This is one of the things that really irritates me about Taiwan's farming methods. There are actually plenty of farmers near my place (I suppose we'd call them 'market gardeners' back home) who have a good system going, with dense polycultures and lots of mulch. I suspect this is the 'traditional' method. They have a massive output - you can tell just by looking at it. Then there are others who plough their field, spray it with chemicals, and raise a pathetic little crop of vegetables that might or might not get washed away by the monsoon rains. When they take the crops away it looks like the surface of the moon. You would have thought somebody would have looked at that and thought, hmm, this doesn't seem to be working very well, does it?
the ironic part is that often these people who have these lush polyculture type homes are the ones who also make their living working fields of XX crop. I notice that a lot. But ya, these people already practice polyculture everywhere, and many do it fairly well. the biggest issue is labor, but most of the small farms in Taiwan are manual labor anyway, If they just did it on a big scale, voila.
I've tried both newspaper and cardboard for mulching and I'd say newspaper is much better. It turns into nice compost after a while, if you heap some vegetation on/under it. Cardboard DOES kill all the weeds, but it seems to kill everything else too - there were loads of termites, but it survived a good six months almost intact. I guess it excludes air too effectively. I don't like plastic mulch because I found about 100kg of it dumped on my land ... and I suspect it 'cooks' the soil and kills animal/bacterial life. It's good for "drowning" tough grasses though.
ya cardboard, and paper too once it gets a little thick, suffocates the ground. one thing that is also pretty bad for soil health is anaerobic conditions, which that can make. thats why real mulch (dead plants) are so much better as they breathe and also rot well to make a nice compost layer. disadvantage is it attracts pests and pathogens because unlike proper compost heaps, it wont get very hot and wont kill all the bad stuff. This is less of an issue with many tree crops though.
Plastic will heat the soil, but I have not seen it heat up so much it hurts any living plant growing above it. weed, annuals, trees etc all do fine. its main effectiveness is cutting out light. And because its woven (I am not talking about that sheet plastic that is like plastic bag material) it readily allows water and gasses through, very important. I will admit it is not natural and does not go away, but it withstands direct sun for many years, and I think ultimately (at least as far as I know) it is the best balance of less pollution and effectiveness. cover crops are great, but require work.
What do you use for cover crops? I've found that natural weeds are great (there's a kind of solanum, especially, that the bugs seem to like eating) but you can't slash them in-place as mulch because they re-grow from the roots too fast. You have to heap them and compost them to kill them. I've had really good results with wheat and 蘿蔔, but again, they're not very useful. Peas, pretty good too. Buckwheat, fenugreek, and peanuts seem to do OK but they're just not big and tough enough to crowd out the weeds - and again, not very useful. Alfalfa, sesbania spp., lablab - mostly failed miserably. Any thoughts on Pueraria lobata? I believe it's an endemic species.
Solanum torvum, i hate the shit due to liek you said it grows from teh roots and it also has big thorns. I slash and mulch it. Other reason i HATE it is that it is woody and if its under the plastic and you step/drive over it the plastic can rip from it. Its spread by bats here, and is used as an eggplant grafting stock. so it gets out everywhere. can make the berries in to a curry like in Thailand, but here in Taiwan its considered poisonous...so I have not tried eating it here (i ate it in thailand and it was ok). I don't risk eating things in the night shade family unless its well known
cover crops I have mostly been using mints right now. When i let fields lay open I am planting beans (velvet beans) and when they get big its easy to kill them and stuff their remains under the plastic to decompose. I would avoid grasses and any other super heavy feeding nutrient mining type plant. when possible.
When I look at a cover crop i first look at height, then their water tolerance and drought tolerance. then i take those and pick out ones i can either make money at or can use myself. THere are lots, but surely the species used on a mountainside is different than down on the flats like me. the mint family has a bit of everything, and I like a lot of plants within it. hence my using them. but they are also kind of heavy feeders. its nice having a crop that isnt a heavy feeder.
locals in rotation often use what I think is a Desmanthus sp. Useless but being a legume it will help regenerate the soil. beans will as well as will much of the fabaceae family. if i switch form mints, I am going to legumes, but i personally dont like growing grains due to how cheap they are worldwide and how large a scale they are already grown. More money in fruit, herbs, vegetables and ornamental.
biggest thing for cover crops I find is shade tolerance so you can grow it right under a canopy if the main crop isnt too dense.
never grown Pueraria lobata, looks interesting.
jesus lighting is really bad going to send this and come back later..our house seems to be a magnet for this storm.