AGRICULTURE SOLUTIONS RECOMMENDATIONS IN IRRIGATION FOR CULTIVATION OF CORN www.azud.com 00000346
The corn is a crop from Central America of the Poaceae family, with thousands of years old. The approximate worldwide production is of 790 million of ton of grain in 158 millions of hectares. The main producers are The United States, China, and Brazil, summing up near the 62% of the total worldwide production. The crop production is one of the most advanced talking about mechanization and technology, maximizing the output and quality of the product, and also saving costs, time and workmanship labours. Thanks to AZUD experience, we provide the farmer the most interesting agronomic solution, which guarantees a higher productivity for the corn crop, taking into account the necessities and resources available on each situation. Edapho-climatic requirements The corn requires temperate climate on its growing stage. It needs a lot of hours of light and its output is worse in especially humid weather. The suitable temperature to the cultivation of corn varies depending on the development of the crop, although the average temperature can vary between the 10-30 ºC. The corn is not resistant to the low temperatures and the frost due to its thermo-periodic feature. It s normally cultivated in different types of soil due to its adaptability. The soils in which the crop better suits are those with a high organic contain, good drainage and certain depth due to its high sensitivity to the humidity excess. Sowing and plantation spacing The previous choice to the sowing of those seeds with better properties, resistance to plagues and diseases, it is an essential labour, which will affect so much to the output as the quality of the production. The best temperature of the soil to the sowing is around the 12 ºC. The sowing season is normally the end of winter (April for USA and Spain). The date will depend on the region. In direct sowing, the dose is from 60.000 to 80.000 seeds per hectare. Depending on the variety, the spacing between crops can vary from 0.5 to 1m and the spacing can be among 15 and 25 cm. The most suitable soils are those of light/medium texture, which keep a high temperature, favouring the development of the plant. It is recommendable to avoid heavy soils (clayey) and too loose (sandy). The storage capacity of water of the soil is essential to guarantee a continuous supply of water between irrigations. 2
Crop coefficient The crop coefficient, K C, states the relation between the two main factors in the description of the hydric necessities of one crop. These two factors are the real Evapotranspiration (ET C ), specific to each crop, and the reference Evapotranspiration ET 0, determined by the conditions and the climate in which the crop is developed. The value of this coefficient is normally among 0.1 and 1.2. The mathematic formula with the variables and characteristic already described is the following. With this formula we can calculate the Real Evapotranspiration of a crop (ET C ): ET C = ET 0 x K C The farmers can use the resulting value of ET C to establish an adequate irrigation programming, which better suits to the hydric requirements of the plant. Picture: Evapotranspiration of the reference crop (ET 0 ) under standard conditions (ET C ). Source: FAO (Food and Agriculture Organization of the United Nations). K C values can change depending on the crop, the development of the same and the culture and practices associated to the exploitation place. Phenological stages of corn STAGES OF CROP Sowing, germination and seedling (3-4 leaves) Vegetative growing Flowering, formation and fill Maturation DURATION (days) 30 40 50 30 Days after sowing 0-30 30-70 70-120 120-150 Phenological stages corresponding to corn cultivation in USA and Spain. Source: FAO (Food and Agriculture Organization of the United Nations) K C 0.7 0.7-1.2 1.2 1.2-0.6 Picture: typical K C values for the four growing stages. Source: FAO (Food and Agriculture Organization of the United Nations). Sowing Harvest Sowing, germination and seedling Vegetative growing Flowering Formation and filling Maturation 3
Irrigation The corn is a demanding crop in water. It needs around 5 mm per day, sometimes 10 mm depending on the development stage. The irrigation intensity varies along the cultivation and depend on factors as climate, precipitations, the own characteristics of this crop and the properties of soil. In the germination stage, it is required less water but with a constant humidity. In the vegetative growing the quantity of required water is increased. It is recommended to apply one irrigation from 10 to 15 days before the starting of the flowering, where this crop is especially sensitive to the hydric deficit. The flowering stage is the most critical. This stage determines the quality and output of the production. A deficiency in this stage could provoke a decrease of until a 30% of the harvest. It is recommendable irrigations which keep a continuous band guaranteeing so much humidity as the optimum conditions to the pollination and the setting. Finally, in the formation, fill and maturation of the corn the quantity of supplied water must be decreased. In the total of the cycle, the corn requires from 500 to 800 mm of water. A performance rate for the corn cultivation without hydric, nutritional or sanitary limitation. Fertigation The corn requires some quantities of mineral elements to its correct development, so, when some of the nutrients are present in defect or in excess, the crop suffers some lacks. It is essential to fertilize adjusting to the specific requirements of the plant and in function of the edaphic features of the area. It is recommended a supply of nitrogen as main macronutrient, especially in the vegetative growing. It is highly recommended to crop in a soil rich in phosphorous (P) and potassium (K). Crop Characteristics Edaphic requirements ph Average Temperature Sowing depth Root depth Salinity 6 7* 10 ºC 2.5 5 cm 0.8 1 m (unti 2 m in Deep soils) 7 mmhos / cm Climatic requirements Minimal Temperature Maximum temperature Germination temperature Growing temperature Formation - maturity temperature 8 ºC 32 ºC 15-20 ºC 21-30 ºC 20 32 ºC Humidity *IT can sometimes tolerate a ph of 8.5 Development stage: 80-85% Maturing stage: 45-65% 4
