Reborn in 1984, fishing and hunting in Jiangnan

Chapter 51

By the end of November, the reeds in Baiyang Lake had turned completely white.

The catkins of reeds drifted everywhere, landing on the pond like a thin layer of snow.

Chen Zheng got up early in the morning, pushed open the courtyard gate, and saw that the edge of the water vat in the yard was covered with a thin layer of ice, which was shiny.

The black cat squatted on the edge of the water tank, reaching out its paw to scoop up ice shards. After trying for a long time without success, it meowed anxiously.

Zhang Cuihua brought out a large pot of corn porridge from the kitchen and ladled out several large bowls of it, placing them on the stone table.

Old Chen squatted on the threshold and slurped down two bowls of wine.

He tapped the tobacco pipe on the sole of his shoe to remove the ash, then tucked the pipe back into his waistband.

He squinted as he looked at the hazy clouds on the horizon.

"The weather's going to change today. Go early and come back early."

Chen Zheng responded, turned up the collar of his cotton-padded coat, picked up the shovel leaning against the wall, and went out the door.

The water level in the fishpond dropped another two inches, and he opened the sluice gate halfway at the inlet to let the lake water slowly seep in.

According to the book Zhou Haiming gave me.

In winter, large water changes should be avoided, as drastic temperature fluctuations can cause strong stress reactions in fish.

In mild cases, the patient may stop eating; in severe cases, they may lose weight or even die.

He squatted on the bank of the pond, using the thin bamboo pole with a white wooden board attached to it to measure the transparency.

As the bamboo pole sank, the outline of the white wooden board in the water gradually became blurred.

It becomes completely invisible when it reaches 37 centimeters.

It's five centimeters clearer than last time.

When the water temperature is low, algae reproduce slowly, and the water naturally becomes clearer.

He wrote down the data in his notebook.

On November 24th, the transparency was 37 and the water temperature was 6 degrees Celsius.

Turning to the previous page, the water temperature was around ten degrees Celsius at the beginning of the month.

The temperature dropped four degrees in three weeks. At this rate, it will fall below five degrees around the winter solstice.

He closed his notebook and walked around the pond embankment.

The grass on the section of the pond embankment near the outlet is not growing well, and there are several places where the yellow soil is exposed.

He took a shovel and scooped up a few more pieces of turf from elsewhere, moved them over, tamped them down one by one, and poured two buckets of water over them.

Grass can survive anywhere as long as its roots are not damaged.

Once the turf has grown firmly next spring, the pond embankment will be sturdy.

When feeding the animals, he would grind the soybean cake, mix it with wheat bran, and then add warm water to make a paste. He would then divide the paste into several small piles and scatter them in the shallow water area.

The fish slowly floated up from the deep water, their appetite for food much weaker than in autumn.

Several grass carp have grown to over a pound, while the black carp have shiny black backs and powerfully flick their tails when they swim.

Chen Zheng squatted on the bank of the pond, watching the fish eat, and silently did some calculations in his mind.

The 1,200 fish fry were released into the pond in August, and almost four months have passed since then, with less than 50 fish lost.

These seedlings are indeed much more resistant to disease than wild seedlings.

Based on the current growth rate, by the end of the year when they are harvested, the silver carp will weigh around 1.2 jin (approximately 0.6 kg), the grass carp will weigh 1.5 jin (approximately 0.75 kg), and the black carp will weigh 2 jin (approximately 1 kg).

As he was doing his calculations, the sound of a diesel engine sputtering came from the other end of the village road.

Looking up, I saw a green sidecar motorcycle driving along the dirt road, kicking up a trail of yellow dust behind it.

The motorcycle stopped in front of his yard, and three people got off.

The first one is Zhou Haiming.

He was wearing a dark blue cotton overcoat, a gray scarf around his neck, and his glasses were fogged up by the cold wind as he wiped them with a handkerchief.

A middle-aged man wearing a baseball cap, tall and thin, with a dark complexion, got out of the back seat. He was wearing an old military overcoat and carrying a canvas satchel.

A young woman with two braids, wearing a floral cotton-padded jacket and black-rimmed glasses climbed out of the sidecar and was carrying a folder in her arms.

Chen Zheng placed the feed bucket on the bank, patted the crumbs off his hands, and walked quickly over.

"Chen Zheng, come over and let me introduce myself."

Zhou Haiming put on his glasses and pointed at the middle-aged man wearing a baseball cap.

"This is Researcher Ma Yuanchao from the Provincial Fisheries Research Institute."

Professor Ma is a renowned expert in the prevention and control of freshwater fish diseases, and he is one of the top experts in the entire province.

He then pointed to the young woman: "This is Xiao Qin, Qin Shulan, Professor Ma's graduate student."

She worked with Professor Ma for two years on a mandarin fish domestication experiment at the Danjiangkou Reservoir.

Chen Zheng shook hands with the two of them.

Ma Yuanchao's hands were large and calloused, and he had a strong grip.

Qin Shulan's hands were small and fair, but her nails were cut very short, indicating that she was someone who often did experimental work.

"Teacher Ma, Comrade Qin, please come inside."

"No rush." ​​Ma Yuanchao waved his hand, his gaze passing over Chen Zheng's shoulder and looking at the fishpond behind him.

"Let me take a look at your fishpond first. Old Zhou told me that this is your first year raising fish, and you only released the fry in August."

I have to see for myself what kind of fish they can grow into in such a short time.

Chen Zheng led the three people toward the embankment.

Ma Yuanchao walked ahead, taking large strides, stepping on the newly moved turf, and looked down at it.

"The turf was just moved? The slope protection is quite meticulous."

I did a retake before winter.

