Green Mulches use Nitrogen...

I have a question regarding nitrogen draw down.... I've learned that you should compost green material by blending with older mulches before adding onto your garden to stop this occurring. (The green waste draws the nitrogen from surrounding soils)
My question is if I already have 3 or 4 inches of old decomposed mulch on my garden will that stop or reduce the effect of adding green waste? And also will throwing a fertiliser high in Nitrogen counter the problem?
I am in a position where shovelling mulch in bulk is no longer possible (due to injury) and I know lawn clippings are really not the best mulch, but it's really the only option I have for now (until sugar cane mulch is again available from the local farms).
If I don't mulch at all the ground dries out far too quickly especially through summer. The mulch I have now is a shredded forest mulch but it's 12mths old and wearing thin in places. Any help is appreciated.

 

I wouldn't worry about anything thrown onto the surface of the soil depleting it.

 

How limited by injury are you? My asking is because as Ron said, surface greens thrown on does not deplete nutrients from the soil, live greens do. If you are able, can you create a compost pile at the location of the garden? Optimally, ready in 1-2 months, slowly in 1 year. I believe size and turning dictate speed of readiness. As for Mulch and compost, how familiar are you with the various techniques to get the success you need? What is your size garden? How deep in the soil for the garden? How often do you mix nutrients and mulch into the soil? Lots to answer I bet.
Acoma.

 

Injury is spinal so quiet held back and it's something that's only just recently happened. I am still adapting to being on a 2kg weight limit let alone other restriction due to imobility.
As for garden size I usually use 20-30 cubic metres to get a 5-6 inch coverage throughout my yard. I have the most amazing sandy loam that holds reasonable moisture if mulched but drains qiuet fast, hence the need for mulch.
Fertilising is someting I do monthly on my fruit trees, twice a year for anything in the ground (spring and autumn). I use a good all round Organic fertiliser with added trace elements on most plants except palms and bamboos which get excessive amounts of lawn fertilser dumped on them and I alternate organic with chemical for the fruit trees.
I added 'zeolite' at planting with every plant and re apply every 12 months with mulch. I replaced 1/2 the soil from planting with 5 in 1 (a manure based soil conditioner). I applied a wetting agent to help with drawing the water into the ground as it can crust over if left to dry and do this every 12 months at the start of summer.
I will have plenty of sugar cane mulch available in 6mths time (local harvest time) and intend on using this then so it's not going to be a permanent problem.
There's an area in particular, with several fruit trees which are my main concern. The fruit trees are all only 3years old so still very young. I have too many other species to mention but was wandering if, especially going into summer this would put any unnesseccary stress on the plants?
I don't water any inground plants except the bamboos and fruit trees which get washing machine water pumped onto them twice a week (with 4 kids we wash alot:}).

 

OK, from what I see by viewing Hervey Bay is that you don't have much of a forest area. Beachy and great for palm trees and fishing. I like the fishing, but back to your concern. I suggest that if you have this much family, you have much kitchen scraps. You also have manure available, straw, grass, all being viable for composting. You can get the family to help erect a compost bin, and educate them on making compost. Doing this for your garden will help with the sandy loam. As for the chem/ non chem, it sounds like you are interested in just fruit trees, no garden vegetables, correct? I would bet that this approach will be great for times where you don't have access to the sugar canes. If you do it right, you can have 2 decent compost piles to care for your needs, one ready in spring, one in fall. When it needs turning, the children do the work. When it comes time to spread it, the children do the work. I bet you get the point. This may be the remedy that does best at the least of expense, time, and effort. If you can, take some photos of the area. Some other members may have more information to contribute that will get you dialed in as well.
Acoma

 

Reading your original question, Chungii, it seems you're wondering about throwing your lawn clippings on top of the year old remnants of existing forest mulch.

I agree with Ron, this will be fine. The clippings and other mulch won't starve your plants of nitrogen, since they are not mixed into the root zone.

The problem would come with mixing un-composted organics into the root zone, which you aren't. Conserving moisture is definitely a priority in your climate, so good luck with it, and with your back :-)

 

Thanks I was more or less concerned that most feeder roots are reasonably shallow, especially on citrus and fruit trees. That and the fact that grass grows incredibly quick through summer and there's going to be a large amount of fresh clippings dumped onto the gardens over the coming months. I have done a simple horticultural course where they suggested that by doing this that your soil would eventually have Nitrogen drawn from it as the clippings break down.
I do have an old compost bin which will have to be dragged out again and put back into action. The kids have become pretty good helpers and I've always tried to get to them out there and involved where possible (sometimes with the odd mumbling and grumbling but they're out there and that's what counts:})

 

I think what you are describing is also called "surface composting". The only way it would tie-up nitrogen (keeping it from being available to your fruit trees or other plants,) is if the Carbon-to-Nitrogen Ratio of the material is very high. Sawdust, for example, would definitely tie-up nitrogen with its high C:N and fine particle size. If you do this green mulching, simply balance the "browns" and "greens" as you would in an ordinary compost pile. You could probably find the C:N of the common materials you use -- sugarcane mulch or whatnot. If your "mulch" has a C:N above 30 it will tie-up nitrogen as it decomposes; if it is below 30, it will release nitrogen as it decomposes. Here is a brief explanation on the subject.

 

Thank you that was a great refresher on the subject. It's been a while since my studies.