Comparative analysis of different irrigation techniques for alfalfa

Alfalfa is a perennial deep root crop with a wide planting area. With the continuous development of the forage industry, alfalfa production has gradually tended to large-scale, intensive and mechanized production mode. Irrigation is one of the most important links in alfalfa production management, which is directly related to the yield and quality of alfalfa products.

Traditional alfalfa irrigation methods have many shortcomings: low water use efficiency, unsuitable for water deficient areas, frequent occurrence of diseases and pests, limited fertilization methods, and difficulty in controlling nutrient and reproductive growth.

Table 1 Comparison of Irrigation Effects of Different Irrigation Methods

The circular sprinkler irrigation machine has good irrigation uniformity (water-saving, increased production), strong adaptability (water source, terrain, soil), easy integration of water and fertilizer, high mechanization (labor and time saving), high automation, large control area, and long equipment life; However, there are drawbacks such as high initial investment, leakage at corners, and being affected by wind speed.

Coupling Experiment of Water and Fertilizer on Alfalfa with Circular Sprinkler

The test site is located in Saiwusu area of Otog Banner, which belongs to temperate semi-arid grassland climate. The annual average temperature is 6.5~7.5 ℃, the daily range is 13.9 ℃, the annual average precipitation is 200~250mm, and the annual average evaporation is 2400~2500mm; Soil type: sandy loam; Soil bulk density: 1.3g/cm (0-30cm); Field capacity: 19.8% (0~30cm average).

Experimental effect

After optimizing the configuration of the circular sprinkler head, the uniformity of sprinkler irrigation is significantly improved. The tail gun control area is 1/3 larger than the average sprinkler depth of the other control areas, reducing the uniformity of sprinkler irrigation for the entire machine;

The annual water demand of Alfalfa in the whole growing season is about 469.37mm. During the first turning green period, irrigation should be appropriately reduced based on soil temperature and alfalfa growth conditions. During the branching and budding stages of each crop, alfalfa consumes a large amount of water, and it is recommended not to irrigate during the flowering period;

The first crop yield contributes the most to the total annual yield, and the yield of each crop gradually decreases. 80% ET did not cause a decrease in alfalfa yield, but at 60% ET, the yield significantly decreased;

Within the same crop, the level of WUE is largely determined by the amount of irrigation: the amount of irrigation decreases and WUE increases. The coupling effect of water and fertilizer is basically not significant during the entire growth season;

Taking into account the effects of different water and fertilizer treatments on the yield, growth, and quality of alfalfa, as well as water use efficiency, it is recommended to use 80% ET treatment for irrigation of each crop of alfalfa in the semi-arid region of Inner Mongolia;

Fertilization reference: 180kg/hm2 Monopotassium phosphate is used for the first crop, 105kg/hm2 nitrogen fertilizer is used for the second crop, and 60kg/hm2 nitrogen fertilizer is used for the third crop.

New Technology Application of Circular Sprinkler Irrigation Machine

(1) Selection, configuration and optimization of nozzle

(2) Application of integrated water and fertilizer technology

(3) Wireless remote control and management system

(4) Variable irrigation and fertilization control system

Implement differentiated variable irrigation based on specific plot boundaries, soil characteristics, crop water requirements, and other requirements;

Install solenoid valves in parallel for each nozzle or several nozzles, and change the amount of water sprayed by controlling the solenoid valve (changing the opening and closing time ratio of the solenoid valve) to implement variable irrigation;

GPS/Beidou positioning, RFID land boundary recognition, implementation of automatic shutdown and zoning irrigation.