Field management is a large area of cultivated land for crops, including tillage, weeding, irrigation, fertilization, soil improvement, harvesting and picking.
Water requirement law of maize
The demand for water in different growth stages of maize is different. During the whole growth period, due to the differences of soil, climatic conditions and cultivation techniques, the water consumption varies greatly. The water requirement of corn is related to the sowing season. The growth period of spring corn is long, and the absolute water consumption is much larger than that of summer corn. Both spring corn and summer corn have similar water demand laws.
1. Seeding stage.
From sowing to germination, the water requirement of corn is small, accounting for 3. 1%-6. 1% of the total water requirement. After sowing, corn needs to absorb 48%-50% of its absolute dry weight before it can expand and germinate. If the soil moisture is not good, even if it barely expands and germinates, it often causes serious seedling shortage because of the weak seedling emergence ability of the topsoil; If the soil moisture is too much and the ventilation is not good, the seeds are easy to mildew, which will also cause seedling shortage, which is more serious at low temperature. When sowing, the topsoil must be kept at 60%-70% of the field capacity to ensure good seedling emergence.
2. Seedlings
From emergence to jointing stage, maize plants are short and grow slowly, and the transpiration on leaves is less, so the water consumption is also small, accounting for about 17.8%- 15.6% of the total water demand. At this time, the growth center is the root system. In order to make the root system develop well and extend deep, it is necessary to keep the topsoil loose and dry and the subsoil moist. If there is too much moisture in the topsoil, the roots are distributed in the plough layer, which is not conducive to cultivating strong seedlings. Therefore, at present, soil moisture should be controlled at about 60% of field capacity, which can create good conditions for squatting seedlings of corn, and play a certain role in promoting root development, thickening stems, reducing lodging and increasing yield.
3. jointing and booting stage
After maize plants started jointing, their growth entered a vigorous period. During this period, the growth of stems and leaves is large, the male and female spikes are constantly differentiated and formed, and the accumulation of dry matter is increased. At this stage, the vegetative growth of maize entered the period of vegetative growth and reproductive growth, and the physiological activities of the plant were gradually strengthened. At the same time, the temperature continued to rise during this period, and the transpiration of leaves was strong. Therefore, corn has a great demand for water, accounting for 29.6%-23.496% of the total water demand. Especially about half a month before tasseling, the male ear has been formed, and the female ear is accelerating the differentiation of spikelets and florets, which requires high water conditions. At this stage, it is appropriate to keep 70%-80% of the field capacity of soil moisture.
4. Heading and flowering period
Corn is very sensitive to soil moisture at heading and flowering stage. If the water is insufficient, the temperature rises and the air is dry, the extracted tassels will be "sunburned" within 2-3 days, resulting in some tassels not being pulled out, or the pulling time is prolonged, resulting in serious yield reduction and even no grain harvest. During this period, the metabolism of maize plants is the most vigorous, and the demand for water reaches the peak of its life, which is called the "critical period" of maize water demand. At this time, due to the short time from heading to flowering, the proportion of water demand to total water demand is relatively low, about 13.8%-27.8%. At this stage, it is best to keep the field water capacity of about 80% of soil moisture.
5. Grouting maturity
Corn still needs a lot of water to meet the needs of growth and development when it enters the late stage of filling and milk ripening. This period is the main stage of yield formation, and sufficient water is needed as a solvent to ensure the smooth transfer of nutrients accumulated in stems and leaves to grains. Therefore, the soil moisture status at this time has more important physiological significance than that in the previous period. After grain filling, the grains were basically shaped, and the cell division and physiological activities of the plants gradually weakened. At this time, it mainly enters the process of drying and dehydration, but it still needs a certain amount of water, accounting for about 4%- 10% of the total water demand, in order to maintain the life activities of plants and ensure the final maturity of seeds.
