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在珠三角主菜区域,选择了18个试验点,通过比对试验初步提出以菜心为供试品种的土壤速效磷诊断指标:小于11.4mg/kg(极度缺磷);11.4～30.9mg/kg(缺磷);31.0～54.6mg/kg(中度缺磷);54.7～87.8mg/kg(不缺磷);大于87.8mg/kg(含磷超标)。在此基础上,结合低、中、高磷水平下菜区的施磷试验提出了相应区域的施肥指标,结果表明在中低磷菜区,施磷量在20～25kg/hm2时,增产效果明显。为了能够把这种量化的指标推广应用,在珠三角主菜区选择了540个蔬菜田,对其土壤速效磷进行了分析研究,结果发现珠三角主菜区土壤以缺磷和中度缺磷为主,总体上和速效氮的分布情况类似,为科学施用磷肥奠定了一定的基础。
In the main area of the Pearl River Delta, 18 experimental sites were selected and the index of soil available phosphorus (P) was first proposed by comparison experiment: less than 11.4mg / kg (phosphorus deficiency); 31.0 ~ 54.6mg / kg (moderate phosphorus deficiency); 54.7 ~ 87.8mg / kg (without phosphorus deficiency); Based on this, the fertilization index of the corresponding area was put forward based on the phosphorus application in the low, medium and high phosphorus levels. The results showed that in the medium-low phosphorus area, the yield was increased when the phosphorus application was between 20 and 25 kg / hm2 obvious. In order to popularize and apply this quantitative index, 540 vegetable fields were selected in the main area of the Pearl River Delta to analyze the available phosphorus in the soil. The results showed that the soil in the main area of the Pearl River Delta was characterized by phosphorus deficiency and moderate phosphorus deficiency Mainly on the whole, similar to the distribution of available nitrogen, which laid a solid foundation for the scientific application of phosphate fertilizer.