"No matter how firmly the embankment is compacted, it will easily loosen after being washed by rain for a long time. Turf is more effective than stones for slope protection," Chen Zheng said.

Ma Yuanchao nodded, squatted down next to the water inlet, and reached out to probe the water flow.

He put his finger in his mouth and tasted it, then frowned slightly.

"The alkalinity is a bit high. Was this pond newly dug?"

"Dug this summer."

"We soaked the soil in water for a few days to draw out the alkali, and then changed the water before releasing the fish fry."

"Replacing it once isn't enough."

Ma Yuanchao stood up, took a test strip from his pocket, dipped it in water, and checked the color against the light.

The alkalinity is still around 7.8.

The water in Baiyang Lake is slightly alkaline, and the soil in Xintang is also alkaline. When the two are combined, the alkalinity is high.

Your water inlet is too small, the water isn't being changed frequently enough, and the alkalinity isn't dropping.

Chen Zheng's eyes lit up.

Zhou Haiming mentioned the issue of alkalinity in his training course, but not in great detail. He only said that it was normal for the alkalinity in Xintang to be high, and that changing the water a few times would solve the problem.

However, the training course did not specify how many times or at what frequency to change them.

Ma Yuanchao's words immediately pinpointed the crux of the problem.

"Teacher Ma, what effect does high alkalinity have on fish?"

"The impact is huge."

Ma Yuanchao stood up, patted the water off his hands, walked to the middle of the pond embankment, squatted down, and looked at the water.

"High alkalinity leads to an imbalance in the ratio of calcium and magnesium ions in the water, causing fish gills to secrete excessive mucus."

Excessive mucus reduces the respiratory efficiency of the gills.

Look at your grass carp, when they swim, don't their mouths open bigger than those of silver carp?

That's a sign of decreased gill respiration efficiency.

It needs to open its mouth wider to get enough oxygen.

Chen Zheng looked in the direction he was pointing.

When several grass carp swam by, the range of their mouth opening and closing was indeed larger than that of the silver carp next to them.

He had noticed this detail before, but assumed it was a normal difference between varieties and never considered the alkalinity.

"How should we adjust it?"

"Open the water inlet to twice its original size."

Bring in the new water quickly to gradually dilute the alkalinity.

Ma Yuanchao took a palm-sized plastic bottle out of his canvas satchel and handed it to Chen Zheng.

"This is pH test strip, used to measure acidity and alkalinity."

Test the alkalinity every three days thereafter. If the alkalinity exceeds 7.5, increase the amount of water to be replaced; if it is below 6.5, decrease the amount of water to be replaced.

The optimal alkalinity for the four major freshwater fish species is between 6.8 and 7.2.

Chen Zheng took the test strip and examined it from all angles.

The test strips are pale yellow and come in a plastic bottle with a color chart printed on the bottle. They are simple and convenient to use.

This stuff isn't expensive, but you can't buy it at the town's supply and marketing cooperative; it's only sold by the county's agricultural supply company.

"Teacher Ma, how much is this test strip? I'll pay you for it."

"Need not."

Ma Yuanchao squatted down again and began to examine the fish in the pond.

"The fact that you were able to patch up the turf on the pond embankment before winter shows that you have a concept of water quality management."

Being able to cure gill rot in seven or eight fish farmers in Lijiawan shows that you have an awareness of technology promotion.

What's the big deal about me giving you a box of test strips?

I'll be counting on you to help me collect water quality data for Baiyang Lake in the future.

As he spoke, he took out a small notebook from his pocket and wrote a few lines in it.

After finishing writing, he stood up and pointed to the low-lying field west of the pond embankment that hadn't been dug up yet: "Is that over there also yours?"

"Yes. We plan to dig two more ponds next spring to make a total of six acres of water surface."

"Six mu of water surface is considered small-scale in family farming."

But your land is in a good location, near Baiyang Lake, with convenient water inlet and drainage, and the terrain has a gradient, so it can be developed into tiered fishponds.

Ma Yuanchao drew a line on the ground with his foot.

"Look, the drop from the lake's inlet to your current fishpond is about two feet."

If you make the three fishponds into a tiered system, the water will flow from the outlet of the first pond into the second pond, then from the second pond into the third pond, and finally drain back into the lake.

In this way, the water is dynamic, with high dissolved oxygen levels, making it less likely for diseases to break out.

Chen Zheng stared at the line on the ground, his mind racing.

Zhou Haiming only briefly mentioned the concept of tiered fishponds in the training course.

They said that the design was only needed for large-scale farming, and small farmers didn't need it.

But Ma Yuanchao's analysis made him realize that the key to tiered fishponds is the difference in elevation.

His family's low-lying field had a gentle slope that dropped more than two feet from east to west, making it a natural fit for terraces.

"Teacher Ma, how should the inlet and outlet of a tiered fishpond be designed?"

Ma Yuanchao smiled, pushed his baseball cap up further, revealing a pair of bright, piercing eyes:

"That's a good question. The key to designing a tiered fishpond is the overflow outlet."

The overflow outlet should be located at the edge of the deep water area of ​​each pond, allowing the surface water to flow naturally to the top of the next pond.

The surface water has the highest oxygen content, which is best for fish downstream.

The inlet of each pond should be positioned diagonally opposite the overflow outlet, allowing fresh water to travel the longest possible path within the pond for thorough exchange.

Qin Shulan opened the folder in her arms, took out a drawing, and handed it to Chen Zheng.

The drawing was hand-drawn, with neat lines and clear annotations; it was a cross-sectional diagram of the tiered fishpond.

The locations of the inlet, overflow, deep water area, and shallow water area were marked with different colored pens.