格拉姆柱花草在南亚热带典型土壤上对施肥的反应

试验结果表明:施用磷肥对格拉姆柱花草(Stylosonlhes guiancnsis cv.Graham)性状表现普遍较好;钾肥对前期生长不表现作用,而后期表现为一种积累效应。施磷肥在土壤有效磷>5ppm时对柱花草促进作用不明显;在有效磷3～5ppm,pH>7的土壤上施磷也无显著作用;施石灰和土壤pH>7均降低磷的有效性。在土壤缺磷纠正后,施钾肥效果明显;施钾肥容易导致植株钾的奢侈吸收和品质下降,施磷则能降低植株钾含量,提高柱花草品质。石灰的施用在pH<5的第4纪红土母质与花岗岩母质土壤上有显著促进作用,而在pH>5的微酸性及碱性土壤上施石灰的效果不显著或产生负效应。

RESEARCH ON FERTILIZER RESPONSE OF GRAHAM STYLO GROWN ON DIFFERENT SOILS

Ten types of soil were collected from Guangdong Province in South China and planted to Graham stylo (Stylosanthes guianensiss cv. Graham) in pots so that nutrient requirements could be assessed. The main results of the experiment are as follows: The response of the stylo to P fertilizer in many soils was good, but P fertilizer had no significant effect on stylo in the soil where available P was higher than 5 ppm. or available P was ranging from 3 to 5 ppm and the soil pH was greater than 7. Liming on high pH (>7) soil would decrease the availability of P. After soil P deficiency was corrected. K fertilizer was good for stylo growth and achieved significant effect on dry matter production, but it usually reduced crude protein content and caused luxury absorbption of K. P fertilizer could reverse the situation. The stylo in early growth stage showed no response to K fertilizer. K fertilizer had an accumulative effect on the late stage of the stylo. Liming in soil with the pH lower than 5 such as Quaternary red soil and granite soil had highly positive effect on the growth of the stylo and liming in soil with the pH greater than 7 such as limestone soil or purple sandy shale soil had highly negative effect on stylo growth. Liming in soils with the pH ranging from 5 to 7 had no significant effect. Liming. P. K fertilizing might affect the availability of trace elements such as B. Mo etc..