136 COMMON WEEDS 



mixed with a proportion of lime to form a heap of 

 useful compost. 



See also Agrostis sp. (p. 128), and Arrhenatherum 

 avenaceum, var. bulbosum (p. 131). 



EQUISETACE^: 



Horse-tail (Equisetum arvense L.) is quite as trouble- 

 some in arable as in grass land (see p. 228). In arable 

 land it must be attacked by deep draining if necessary, 

 followed by a thorough system of cultivation. The 

 regular and persistent cutting of the young spore-bear- 

 ing shoots in March before fructification has occurred, 

 and of the barren green stems later, will have some 

 effect in reducing it. Deep draining and two heavily 

 manured root crops, followed if need be by a smother- 

 ing crop like vetches or maize, is perhaps the most 

 satisfactory method of dealing with Horse-tail. 



Weeds in Orchards on Arable Land. The question 

 of destroying weeds in tilled orchards is deserving of 

 further consideration in particular instances. As a 

 general principle such orchards in Britain should be 

 regularly weeded ; but in tropical countries, where alter- 

 nate influences of baking sun and heavy downpours of 

 rain are experienced, the economy of thorough weeding 

 has been questioned. 1 Dr. Watts drew attention to the 

 good effect on the tilth of the land which is brought 

 about in tropical orchards as the result of allowing the 

 weeds to grow to a certain height and then cutting 

 them down, leaving them as a surface mulch. It may 

 be suggested that a similar practice would not be out of 



1 Dr. Francis Watts, "The Treatment of Soils in Orchard Cultivation in 

 the Tropics " : West Indian Bulletin, vol. ii. p. 96. Also Agricultural Neius, 

 Barbados, June 12, 1909. 



