The effect of tillage, compost and mulch on soil physical properties and crop yield

Abstract

A study was conducted to assess the effect of tillage (double digging), compost and mulch on crop yield and soil physical properties of a humic Nitisol. The experiment was a 2*2*2 factorial treatment design consisting of 8 treatments replicated 4 times. Sunflower (Helianthus ann us L.) and Maize (Zea mays) were used as test crop in the 1992 short rains and the 1993 long rains respectively, The results indicate that compost sig~ificantly (P<O.OS) increased hydraulic conductivity by 47%, available water by 9%, total porosity by 4% and reduced bulk density by 8% at 0-5 cm layer when compared with treatments without compost. Only bulk density and total porosi ty were affected by mulch placement. Double digging reduced bulk densi ty of the 2S-30 cm and 50-55 cm layers and consequently resulted in significant increases in total porosity, hydraulic conductivity and available water (w/w). A combination of compost and mulch gave significantly (P<O.Ol) higher sunflower seed yield (26%) and dry matter production (13%) than the control. Double digging and normal hand tillage produced similar sunflower yields. Maize was adversely affected by drought. This stud.i'sh~ws that compost and mulch are effective in increasing crop yields and improving soil physical properties of the topsoil. Although double digging improved the physical properties of lower horizons, there was however no evidence that this tillage system had significant influence on crop yield.