A TALK ON INOCULATED SEED.

Alexandra Herald and Central Otago Gazette, Issue 1689, 5 June 1929, Page 1

A TALK ON INOCULATED SEED.

(By Mr A. S. Duff, B.Sc., C.D.A., Instructor of Agriculture); !.? Inoculated Seed Increases Yield and Quality of Legumes:— r The purpose, of sowing bacteria *;with legume seeds is to ensure the pro&M>le arid economical production of leguminous crops witu-1 out robbing the soil of its nitrogen. Many farmers have recognised that the; stand, yield, quality and the life of the legume plants are/jii creased by the use of inoculation. In spite of these recog-' nised facts, however,' there are numerous farmers not yet aware of the bene-;' fits to be derived from the. use of cultures of root nodule bacteria.

The proper bacteria for eacli legume should always be used with every newseeding of the legume. From the standpoint of the soil alone, no farrner can afford to continue to deplete the supply of nitrogen «in his soil when it can be so cheaply maintained and eveir increased by the use of cultures of bacteria applied to the seeds of legumes.

Inoculation Increases Yield.—The yields of ! cultivated legumes e.g. lucerne, sweet clover, red clover, white clover, alsike, soybeans, vetches; peas and garden beans ~ are increased by imoculation. Sometimes the increase is very large and at other times it is small, but if any increase is obtained it is at very low cost. Inoculation is conceded to be a highly profitable method of increasing yields of leguminous crops. The writer has a case in mind where in one field of lucerne the inoculated plants were found to weigh four times the uninoeulated plants, The inoculation cost was recovered many times by this gain. If, by the use of the cultures, the legumes are at once successfully established, a large saving is obtained 'in labour, time and money.Inoculation- Increases Quality.—The effect of Seed inoculation, on the 1 quality' of'legume crops has been studied; rec|ittjy"froim the standpoint of the ' protein-" con tent. Large increases have beehfojiSd'where inoculation has been pr&e'tiseUT these increases are not visible;*' and %flst Be, accepted from chemical'studied.. ''A. large increase in portein due'to inoculation may be ae-, companiedi-SyiJio increase in yield, or it may accompany an increase in yield. In'an experiment Which the writer has in mind every.ton of the inoculated lucerne tops contained 3051b of protein, while the uninoeulated contained only 227.51b per ton. This difference in favour of inoculation was determined by chemical analysis, and was not one that could be seen in field. Similar results have been obtained for other legumes. The increase in protein content from inoculation is worth almost as much as a ton increase in yield of lucerne hay.. These are some of the benefits of inoculation which should be considered more often than has been the case in the past. "Quality production of farm crops is as essential as quantity production, and the use of inoculation is a means to that end. Sow Inoculated Seed!—-Mrstj' where the legume to be seeded has never been grown before; second, where the legume to be seeded has grown only once; third, where the legume to be seeded has not grown recently; four, where any doubt exists as to whether' the legume to be seeded has been giowu before on a given padfibek'; five, w'h're the soil is.sour and the he seeded grew poorly. • ' L ''■*^ J - Inoculation Enriches the .Soil:--eoiv siderable data has beon obtained which proves that properly inoculated legumes add nitrogen to the soil or conserve that already present in the soil. This in itself justifies the use of inoculation even if no increase in •'yield or protein content is obtained. ] The amount of nitrogen fixed rrom"%ie air

by inoculated legumes, per acre, per year, varies with the kind of legume, .soil, season, aid the manner in which !.the crop is handled. As an average of 'all legumes, the amount fixed is variously estimated at 50 to 100 pounds per acre per annum. On some soils, possibly as much' nitrogen is saved by the presence of legumes that grow' at J periods of excessive leaching as-.;ijj; ; added by the fixation process. ' -'''V .Soils Lose Nitrogen.—The fixation of nitrogen by legumes and nodule , teria is large compared with the nitrogen,, applied in commercial, manures. The fixation, hQwever, is small compared with the nitrogen'Tremoved in the crops grown in this country each year. There is, eafch year, a deficit in the nitrogen balance sheet of several hundred thousand tons of nitrogen. • The soils of this country lose that amount each year. In farming systems, where more : nitrogen is removed than is added, decreasing productivity t results. The farmer who wishes to improve his soil, must protect it with inocu- v luted leguminous cover crops, and must grow inoculated, legumes as often as possible in all his crop rotations. I Every farm should have from 20 per. cent, to 25 per cent, of the land in a leguminous crop, and, in addition, a leguminous green manure crop should be seeded in the small grains, and in peas, every year in order to help'to maintain the nitrogen content of the soils of every farm. Sow Inoculated Seed Immediately.— A number, of cases have been reported in which inoculation gave only a small percentage of nodijles where conditions were seemingly ideal.

From a study of these conditions it was found that the seed was not treated according' to directions. In many cases it .was not sown ~ until several days after the culture was applied. '

Cultures must be fresh, too, and kept in the dark away from bright or direct sunlight. Inoculated seed should also be sown on it dull day, as sunlight •kills the nitrogen-fixing bacteria.

The root-nodule bacteria requires a home in Which to live and work, and food for energy and tissue building, while moisture enables them to obtain their-food.

In the water on the seed the bacteria live arid multiply, but as soon as the seed dries, then the bacteria has its food shut off and dies.

There are other kinds of- bacteria which are able to protect themselves against, such a condition by producing spores. The root-nodule bacteria does not produce spores and hence cannot protect itself against loss of moisture by this means. Inoculated: seed should- be sown as soon as possible after\ treatment. Many farmers sow, or start sowing, a given lot of seed while wet. In normal seasons with normal soil 'moisture, this advantage would not be so great as in the dry periods. Even the larger seeds such as soyabeans, peas, and garden beans are seeded wet. If the seed is allowed to dry sufficiently for good handling, there is no benefit to be deprived from further drying.

j If- seed is kept over a day 'treatment with bacterial culture, it should be re-inoculated, u»less it is kept moist,' which cannot be accomplished safely unless the temperature is kept low. (Continued elsewhere-in tlus issue).