Brief description of several water management and mechanisms commonly used in dry farming in China

China's dry farming and water sharing technology

Dry farming, also known as rain-fed agriculture, refers to agricultural production that relies solely on precipitation to provide the water needed for crop growth in the absence of irrigation

. The dry farming area in the north of China mainly refers to the arid, semi-arid and semi-humid drought-prone

areas with annual precipitation

below 250-600mm, with more than 26 million hm2 of dry slopes in about 15 provinces and districts. In China's southern

square, although abundant rainfall, but due to the uneven distribution of rainfall within the year, and the distribution of cultivated

land in the hilly and mountainous terrain, subject to topographic conditions, technology, economic and other factors

constraints, but also unable to develop irrigation. Crops often encounter seasonal

seasonal drought threat, such as drought, fall drought. There are about 1300

million hm2 of such dry slopes, and from the existing yield level, the average yield of grain in semi-arid areas in the north is only 1,500kg for 1 hm2, and only 2,250kg for semi-humid and drought-prone areas, and only 2,250kg for 1 hm2 in the dry areas in the south.

There are also a lot of drought-prone areas in the north, and there are a few drought-prone areas in the south. Therefore, in the dry farming area

need to maximize the collection and full use of

rainfall through a variety of integrated measures to meet the crop growth on the water needs, thereby increasing crop

yield level.

Breakthroughs in dry farming technology and its popularization and application during the Eighth Five-Year Plan period

China has a long history and traditional experience in dry farming. Since the founding of the new China

New China, especially in recent years, in the scientific and technological departments and the majority of scientific and technological

personnel efforts, all over the world in the development of dry farming technology to do some

exploration, the development of a lot of new technologies. For example, the straw mulching technology in Shanxi Province,

can make the same natural conditions and production conditions, wheat, corn average yield increase

15% or more, 1hm2 output increased by an average of 600-750kg. Ningxia's micro

type catchment irrigation project, rainfall of only 200-300mm of arid areas,

corn yield from 1hm2 of 450kg to 3,000kg.

Sichuan East

area, combined with poverty alleviation and agricultural development, created a comprehensive

technology to transform dry slopes. The dryland corn cultivation technology of water and fertilizer collection in Hebei Province, and the fertilizer and grain (belt) rotation promoted in many areas in the north and south

have all brought considerable

economic benefits, and have been welcomed by the general public. However, at present, the popularization and application of these new technologies

are not strong, which affects the benefits.

The main content of dry farming technology

1 Agricultural engineering. Agricultural engineering includes large-scale engineering and micro-engineering,

Large-scale engineering mainly refers to the slope-to-staircase project, micro-engineering mainly refers to the productive ditch,

monopoly furrow cultivation technology and micro water collection project and so on. The purpose of the implementation of agricultural engineering

is to maximize the soil to precipitation storage, reduce the evaporation of soil water

minutes, in order to ensure that crop growth on the water needs. Agricultural engineering has an important role in

improving the basic conditions of agricultural production, soil and water conservation, rainfall retention, and increasing the water content of the soil

.

( 1) slope to ladder. That is, the sloping arable land along the contour of the construction of horizontal terraces

fields, also includes the slope terraces. High-standard terraces, can be a precipitation

100mm of runoff in all the terraces, 1hm2 can increase the soil

storage of 180 ~ 225m3. This is to improve and raise the level of dry farming production

an important measure. The state has taken the construction of horizontal terraces as an important part of farmland basic

construction, and has completed 267,000hm2 of terraced area every year.

( 2) Field micro-projects. Agricultural production on large dry slopes must

adopt some field micro-projects that are low-investment, high-efficiency and easy to be operated by farmers

. These field micro-projects are also effective in improving soil moisture and

keeping soil and water on dry slopes. In the northwest, the field micro-

projects implemented include productive ditching, equal-height plowing, and ridge and furrow plowing. In the south of the implementation of

field micro-projects such as poly-row plowing.

( 3) micro irrigation project. In China's northern region, rainfall is sparse

and relatively concentrated in the summer months; in China's south, heavy

rain, storms, the real runoff water can penetrate into the soil is generally only

accounted for about 10%, most of the precipitation with the loss of surface runoff. Therefore,

in both the southern and northern regions, farmers in the dry slopes to build some

capacity of about 50 ~ 80m3 of the water collection cellar, to collect rainwater for drought

use. Repair 1 such water cellar, if full of water, spring drought can be planted

0. 20 ~ 0. 27hm2 sweet potatoes and corn, 0. 13 ~ 0. 20hm2 cotton, drought

drought can be used micro-irrigation technology, to achieve drought effects.

2 Biotechnology. Biotechnology refers to the planting of green manure crops,

the implementation of crop rotation or grain fertilizer rotation, etc., to increase the rate of infiltration of surface runoff,

improve the fertilization of the soil, control soil erosion, reduce soil moisture evaporation, regulate

section of the soil micro-ecological environment, in order to facilitate the growth of the crop, for a stable, high

yield.

