一、Corn storage characteristics
(1)Maize embryo is large and breathy:
The maize embryo is very large, accounting for almost 1/3 of the total grain volume and 10% ~ 12% of the grain weight. Maize embryo contains more than 30% protein and more soluble sugar. It has strong hygroscopicity and vigorous respiration. Its respiration rate is 8 ~ 11 times that of wheat. Corn absorbs and emits water mainly through the embryonic part. So when the storage environment temperature is high, high humidity, it is easy to mold. The whole corn embryo contains 77-89% fat, the fatty acid value is always higher than the endosperm, the rancidity starts from the embryo.
2)Susceptible to infection by pests:
There are many harmful insects on maize, such as maize elephant, big corn borer, mixed grain robinia, sawdust borer, Indian corn borer, wheat moth, etc. Because maize embryo is rich in nutrition and soluble sugar content is high, pests usually harm embryo first. Once wang Rice is infected with pests, it is more serious than other grain seeds.
(3)Easy to mould:
Maize embryo is rich in nutrients and has a large amount of microbial attachment. It has been determined that after a period of storage, the amount of bacterial in maize is much higher than other cereal grains. After the embryo hygroscopic, when the temperature and water condition are suitable, the mould multiplies in large quantities and is prone to mildew.
(4)Corn has large original moisture and uneven maturity:
China's corn producing areas in the north, the annual corn harvest weather has been cold, so the newly harvested corn moisture is higher. In addition, due to the different pollination time at the top and base of the same ear, the ripening of corn kernels is not uniform and there are more immature kernels. In addition, it is easy to be damaged during threshing and there are more broken kernels. The presence of immature and broken grains increases the difficulty of corn storage.
二、Inspect the food situation strictly
In the safe storage of corn, one word should be strict, one word should be fine, and one word should be controlled. "Strict" means strict quality control and strict management of the preparation work before warehousing. "Meticulousness" refers to the careful and meticulous inspection of grain conditions and the careful and meticulous implementation of various grain storage measures. "Control" refers to the control of the warehouse temperature, the warehouse temperature down.
Early report, early consultation and early treatment of problems found.
Food situation inspection, to be careful, careful, comprehensive, resolutely to prevent paralysis and negligence, go through the motions.
(一)Inspection requirements
1、Conduct regular and timed systematic detection (no less than twice a week) on the changes of corn grain situation, and use sensory identification and other auxiliary means to find hidden dangers of grain storage as early as possible, and take timely measures to deal with them.
2、Temperature measuring rods are set up at the corners, falling points, and around high temperature points, and the grain temperature is checked and measured manually at regular and irregular intervals.
3、Between April and August, corn is prone to insects, fever and mildew. During the seasonal change, the corn is prone to dew. During these two critical periods of corn storage, inspection of grain situation must be intensified. Special attention should be paid to the tent barn where corn is stored instead of stored because of the great influence of external temperature.
4、In the high temperature season, it is advisable to choose the time slot with low temperature from 8:00 am to 9:00 am, and do "fast entry, close the door tightly and check quickly".
(二)Grain temperature measurement
The computer grain situation detection system is used to detect the "three temperature" data. Temperature anomaly points are compared with the temperature measuring rod. Combined with other grain situation data, the reason of grain temperature change is analyzed to determine whether the stored grain is safe.
Before 9:00 o 'clock every Monday, the food situation tester shall check the temperature and humidity data, print the thermometer and deliver it to the responsible keeper. The storekeeper conducts a comparative analysis of grain temperature, judges whether there is any abnormal situation in the warehouse, and fills in the weekly storage work after checking and comparing. A grain situation analysis meeting was held that afternoon to report and study the grain situation and existing problems, and put forward measures to deal with them.
(三)Moisture detection
In principle, water should be tested once a month, but the number of tests can be increased appropriately according to the actual situation in case of corn heating, condensation and other conditions or during ventilation. In the spring, autumn switching season, the focus of the moisture transfer. The moisture detection should be stratified point sampling, the easy hygroscopic and abnormal grain temperature should be multi - sample. During the detection, the method combining sensory identification and rapid water detection instrument was adopted to detect both local water and average water, and all the detection results were analyzed and compared carefully, so as to thoroughly find out the water changes of corn.
(四)Pest detection
When the grain temperature is lower than 15℃, check it at least once a month. When the grain temperature is 15-25℃, check it at least once within 15 days. When the grain temperature is higher than 25℃, check at least once within 7 days. During inspection, stratified sampling shall be set up according to the requirements, and insect species, insect period and density of stored grain pests shall be checked by insect screening.
The active parts of stored grain pests are different in different seasons. In spring, they generally gather in the sunny part or the surface layer of grain pile. In summer, autumn and winter, they gradually move downward.
(五)Judgment of grain pile heating
Fever is the most common symptom in corn storage. During corn storage, the "three temperature" data should be regularly detected, carefully observed and carefully compared to determine whether the grain pile is hot or not.
1、The grain temperature of different parts in the same barn was compared. If the grain temperature of one part is 4℃ higher than that of other parts, "fever" may occur in that part. In particular, when the grain temperature of a certain part of the back sun surface was higher than the grain temperature of the back sun surface, "fever" symptoms might appear in that part.
2、Compare with the temperature results from the last inspection. A sudden increase or an accelerated rate of temperature rise (if the temperature rises more than 2 ° C per day) will be considered as "fever".
