Distribution of some selected soil properties under agroforestry and agricultural crops
Distribution of some selected soil properties under agroforestry and agricultural crops
Aman Ullah Bhatti, Shamsher Ali and Farmanullah Khan
ABSTRACT
Field and laboratory investigations were made to study the distribution of some soil properties under agro-forestry (Eucalyptus + wheat) and agricultural crops (wheat). Eighteen soil samples were collected at a regular grid spacing of 15 m x 25 m and 15 m x 20 m from two depths (0-15, 15-45 cm) under agro-forestry and agricultural crops, respectively from D. I. Khan. Soil samples collected were analyzed for soil pH (1:5), electrical conductivity (1:5), organic matter, lime, mineral N, and AB-DTPA extractable P and K. The total number of plants were 410 in agro-forestry field and were about 5 years old Data collected on soil properties were statistically analyzed. In the field of agro-forestry, the percent co-efficient of variation (% CV) for EC (1:5) and P were 57.4 and 35.2 for surface soil and 49.8 and 72.7% for sub soil, respectively. Based on critical level for soil P. all the soil samples in both the depths were deficient, except one sample which was medium in subsoil. About 83% in the surface soil and 94% in the subsoil of the samples were found low (<1%) in organic matter. Soil K was found in adequate amount with low variability having CV=6.81% and 6.43% in surface and sub-surface soil, respectively. In the field of agricultural crops (wheat) the CV values for EC and P were 34.9 and 49.98% for surface and 32.02 and 29.48% for sub soil, respectively. Based on critical level, soil P was deficient in 27%, medium in 40% in surface soil while deficient in all the sub soil samples. Variation was also observed in mineral N (25.4 and 31.13%) organic matter (22.57 and 25.61%) in both the depths and in subsoil K (21.41%). Twenty eight percent samples were deficient, 72% medium in organic matter in the surface soil and 94% were deficient in the subsoil. In the surface soil, organic matter, mineral N and soil P were significantly (P<0.01) lower under agro-forestry than under agricultural crops because eucalyptus is evergreen and shed little leaves and also utilize the soil nutrients. In the subsoil, soil pH, EC, soil P and K significantly differed between the two systems. Geostatistical analysis of data showed that EC and soil P were spatially distributed in the surface soil while only EC in subsoil under agro-forestry. While organic matter and mineral N in the surface soil and EC, organic matter, lime and soil P in the subsoil were spatially distributed under agricultural crops. Maps of soil properties were prepared using geostatistical technique of kriging. Almost all of the maps showed spatial distribution of soil properties.
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March 2002
Vol. 52, Iss. 1
