TY - JOUR ID - 30009 TI - Assesment of the Standard Index of Annual Precipitation,Standardized Precipitation Index and Palmer Drought Severity Index in the Rangelands of Qom Province JO - Journal of Range and Watershed Managment JA - JRWM LA - en SN - 5044-2008 AU - Azarakhshi, Maryam AU - Farokhzadeh, Behnoush AU - Mahdavi, Mohammad AU - Arzani, Hossein AU - Ahmadi, Hassan AD - Y1 - 2012 PY - 2012 VL - 65 IS - 2 SP - 159 EP - 174 KW - Drought KW - Forage production KW - Palmer Drought Severity Index KW - Qom province KW - Regression KW - Standard Index of Annual Precipitation KW - Standardized Precipitation Index DO - 10.22059/jrwm.2012.30009 N2 - Iran is located in dry belt of the earth and always involved with drought in different sections. Drought has already caused many losses to natural plant cover, agriculture and human society. For drought monitoring, we can use some drought indecies. In this research, the Standard Index of Annual Precipitation)SIAP),Sandardized Precipitation Index (SPI) and Palmer Drought Severity Index (PDSI) were used for assessment of drought effects on rangeland plant production. The research area is located in Qom province that contains eight rangeland sites. Plant production and soil factors were measured in rangeland readiness period from 1997-1998 to 2005-2006 annualy. Regression techniques were used between drought indices and total production and also production of different vegetation forms in seven time scales (early March to late July (growth season) and early February to late July (growth season and the previous month), March to June, March to May, March to April and March (start of growth season). The best drought index was then selected based on the highest correlation coefficient and lowest standard error. The result showed that the best drought indices in Qom rangelands are SPI-3, PDSI, SPI-24 and SPI-6, respectively. Also the most significant time step was resulted growth season and specially early stage of growth season. UR - https://jrwm.ut.ac.ir/article_30009.html L1 - https://jrwm.ut.ac.ir/article_30009_709d95ba1a91f7dec274771c5d2d9ffb.pdf ER -