Macronutrient status of the soils of Latif farm: blocks D and E [Pakistan]

In order to determine the macronutrient (NPK) status of the soils of Latif Farm, Sindh Agriculture University, Tandojam, ninety six composite soil samples were secured from forty eight different sites of blocks D and E at 0-15 and 15-30 cm depths during the year 2000-2001. The soils samples were analyzed for NPK status alongwith some physico-chemical properties. The research findings are summarized as under; The majority of the soils of blocks D and E were heavy and ranged between clay to clay loam in texture. Almost all the soils were alkaline in reaction with 84% samples in the range of 7.6-8.4 and 16% samples were in the range of 8.3-9.0 in pH. All the soils samples of both blocks were non-saline, as the 100% samples were found with EC value less than 2 dS m-1. The analysis results regarding soluble cations showed that calcium occupied a major portion than soluble magnesium, as an average value of 11.6 meq/L and 4.6 meq/L in both blocks. The analysis for soluble anions i.e. CO3 HCO3 and C1 indicated that among soluble anions chlorides occupied a major portion with an overall average value of 5.9 meq/L in both blocks. Mostly all the soil samples of both blocks were poor to medium in organic matter content, as 65 % samples were found poor (less than 0.86 %), 33% were medium (0.86- 1.29%) and 2 % were adequate (greater than 1.29%). The soils of blocks D and E were moderately calcareous to highly calcareous in nature, as 6% sample were slightly calcareous. 41% samples were moderately calcareous, while 53% samples were found highly calcareous. Majority of the soils of both blocks i.e. D and E were found poor in total nitrogen content, 84% soil samples contained less than 0.05%, while 16% soil sample contained 0.05-0.067 % total nitrogen. Almost all the soil samples of the study area were found low in available phosphorus, as 84% soil samples were low (0-3 mg/kg) and the rest were medium (4-7 mg/kg) in available phosphorus. The soils were medium to high in extractable potassium with 6% samples between 61- 120 mg/kg and 94% samples were greater than 120 mg/kg in extractable K. The correlation study showed that there was positive and significant relationship between NPK with organic matter. However, the relationship of NPK with other soil properties was mostly non-significant. It can be concluded from the results that the soils of Latif Farm (blocks D and E) were mostly heavy in texture. Moderately alkaline in reaction, non-saline. Moderately to highly calcareous in nature. Organic matter, total nitrogen and available phosphorus were low, however extractable potassium was adequate in all soil samples. Therefore organic manures (FYM and green manuring) and inorganic nitrogenous and phosphatic fertilizers may be added to improve macronutrient status of soils of the study area.