The water demand of maize in each growth period is: the growth is slow in germination and seedling stage, and the water demand is small. At jointing and booting stage, the growth is vigorous, the leaf area increases, the temperature rises and the water demand increases. Especially before and after heading, it is the period of maximum water demand and water consumption in maize life, and it is the "critical period" of water content. During this period, water shortage caused "neck drought", and more water was still needed for filling to maturity, which promoted filling and increased grain weight.
How to do a good job in site management
1, timely check and replenish seedlings: thin seedling fertilizer should be applied in time to avoid burning seedlings, and nitrogen and phosphorus fertilizers should be used together to promote early growth and rapid development. Check the seedlings frequently within 20 days after transplanting. 2. Water management: (1) Before the whole border is covered with plastic film, the soil in the border must be kept in a semi-humid state. (2) Pouring sufficient root-fixing water: it can be applied together with drugs and fertilizers. Transplanting in fine weather and watering the roots are especially important for K326. (3) Returning seedlings to clumped trees: no serious drought will occur during this period, and no irrigation will be carried out. From the flourishing period to the mature period, the border soil should be kept in a semi-humid state, and after the border soil is completely wet, it will be drained in the ditch. During the drought, water should be replenished, and water should be poured in the ditch every harvest in the mature period. (4) Drainage: There is more rain in the field growing season, so ditch cleaning and drainage should be done well to reduce fertilizer loss. (5) Mulching and ridging: Mulching and ridging are carried out before tobacco plants enter the open period (about 20 days after planting) to prevent root damage. Cover the soil with plastic film immediately after ploughing, and press the film with clods. At the same time, weeds in tobacco beds and furrows should be shoveled manually to ensure that there are no weeds in tobacco fields. Or uncovering the film, cleaning ditches, weeding and ridging in the early stage of vigorous growth. It is required to completely remove the plastic film to protect the root system of tobacco plants and prevent the occurrence of root diseases in the vigorous period of tobacco leaves.
Application of Sprinkler Irrigation in Field
First, the characteristics of sprinkler irrigation technology:
Field sprinkler irrigation technology is an advanced water-saving irrigation method. Compared with other water-saving irrigation methods, it has some characteristics:
1. Save water. The average water consumption per mu of canal irrigation land is about 100 cubic meters, and the highest is 150 cubic meters in mountainous areas, while the water consumption per mu of sprinkler irrigation land is about 25 cubic meters, and the water saving rate is as high as 75%, especially in mountainous areas with uneven terrain and poor water resources.
2. Save land and increase production. The multiple cropping rate of canal irrigation 1.5 m small border field is less than 60%, and the multiple cropping rate of land is over 90% when the ridge is removed in the flat canal of sprinkler irrigation field; Annual yield per mu can be increased by about 300 kg in two seasons.
3. Wide adaptability. Sprinkler irrigation can also be used for gentle slopes with low requirements for land leveling and complex terrain; It can be used not only to irrigate crops, but also to irrigate gardens, grasslands and flowers, and to spray chemical fertilizers and pesticides.
Save time. It takes about 15 days to irrigate alternately, and only 4 days to irrigate the field once, saving 2/3 of the time.
5. Save labor and money. A professional service team of 3-4 people will be set up in the sprinkler irrigation demonstration village, and farmers only need to pay the water fee without watering the land manually.
6. Improve the soil structure. Excessive irrigation in the canal is easy to cause soil hardening. Sprinkler irrigation can artificially control soil moisture, effectively improve soil physical properties and loosen soil, which is suitable for crop seeds to break ground and emerge. It can also improve the microclimate in the field and reduce the harm of low humidity, high temperature and dry hot wind.
7. Conducive to the implementation of mechanized operations. Shorten the cultivation time of three summers and Sanqiu, gain time for timely sowing of wheat and summer corn, and form a virtuous circle of complete maturity of crops; Corn can be planted immediately after wheat is harvested in the sprinkler irrigation field, and soil moisture can be replenished in time, which can lead to seedling emergence 10 days in advance.
8. Spraying fertilizer to improve the effective utilization rate. The traditional fertilization method has uneven spraying and the effective utilization rate is about 30%. The effective utilization rate can be increased to more than 70% by using sprinkler irrigation to spray fertilizer evenly.
