Golden autumn yam sells well Harvesting and storage are the most important

As a traditional domestic export vegetable variety, yam is deeply loved
by consumers because of its rich nutrition, diverse eating methods, and can be fried and steamed.
Not only that, yam is also loved
by producers because of its relatively simple cultivation methods, wide range of product uses, and large market demand.

Yams are harvested in autumn and can be supplied
annually after storage.
Long buds, discoloration and decay of pulp are common problems in the storage process, which not only has a high loss rate, but also affects the commerciality
.
If the storage essentials are not mastered, the quality of yam deteriorates rapidly and can only be stored until mid-to-late April, in which case, good storage is crucial
to maintain the quality of yam.
To this end, Beijing Agricultural Technology Extension Station hereby puts forward the following guidance for the reference
of the majority of producers and operators.

Yams to be harvested Image source: Beijing Agricultural Technology Extension Station

Digging trenches to reduce yam mechanical damage Image source: Beijing Agricultural Technology Extension Station

Yams are generally harvested in autumn when the stems and leaves are yellowed at the beginning of the frost, and in northern China, it is mostly carried out
after the frost falls.
The frost falls in Beijing around 10 days, from mid-to-late October to early November, and there are certain differences between years, so as not to cause cold damage to yam
.
The yam harvesting standards are not strict, but the harvest is early, the nutrients have not been fully gathered into the tubers, the tissue is not full, the yield is low, and the quality is poor; If the harvest is too late, it is easy to cause cold damage and frost damage, the storage quality is reduced, and it is easy to rot and deteriorate, which affects the commerciality
.

Before the yam harvest, remove the support, cut off the vine stem, dig a deep trench at one end of the ridge, next to the row of the ridge, and harvest the yam from the side, which can ensure the integrity of the yam and reduce the problem of
breakage.
During harvesting and transportation, attention should be paid to prevent damage to tubers
.
After yam harvesting, if it is sold directly, the surface soil should be removed to maintain good commerciality; If used for storage, soil should be retained to protect the epidermis from scratching
.
In autumn rainy years, harvesting should be done when soil moisture drops to suitable levels
.
Rain and snow, not suitable for yam harvesting
.

Common problems affecting the commerciality of yam generally include: damage, fracture, scars, spots, decay, wormholes, wilting, frost damage, etc
.
In addition to the variety, the commercial quality of yam is also related to
the skin, pulp color, flesh quality, etc.
Mechanical damage, fracture, wilting, decay and freezing damage are mostly caused by
improper measures in the mining, storage, transportation and marketing links.
Most of the disease spots are soil-borne diseases formed by continuous cropping, and the wormholes are mostly caused by underground pests.
In order to prevent yam from breaking, preventive measures should be taken in all links of harvesting, storage, transportation and sales; Frost damage can occur in all links of harvesting, storage, transportation and sales; Wilting is mainly caused by water loss; Most of the decay is caused by the pre-storage link not working in place and the storage humidity is
too high.

Yam commerciality requirements: tuber long cylindrical, yellow-brown epidermis, beard roots, cross-sectional flesh white, powdery (brittle), mucus, no fracture, scar, wilting, rot, frost damage, wormholes, etc
.

White jade yam box packaging Image source: Beijing Agricultural Technology Extension Station

Yam suitable for storage temperature of 3-5 ° C, humidity 80%-85%, different varieties due to different water content, storage temperature, humidity slightly different, long-term storage, the need for annual supply of temperature and humidity requirements are strict, short-term storage conditions can be relaxed
.
Yams can be stored in cold storage, cellars, indoor storage
, etc.
Yam has a dormant period, after the dormant period, the storage conditions are suitable for storage for 6 months, and the long can reach more than 1 year, to meet the annual supply requirements; The storage temperature is high, the color of tuber pulp is easy to turn yellow and brown, and the storage time is shortened; If the temperature is too low, it is easy to cause cold damage or even frost damage, resulting in rot; Different types of yam have slightly different
storage temperatures due to their different water content.
After harvesting, the yam is graded according to the length, diameter and other indicators to facilitate storage management
.
Mechanical damage, diseased wormholes, freezing damage and other yam that are not suitable for long-term storage are selected and directly sold or processed into dried yam, yam powder, yam juice and other products
.

Yams without mechanical damage, diseases and pests, and suitable moisture content can be directly stored and stored; Yams that need to be stored with mechanical damage should be pre-stored, that is, stored at a temperature above 20 °C for about a week to promote mechanical wound healing and prevent decay during storage; In case of rain and snow before harvesting, yam with high moisture content, the yam after harvest should be placed in a ventilated place to reduce the water
content of yam as soon as possible.
Yams in low-lying plots are not suitable for long-term storage
.
When the yam is stored and stacked, the flat yard method is adopted, and the gap between them can be filled with moist fine sand to avoid the uneven force of the yam after the gap, resulting in the phenomenon of
breakage.
In this stacking method, the area storage quantity is large, and the force is uniform, the yam is not easy to break, and the mechanical damage is less
.
When the yam yard is too high or too wide, ventilation channels should be placed at certain intervals to maintain air circulation, so that the temperature and humidity in different positions in the storage warehouse are basically the same
.
The ventilation duct can be made of three wooden planks in a triangle, or perforated plastic pipes
can be used.
Store yam indoors at room temperature, temperature and humidity cannot be controlled, and the storage time is short
.
When the storage temperature after the dormancy period is too high, the yam is prone to problems such as long buds, flesh discoloration, wilting of the peel, etc
.
, and cold damage is easy to occur when the temperature is low, and rot will occur in severe cases.
During storage, you should always pay attention to temperature and humidity changes, and temperature changes are best controlled within
±0.
5 °C.
Pre-storage work and temperature and humidity management are operated in accordance with standard specifications, and the annual supply
of one season of production can be realized.

Yam storage Image source: Beijing Agricultural Technology Extension Station

Post-harvest quilt cushion reduces mechanical damage during transportation Image source: Beijing Agricultural Technology Extension Station

If the yam is sold directly after it is out of the warehouse, it can be washed with water to remove the soil on the tuber; After leaving the warehouse, in order to avoid frequent warehouse opening, the temperature fluctuation in the warehouse is large, and it can be used once out of the warehouse and used
in stages.
After washing, the yam is more likely to germinate and the pulp turns yellow at a suitable temperature, and should be sold
in time after washing.
Facilities with poor storage conditions, unstable temperature and humidity, yam in mid-to-late April of the following year prone to buds, water loss and other problems, if the later storage quality cannot be guaranteed, it is best to complete the storage before mid-April
.

Check the storage effect of yam from time to time Image source: Beijing Agricultural Technology Extension Station

Yams can be stored
at room temperature during the dormancy period.
After the dormancy period, a small amount can be stored in
the refrigerator freezer.
When the storage quantity is large, it can be peeled, placed in a vacuum plastic bag according to each dosage, stored in the freezer, and taken out before eating, which not only maintains the quality, but also saves storage space
.
(Editor Li Chuang)