译 名：
FERTILIZER EXPERIMENTS ON CITRONELLA GRASS ON LATERITIC RED SOIL
作 者：
Y. Y. SH, H. K. YOUNG AND C. S. HU
摘 要：
Fertilizer experiments on citronella grass (Cymbopogon winterianus Jowitt) were conducted on the lateritic red soil originated mainly from the weathered crust of basaltic materials in the northern part of Laichow peninsula, Kwangtung. The experiments covered the complete life cycle of citronella grass during the period from 1960 to 1963. The soil contains 2.21% of organic matter, 0.10% of nitrogen, and 8 mg/100 gm of exchangeable potassium, but it is low in available phosphorus. Chemical fertilizers were applied with compost as basic manure which was prepared from the distilled material of citronella grass and was dressed at a rate of 15,000kg per hectare. The muddy compost contains only 11.63% of organic matter. Results of the experiments may be summarized as follows:
1. Nitrogenous fertilizer (ammonium sulphate) was found most beneficial to the growth of citronella grass with increases in total yield from 51% to 61% in all plots receiving this fertilizer. The response of plant to ammonium sulphate was much less significant in the first year.
2. Effectiveness of phosphatic fertilizer (double superphosphate) was most prominent in the first year. After 2-years application of this fertilizer at the rate of 120 kg P_2O_5/hectare annually, no response of citronella grass was observed in the third year.
3. Provided with sufficient supply of nitrogenous and phosphatic nutrients, average response of potassic fertilizer (potassium sulphate) ranged 5-19%. Effectiveness of this fertilizer was significant only at a higher rate of ammonium sulphate.
4. Changes of soil fertility were examined both before and after the planting of citronella grass. Despite of the addition of 60,000 kg/hectare of crude compost and 1,200 kg/hectare of ammonium sulphate during the growing period of citronella grass from 1960 to 1963, the contents of organic matter and nitrogen in the soil were decreased in all plots. However, available phosphorus and exchangeable potassium were increased markedly in plots received these fertilizers.
