»» CHAPTER VI 



surface of the soil , or at such a stage when no hkcUhood of their 

 being covered completely by the loose soil is possible. If on 

 clay soils shower crusts should have formed before the plants 

 appear, it will be found to be necessary to harrow in order to 

 break the crust to allow the plants to come through and to assist 

 in soil aeration. On normal soils, though, crops should not be 

 harrowed until four leaves are shown ; if necessary before this 

 time on account of weeds, the operation is best carried out 

 when the plants are coming through and before the leaves have 

 unfurled. The harrowing may be rejieated until the crop is 

 shown to be too severely injured by the o]5eration. During the 

 heat of the day, when the plants arc in a wilted condition, 

 harrowing may be safely carried out until the plants are a foot 

 high. The object of this practice is to destroy weed growth at 

 the most susceptible period of the seedling condition ; to aerate 

 the soil ; to make it more receptive for rain , and to render the 

 plant food more available. On sandy soils the weeder might be 

 used to advantage when the harrow can no longer be employed. 

 The fields should be harrowed across, and not with the rows. 

 After this, cultivators are used between the rows ; how often 

 and when to cultivate must be left to the discretion of the 

 grower, who should bear in mind the object of cultivation. As 

 the root systems extend, cultivation aiiust become shallower and 

 must be restricted to the centre of the space between the rows, 

 otherwise injury will be caused by destroying the roots. In 

 drier parts the soil should be left as level as possible and not 

 ridged by the cultivators. Cultivation should cease as soon as 

 the ears are well formed. 



Manuring. — While maize may be considered a gross-feed- 

 ing crop, it requires plenty of available plant food. 



The follow^ing table show^s the amounts removed from the 

 soil by a good crop of those mentioned : — 



N. P^O, K^O 



25 bushels maize ... 39-2 lbs. 13-8 lbs. 27-6 lbs. 



25 bushels wheat ... 42-5 lbs. 16-6 lbs. 21-0 lbs. 



10 tons turnips ... 50-0 lbs. 20-0 lbs. QO'O lbs. 



Productive maize soils are almost invariably characterised 

 by a high content of organic matter ; where this is deficient as 

 evidenced by the deflocculated and light colour of the soil, it 

 must be remedied by the application of kraal manures or by 

 green-manuring. The addition of artificial nitrogenous fer- 

 tilisers is not considered necessary, as although maize is a 



