How much is the effect of the increase/decrease of moisture contents in the food grains?

Question

I want to know the approximate storage loss in the food grains due to decrease in the moisture content percentage

Answer 1

Link has some useful graphs too.

Grain moisture content continually decreases as the kernel develops. Loss of grain moisture occurs partially through the plant (cob and ear shank), partially through the husk leaves and partially through the exposed end of the ear.

Hybrid variability for the rate of grain moisture loss during post-maturity drydown and the resulting grain moisture content at harvest are of great interest to grower and seed industry alike. Growers desire hybrids with superior yielding ability (maximum gross income) that also dry very quickly in the fall (minimum drying or grain shrinkage costs). For an excellent discussion on grain weight shrinkage, see Hicks and Cloud, 1991. Calculating Grain Weight Shrinkage in Corn Due to Mechanical Drying. NCH-61. Purdue Univ. Cooperative Extension Service, W. Lafayette, IN 47907.

The seed industry also uses grain moisture loss data to rate hybrids for relative maturity. Many seed companies assign relative hybrid maturity ratings on the basis of relative harvest moisture differences among a group of hybrids. Two hybrids that differ in one 'day' of relative maturity will typically vary by about 0.5 % grain moisture if planted and harvested on the same days. Relative hybrid maturity ratings are most consistent within, not among, seed companies.

Certain hybrid characteristics interact to influence grain moisture loss rates. The relative importance of each trait varies throughout the duration of the field drydown process.

Husk Leaf Number. The fewer the number of husk leaves, the more rapid the grain moisture loss.

Husk Leaf Thickness. The thinner the husk leaves, the more rapid the grain moisture loss.

Husk Leaf Senescence. The sooner the husk leaves senesce (die), the more rapid the grain moisture loss.

Husk Coverage of the Ear. The less the husk covers the tip of the ear, the more rapid the grain moisture loss.

Husk Tightness. The looser the husk covers the ear, the more rapid the grain moisture loss.

Ear Declination. The sooner the ears drop from an upright position to a downward position, the more rapid the grain moisture loss.

Cob Diameter. The narrower the cob diameter, the more rapid the grain moisture loss.

Kernel Pericarp Thickness. The thinner the pericarp, the more rapid the grain moisture loss.

Grain moisture loss in the field occurs at a nearly linear rate within a range of grain moisture content beginning at about 40 percent and ending at 15 to 20 percent, then tapers off to little or no additional moisture loss after that. Figure 1 illustrates changes in grain moisture content over time for an adapted medium maturity hybrid grown in Indiana in 1992 (unusually cool fall) and 1994 (more typical fall temperatures). Grain moisture loss was linear in both years until early to mid-October when loss rates leveled off to near zero

As you might expect, the exact rates of grain moisture loss in the field are closely related to air temperature during the dry down period. The warmer the drydown period, the faster the grain will dry. In fact, there is a close relationship between the average rates of grain moisture loss per day and the average daily heat unit accumulation during grain drydown (Fig. 2).

Bear in mind that grain moisture loss for any particular day may be quite high or low depending on the exact temperature, humidity, sunshine, or rain conditions that day. It is not unheard of for grain moisture to decline more than one percentage point per day for a period of days when conditions are warm, sunny and dry. By the same token, there may be zero drydown on cool, rainy days.

Since heat unit accumulations are closely related to calendar date, there is also a close relationship between the average rates of grain moisture loss per day during the drydown period and the date when the grain nears physiological maturity (approximately 30 % moisture content). Average daily drydown rates will range from about 0.8 percentage point per day for grain that nears maturity in late August to about 0.4 percentage point per day for grain that nears maturity in mid- to late September (Fig 3).

Given the opportunity for early maturation of corn in Indiana in 2001, it is quite likely that grain drydown rates will be favorably high. Be prepared for an early start to grain harvest

Answer 2

Standard moisture content for corn is 15.5%, grain sorghum 14%, and soybeans 13%.  Usually storage losses are when the moisture is too high and your loss is from spoilage.  Grain should placed in storage at less than 14% moisture, and preferably 13%  for safety.  Too much moisture and you could lose all of your crop. You wanted to know storage losses due to decrease in moisture.  The losses here is not quality but actual weight loss. Just to look at an example, if you stored 10,000 lbs of corn at 15.5% moisture and during storage it dried down to 12.5% you would have lost 3% of the weight of your grain or 300 lbs.  This is an actual loss even though it's just moisture because you have 300 lbs less grain to sell.

Answer 3

Grain moisture content is very important point when the seed comes to maturity .If the moisture content is more than its specificity there is always a danger of spoilage of the grain.The moulds will develop and the seed gets spoiled and can not be uesd for human consumption and it is not at all useful for seed purpose.It is because the germination capacity of the seed will get reduced.Actually these moulds will affect on the embryo of the seed so it can not germinate.for example in case of groundnut the aflotoxins will develop if the seed is stored at higher moisture level which are very poisnous to human health.

                       In the same way if the seed is dried to lesser moisture levels then also there is a danger of loosening the germinating capacity as the embryo in the seed can not get the required miosture for its survival and looses its germinating capacity.

                  At final it always better to reduce the moisture level of the grain to specific level as prescribed by the scientists which is specific to each crop and store.