July, 1913 



the" garden and field. 



039 



Sulphate of Ammonin and 

 Acidity in Soils. 



A note in tlie Garclcnvrs' Chroni- 

 cle draws attention to the " cnri- 

 ous appearance of the herbajje " 

 in a jfrass plot at the Rotham- 

 sted Ajjricultural Experiment Sta- 

 tion, England, which has been 

 manured continuously with sul- 

 phate of ammonia and chloride of 

 ammonia for a long i>erix>d of 

 years. The veg-etation on this i)lot 

 is described as being composed al- 

 most entirely of three grasses, 

 while) the ■ surface soil consists of a 

 I>eat-like mat of semi-decayed plant 

 reniains. The following particulars 

 are given of investigations carried 

 out in connection with the condi- 

 tion of the soil of this plot : — 



Recent investigations that ,have 

 been made in the laboratory show 

 that the s'oil has become acidl a 

 result that often may occur as a 

 consequence of the long-continued 

 use of ammonium salts. . It was 

 found that the organisms which or- 

 dinarily oxidize the ammonia to 

 nitrates were only present in small 

 quantities, and their action was 

 almost inhibited owing to the 

 acidit}- of the soil. The slight 

 amount of nitrification observed, 

 together with the other facts, which 

 need not be considered here, point 

 to the fact that this condi- 

 tion is attributable to the, bene- 

 ficial action of the small residual 

 quantity of lime present in the soil. 

 This acts partly, no doubt, as lo- 

 cally neutralizing the acidity, and 

 it is possible that further investi- 

 gation mav show that, its, influence 

 may also be connected with other 

 physiological properties which this 

 substance is known to possess. 

 The acidity of the soil is, at least 

 mainly, broug'ht about by the 

 action of various micro-fungi, which 

 are able to iitilize the ammonia, 

 setting free the acid in the soil. 

 The general result of the investiga- 

 tion, which has a practical value 

 of considerable importance, indi- 

 cates that ' the decline in fertility 

 of the acid plots may be attributed 

 to the repression of the normal 

 bacterial activities of the soil, 

 and the encouragement of the 

 growth of moulds." 



4 



Soil Moisture and Humus. 



Dealing with methods of improv- 

 ing the condition of land in a low 

 state of fertility, Farmers' Bulletin 

 245 of the United States Depart- 

 ment of Agriculture, entitled "The 

 Renovation of Worn-out Soils," has 

 the following passage on the im- 



portance of maintaining a proper 

 .•supply of humus in the .soil : — 



In producing suflicient grass to 

 yield a ton of dry hay on an acre 

 of land, a quantity of water ap- 

 proximating to 300 tons is with- 

 drawn from the soil bv the grass. 

 In order to supply this enormous 

 quantit}' the land must not only 

 be in condition to absorb and hold 

 water well, but it muvst be porous 

 enough to permit water to • pass 

 freely through the soil. The pre- 

 sence of large quantities of decay- 

 ing organic matter (humus) adds 

 enormously to the water-holding 

 capacity of the soil. One ton of 

 humus will absorb two tons of 

 water and give it np readily to 

 growing crops. Not only'that, but 

 the shrinkage of the particles of 

 decaying organic matter and the 

 consequent loosening of soil grains 

 keep the soil open and porous. 



Furthermore, humus of good 

 quality is exceedingly rich in both 

 nitrogen and mineral plant food. 

 The maintenance of fertility may 

 almost be said to consist in keep- 

 ing the soil well supplied with 

 hximus. The first step in renovat- 

 ing worn-out soils is to give themi 

 an abundant supply of humus of 

 good quality. Perhaps the best 

 source of humus is stable manure 

 containing both the liquid, and the 

 solid excrem.ent, especially when thd 

 stock are fed on rich nitrogenous 

 foods. Even a poor quality of 

 barnvard manure, which has had 

 much of the plant food leached out 

 of it, has considerable value be- 

 cause of the humus it makes. 



Another cheap and valuable 

 source of humus, but one which 

 must be used with judgment, ' is 

 the use of green crops grown to be 

 ploughed under as manure. 



♦ ■ 



Cross Fertilizing Mediums. 



The experience gained by a sub- 

 urban resident, while it may be 

 valuable to growers, is not likely 

 to be forgotten by him for some 

 time. Three years ago he had a 

 Coe's Golden Drop plum growing 

 in his gard,en close alongside a 

 blue plum., the name of which can- 

 not be obtained, writes the "Aus- 

 tralasian." The Golden Drop for 

 years carried heavy crops of fruit, 

 but as two plum trees were con- 

 sidered superfluous in a garden of 

 this kind the owner decided to 

 chop the blue plum down and 

 utilise it for firewood. This was 

 done two vears ago, and the Coe's 

 has since failed to bear. Among 

 animals this might have been re- 



garded as a mark of svmpathy to- 

 ward."! a comrade, though fruit- 

 growers with experience ot the 

 Coe's Golden Drop will realise 

 that the medium by which the 

 blossoms were cros.s-fertilised hav- 

 ing been taken away the tree na- 

 turallv returned to its .shy bearing 

 characteristics. The most sucoes.s- 

 ful growers of this variety of 

 plum are men who have planted 

 other varieties close alongside to 

 provide the cross-pollinating influ- 

 ence so necessary to ensure the 

 proper setting of the crop. Of late 

 vears many instances of the value 

 of planting varieties with the ob- 

 ject of securing proper fertilisation 

 have been referred to. Such bene- 

 ficial results have followed this 

 practice that intending planters 

 would be unwise to plant out a 

 block of trees without first giving 

 consideration to those kinds which 

 are benefited by being grown in 

 close proximity to others which 

 bloom over the same period, and 

 provide an interchange of pollen. 

 One of the most striking instances 

 of this kind recently came under 

 notice in a Narre Warren orchard. 

 Mr. Bailey carried out a large ex- 

 periment with his pear trees by 

 placing bottles filled with blossom 

 in the forks of the trees,, while at 

 the foot of others he put out dwarf 

 trees in pots. In almost every 

 instance the lower parts of the 

 trees were heavily loaded with 

 fruit, which hung in dense clusters, 

 while towards the tops the trees 

 scarcely carried any fruit. Similar 

 results have been obtained by 

 blending together varities of apples 

 in the one plantation. Cross-pol- 

 lination mav not be necessary to 

 secure fruit, but it is essential to 

 the regular development of good 

 average crops. 



4 



To Prevent Hares from 

 Touching Fruit Trees 



The following- recipe is from an old 

 English book: — "Put a teaspoonful 

 of asafoetida in half a bucketful of 

 thick clay water, and applied with a 

 brush on the stems or branches of 

 young trees, will preserve them from 

 the attacks of hares or rabbits with- 

 out injury to the trees. It has to be 

 renewed three or four times every 

 season." The renewing is the trouble. 

 Weak carbolic acid or cowdung will 

 preserve the trees for a time, but sud- 

 denly the owner finds he has left the 

 fresh application a day or two too 

 long, and a number of trees are bad- 

 ly bitten. 



