Soil Phosphorus Evaluation and Mapping of Onion Growing Areas of Tehsil Baghbana, Balochistan Using Remote Sensing Tools

Abstract

Onion (Allium cepa L.) is an important commercial plant. Pakistan is a main onion growing country globally. The study was conducted to find out the nutrient status of onion growing areas of tehsil Baghbana, Balochistan. Soil samples were collected from 05 union councils including 50 samples in depth of 0-20cm. For location referencing of the soil samples latitude and longitude values of the sample’s points were recorded. The location was logged by Canota software and maps were using by remote sensing tool (Google earth). The soil nutrient analysis was conducted at Agriculture Research Institute (ARI) Quetta. Soil nutrient level including soil texture, pH, EC, Organic matter, Lime content & AB-DTPA extractable P content were examined. The findings showed variation in soil texture, although the pH values range from 7.69 to 8.81 (Mean 8.1, Mode. 8.04). 76% soils were medium alkaline (pH:7.6-8.2) while remaining 24% were strongly alkaline (pH: 8.3-9.0). The EC values (dSm^-1) ranged between 0.19 to 2.84 (Mean. 0.60, Mode.0.46). Only 04% of soil samples were very slightly saline (EC: 2-4) whereas, remaining 96% were non-saline (EC: <2). Results of organic matter showed that soil samples ranged 0.13 to1.02% (Mean.0.52%, Mode.0.32%). Majority (98%) of the samples low in organic matter (OM:<0.86%), while there is 02% were medium in organic matter (OM: 0.86-1.29%). The lime content (CaCO₃) lied between 13.3 to 45.7% (Mean. 31.09%, Mode.17.20%). Mostly (96%) soils were strongly calcareous (CaCO₃: >15) and remaining 04% were moderately (CaCO₃: 2-15) calcareous. The results of AB-DTPA showed the phosphorus level at tehsil Baghbana, Balochistan soil were deficient (94%) & ranged between 2.15 to 4.20 mg kg^-1.