How to save water during the summer water shortage for stump bonsai?

Major cities in our country are suffering water shortages, water prices are soaring, and some even ration water per person. Water use is becoming increasingly tight, and the water used by individuals to grow bonsai is not within the planned supply range. Only by taking the path of water conservation can stump bonsai survive in the city.

Since 2003, the author has been conducting experiments on water-saving bonsai cultivation, and over the past two years good results have been achieved. Now I would like to share them with everyone.

The space for growing bonsai in the city is very limited, and most people use rooftop platforms. There are two main reasons why growing bonsai on rooftops consumes more water than on flat ground: first, the roof receives sunlight for a long time (generally around 10 hours), and under strong direct sunlight, the temperature of the potting soil often rises to 37°C to 42°C, and the high temperature causes the moisture in the potting soil to evaporate rapidly. Second, the roof is exposed to wind on all sides, and the airflow is strong, which easily carries away the water vapor on the surface of the pot, causing the potting soil to dry out quickly.

In response to the meteorological characteristics of rooftop platforms, the following measures for cooling and preventing evaporation were adopted. I use disposable baby diapers, which have strong water absorption, can quickly absorb enough water in a short time, and are not easy to dry out afterward, as a material for absorbing water, preventing evaporation, and preserving soil moisture in bonsai. The specific operation method is as follows:

Take the disposable diapers used by babies and lay them one after another along the inner side of the pot wall all around, then fill in soil and plant the bonsai. After watering, the diapers immediately absorb enough water and swell up. Only when the potting soil dries does it slowly release water. The swollen diapers also separate the pot wall, which conducts heat well, from the potting soil, blocking the high temperature outside the pot wall from being directly transmitted in. This action plays a double role of both holding water and insulating heat. It can be said to kill two birds with one stone.

In addition, multiple layers of shade netting are also covered over the pot. This measure can lower the temperature of the potting soil and prevent rapid evaporation of water from the surface of the potting soil, while at the same time not affecting daily watering and fertilizing work.

After the above treatment, when the sun is blazing, the temperature of the potting soil can be reduced by 3°C to 7°C. Lowering the temperature can effectively slow down the transpiration of water, protect the moisture of the potting soil, and reduce water consumption. A 24-hour water-saving comparative experiment conducted on a day with a maximum summer temperature of 37°C showed that the water-saving measures are effective, generally saving 30% to 40% of water.

When the rainy season comes, the diapers at the edge of the pot can be easily removed and replaced with soil or sand, and after the rainy season the original state can be restored. If the summer rainy season is not long, not removing the diapers will not affect the growth of the stumps.

The tree species used in the water-saving measures include banyan, elm, orange jessamine, and Chinese sweet plum. Over the past two years, no adverse irritating effect of the sponge-like water-absorbing material inside the diapers on the growth of the stumps has been found.

There are many different methods of saving water, such as using shade netting for appropriate shading without affecting sunlight, or appropriately grouping bonsai together so they shade each other, or adding humus soil to the potting soil to make it looser. All of these measures can achieve the effect of saving water.

Water-saving measures for stump bonsai in summer

Talking about trees through numbers

March 12 is our country's Arbor Day, but reverse the number 12 and you get the Arbor Day of some foreign countries. March 21 is World Forestry Day. This festival was proposed by Spain at the conference held on the island of Tenerife by the European Confederation of Agriculture in 1971 and was unanimously approved by the conference. In November of the same year, the Food and Agriculture Organization of the United Nations officially confirmed it, so many countries set this day as their national Arbor Day or tree-planting day.
A foreign scholar once calculated the ecological value of a tree: a 50-year-old tree creates a cumulative value of about 196,000 US dollars. Whether this calculation is precise or not aside, in terms of the practical value of trees, it is indeed obvious.
One tree can produce 200 kilograms of pulp, and if this pulp is used to produce toilet paper, then there would be at least 750 rolls of toilet paper weighing 100 grams each.
In the city, one tree can store the pollutants emitted by a car traveling 16 kilometers in a year. Many trees can absorb harmful gases. For example, 1 hectare of Japanese cedar forest can absorb 60 kilograms of sulfur dioxide per day. Others such as tree of heaven, oleander, ginkgo, and Chinese parasol tree all have the function of absorbing sulfur dioxide. When urban green coverage reaches more than 50%, pollutants in the atmosphere can be effectively controlled.
Urban forests can increase air humidity. One mature tree can evaporate 400 kilograms of water per day, so the air humidity in forests rises noticeably. According to calculations, for every 1% increase in urban green space, the local summer temperature can drop by 0.1°C.
Urban forest belts and hedgerows have the effect of reducing noise. A forest belt 30 meters wide can reduce noise by 6 to 8 decibels.
In forest areas there are 3.5 bacteria per cubic meter of air, while in densely populated cities lacking greenery it can reach 34,000. Urban streets with trees have about 80% fewer bacteria in the air than urban streets without trees.
Urban shelterbelts have the effect of slowing wind speed, and their effective range is within 40 times the tree height, with the best effect within 10 to 20 times, where wind speed can be reduced by 50%.
Within farmland forest networks, wind speed can usually be reduced by 30% to 40%, relative humidity increased by 5% to 15%, and soil moisture content increased by 10% to 20%. According to measurements, the forest canopy can intercept about 20% of precipitation, greatly weakening the impact of raindrops; as long as there is 1 cm of fallen branches and leaves on the ground surface, surface runoff can be reduced to less than 1/4 of that of bare land, and sediment reduced to less than 7% of that of bare land.
Compared with bare land, one hectare of forest land can store at least 3,000 cubic meters more water. The water storage capacity of 10,000 mu of forest is equivalent to a reservoir with a storage capacity of 1 million cubic meters, and building such a reservoir requires an investment of more than ten million yuan.
Some experts predict that if the Earth lost its forests, about 4.5 million biological species would cease to exist, 90% of the fresh water on land would flow uselessly into the sea, and humanity would face severe water shortage. The loss of forests would increase wind speed in many areas by 60% to 80%, and the number of people killed by wind disasters would reach over one hundred million... (Zhou Hong)
Excerpted from "Beijing Youth Daily"