Science and Technology Daily reporter Yong Li
According to the monitoring of soil moisture , the soil ploughing layer in Chongqing has reached the moderate drought level, among which, the soil drought in 15 districts and counties including Qianjiang and Banan has reached the severe drought level. On August 17 , a reporter from Science and Technology Daily learned about this situation from a special press conference on Chongqing’s high temperature and drought relief work in 2022 . Affected by the continuous high temperature and low rainfall, some areas of Anhui, Hubei, Shaanxi and other provinces have also experienced soil moisture shortage recently.
The Tongliang District of Chongqing City implemented the emergency water supply pipe network project for drought relief. Photo courtesy of Chongqing Water Resources Bureau
Why lack of moisture? Moisture is divided into five levels
” Moisture refers to the humidity of the soil suitable for seed germination and crop growth. The condition of soil moisture is also called moisture. ” Li Chunlei, Section Chief of the Hydrology Station of the Chongqing Water Conservancy Bureau, said that moisture is an important monitoring indicator for drought conditions, mainly reflecting the situation of soil water content.
According to the soil relative humidity, it is divided into five grades. The soil relative humidity of the ploughing layer is greater than or equal to 90% , which is too wet, the humidity is 60%-90% , the suitable humidity is 50%-60% , and the humidity is 40 %. %-50% is moderate drought, and humidity is 30%-40% is severe drought.
“We have more than 200 monitoring stations in the city. The earliest forecast of mild moisture content was on July 11, and the moisture content has gradually increased since August . ” Li Chunlei said that the core factor for the lack of moisture is that there is no effective rainfall and high temperature persists. Over time, soil evaporation gradually increased and soil water content decreased.
It is understood that since July 1 this year , the temperature in Chongqing has been significantly higher and the precipitation has been significantly lower. The highest temperature in 9 districts and counties has broken the local historical high temperature record. In the same period , the number was 90 % lower, and 881,000 people in 33 districts and counties were affected, and 300,000 people needed living assistance due to drought . According to monitoring, 67.9% of the cultivated layers of soil moisture observation stations have reached moderate to severe drought.
” Lack of moisture is drought. ” Xie Deti, a professor and doctoral supervisor in the School of Resources and Environment of Southwest University, said that if there is a continuous severe lack of moisture, agricultural drought may form. If the drought lasts for a long time, it may lead to reduced crop yields or even no harvest .
The Fengyan Reservoir in Banan District, Chongqing City transfers 100,000 cubic meters of water to the Nanhu Reservoir every day for drought relief. Photo courtesy of Chongqing Water Resources Bureau
In addition to rain, there are other ways to face lack of moisture
“The best way to face the lack of moisture is to replenish water, but in the weather with continuous high temperature and no rainfall, the test is the construction of farmland infrastructure.” Xie Deti said that the construction of water conservancy infrastructure can help farmland quickly discharge excess water when there is too much water. Water is delivered in a timely manner when it is needed. Standardized farmland construction is to build modern farmland that is suitable for machine and ploughing, capable of drainage and irrigation, high yield and stable yield, and guaranteed income under drought and flood by increasing the size, water, road, and soil .
“We found after inspection that in the face of continuous high temperature and drought, it has little impact on Chongqing’s rice and other staple food.” The Ministry of Agriculture and Rural Affairs sent to Chongqing to guide the high temperature and drought to protect autumn crops, the leader of the science and technology team , and the deputy director of the Institute of Plant Protection, Chinese Academy of Agricultural Sciences . Chen Chang said that Chongqing’s rice harvest time is earlier, and thanks to the construction of water conservancy facilities in Chongqing, even if the harvest is later, irrigation water is guaranteed. At present, economic crops such as vegetables and citrus are more affected. In this regard, the team has given guidance on moisture conservation and sun protection. Of course, the best way to relieve moisture is rainfall.
“Generally speaking, most areas can maintain a tight balance between supply and demand, but there is a shortage of water supply in some areas.” Ren Lijuan, member of the party group and deputy director of the Chongqing Municipal Water Conservancy Bureau, introduced that at present, Chongqing’s water supply has been affected by drought for 415,000 people, extending through the pipe network , new water source, water supply, split water supply in turn, etc., and the water supply is generally guaranteed. In farmland irrigation, the role of 153 medium-sized irrigation areas and 2,442 small-sized irrigation areas was brought into full play, accumulative agricultural irrigation water was 629 million cubic meters, and 4.366 million mu of farmland was irrigated.
“According to the latest meteorological data, from August 30th to September 1st and from September 8th to 9th , Chongqing has a relatively obvious cooling and rainfall process, and the high temperature weather will gradually ease. ” Yang, member of the party group and deputy director of the Chongqing Meteorological Bureau Zhi introduced that there was a weak rainfall process around the 25th , and the high temperature weakened. The city ‘s 266 weather-affected operation sites, 107 anti-aircraft artillery pieces, 96 rockets and nearly 600 operators have made preparations for artificial precipitation. Once there is an opportunity, artificial precipitation will be carried out in a timely manner to cool down, so as to alleviate the high temperature and drought.