Irrigation in warm climates
I am looking for some advice about irrigation in warm climates.
I've been working on a project in Northern Portugal (www.flirtingwithyurting.com) since January. We have already started growing quite a lot of fruit and veg and, considering what we started with, it hasn't been too bad. The main problem we are facing is how to most efficiently water the annual veg. The fruit trees and perennials seem to establish very quickly and are quite happy being left to it with a big pile of mulch around them. We have found however that the annuals are much more thirsty (probably because of smaller/less developed root system).
We mulched all the annual beds with newspaper and then shredded bracken/leaves or whatever else we could rake up. In the UK, I've found this method to be sufficient enough to stop watering all together with most crops, once they are settled in. But Portugal is obviously much hotter, and receives less rain in the summer. Furthermore, the soil here is very sandy so it doesn't hold on to moisture for long. We are having to water the annuals quite frequently, but the mulch prevents the moisture getting into the soil, so we are throwing much more water onto it than if we had no mulch. It is currently quite inefficient. The locals use flood irrigation. They make gullies between the rows of veg and flood the whole veg bed once or twice a week (water is not in short supply here as nearly everyone has a water mine/spring). This seems like a great idea were it not for the massive soil erosion and over time it increases salt in the soil. We have also considered leaky pipe, but I've used them before and I HATE them. They cost money, they restrict access to the soil, generally get in the way and end up in a mess.
So.... Has anyone got any tips on how we can keep are annual veg well watered?
Thanks very much