HORTICULTUIIE. 351 



caupe evaporation to be much slower than duriiii; the remainder of the year. In 

 applying water, therefore, comparatively little escapes into the atmosphere. The 

 supply of water l)ein<r greatest at that time of the year makes it possible to apply 

 large amounts at short intervals, thus avoiding the loss that occurs if small amounts 

 are applied at greater intervals. Then, too, the trees are dormant and the roots need 

 little air; hence, no injury is done them by keeping the soil supermoistened, or by 

 letting the surface bake to some extent. Consecjuently, cultivation after each irriga- 

 tion is not necessary, much time thus being saved." 



In these experiments it was found that root growth took place at depths of 10 to 

 16 ft. as early as February 20, when above ground there was no indication of growth 

 whatever. Some data were also secured on the evaporation of soil moisture by weeds. 

 A jiortion of the orchard which had been left uncultivated was overgrown with 

 weeds. An examination showed that the upper 5 ft. of soil in the cultivated portion 

 of the orchard contained about twice as much available moisture as the upper 5 ft. 

 of the soil in which the weeds were growing. 



In the irrigation experiments here reported the water content of each foot of soil 

 from the surface down to ground water (34: ft.) was determined in different months 

 from April to October. These data are tabulated and commented upon. The greatest 

 amount of water was used by the trees during spring and early summer. This is 

 the time when water for irrigation is least abundant, and "emphasizes very strongly 

 the importance of filling the subsoil with water during the winter, when the supply 

 is comparatively abundant." The total loss of water during the whole season was 

 about 20 in., of which about 80 per cent was lost during the first 3 months, 16 per 

 cent the next 3, and 4 per cent the last 3 months. The indications seem to be that 

 deciduous orchard fruit trees in Arizona begin using water early in February. 



"From this date until about the end of June the amount used evidently gradually 

 increases, and after the latter date evidently gradually diminishes. These facts indi- 

 cate plainly that much of the water should be applied as soon after the first of 

 January as possible. 



"The amount of water needed by a deciduous orchard to keep it in good condition 

 in southern Arizona from March to November is about 21 in., which can be stored 

 in the soil by the apj^lication of about 3 ft. during winter." 



A crop of clover {MeUlotus indica) grown in the orchard for green manuring, from 

 December 16 to March 5, withdrew from the^soil about 20 in. of water. It is calcu- 

 lated that in order to supply an orchard with sufficient moisture to grow a crop of 

 green manure and to mature a fruit crop about -1 ft. of water will be required in the 

 warm valleys of southern Arizona. 



Relative to summer irrigation of orchards the author states as follows: "If about 

 the middle of the summer water is available in abundance, it would probably be wise 

 to give the orchard a thorough irrigation in as short a time as possil)le, and then fol- 

 low the irrigation with a thorough plowing, as in the spring after the winter irriga- 

 tion ceases. But frecjuent sunnner irrigations are decidedly not advisable under 

 our conditions, where the soil is fairly deep and retentive of moisture." 



Report on horticulture, S. M. Emery {Montana Sta. Bid. 28, pp. 6-10). — Lists 

 are given of the hardy, semihardy, and poor or useless ornamental shrubs, apples 

 (including crabs), pears, cherries, and plums grown at the station. In a study of 

 the relation between the maturity of the terminal buds at the beginning of winter 

 and the hardiness of the variety, there was found to be little or no correspondence 

 between bud maturity and the bark bursting of the stems and twigs. In a test of the 

 Stringfellow system of root pruning, 89 trees of the "Wealthy and Alexander apples 

 were pruned ])ack close to the tap root and the stem cut to about 12 in. These stubs 

 were planted in clean, mell(jw soil with a crowbar, and irrigated twice before July 1. 

 "At that date about 18 i)er cent of the trees were dead, 56 per cent were in good 