(六)Sensory test
Each time when entering the warehouse inspection, should take the nose, eyes, hands touch, foot to sensory inspection of food situation. Sensory examination is particularly important for grain storage hidden trouble spots, such as the surface of grain pile, around the barn and impurity gathering area.
1、Smell whether there is any peculiar smell in the warehouse with the nose. If there is sweet taste or other peculiar smell, it is judged that there is "mildew".
2、Feel the softness of the flour with the foot. If it is found that the surface of grain pile is hard, it is judged that there is a "top" situation.
3、Grasp grain by hand to feel its dry and wet, soft and hard degree. If the grain is found to be damp, it is judged to be "sweating" or "dew". If the grain is found to be soft, the possibility of "hygroscopic mildew" will be judged.
4、At the same time of sensory examination, it is also necessary to observe whether there are rain and snow leakage points, insects and other abnormal phenomena in the warehouse and grain pile.
三、Scientific food situation control and food situation management
(一)To prevent condensation
Maize embryo is large and hygroscopicity is strong. Hygroscopicity will lead to fever and dew formation under suitable conditions. The corn at the gathering site of pests and the gathering site of impurities is also easy to get hot and dew. In addition, if the temperature difference and water gradient difference between each layer in the grain pile is large, it is also easy to form dew. During the transition period of spring, summer, autumn and winter, or when the grain temperature changes greatly due to the sudden rise in temperature, it is also the frequent season of corn dew.
1、Try to keep the moisture of corn in the barn not higher than the standard moisture, because low moisture grain is not easy to dew even in the case of large temperature difference.
2、Ventilation and airtight work should be done in the grain pile timely. Heat accumulated in the grain pile should be removed in the high temperature season in summer. Ventilation and cooling should be gradually carried out in autumn and winter to reduce the temperature difference between inside and outside the grain pile, and airtight work should be done in the spring to prevent external temperature from affecting the temperature of the grain pile.
3、Daily management to timely switch doors and Windows, reasonable ventilation, to prevent the phenomenon of condensation caused by human factors.
(二)Prevent infection by external pests
1、Ensure the warehouse door intact, if there is any damage timely repair, prevent pests outside the warehouse through the warehouse door infected grain inside the warehouse.
2、Regular disinfection of the surrounding barn, regular spraying of pest control line and ensure effective, to build a strong barrier to prevent the infection of external pests.
3、When the custodian enters the warehouse, he/she shall ensure that there are no pests on the person or the operating equipment. If there are pests, he/she shall deal with them in advance to prevent infection caused by human factors.
(三)Mechanical ventilation
In case of hidden danger of grain storage, such as heating, dew condensation and moisture absorption, ventilation and cooling or precipitation can be carried out according to the situation. For covering warehouse existing ventilation system, ventilation, appropriate USES high power fan and pumped air supply mode, in the process of ventilation and grain heap surface by the grain heap on the effect of temperature, humidity and moisture up within, can appear sometimes dewing phenomenon or condensation phenomenon, should continue to be ventilated, at this time and in the grain pile surface trenching dig ponds or flip back and forth grain surface, until condensation disappears.
If ventilation is needed, a separate ventilation plan shall be formulated according to the specific situation.
(四)Pest Control Workers
1、Daily protection.
In the breeding season, laying sacks on the grain surface of the barn and spraying dichlorvos regularly on the sacks can inhibit the hatching of pests and smoke and kill the initial pests. If conditions permit, we can use the phototactic habits of pests to install fluorescent killing lamps with daylight induction switches in the barn to trap and kill pests.
2、Chemical Fumigation
When a large number of pests occur in the warehouse, the stored grain should be fumigated in a timely manner, and the fumigation can be a mixture of DDVP and ALP. The complementary effects of dichlorvos and aluminum phosphide can greatly improve the effective lethal ability and degree of resistant insect species, completely kill all insect species and insect state in the bin, and avoid secondary fumigation. When dichlorvos is used, the original solution is volatilized naturally, which can make the medicine lasting and the labor intensity small. If the conventional method dichlorvos diluted spraying with water, the drug is slowly decomposed in water, which reduces the efficacy and increases the humidity in the warehouse, it is best not to be used.
(五)Emergency processing
1、Treatment of fever and condensation
①For slight dew on the surface, measures such as ditching and turning grain surface can be taken, and natural ventilation can be used to remove moisture and heat.
②Dews caused by excessive temperature difference during seasonal conversion shall be balanced by natural ventilation or mechanical ventilation to eliminate dews under the temperature and humidity conditions that allow precipitation ventilation.
③In case of heat and dew forming in the middle and lower part of the grain pile, manual trench turning treatment should be carried out, and a single-tube fan should be installed according to the situation for heat and humidity ventilation, so as to reduce the temperature and moisture in the heat and dew forming part. In the case of "nest" fever caused by insect infestation, local fumigation should be performed in addition to toppling and single-pipe ventilation.
④In case of serious condensation at the bottom of the grain pile, which cannot be completely solved in the warehouse, the dry and low-temperature weather should be chosen for warehouse turnover.
2、Top treatment
When the grain pile is topped, artificial furrow picking is generally adopted to loosen the grain surface and destroy the grain top, and natural or mechanical ventilation is implemented according to the situation to promote the internal heat and humidity to disperse as soon as possible, so as to avoid serious hidden dangers of grain storage such as germinating, heating and mildew. If the top knot situation is more serious, the top knot grain can be taken out of the barn, drying treatment.
