氮肥施用對地毯草生育之影響與應用葉綠素計於氮素狀態診測之探討

The Effect of Nitrogen Fertilization and the Application of Chlorophyll Meter to Evaluate the Nitrogen Status on Axonopus compressus (Swartz) Beauv..

鍾翊嫻(Yu-Shian Chung) ； 張育森(Yu-Sen Chang)

《中國園藝》 49卷4期 (2003/12) Pp. 361-374

https://doi.org/10.6964/JCSHS.200312.0361

摘要

Nitrogen fertilization is one of the most important practices in turfgrass management. Since the methods of diagnosing nitrogen status presently used are time-wasting and destructive. There is an immediate need to develop a convenient, rapid, and reliable tool for improving nitrogen fertilizer management. Chlorophyll meter reading (CMR) is directly related to leaf chlorophyll concentration (CHL.), and leaf CHL. is often well correlated with leaf nitrogen content (N.). Therefere CMR may serve as a surrogate for leaf N and assist in prediction of nitrogen requirement for crops. The objectives of this research are to (1) determine the relationship among CMR, leaf CHL., and leaf N, (2) determine the feasibility of using a chlorophyll meter for evaluate nitrogen status, (3) determine the critical range of nitrogen for tropical carpetgrass (Axonopus compressus (Swartz) Beauv.). In the first experiment (1997.8.30~1997.12.30), nitrogen fertilizer (NH4NO3) was applied at the rates of 0.0, 2.5, 5.0, and 10.0gN/m2/mo. The plant height, leaf length, and number of leaf were increased with nitrogen fertilizer increasing in both turfgrasses. In the second experiment (1998.3.28~1998.5.25), the nitrogen was applied at the rates of 0.0 (gN/m2/mo), 0.0+Os(Osmocote 6g/pot), 2.5+Os, 5.0+Os, and 10.0+Os to determine the effect of slow release fertilizer. The tropical carpetgrass plants with 5.0+ Os and 10.0+Ostreatments had heigher growth rate. The plant height, growth rate, leaf length, number of tiller. and shoot dry weight of the four treatment plants with slow release fertilizer were significantly increased when compared to that of control plants (no nitrogen treatment). There was a significantly positive linear correlation between CMR and leaf CHL. in tropical carpetgrass (r2=0.95, p＜0.001). The CMR was also well related to leaf N (r2=0.85, p＜0.001). In addition, the ratios of CMR 3/1 (The CMR of third fully expanded leaf/ The CMR of first fully expanded leaf) and ratios of leaf L/W (length/width) also had well relationship with leaf N. According to the regressions of CMR 3/1, leaf L/W and leaf N, the critical range of nitrogen was made from the N of CMR 3/1=1 to the N of the largest leaf L/W. Thus, in the first experiment the critical ranges of nitrogen in tropical carpetgrass were 1.86~3.41%, and the critical ranges of CMR were 32.0~48.4. In the second experiment, the critical ranges of nitrogen were 3.52~4.08%, and the critical ranges of CMR were 39.0~43.0. Based on the results, it is possible that chlorophyll meter can be a rapid, convenient, and reliable tool to diagnosing of nitrogen status in turfgrasses.

關鍵字

地毯草 ； 氮素 ； 緩釋肥 ； 葉綠素計 ； 葉綠素計讀值

並列摘要

Nitrogen fertilization is one of the most important practices in turfgrass management. Since the methods of diagnosing nitrogen status presently used are time-wasting and destructive. There is an immediate need to develop a convenient, rapid, and reliable tool for improving nitrogen fertilizer management. Chlorophyll meter reading (CMR) is directly related to leaf chlorophyll concentration (CHL.), and leaf CHL. is often well correlated with leaf nitrogen content (N.). Therefere CMR may serve as a surrogate for leaf N and assist in prediction of nitrogen requirement for crops. The objectives of this research are to (1) determine the relationship among CMR, leaf CHL., and leaf N, (2) determine the feasibility of using a chlorophyll meter for evaluate nitrogen status, (3) determine the critical range of nitrogen for tropical carpetgrass (Axonopus compressus (Swartz) Beauv.). In the first experiment (1997.8.30~1997.12.30), nitrogen fertilizer (NH4NO3) was applied at the rates of 0.0, 2.5, 5.0, and 10.0gN/m2/mo. The plant height, leaf length, and number of leaf were increased with nitrogen fertilizer increasing in both turfgrasses. In the second experiment (1998.3.28~1998.5.25), the nitrogen was applied at the rates of 0.0 (gN/m2/mo), 0.0+Os(Osmocote 6g/pot), 2.5+Os, 5.0+Os, and 10.0+Os to determine the effect of slow release fertilizer. The tropical carpetgrass plants with 5.0+ Os and 10.0+Ostreatments had heigher growth rate. The plant height, growth rate, leaf length, number of tiller. and shoot dry weight of the four treatment plants with slow release fertilizer were significantly increased when compared to that of control plants (no nitrogen treatment). There was a significantly positive linear correlation between CMR and leaf CHL. in tropical carpetgrass (r2=0.95, p＜0.001). The CMR was also well related to leaf N (r2=0.85, p＜0.001). In addition, the ratios of CMR 3/1 (The CMR of third fully expanded leaf/ The CMR of first fully expanded leaf) and ratios of leaf L/W (length/width) also had well relationship with leaf N. According to the regressions of CMR 3/1, leaf L/W and leaf N, the critical range of nitrogen was made from the N of CMR 3/1=1 to the N of the largest leaf L/W. Thus, in the first experiment the critical ranges of nitrogen in tropical carpetgrass were 1.86~3.41%, and the critical ranges of CMR were 32.0~48.4. In the second experiment, the critical ranges of nitrogen were 3.52~4.08%, and the critical ranges of CMR were 39.0~43.0. Based on the results, it is possible that chlorophyll meter can be a rapid, convenient, and reliable tool to diagnosing of nitrogen status in turfgrasses.

並列關鍵字

Axonopus compressus Swartz Beauv ； nitrogen ； slow release fertilizer ； chlorophyll meter ； chlorophyll meter reading