The yields of the clover seed will be much influenced by the character of the weather. Excessive rankness in the crop and excessive rainfall during the blossoming season are adverse to abundant seed production. But the seed crop is more injured by drought than by too much rain. When injured by drought the growth will not be sufficiently strong, or, if it is, the blossoms will be of a pale red tint. Warm winds while the seed is forming are also adverse to seed production, since they cause the crop to mature too quickly. Some experience will enable the capable observer to forecast with no little certainty the probable yield of the seed. If the indications point to a yield of seed less than 2 bushels per acre, it is deemed more profitable, as a rule, to cut the crop for hay. Large heads of a rich dark purple shade accompanied by vigor in the entire plant are indicative of abundant seed production.
The crop is ready for being harvested when a majority of the heads have ripened so far that the bloom on them is all gone and the shade of color in the head has not yet become brown. If left until a majority of the heads are brown many of them will break off while being harvested. The crop is usually cut with a self-rake reaper, but it may be cut with a mower. When cut by either method the sheaves should be made small, so that they will dry out quickly.
It is important that the crop shall be threshed before it is rained on, as one thorough wetting will so far bedim the attractive brightness as compared with seed that has not been rained on that it will considerably discount the price that would otherwise be obtained for it. It is usually threshed with a huller, but may also be threshed like the medium red variety by a grain separator with a suitable attachment.
The yields of the seed vary much. Instances are on record where as much as 11 or 12 bushels per acre have been reaped, but ordinarily even on good producing soils the yields are not more than 4 to 5 bushels per acre, and under ordinary conditions for the production of mammoth clover they are even less than the amount named. Notwithstanding the greater strength of the plants, the seeds are apparently no larger than those of the medium red variety, nor can they be distinguished from them unless by an expert.
Renewing.—Much that has been said with reference to the renewing of medium red clover will apply equally to the renewing of the mammoth. (See [page 109].) Where seed crops are much grown, the soil becomes so impregnated with the seed that more or less of the plants will appear any season. Renewal in the South is more important, relatively, than in the North, as under some conditions the plants survive for a longer period in Southern soils.
Compared with Medium Red Clover.—1. The mammoth is larger and coarser than the medium red and is considerably less erect in its habit of growth. It has larger and longer roots; hence, it goes down more deeply into the subsoil in search of food.
2. It is, on the whole, longer lived than the medium red variety and has greater power to grow in a sandy soil and under conditions in which moisture is not plentiful.
3. It provides more pasture than the medium red variety during the early part of the season, but not so much after harvest, the season of growth being less continuous then than with the former.
4. The hay which it furnishes is usually considerably more bulky and coarse, and because of this it is not so highly prized by stock.
5. It blooms about three weeks later than the medium red variety and remains a little longer in bloom and seeds more freely, but can only be cut once in a season.