PHYSICO – CHEMICAL AND MECHANICAL PROPERTIES OF SOIL AND YIELD COMPONENT OF AMARANTHUS CRUENTUS UNDER DIFFERENT TILLAGE AND COMPACTION MANAGEMENT

Abstract

A study was conducted to determine some physical, chemical and mechanical properties of agricultural soil at the Research and Experimental Farm of the department of Agricultural Engineering Federal University of Technology, Akure (FUTA). Soil parameters such as physical, chemical, unconfined compressive strength, soil moisture content, penetration resistance, hydraulic conductivity were monitored under four soil management systems no tillage (NT), primary tillage (PT), secondary tillage (ST) and compaction (CP) to determine the yield and yield parameters of Amaranthus cruentus. The soil penetration resistance (PR) was measured using cone penetrometer and hydraulic conductivity determined using Decagon mini disk infiltrometer. Soil moisture content (SMC) was monitored weekly using gravimetric method. Agronomic measurements such as plant height, root length, leaf area and yield of Amaranthus cruentus were conducted from the 2nd to 8th weeks after planting (WAP). Soil analysis according to the USDA textural classification showed a sandy clay loam texture for the experimental site. An increase in unconfined compression strength (UCS) from 0 – 20 cm depth was observed with values in the NT varying from 72.15 (±1.22) - 78.59 (±0.98) kPa, while the values for the PT varied from 78.07 (±2.12) - 80.3 (±1.33) kPa, ST varied from 76.53 (±1.12) - 79.60 (±0.12) kPa and the CP plots varied from 76.52 (±1.06) - 81.90 (±0.19) kPa. There were decrease in compression strength from 20 – 30 cm depth with values of 78.59 (±0.98) - 59.98 (±0.86) kPa, 80.30 (±1.33) - 72.15 (±1.04) kPa, 79.60 (±0.12) - 76.77 (±0.16) kPa and 81.90 (±0.19) - 77.56 (±1.13) kPa for the NT, PT, ST and CP, treatment plots, respectively. In all the treatments NT has the lowest unconfined compression strength while compaction has the highest unconfined compression strength. Soil moisture content (SMC) in all the soil tillage treatments reduced with increase in depth from 0 - 30 cm soil layer except in compacted plots. In compacted plots, SMC increased from 0 - 20 cm depth i.e 1.37 (±0.05)% - 8.21 (±1.32)% and later decreased from 20 – 30 cm depth i.e 8.21 (±1.32)% - 6.42 (±1.11)% i during the 2 WAP. The penetration resistance (PR) was highest in compacted (CP) treatment plots with values 1.38 (±0.08) mPa, 1.32 (±1.32) mPa and 1.47 (±0.51) mPa and lowest in secondary tillage (ST) with values 0.14 (±0.01) mPa, 0.13 (±0.02) mPa and 0.44 (±0.04) mPa at the 7.50 cm, 15 cm and 22.50 cm soil depths respectively. Hydraulic conductivity (Ko) was highest in PT treatment plots with value 0.76 (±0.12) cm/h during the 2nd week after planting (2WAP) and lowest in NT treatment plots (0.45 (±0.05)cm/h) during the 2nd week after planting (2WAP). Yield parameters plant height, leaf area and root length of Amaranthus cruentus under different tillage systems and compaction. Results showed the total biomas yield in kg/ha obtained from the NT, PT, ST and CP plots were 44.36, 131.87, 46.72 and 76.67 kg/ha, respectively. The yield under the PT plot represented about 200%, 183.26% and 66.11% increase over the yield obtained in No - tillage (NT), secondary tillage (ST) and compaction (CP), treatment plots, respectively