102 IOWA DEPARTMENT OF AGRICULTURE 



WEATHER AND CROP REVIEW. 



All reference in this publication to the effect of weather on crops is 

 the result of cooperation between the United States Weather Bureau and 

 the Iowa Weather and Crop Service. 



Winter set in early and severely, preceding the crop season of 1920. 

 For the three winter months the average precipitation was the least of 

 record, but that of the early winter fell mostly as snow, giving ample pro- 

 tection to winter grains and grasses during the rigorous, record breaking 

 temperatures of early December. Under the snow covering, the ground 

 froze very little, though cold weather was practically continuous till after 

 the middle of February, There were considerable periods without snow 

 covering in the south central and southeast districts and extending a few 

 counties northward along the Mississippi and Missouri rivers. About 6 

 per cent of the winter wheat was winter killed, which is less than the 

 average. 



March was wet, warm and windy. The snow cover disappeared in the 

 northern portion about the middle of the second week, having been con- 

 tinuous there since November. By the end of the third week frost had 

 left the ground. Several wind storms seriously damaged farm buildings. 

 The ground was too wet for much field work. 



April was cold and wet with a snow storm in the southern third of 

 the state on the 3d-4th. It was too cold for plant growth and too wet 

 for field work. However, a larger oats acreage than last year was sown 

 in the larger producing counties of the west and northwest portions of the 

 state. In the wetter, later, southern districts, oats seeding was prolonged 

 unusually till as late as the middle of May. The development of fruit buds 

 was beneficially delayed by the cold weather. 



The season continued cool till about May 20, when a warm spell set In 

 that brought vegetation forward rapidly. Field work progressed slowly, 

 particularly in the south central and southeast districts, where much corn 

 was yet to be planted at the close of May. The most advanced section 

 was the upper Raccoon river watershed where corn planting began about 

 May 4 and was finished before the close of the month. In Union and por- 

 tions of adjacent counties not more than one-third of the corn had been 

 planted up to June 1. Fruit bloomed generally about the middle of May, 

 with conditions favorable for pollenation. Peaches in the southern tier of 

 counties showed more bloom than for the past seven years. Young live 

 stock suffered greatly from the cold, wet, cloudy spring. 



June was warmer and drier than usual in most sections of the state. 

 The week ending June 15, with a mean temperature of 80 degrees, was the 

 warmest week of the entire season and the warmest June week since 

 June 3-9, 1911. The humidity, however, averaged 20 per cent lower than 

 during a similar hot perio' : • ; \ vrith the result that diseases of 



small grains were, much less prevalent, though causing considerable dam- 

 age to spring wheat in the west central and northern counties. The fol- 

 lowing week averaged 15 degrees cooler and was very beneficial for 

 small grains, which were in or approaching the critical heading and 

 blooming period. All crops improved during June but were still below 