It is advisable a limited fertigation during the first development stage of the plant until the seedling has about 6-8 leaves. It is also recommendable an important restriction of fertigation during the formation of the grain. The most common fertilizers soluble in water are: Urea (46-0-0), potassium nitrate (13-0-46), monoammonium phosphate (12-61-0), Ammonium nitrate (34-0-0). Irrigation System There are two recommended irrigation systems for corn cultivation: High Frequency Localized irrigation in Surface. Subsurface Drip Irrigation (SDI) Although both irrigation systems are considered to be suitable for the corn cultivation, nowadays, the subsurface Drip Irrigation is at the forefront of technology in irrigation systems. The use of a SDI system has important advantages: Saving of water Energy efficiency Use of fertilizers. Subsurface drip Irrigation (SDI) Applied to corn cultivation SDI is an irrigation technique that allows the supply water and nutrients to the soil in a localized way and under the Surface, so it conditions and optimizes the growing of roots and the development patron of the plant. The application of doses of water is made though the emitters, with very specific characteristics. The subsurface drip irrigation allows to apply water and fertilizers directly to the root system of the plants, allowing an important saving of the same and becoming the best alternative economically, ergonomically and ecologically talking for the cultivation of corn. Hydric Requirements K C CHARACTERISTIC VALUES ET 0 (mm/day) ET C * (mm/day) Sowing, germination y seedling Vegetative growing *Requirements without having into account the rain water. *Calculations made according to climate conditions in Spain. Source: FAO (Food and Agriculture Organization of the United Nations). Nutritional requirements Nitrogen N (Nitrogen fertilizer - N) Phosphorus P (Phosphate fertilizer - P 2 O 5 ) Potassium K (potash fertilizer - K 2 O) Calcium - Ca Magnesium - Mg Sulphur - S Source: INPOFOS CROP STAGE Flowering, formation and fill Maturity 0.7 0.7 1.15 1.15 1.2 1.2 0.6 3.43 4.26 5.63 6.95 6.95 6.16 2.15 2.60 3.07 4.88 6.04 8.68 8.24 3.80 NUTRIENT TYPE Requirements (Kg/ ton) Harvest index HI (%) Macronutrient 4 Secondary Nutrient 22 0.66 0.75 19 0.21 3 0.07 3 0.28 4 0.45 5
SDI Benefits Positive evolution of the physical properties of soil. Stability of the water contain in the wet bulb. Increase of porosity in the root area. Excellent relation between the water contain and the soil atmosphere. Increased efficiency of the irrigation water application. Reduction of the use of water and fertilizers due to a more accurate control on the application of nutrients. The volume of water is applied only where required. The lack of leakages due to less risk of damage favours the saving of water and also to keep the uniformity of the application. Increase in irrigated area. The subsurface drip irrigation doesn t require specific Access ways. The geometry, size and topography of the area doesn t affect the uniformity of water application. Allows the use of waste water. Lack of contact between the supply source (with infection potential), and the air part of the crop, operators and animals. Lack of bad smells coming from water. Extra supply of nutrients for the crop. Stability in the emitting points. It is avoided that the accidental action of the operators making the cultivation labours can move the dripline, changing the place of the emitting points. Decrease the risk of plagues and diseases. The diseases which spread is favour by the presence of water in the Surface of the soil are drastically reduced. Energy reduction. Low operation pressure. High application efficiency. Reduction of damages made by animals. It is difficult to reach the dripline by the rodents, birds and borers. In certain areas this is the main reason to install this irrigation system. Less presence and development of bad weeds. The seeds which are in the surface don t reach the humidity levels necessary to the germination. Less water and nutrients availability for the already growing bad weeds. Less expenses (workman labour and chemical products) associated to the bad weeds elimination. Eases the cultivation labours. The operators and the mechanical equipment are able to move and work in any direction. The irrigation system is not exposed to mechanical damages. Possibility to make any work during and after irrigation. Absence of vandalism It is dramatically reduced the possibility of intentioned damage and/or theft of material of the irrigation system. Solar radiation is avoid Longer life of the dripline, because it isn t exposed to the degrading action of the UV solar radiation. Definitely, thanks to the installation of the SDI system, we can obtain better output as consequence of an increase in the production and an important decrease of the operational costs. 6
1 2 3 4 5 5 Components of a subsurface drip irrigation installation 1. Pumping system It supplies water to the necessary pressure to all the irrigation circuit. 2. Filtration system The dimensioning and quality of the filters is especially important in a subsurface drip irrigation installation. Specific emitter: azud premier pc as The location of the emitting dripline under the Surface makes essential the use of pressure compensating emitters with antisuction system and maximum anti-clogging efficiency. The anti-suction device avoids the entrance of water with particles of the soil, preventing from clogging and increasing the life of the system. 3. Fertigation Fertilizers Automatic supply to all the irrigation sectors 4. Control and operation elements Flow control: Control flow valves. Pressure control: Manometric intakes and air release valves. Water consumption control: Flow meters and counters. 5. Microirrigation dripline Installation It varies depending on the area and type of cultivation, although generically the following features are established: Irrigation emitting pipe between alternating rows. Spacing between emitting driplines: from 0.76 to 1.00 m Spacing between emitters: 0.20 0.60 m Characteristics Diameter: Ø16 / Ø20 mm Thickness: 1mm /1.1mm / 1.2mm Emitter flow rate: 1 l/h, 1.6 l/h, 2.3 l/h. 7
SISTEMA AZUD, S.A. Avda. de las Américas P. 6/6 Polígono Industrial Oeste 30820 Alcantarilla Murcia - Spain Apdo. 147 30169 San Ginés Murcia - Spain Tel.: +34 968 808 402 Fax.: +34 968 808 302 E-mail.: azud@azud.com www.azud.com