Growth Response of Second-Rotation Pinus radiata on an Orthic Allophanic Soil to P Fertilizer and Weed Control

放射松二代林於正鋁英土對磷肥與除草的生長反應

Achmad Arivin Rivaie ； Russ Williams Tillman

《台灣林業科學》 24卷4期 (2009/12) Pp. 243-256

https://doi.org/10.7075/TJFS.200912.0243

摘要

研究放射松(Pinus radiata)於可溶性與略溶性磷肥與除草的交互作用下其磷營養與生長反應，是決定放射松二代林磷肥施用與下層植被適當管理的必要措施。包括二型磷肥（重過磷酸鈣、本吉爾磷礦粉）、四級用量（0、50、100、200公斤磷／公頃）與有無除草等試驗組合，於生長於正鋁英土的放射松二代林施用二年後，進行林木生長分析以及針葉磷與土壤磷濃度的相關性分析。試驗結果顯示，二型磷肥的施用皆可增高針葉的磷濃度。依據傳統土壤磷Bray and Olsen的測定法，雖然針葉磷濃度在施肥前已略高於標準磷濃度，而土壤磷濃度卻是呈磷缺乏的狀態。二年磷肥的施用雖未影響林木生長，其針葉磷濃度仍有增加。然而，除草的確能增加胸高直徑與樹基直徑。由於該處針葉磷濃度已高於標準磷濃度，因此除草之增加林木生長，並非僅是幫助磷肥吸收，亦可能是幫助水分與其它土壤養分的吸收。由土壤Bray-2 P、Olsen P、resin-Pi及NaOH-Pi的測定結果顯示，針葉磷濃度可由土壤磷濃度預估。其中，土壤Bray-2 P的測定最能代表土壤有效磷的濃度。針葉磷濃度與土壤NaOH-P(下标 i)的測定有較高的相關性，但與H2SO4-P(下标 i)的測定有較低的相關性。據此結果推論，放射松利用此高固定磷酸性土壤的途徑，主要是藉由吸取附著於鋁英與鐵鋁氧化物(NaOH-P(下标 i))上的磷，而不是鈣磷。

關鍵字

肥料 ； 放射松 ； 磷 ； 除草

並列摘要

Information on the interactive effects of soluble and less-soluble P fertilizers and weed control on the growth and P nutrition of second-rotation radiata pine (Pinus radiata) trees is required to determine appropriate management practices of P fertilizer and understory vegetation in radiate pine forest plantations. A field trial was conducted to investigate the growth of second-rotation P. radiata and determine the relationships between needle P concentrations and soil P forms in an Orthic Allophanic soil 2 yr after application of 4 doses (0, 50, 100, and 200 kg P ha^(-1)) of P applied in 2 forms of P fertilizer (triple superphosphate (TSP) and Ben-Guerir phosphate rock (BGPR)) in combination with 2 weed control practices (weeds present and weed-free). The application of TSP and BGPR increased the tree needle P concentration although the needle P concentrations before fertilizer application were marginally higher than the critical P concentrations, despite the soils being P deficient according to traditional soil P tests (Bray and Olsen tests). The application of P fertilizers had no effect on tree growth during the 2-yr period of the trial, although it increased radiate pine needle P concentrations. However, weed removal increased the diameter at breast height (DBH) and basal area (BA). Trees in this forest site had needle P concentrations higher than the critical P concentration. This suggests that the growth increase due to weed removal treatment was probably due to an increase in the availability of soil water and nutrients other than P. The needle P concentrations of P. radiata can be predicted by soil tests, and Bray-2 P, Olsen P, resin-P(subscript i), and NaOH-P(subscript i) tests. Of these soil tests, Bray-2 P seemed to be the best test for predicting soil P availability for radiata pine. P concentrations in the needles had a strong relationship with the NaOH-P(subscript i) fraction in the soil but it had only a weak relationship with the H2SO4-P(subscript i) fraction. These results suggest that radiata pine was probably taking up P more from the pool of P-adsorbed onto allophane and Fe+Al oxides (NaOH-Pi) than from the Ca-P pool in this high P-fixing acidic soil.

並列關鍵字

fertilizer ； Pinus radiata ； phosphorus ； weed control