922 Popular Editions of Station Bulletins of the 



Low winter temperatures, affecting immature wood and buds 

 caused by unfavorable weather of the previous season, reduced yields 

 materially during two of the five years, and practically neutralized 

 any anticipated benefit from fertilizers. Following the first of these 

 low-crop years, came a season, 1911, in which favorable conditions, 

 acting upon vines left undiminished in vigor by the light crop of the 

 previous year, resulted in heavy and quite uniform yields on all the plats. 



The yields for the five years are shown in Table I ; and a summary 

 showing the average gains from each treatment is given in Table II, 

 with the average financial balance after deducting the cost of fertilizer 

 application from the increased returns from the plats receiving them. 



Table I.— Yield of Grapes (Tons per Acre) in Fertilizer Experiments. 



Plat 



No. 



5-year 

 average. 



1 

 2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 



10 

 11 



Complete fertilizer; lime. 



Complete fertilizer 



Nitrogen and phosphorus 



Nitrogen and potash 



Phosphorus and potash. . 



Check 



Complete fertilizer; lime. 



Complete fertilizer 



Nitrogen and phosphorus 



Nitrogen and potash 



Phosphorus and potash . . 



Tom. 

 3.51 

 3.98 

 3.83 

 3.87 

 3.39 

 3.12 

 4.10 

 4.02 

 3.97 

 4.18 

 3.61 



Table II. — Average Increase in Grape Yields and Average Financial Gain 



from Fertilizer Applications. 



N = nitrogen, P = phosphorus, K = potash, Ca = lime. Gains in tons per acre. 



First plat of pair 



Second plat of pair . . . 



Average 



Check plat 



Average gain 



Average financial gain 



N, P, K, 

 Ca. 



Tons. 

 3.51 

 4.10 



3.80 

 3.12 



.68 



$5.82 



N, P, K. 



Tons. 

 3.96 

 4.02 



3.97 

 3.12 



.85 



$13.84 



N, P. 



Tons. 

 3.83 

 3.97 



3.90 

 3.12 



.78 

 .05 



N, K. 



Tons. 

 3.87 

 4.18 



4.02 

 3.12 



.90 

 $18.54 



P. K. 



Tons. 

 3.39 

 3.61 



3.50 

 3.12 



.38 

 $6.99 



From this last table the benefit from nitrogen appears quite evident 

 since every combination in which it appears gives a substantial gain 

 over the one from which it is absent. Phosphorus and potassium, 

 without the nitrogen, lead to only a slight increase over the check; 



