Spatial Variability Mapping of Selected Soil Properties of District Tando Allahyar, Sindh, Pakistan

Spatial variability mapping of soil properties is essential to understand the differences among soils found in a geographical region for their better management. This study aimed at spatial variability mapping of selected soil properties of district Tando Allahyar, Sindh which is one of the most important districts of Sindh province. The results revealed that majority of soils (35.6%) had loamy slightly medium-textured type, including 30.8% silt loam, 3.8% loam and 1.0% silt, followed by clayey, fine-textured heavy type (27.9%), including 18.3% clay, 6.7% silty clay and 2.9% sandy clay. Soils with sandy, coarse-textured light type were 20.2%, including 16.3% sandy loam and 1.9% loamy sand and sand each. Soils with loamy, moderately medium-textured type were 16.3%, including 9.6% clay loam and 6.7% sandy clay loam, while silty clay loam soil texture was total missing. The EC ranged from 0.14 to 4.44 dS m-1 (mean: 0.69 dS m-1, mode: 0.42 dS m-1). Majority (91%) of soils had low (46%) to medium (45) level of salinity. Soil pH ranged from 6.2 to 8.6 (mean: 7.7, mode: 8.3). Majority of soils (84%) had either slightly (24%), medium (22%) or strongly alkaline (38%) soil pH. Interestingly, some soils (13%) had slightly acidic pH. Organic matter ranged from 0.10 to 1.6% (mean: 0.64%, mode: 0.17%). Majority (84%) of soils were deficient in organic matter. Soil ABDTPA-P ranged from 1.2 to 18.8 mg kg-1 (mean: 5.38 mg kg-1, mode: 2.4 mg kg-1). More than half (55%) of the soils had low P, while soils with marginal (14%) or adequate (31%) P were also present. Soil ABDTPA-K ranged from 31 to 376 mg kg-1 (mean: 154 mg kg-1, mode: 230 mg kg-1). Majority of soils (62%) had adequate K, while soils with marginal (28%) or low (11%) K were also found. Spatial variability mapping revealed the dominance of loam, sandy clay loam, sandy loam, silty clay and clay loam textures, medium > low and high > salinity, slightly to medium alkaline soils > strongly alkaline soils, low organic matter content, medium to adequate > low soil P, and adequate soil K. The spatial variation found in various soil properties of district Tando Allahyar, Sindh must be taken in mind while deciding about their site-specific management, using the recently developed maps.