Comparing some data with border irrigation, it can be seen that sprinkler irrigation has many obvious advantages: saving water by about 50%, increasing cultivated land by 7%-20% and saving labor force by 50%. Field crops increased by 20%-30%, vegetables increased by 50%- 100%, and the irrigation quota of wheat decreased from 400 m3/mu to 168 m3/mu, an increase of 30%.
Second, the classification of sprinkler irrigation system:
Sprinkler irrigation system generally includes water source, power machine, water pump, channel system and nozzle. According to the movable degree of main components of sprinkler irrigation system in irrigation season, it can be divided into three types: fixed, semi-fixed and movable.
1. Fixed sprinkler system. The fixed pumping station, main pipe and branch pipe composed of water pump and power machine are mostly buried underground, and the nozzle is installed on the fixed riser. The investment per mu is high, but the operation is convenient, the production efficiency is high and the land occupation is small.
2. Semi-fixed sprinkler irrigation system. The water pump, power machine and main pipe are fixed, and the branch pipe is movable. The investment per unit area is much lower than that of fixed sprinkler irrigation system.
3. Mobile sprinkler irrigation system. Only the water source is arranged in the field, and the power machine, water pump, main pipe, branch pipe and nozzle are all movable. The equipment utilization rate is high and the investment is low, but the moving units and pipelines are labor-intensive and occupy a large area.
Nozzle products: there are many kinds of nozzles, which can be divided into three categories according to working pressure: high pressure, medium pressure and low pressure; According to the spray characteristics of the nozzle, it can be divided into three types: water spray type (micro-nozzle) and jet type (rocker type). Rocker-arm nozzle can be divided into two kinds of materials, metal and engineering plastics. The materials are engineering plastics such as polyformaldehyde. Because of its low price and convenient use, it has been welcomed by the majority of users. According to the nozzle diameter of the nozzle, the nozzle can be divided into different caliber varieties. Generally, the larger the nozzle, the farther the range.
Normal pressure microtubule irrigation technology
In order to solve the problem of water shortage in agricultural production, combined with the actual agricultural production in bohu county, in 2005, the county agricultural technology station will promote the atmospheric pressure microtubule irrigation technology in Chagannuoer Township, which is a water-saving technology that irrigates the land by using the pressure generated by the natural water level difference of farmland irrigation, and irrigates the water to the roots of crops in a trickle way through the small holes of microtubules under the film. Normal pressure micro-tube irrigation technology is simple in operation and remarkable in water saving, which can improve soil salinity, increase ground temperature, increase plant disease resistance and disaster resistance, and improve irrigation management level. It is a high-tech that greatly improves the utilization rate of irrigation water and is expected to be widely popularized and applied in the county.
A New Technology of Water-saving Irrigation —— Immersion Irrigation
It is understood that the key technology of automatic water-saving immersion irrigation is to use the immersion irrigation belt to soak along the belt and directly supply it to the roots of plants to form an ecological microenvironment suitable for plant growth, so as to simulate the drizzle of spraying nutrient solution to the main roots of crops at any time. Nourished by dew-like rain, the new seedlings can safely survive the death period and successfully survive the current period, and then grow steadily on their own, so that the crops that died frequently due to lack of water can quickly turn green and rejuvenate. According to experts, there is only one word difference between spraying and dripping, which leads to a series of advantages of immersion irrigation technology. The most important thing is anti-clogging, which is determined by the nature of "liquid absorption and soaking". Therefore, immersion irrigation can be used directly, without any treatment of any natural water source, and at the same time, it can automatically and continuously complete the work of watering, fertilizing and killing insects, and the survival rate of the original plants is high.
According to experts, immersion irrigation technology is a simple and efficient water-saving irrigation mode, which can be applied to agriculture and forestry in areas with tight water resources. It is not limited by topography and landforms, and can be widely used to prevent and control desertification, return farmland to forests and protect crops against drought. The economic and social benefits are remarkable.