6 FORAGE-CROP EXPERIMENTS AT SAN ANTONIO. 



Table I. — Monthly rainfall at the San Antonio Experiment Farm for the years 1907-191 .', 



i nc! iisi r<\ toe/ether with the averages of the years 1891-1911. 



Month. 



January 



February 



March . .' 



April 



May 



Juiie 



July 



August 



September 



October 



November 



December 



Total 



Monthly n n 



Monthly 



average 



rainfall, 



1S91-1911.1 



Inches. 

 1.35 

 1.47 

 1.41 

 2.84 

 3.01 

 2 

 2 

 2 

 2 

 1 

 1 



i :>'i 



24.47 

 2.04 



Rainfall by months. 



1907 



Inches. 

 0.56 

 1.72 

 1.70 

 4.50 

 2.81 



.31 

 2.65 



. 39 



.64 

 2. 98 

 6. 78 



.64 



25.68 

 2.14 



1908 



Inches. 

 0.47 

 2.61 

 1.27 

 2.39 

 5.44 

 .88 

 1.37 

 3. 79 

 2. 5(1 

 1.62 

 2.87 

 1.50 



26.80 

 2.23 



1909 



Inches. 



0.00 



.41 

 1.12 



.85 

 1.72 



.72 

 2.86 

 1.75 



.29 

 1.20 



.27 

 1.95 



13.14 

 1.09 



1910 



Inches. 



I. lb 



.68 



.21 



4.4H 



1.77 



2. 24 



1.12 



.45 



Jin 



3.7(1 



L.30 



1.74 



20.H2 

 1.67 



1911 



Inches. 

 0.16 

 1.73 

 3.34 

 23.41 

 1.41' 

 .OS 



1.14 

 2. lfi 

 1.24 

 3.09 

 2.13 

 1.53 



21.42 

 1.64 



1912 



Inches. 

 0. 31 

 6.21 

 2.30 

 2.00 

 1.(4 

 3.42 

 .IIS 



1 Average for the years 1891-1911 from records of the United States Weather Bureau. Rainfall from 190V 

 to 1912 from records at the San Antonio Experiment Farm. 

 -> Record for April, 1911, from the United States Weather Bureau service at San Antonio. 



The rainfall for the years 1909 to 1911 w^as considerably below 

 normal, while that of 1909 was the lowest thus far recorded. Con- 

 sequently the crop yields reported in these experiments were rather 

 lower than may be expected under normal conditions. The year 

 1908, as indicated by the crop yields, w r as perhaps more favorable 

 than normal, although the total rainfall for the year does not indi- 

 cate it. The heavy rains in November of the preceding year w r ere 

 apparently stored in the soil and used during the season of 190S. 



FACTORS INFLUENCING CROP YIELDS. 



The yields of forage crops reported in the following pages are 

 extremely variable and often are not significant. They are pub- 

 lished as a matter of record, but the interpretation of the experi- 

 ments should be based on the printed conclusions and recommenda- 

 tions rather than on the figures alone. It is not always clear which 

 way the crop or the treatment of the land the previous season affected 

 the subsequent crop yields. Usually, fallowing land for several 

 months results in larger yields of the following crop, but this is not 

 always the case. The kind of crop grown the previous year also 

 affects the yields obtained. For instance, the small grains, such as 

 wheat or oats, are harvested in May or early in June, corn in July, 

 while cotton and sorghum occupy the land until late in October 

 and use any available soil moisture until harvested. A crop planted 

 the following March or April on land that had been devoted to cotton 

 or sorghum is ordinarily at a disadvantage wdien compared with a 

 crop on land that had been in oats or corn the previous year. 



It lias seemed advisable to publish the crop yields even at the risk 

 of some misinterpretation, but in each case it is urged that for pur- 



[Cir. 106] 



