The weather recjuirement is greatest under such conditions just as if 

 the plant made the greatest struggle to produce as much as possible from 

 the ver)^ scarce nutrient substances present. The leaves, then formed, are 

 very large and well spread, but are very little resistent to cold as well as to 

 heat. They react unfavorably to influences which pass over other plants 

 without leaving any ill effect. 



Such disturbances occur earlier in plants in moist localities. On hot 

 and especially windy days, evaporation is enormously increased, the amount 

 of water transpired is then considerably greater than that supplied by the 

 axial organs. Consequently the leaves on many plants wilt. The smaller the 

 normal transpiration per square centimeter surface, the longer the amount 

 of water brought by the stem, even on extremely hot days, will compensate 

 for the loss of transpiration. The plants of damp localities which, as ex- 

 perimentally determined, evaporate much more water in the same unit of 

 time than do plants from dry places, have thereby first of all reached the 

 limit when lack of moisture in the cell acts injuriously. In these plants the 

 leaves dry up first and not the very youngest nor the very oldest but, as a 

 rule, those working most actively and in part still elongating.. 



Proper drainage to remove the water from those particular tracts of 

 ground is the surest method of overcoming the trouble. 



Delayed Seeding. 



As a result of damp soil tlie time for planting is frequently delayed. 

 The following are the results of experiments by Fr. Haberlandt' and H. 

 Thiel-. The most detailed experiments were made by Haberlandt in 1876 

 with four kinds of summer grain in which, on the ist and 15th of the months 

 April, May and June, the seed was sown on a bed 3 sq. m. in size. The 

 results may be summarized as follows : The amount of harvest in all sum- 

 mer grains decreased more and more as the seeding was delayed. This was 

 based first of all on the considerably weaker growth of the grain planted 

 late and was most evident in the smaller number of fertile stems. A de- 

 crease not only in the quantity, but also in the quality was very noticeable. 

 The weight in straw increased with delayed sowing. In general the chaff 

 and roots of the crop increased disproportionately to the weight of the grain. 

 The quality of the grain itself also decreased greatly. Barley and oats from 

 later sowings had a greater amount of chaff by weight ; the smaller the in- 

 dividual grains were, the greater this disproportion became. 



The later sowings -were attacked to a greater extent by ergot, mildew, 

 rust and especially by leaf lice. Besides this, up to the time of forming the 

 blades, as well as blossoming and ripening, they required a greater amount 

 of heat than did earlier sowings. Even the germinative power of the har- 

 vested grain was affected and of a lowered quality in seed from plants of 



1 Haberlandt, Fr., Die Beziehungen zwi.schen dem Zeitpunkt der Aussaat und 

 der Ernte heim Sommergetreide. Oesterr. landw. Wochenbl. 1876, No. 3; 1877, No. 2. 



- Thiel, H., Ueber den Einfluss der Zeit der Aussaat auf die Entwicklung- des 

 Getreides. Ref. in Biederm. Centralbl. f. Agrikulturchemie. 1873, p. 47. 



