Compaction Characteristics of Some Agricultural Soils in Niger State of Nigeria

Abstract

The movement of farm tractors and other heavy duty machineries leads to soil compaction. The dry density, penetration resistance and hydraulic conductivity are seriously influenced as a result of this, thus affecting plant physiology. In this study, soil samples were collected from three locations in Niger state, Nigeria namely Gidan kwano, Maikunkele and Maizube farms. Particle size analysis showed the textural class of the soils as sandy clay loam, loamy sand and clay loam, respectively. Atterberg limits of the soils samples were determined using the consistency test. The soils were characterized for their compaction behavior using 5, 10, 15, 20 and 25 blows compactive efforts of a proctor hammer in the moisture range of 8 to 26% (wet basis). The results of the compaction test showed that dry density increased with increase in compactive efforts, and that loamy sand had the highest dry density with accompanying low moisture content at all compaction levels. The result of the consistency test revealed that the optimum moisture content required for machinery traffic occurred between the plastic and liquid limits for all the three soil samples. Consequently, the use of tractors in carrying out farming operations is better suited when the soils are not too wet, so that the soil can support the machinery and hence avoiding wheel skidding. Predictive equations were established to relate the dry density of the different compactive efforts with moisture content of the three soils.

Kretanje poljoprivrednih traktora i drugih teških mašina uzrokuje sabijanje zemljišta. Zapreminska težina, otpor penetracije i hidraulična provodljivost su pod značajnim uticajem sabijanja, što ugrožava i fiziologiju biljaka. U ovom istraživanju sakupljeni su uzorci zemljišta sa tri lokacije u državi Niger u Nigeriji, farme: Gidan kwano, Maikunkele i Maizube farms. Analiza dimenzija čestica pokazala je da teksture zemljišta pripadaju klasama peskovito-glinovita ilovača, pesak i glina ilovastog sastava, redom. Atterberg granice uzoraka ovog zemljišta određene su testom konzistentcije. Uzorci zemljišta su bili karakterisani koristeći intervale za sabijanje od 5, 10, 15, 20 i 25 udaraca Proctor čekića u opsegu vlage od 8 do 26% (mokra osnova). Rezultati testa sabijanja pokazuju da se zapreminska težina suvog uzorka povećava sa povećanjem broja udaraca i da frakcija ilovasti pesak ima najveću gustinu koja prati nizak nivo vlage na svim nivoima sabijanja. Rezultat testa konzistencije je pokazao da je optimalna vlažnost potrebna za saobraćaj mašina bila između plastične i tečne granice za sva tri uzoraka zemljišta. Shodno tome, upotreba traktora u obavljanju poljoprivrednih radova je bolje prilagođena kada zemljišta nisu prevlažena, tako da zemljište može da izdrži opterećanje mašina, a da pri tome bude izbegnuto proklizavanje točka. Postavljene su jednačine za predviđanje odnosa zapreminske težine suvog uzorka za različit broj udaraca čekića sa sadržajem vlage kod tri uzorka zemljišta.