300 Mineral Nutrition of Plants 



per acre before a response to boron is noted. In one experiment in 

 Canada no increase in yield with borax was observed until sufficient 

 nitrogen, phosphorus, and potassium were added to produce a yield of 

 15 tons. Then 10 pounds of borax per acre produced 3 additional tons of 

 tomatoes. The pH values of the Canadian soils are practically all within 

 the optimum range for the growth of tomatoes or above the optimum 

 range. This statement, of course, applies only to those regions in which 

 tomatoes are primarily being grown, that is, near Chatham, Toronto, 

 and the lake border. 



The principal limiting factor in Canada is the length of the season. 

 For that reason, getting the plants started early in the spring is very 

 important and controlling the vegetative growth is equally important. 

 Owing to the heavy nature of the soils, the long winters, and the wet 

 springs, phosphorus is particularly unavailable. Therefore, response to 

 phosphatic soil supplements is great. Oats, for instance, have been ob- 

 served to be two weeks earlier on the heavily phosphated plats as com- 

 pared to those grown on the regularly fertilized plats. Therefore, to- 

 matoes mature earlier when adequate phosphate is supplied early in 

 close proximity to the root zone. 



A definite response to manganese and an improvement in the red 

 color of tomatoes have been noted on the alkaline soils of Illinois. 



QUALITY OF TOMATOES 



The quality of the tomatoes is a determinate factor in the amount of 

 tomato products sold. Two important factors influence the quality of 

 tomatoes: climatic conditions and soil conditions. The climatic condi- 

 tions influence the yield and quality throughout the season, but a cold, 

 wet picking season probably has the most unfavorable effect. Analyses 

 for three very different seasons serve to illustrate: a poor season (1938), 

 a fair season (1939), and a good season (1943). These data are given 

 in Table I. It is noteworthy how the total solids, sugars, titratable acids, 

 and vitamin C increased due to better growing and picking conditions. 

 In other words, the season, as it influenced the soluble plant nutrients 

 in the soil, also influenced the quality of the fruit. 



Soil type influences yield and quality of tomatoes. In 1939, tomatoes 

 grown on four different soil types were investigated for yield and 

 quality. These data are given in Table II. 



