Beljate of contaminated solis and mulches

摘要

Early last year a dear friend of mine gifted me with a healthy-looking hybrid plum tree, a fresh one from a well-known nursery near Modesto, California. A few days later I planted it in a sunny backyard spot, and began to feel great pride in having such a healthy young fruit tree that promised to provide me an abundance of tasty plums. Not a day went by that I walked past this tree without taking a few moments to admire it and consider its great potential. As March came and went, however, and all myother deciduous fruit trees were growing vigorously, my prized new plum tree refused to break dormancy. This was a shock. What could be wrong? I had recently removed a nearby navel orange tree which had died from a disease at its graft union from an accumulation of soil over the joining scar. Besides, the graft of my new plum was 8 inches above ground and showed no evidence of any such infection. About a month after my other plum trees had started pushing new growth, my prized plum tree broke dormancy,but its belated growth was weak and chlorotic. This baffled me; was it due to a disease or soil toxicity?