the annular top of the annular body, and the submerged plant planting blanket on which submerged plants are cultivated is laid on the riverbed of the riverway, so that the aquatic plants can be used for further purifying the water body and beautifying the island body.
C: A method for ecological configuration of the constructed wetland having oil production wastewater to achieve the standard operation in winter is to achieve the standard operation in winter by means of ecological configuration transformation of the subsurface flow constructed wetland and the surface flow constructed wetland when the constructed wetland is used for treating high-salt wastewater from oil production. The subsurface flow constructed wetland consists of a soil matrix, water pipes for conveying wastewater that is placed at the bottom of the soil matrix and wrapped with a permeable non-woven fabric, and reeds of which the root system grows on the inner side of the pipe wall, the stem grows on the outer side of the pipe wall, and the length is larger than the thickness of the soil matrix layer. The surface flow constructed wetland consists of a soil matrix, reeds growing on the matrix, water, aquatic plants which are salt-tolerant and cold weather-tolerant in winter, free-range fish, shrimps, crabs, sea rainbows, mussels, oysters or clams in blocks, and artificial sand dam. The method overcomes the shortcomings of the prior art, enables constructed wetland having high-salt wastewater from oil production to operate normally in winter, and has low costs and significant economic benefits.
D: Disclosed is a method for remediating soil polluted with lead-polychlorinated biphenyl (Pb-PCBs) compounds, comprising: sterilizing Impatiens balsamina seeds with hydrogen peroxide and then spot-sowing in a seedling raising pot, transplanting into soil polluted with Pb and PCBs when the seeds have germinated and the young seedlings have grown to 5-8 cm, watering periodically to maintain an appropriate humidity, harvesting whole plants after growing for 120 days and handling properly, thereby completing a remediation cycle. The above operations are repeated until the content of Pb-PCBs in the soil is reduced to environmental safety standards. The present invention has the advantages of: Impatiens balsamina has strong adaptability and resistance to the cold and infertility, and seeds which are scattered on the ground can grow by themselves under appropriate humidity and heat conditions and can grow rapidly, facilitating cultivation and management; and compared to conventional polluted soil remediation methods, the remediation of soil polluted with Pb/PCBs compounds using the tolerant flower plant Impatiens balsamina has the characteristics of less investment, a low engineering workload, low technical requirements and no secondary pollution and the like, and the environment is beautified while the polluted soil is remediated.
Answer: A