70 MASS. EXPERIMENT STATION BULLETIN 315 



time a complete fertilizer has been applied annually. These two plots produced 

 rather better than the other cultivated plots in the earlier years of the test, then 

 showed signs of a decline. The crop of both varieties for 1933-34 shows remarkable 

 gains. If continued for a few years more it will be an argument for complete 

 fertilizer. 



Plot 2 in sod has had nitrate of soda 300 pounds per acre and a supplemental 

 application of about 200 pounds in July. Plot 4 has had the same treatment but 

 without the summer application. The additional nitrogen seems to have in- 

 creased yields. Plot 6 had the same treatment as Plot 4 until 1927 when sulfate 

 of potash 150 pounds per acre annually was added. Mcintosh seems to have 

 responded after a year or two with increased yields, while Baldwin has not. The 

 appearance of the trees on Plot 6 is better than that of those on Plot 4 and the 

 potash content of the leaf petiole is higher. 



Comparison of Clover Sod and Grass in a Sod Mulch Orchard. (J. K. Shaw.) 

 This project is closed. Results have been meager, but it is concluded that white 

 clover cannot be easily maintained in orchards with phosphorus-potash-lime 

 fertilization under our conditions. There has been some evidence that the white 

 clover when present does supply some nitrogen to the trees but not an adequate 

 amount. The conditions favoring the clover seem also to favor blue grass and it 

 tends to crowd the clover out. However, it is felt that the trees grew and pro- 

 duced better than they would have done without fertilizer. 



Tests of Different Amounts of Nitrate of Soda. (J. K. Shaw.) The practice of 

 fertilizing in the off years only has been continued. Yields in the on year have not 

 been maintained but in the off year, when the fertilizer has been applied, they 

 have increased. In other words there is evident some tendency toward more 

 regular bearing. The net result, however, is a lower total yield. 



Comparison of Cultivation and Heavy Mulching for Apples. (J. K. Shaw.) 

 Fertilization of the cultivated plots with nitrate of soda was continued and addi- 

 tional mulch applied to the mulched plots as it was available. Mulching has been 

 very heavy, enough to suppress nearly all the grass beneath the trees. The lower 

 layer of the mulch, which has accumulated for twelve years, is well decayed and 

 filled with a mat of fine rootlets. No injury from the severe winter was noticed. 

 The yields by two-year periods in pounds per tree since 1926 are as follows: 



McINTOSH 1027-2S 1929-30 1931-32 1933-34 



Mulched 1452 2550 2272 2154 



Cultivated 785 1220 1437 14til 



Difference 0U7 1330 835 693 



WEALTHY 



Mulchea 417 752 836 896 



Cultivated 323 474 676 597 



Difference 124 278 160 299 



The nitrate applied to the cultivated plots beginning in 1930 has apparently 

 increased production of Mcintosh, but Wealthy trees have increased in yield 

 no more than those mulched. Perhaps the Wealthy trees are deriving some nitro- 

 gen from the seepage waters from the mulched plot located adjacent on higher 

 ground. The filler trees on Doucin stock in these plots were cut out in 1932 and 

 this may have been to the advantage of the trees on seedling stocks remaining. 

 The stocks under these Doucin trees prove to be Mailing Type 5 and not 6 as 

 reported last year. 



