HOME GARDENS

Bay of Plenty Beacon, Volume 14, Issue 96, 10 February 1950, Page 7

HOME GARDENS

(By J. S. Yeates, Massey Agricul-

tural College) FREEN MANURE CROPS

Rather than rot down waste material in a compost bin or heap, it is often a more economical proposition to grow a crop on the ground to be manured, and then to mix this crop material with the soil as a “green manure crop.” Growing and digging in of green manure crops is an established practice in most gardens, and could with advantage be used in many others. It is certainly the easiest way to incorporate organic matter in the soil and is very expensively used in orchards.

There are various crops which can be used for the purpose. Even a good growth of weeds is not at all to be despised for digging in, provided the weeds concerned are not really dangerous ones like couch grass or Californian thistle. For convenience, the crops available for green manuring, can be divided into legumes and non-legumes. The legumes /have one very important advantage over the others —namely that they have nitrogenfixing bacteria in their root nodules, and therefore they enrich the soil quite considerably. For instance the Grasslands research workers in Palmerston North have found that the white clover in a good ryegrass and white clover pasture can fix enough nitrogen to give the equivalent of about one ton of ajnmonium sulphate a year. For this reason legumes are generally the first as green manure crops.

The blue lupin is the most common legume for green cropping and is rightly the first choice in most cases. It is easf and fast to' grow, produces a large bulk of organic matter and enriches the soil with nitrogen. You can sow blue lupins at most times of the year, according to when you can leave the soil free, from other crops. January or February are probably the best months for sowing lupins. Work the ground well, give it some superphosphate, broadcast the lupins and rake them in. Do not sow too thick. If the seeds average two inches apart in each direction, that should give you a good crop. Sown now, they should be in late flowering or early pod stage in late autumn, and should be dug in then. If you expect your soil to be too wet to handle in late autumn or winter, plant the lupins a month or so later and dig them in in early spring. Another legume which ipakes first class green manure is red clover. To get the best advantage from it, the land should be out of use for a whole season, but you can expect to gain a very large amount of organic matter and of nitrogen, r would sow the seed preferably in the autumn, or in the spring, and dig the resulting crop under in the following autumn. A dressing of superphosphate at the time of sowing the seed is an advantage. Of the non-legumes, oats or Italian ryegrass are the two most often used. Either of these crops can be sown at any convenient time, though autumn or spring sowing is much better than mid-summer or mid-winter. They can be worked in at any convenient time after three or four months, but care should be taken not to let them set seed. At the seed stage the stems may take too long tor rot down, and herd* is a risk of getting unwanted seeds into the soil. The digging-in of any green manure crop is rather a problem. The idea is to have it fairly well chopped up and mixed in the top spit of soil. That is not very easy to do with a spade. The best way is perhaps to knock a tall crop over and chop it on the ground as much as possible before digging. Except for some very good reason, do not trench the, material in a layer deep down in the soil. It may look neater that way, but results are more important than neatness. .