( 1) Southern dryland green manure polytunnels farming technology. This technology is a new type of farming system based on compound

compound group production structure as the main body, strip planting as the basis, multi-maturing and crop rotation

crop change as the core. It is characterized by a scientific combination of economics, grain,

fertilizer, vegetables, forage, beans, etc., combining the economics, grain growing and land raising organically

. Such as wheat - corn - sweet potato, and beans, vegetables, green manure

and other sub-band rotation of stubble, a variety of crops to coordinate the development of the southern mountainous and hilly

Ling areas of dry slopes agriculture sustained high-yield one of the technical measures.

( 2) Northern grass rotation and summer green manure. In some areas in the north of China

area, there is a lot of land and few people, and most of the dry cultivated land is distributed on the slopes, and the soil and water erosion is serious

heavy. Grass field rotation is in a field according to a certain proportion of planting agricultural

crops and perennial pasture, not only can maintain soil and water, increase the infiltration of precipitation,

and can fertilize the ground, increase crop yields. Some areas of the summer crop harvest

After the climatic conditions of the limitations, can not plant the second crop, the land at

in the leisure state. Gansu and other provinces after years of practice, screened out some suitable

suitable for planting green manure varieties, summer crop harvest after planting, both increase

rainy season ground cover, conducive to precipitation infiltration, increase soil moisture content,

and improve the fertilization of the soil, the farmers can also harvest part of the fodder for livestock.

( 3) Straw mulching. Straw mulching is to cover the crop straw on the crop

monopoly or between the rows, when rainfall to slow down the surface runoff, increase the role of soil infiltration

permeability, drought can reduce the loss of soil moisture evaporation, to improve the drought-resistant crops. After the crop stalks rot, and can fertilize the soil, increase

increase the organic matter content of the soil. Therefore, for dry farming areas is an important

important technology to increase production. According to the data of Shanxi Province, in 1991 (annual precipitation

377mm), the yield of dryland corn covered with straw field 1hm2 reached 1.05

million kg, which is 43% higher than that of non-covered field.

3 Agronomic technology. It refers to the selection of drought-resistant varieties, reasonable adjustment of crop

location, and water storage and moisture conservation farming measures, in order to fully improve the utilization of water

use rate, to improve the yield of dryland crops.

( 1) Selecting drought-resistant crop varieties and rationally adjusting planting structure.

The difference between the water requirement and yield of drought-resistant varieties of crops and ordinary varieties is

large, and the selection of drought-resistant and high-yielding varieties can reduce water consumption and obtain higher

yields. Maize, sorghum, sweet potatoes, cereals, tobacco and other crops are relatively drought-tolerant

stronger than wheat, so it is the main crop in dry farming areas. At the same time

expanding rain-heat synchronization of spring and summer crops, for local conditions to take a reasonable

crop rotation system, accordingly can improve the utilization of precipitation, increase crop

yield.

( 2) Increase organic fertilizer. Organic fertilizer is the basis of agricultural production, dryland

agricultural areas should emphasize the input of organic fertilizer. Especially in combination with the last

plowing in the fall, the organic fertilizer will be y applied to the soil, on the physical and chemical properties of the soil

changes, improve the soil structure, increase the porosity of the soil, especially

capillary pore increase, improve the soil water-holding and water-supply capacity as well as inhibit

water evaporation has an obvious effect.

It is the basis for enhancing the drought-resistant ability of crops, improving

the utilization rate of precipitation, and realizing stable and high yields.

( 3) Water storage and conservation farming measures. On the basis of the implementation of water-storage agricultural projects

, it is still necessary to combine farming measures to store rainwater. The most basic

methods are: deep plowing to store water, harrowing to preserve moisture, winter and spring crushing, and mid-plowing to remove grass. According to

according to the characteristics of the rainfall concentration in the dry zone, before the rainy season, deep tilling water storage, combined with plowing to open

ditch or ditch to play the horizontal ridge, the top of the harrowing and raking rake in case of rain, etc., can be the rainfall

in the ditch in the inter-montane storage, to increase the water permeability of the soil, so that the rainfall slowly seeped

into the soil, and to reduce the evaporation.

4 Drought water retention agent application technology. The use of water retention agents, drought agents, anti-evaporation

transpiration agents, seed mixing, can save water and moisture; mid- and late foliar spraying, can reduce

less foliar evapotranspiration, improve a variety of enzyme activity and chlorophyll content, thus

enhancing the crop's resistance to drought, cold, pests and diseases, and to achieve the purpose of increasing yields.

In addition, dry farming technology also includes formula fertilization, micro-fertilizer application,

film cover, crop rotation, pest control and other conventional agricultural technology measures

Support, the promotion and application of dry farming technology, the important issue lies in the reasonable combination of technology

supporting and classified guidance.

Dry farming technology has been included in the 10 major agricultural

technology promotion projects of the Ministry of Agriculture in 1996, and in 1996, the National Agricultural Technology Promotion Service Center

will focus on the demonstration and promotion of mature

technology in the northern water-saving dry farming development demonstration area, and at the same time carry out the small-scale technology demonstration project in the south.

Beginning from 1997, the national agricultural technology promotion service will focus on demonstrating and promoting mature

technology in the demonstration area in the north, while carrying out small-scale technology demonstration projects in the south. Starting from 1997, the Center will gradually increase its efforts to popularize dry farming technologies and expand them to 15 provinces (regions) across the country, promoting and applying dry farming technologies in different regions, classifications

types, and in accordance with local conditions.