VOA慢速英语:Getting to the Root of How to Water Trees

Some trees can survive a long time without water. Think of trees that grow in the desert. But other trees may need more moisture than they can get from rainfall or from the air -- from, say, coastal or mountain fog.
一些树木可以在没水的情况下生存很长一段时间。想想在沙漠中生长的树木。但是其他树木需要的水分超过从降雨或空气中获得的水分，比如说，沿海或山区的雾气。

The soil stores moisture during cooler weather. But most of that moisture is gone by the middle or end of the hottest months of the year.
在天气比较凉爽的时候，土壤会储存水分。但是在一年中最炎热的月份中间或结束时，水分会消失。

Trees and other plants can look thirsty. Leaves can become droopy and hang downward. They can also turn yellow. Yellowing can be a sign of too much water. But it can also be a warning sign of too little water.
树木和其他植物能够看得出口渴的迹象。叶片会枯萎下垂，变黄。变黄可能是水分过多的现象，也可能是由于水分不足的警告信号。

The Vacaville Tree Foundation is a volunteer community group in California. It has advice for watering newly planted trees and established trees.
瓦卡维尔树木基金会是加利福尼亚州一个志愿者组织。该组织提出了怎样为新栽种的树木和已经稳固的树木浇水的建议。

With a newly planted tree, the roots have not yet spread out from the root ball. The root ball can become dry faster than the dirt around it. So put water on the area of the root ball and the surrounding soil until the roots become established.
新种植的树木，根部还没有从根部球茎中开始扩散。根球比周围土壤更容易变干。所以在根部完全长成之前，在根球区域及其四周土壤浇水。

Once a tree is well established, water deeply instead of often. The amount of water needed depends on the tree and the soil. Clay soils hold water for longer periods while sandy soils hold less water. During the hottest season, a deep watering may satisfy a tree for anywhere from ten days to four weeks.
一旦树木已经成熟，要一次浇足而不是经常浇水。所需的水量取决于树木和土壤。粘土可以长时间保持水分，而沙土保持的水分就很少。在最热的季节，浇透一次可以满足任何地方的树木十天到四个星期的需求。

Part of skilled watering is knowing to stop when the soil needs a little time to absorb the water. Otherwise the water runs off the surface and gets wasted.
浇水的部分技巧是知道何时停下来给土壤吸收水分的时间。否则水会从表面流失，造成浪费。

Ted Swiecki is a plant scientist in California with the Phytosphere Research company and the Vacaville Tree Foundation. He says people should not water established trees at the base of the trunk. This can harm the tree.
Ted Swiecki是加利福尼亚州植物圈研究公司和瓦卡维尔树木基金会的植物学家。他称，不应该在树干底部为已经成熟的树木浇水。这会对伤害树木。

Too much water in the soil at the base of a tree can lead to the growth of fungi. If the area is too wet, harmful organisms have a better chance to invade the tree and cause disease.
树木底部土壤中太多水分会导致真菌的滋长。如果该区域过于潮湿，有害生物就有可趁之机侵入树木导致疾病。

Mr. Swiecki says this is true especially in Mediterranean and semi-dry climates. Many trees in these climates have adapted to having a dry area near their base during the hottest season.
Swiecki表示，这一观点对于地中海和半干旱气候尤其适用。这类气候的很多树木已经适应了在最热的季节期间保持树干底部干燥。

TED SWIECKI: “Water displaces air in the soil. And roots are aerobic; they require oxygen for the soil to function properly. So if you keep the soil saturated and there’s no air there, and then you are basically starving the roots for oxygen.”
Ted Swiecki：“水分会替换土壤中的空气。树木的根部是需氧的，需要从土壤中获得氧气来正常工作。所以如果土壤水分饱和，没有空气，根部就基本处于缺氧状态。”