INDONESIAN ROCK-PHOSPHATE EFFECTIVITY FOR MAIZE CROP ON ULTISOLS SOILS

摘要

Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable{mso-style-name:"Table Normal";mso-tstyle-rowband-size:0;mso-tstyle-colband-size:0;mso-style-noshow:yes;mso-style-priority:99;mso-style-qformat:yes;mso-style-parent:"";mso-padding-alt:0cm 5.4pt 0cm 5.4pt;mso-para-margin:0cm;mso-para-margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:11.0pt;font-family:"Calibri","sans-serif";mso-ascii-font-family:Calibri;mso-ascii-theme-font:minor-latin;mso-fareast-font-family:"Times New Roman";mso-fareast-theme-font:minor-fareast;mso-hansi-font-family:Calibri;mso-hansi-theme-font:minor-latin;mso-bidi-font-family:"Times New Roman";mso-bidi-theme-font:minor-bidi;} Rock phosphate is a slow release phosphate source which can be directly used on acid soils. There are some rock phospahate deposit s in Indonesia. Total phosphate and calcium content in rock phosphate vary between 8.79 – 31.88% P 2 O 5 , and ? 0.60 – 57.50% Ca. The objective of these research is to study the Indonesian rock phosphate effectivity for maize on Ultisol soil. The research wasconducted at green house using randomized complete block design, 8 treatments and 5 replications. The treatments consist of 5 kinds of differen t Indonesian rock phosphate, control, supherphos fertilizer and Tunisia Rock Phosphate as a standard comparison of P fertilizer.Relative Agronomic Effectivenes Analyses was used to see the effectivity of each ? rock phosphate. The result of these study shows that the effectiveness of Rock Phosp ha te from Jampang Tengah Sukabumi (DE-1), Brati Kayen Pati (DE-9), Padaherang Ciamis (DE-3), and Karang Mulya Ciamis (DE-5) were aqually the same as Superphos. Indonesian Rock Phosphate’s effe c tivenes swas almost the same as Tunisian Rock Phosphate. Phosphate fertilizing using rock phosphate obviously increase d the soil content of phosphorus, both the available P and the reserved ones, and Superphos d id better than the rock phosphate. Rock phosphate effectivity on Typic Plintudults was lower than th at on Typic k anhapludults. ? Keywords: ?? rock phosphate, effectivity, typicplin-thudults, typickanhapludults, maize