Year: 2014
Type: dissertation
Abstract: Soil degradation in crop production is becoming increasingly important because of the growing\nconcern it poses on soil functions. Prominent among the degradation factors is soil compaction. It\nimpairs soil productivity by impeding the soil conductivity potential and moisture retention ability,\nthereby preventing root penetrability and nutrients uptake among other things. This paper is\nconcerned with identifying and characterizing the degree of compaction that may result in\ndeleterious effects on soil physical properties, and the interaction that exists between crop growth\nand productivity. The above shall be achieved through field and laboratory determination of soil\nmeasurements from samples collected on a silty clay loam, and a silty loam soil at the University\nof Life Sciences (UMB / NMBU) experiment field\nThree land preparation practices (Autumn ploughing at 20 – 22 cm depth; Spring ploughing at 12\n– 15 cm depth and Spring harrowing at 4 -6 cm depth i.e. without ploughing), stubble cultivation\nand compaction were the treatments used in a three factorial field trials on a silty clay loam and a\nsilty loam soil to conduct the investigation at the UMB / NMBU experiment field. The three main\ngrain crops produced for the last 20 years were: wheat (Triticum aestivum L.), oats (Avena sativa\nL.) and barley (Hordeum vulgare L.). Field data collection and standard laboratory procedures\nwere performed using different equipments and gadgets to process the data. These were calculated\nand statistically analyzed by the ANOVA methods (GLM procedure), (SAS Institute, 1990).\nThe various treatments did not show much diversity in densification save few tillage applications\nwith stubble cultivation, compaction, and a combined tillage and compaction treatments that were\nsignificant S* (i.e. Pr > F) than the others as shown in Tables 2, 4, 8 and 9 in results. Tillage in\ndepths 5-10 cm and 15 – 20 cm showed significant penetration resistant (PR) (Pr > F), and stubble\ncultivation in depths 10 – 15 cm and 25 – 30 cm also gave significant PR (Pr > F). Fraction 6 – 20\nmm exhibited significant aggregate size distribution with tillage application (Pr > F) in Tab.4.\nVolume % was significant (Pr > F) with compaction application for pF 4.2 in depth 25 - 30 cm,\nwhile weight % was equally significant for pF 4.2 in the same depth with the same treatment. The\nsame trend occurred for both pF 4.2 weight % and volume % for combined tillage times compaction application in the same depths. There was minimal\ndifference in dry matter (DM) % between treatments, as well as water content in grain yield at\nharvest. However, both grain yield and dry matter % showed significant level (Pr > F) with tillage\ntreatment, but only grain yield gave significant level with compaction treatment.\nThe maximum bulk density (BD) observed in this trial was 1.60 g / cm³, which is just slightly\nabove the minimum critical limit of 1.55 g / cm³ that may restrict root penetration. In this case,\nany hindrance to root piercing may eminate from the presence of clay minerals, ions bonding and\nparticle density. This implies that a minimum level of compaction resulted from the treatments.
Author: Cassius G. V. Fahnbulleh
Language: English
Subfield: Soil Science
Domain: Life Sciences
SDGs: Zero hunger, Life on land
Open Access status: green
OpenAlex ID: W2474281919