(6(3):11-22)AN EXPERIMENT ON THE N-P-K REQUIREMENT OF JUTE

本試驗係於民國40年開始，在竹南、臺中、嘉義、臺南、臺東五地繼績舉行三年，其中僅臺東一地有二年試驗成績，嘉義一地因第一年受線蟲病侵襲，為害甚烈，僅列其成績供作參考，討論時則以最後兩年成績為憑，茲將獲得結論臚列於後： 1. 肥料處理對於黃麻生育之影響： 氮與鉀肥具有促進黃麻全植株高度效應，但就黃麻有效高度效應言，氮肥不及鉀肥，磷肥對於黃麻植株高度及有效高度效應均不甚顯明，至黃麻莖徑粗細亦受氣與鉀影響，磷肥效應則甚微。 2. 肥料處理對於生莖與粗麻收量之影響： 施用氮與鉀肥均促進生莖產量顯著增加，但因地點不同，在增產程度上略有差異，磷肥效應仍然甚微，至氮與鉀肥對於粗麻收量效應，共趨向與其對於生莖收量效應相似，但鉀肥施用對於粗麻收量增產指數顯然高於其對生莖收量增產指數。氮肥施用，僅在竹南、臺中兩地對於粗麻增產指數較生莖增產指數為高，磷肥對於粗麻收量效應仍不若氟鉀明顯。 3. 氮鉀比率對於粗麻增產之關係： 粗麻收量深受氮與鉀肥影響，設磷肥施用量予以固定，氮與鉀比率小時，則粗麻增產趨向較為明顯，如竹南、嘉義及臺東三試驗地情形告屬如此，氮鉀比率大時，則以粗麻增產趨向較為顯明，此於臺中、臺南兩試驗地告可獲得明證。 4. 黃麻三要素適量比之決定： 自本實驗三年來平均成績測知各地黃麻三耍素適量比為： 由本試驗結果，參照當地農家慣行施肥法，可知麻農施用鉀肥稍欠不足，有加以倡導必要，同時建議有關機關應加強鉀肥配給。 Owing to the bulk production of rice and sugar in Taiwan, a great quantity of jute fiber is annually needed for packing these goods. In recent years, the cultivation area of jute, through our government’s effort, has been extended from 11,000 to 16,000 hectares. Available data concerning the rational application of N-P-K fertilizer for jute in different locations are insufficient for present use. That was why this experiment was conducted in the places of Chunan, Taichung, Chiayi, Tainan, and Taitung, from 1951 to 1953. In these tests nitrogen as ammonium sulfate was varied on different plots in amounts of none, 40, 80, 120, 240 kilograms per hectare, the P2O5 as calcium superphosphate in the amounts of 0, 40, 80, and 120 kilograms per hectare, and the K2O as potassium sulfate in the amounts of 0, 60, 120, 180, and 240 kilograms per hectare. There were 16 treatments in a systematically arranged block with two replications. Following are the summaries of this experimental results: I. Effect of N-P-K fertilizer on the growing state of jute It was observed that nitrogen or potash would significantly increase the height of whole plant and enlarge the diameter of stem, but the potash would cause a much better effect on the available height of jute (that is the height from the surface of ground to the first leaf of the stem) than did the nitrogen. There were no striking effect on the growing state of jute from phosphatic fertilization. II. Effect of N-P-K fertilization on yield of crude jute fiber It was found that increases in yields were obtained with insreasing amounts of nitrogen applied in the fertilizer up to 80 kilograms per hectare, in 4 of 5 experiments. Further increase in yield were obtained from use of 240 kilograms of nitrogen in 2 of 5 experiments. Results of the phosphorus rates test were striking in showing the lack of response of jute to high rates of a application of P2O5. Of the 5 tests only one showed a response to more than 40 to 80 kilograms of P2O5 applied per hectare. Response of jute to potash is something similar to nitrogen, but it should be noted that potash would cause higher increase in yield of crude jute fiber than that of green stem as compared with the checks respectively. III. Reletionship between the yield crude jute fiber and N:K (K2O) in the fertilizer The exact ratio of N: K (K2O) in fertilizer in relation to the yield of crude jute fiber has not been found yet. However, the smaller the ratio of N: K, the higher the increase in yield of crude jute fiber was found in the places of Chunan, Chiayi, and Taitung while the reverse was something evident in the place of Taichung and Tainan. IV. A recommandation concerning the optimum fertilizer ratio for jute According to the result of this experiment, a recomandation concerning the optimum fertilizer ratio for jute in different locations of this province has been suggested as follows: V. Based on the farmers’ profitable point of view, a suggestion concerning the economical fertilizer ratio for jute has also been submitted