1 Frz., 1900. ] QUEENSLAND AGRICULTURAL JOURNAL. 109 
5. Green manuring, in addition to supplying the soil with organic matter 
and nitrogen, also provides a considerable quantity of other plant food, such as 
phosphoric acid and potash, in an available form tor the succeeding crop. The 
steen crop, grown as a manure, extracts the potash and phosphoric acid 
hecessary for its own development, and stores them up in its roots, leaves, and 
stems, so that, when returned to the soil, this plant food is in an available form 
and within easy reach of the succeeding crop. The most suitable crops for 
steen manuring usually produce a large amount of roots, and these roots 
penetrate the soil to a considerable depth in search of plant foods so that when 
ey are returned to the soil this plant food, instead of being in the soil in an 
Uavailable condition, is in a condition to be readily assimilated by the 
Succeeding crop. 
6. When land has become thoroughly worn out by the continuous 
stowing of one particular crop, such as sugar-cane, it requiries resting, not by 
means of a summer fallow, which does more harm than good in the coast 
districts, but by being planted to a totally different crop and allowing the same 
© Occupy the soil for one or two years, and to be then ploughed in. Perennial 
e€euminous crops, such as the small Mauritius bean and Narico bean, which 
ave been proved to stand two winters at Redland Bay, are especially suitable 
for this purpose. and so treated gets a thorough rest, and it is the nearest 
4pproach that can be obtained to the conditions that produce our scrub soils, 
and to which their fertility, when first brought under crop, is largely due. 
7. By manuring the crop—such as cow pea—that is to be grown as a 
steen manure with a mixture of phosphate and potash manures, you supply the 
soil with a complete fertiliser, and, at the same time, obtain the best results. 
he Phosphoric acid and potash produce a heavy green crop and stimulate a 
vigorous root growth, so that when the sreen crop is returned to the soil the 
Soil receives the benefit of the extra amount of organic matter and nitrogen 
produced by the special manuring, as well as of the special manures themselves 
Which haye been retained in the soil by the green crop, and are available for the 
Succeeding crop. 
The method of improving land by means of green manuring is by no means 
¥ new one, though it is only of comparatively recent years that its value has 
een fully appreciated, as it has been in use in older countries for a long time. 
n older countries its use was confined to the growing of catch crops of mustard, 
rape, &e., which were ploughed under, as it was found that a systematic rotation 
°F crops, combined by the return to the soil of all farm manures, was usually 
Sufficient to maintain a sufficiency of organic matter in the soil, as the conditions 
Prevailing were not so destructive of organic matter as those prevailing under 
eee and semi-tropical conditions. ‘The discovery that leguminous plants 
ad the power of assimilating nitrogen direct from the air, and of fixing the 
Same by means of the nodules on their roots, thus doing away with the necessity 
°r applying nitrogenous manures to such plants, has, however, brought the 
itestion of green manuring by the use of such plants into prominence; as it 
as been clearly demonstrated, both by science and practice in all parts of the 
World, that this is the cheapest way of obtaining the supply of nitrogen that is 
required as plant food for the various farm crops. ‘This discovery has, therefore, 
Sven a great impetus to green manuring, and, from the experience already 
8%ned by its use in this colony, there is every reason to believe that it will be 
‘sed much more extensively in the future than it has been in the past. 
Crops SurraBLe ror Green Manvrine. 
Although many crops have been recommended and grown for green 
Pemuting, none, in my opinion, are so suitable for our local conditions as 
. following varieties of the pea family. As previously stated, many plants of 
“bal family have the power of assimilating nitrogen direct from the atmosphere 
h of storing it up so that it is available for the use of the succeeding crop. 
¢ following pulses thrive remarkably well in this colony, as they are vigorous 
