Effect of long-term application of animal manure on physical properties of three soils

Abstract

Surface soil samples to 15 cm depth were taken from replicated plots in an ongoing long-term field experiment involving application of animal manure on three soils in Virginia. The sampled plots had received either no manure or the equivalent of 289,000 kg ha-1 of manure as dry weight. The manure was applied annually at the beginning of each spring for 15 years from 1978 through 1992. The plots were cropped similarly since 1978. Soil textures were a fine sandy loam at Holland in the Atlantic Coastal Plain region, a silt loam at Blacksburg in the Appalachian region, and a clay loam at Orange in the Piedmont region of Virginia. The following measurements were made on subsamples: liquid and plastic limits, wet aggregate stability, aggregate size distribution, dispersible clay percentage, water retention at 0. 03, 0.1, 0. 3, 0. 5, 1.0, and 1.5 MPa tension, and modulus of rupture of moulded briquettes at a water content corresponding to 0.1 MPa tension. Organic matter content by the Walkley-Black method was significantly higher in the manure-treated soils at all three locations. Increases were 3% for the sandy loam and 25% for the silt loam and clay loam. From these values it was estimated that at least 95% of the total applied manure had been degraded over the 15 years. Results showed that the liquid and plastic limits for all three soils were higher (p< 0.05) for the manure -treated samples. However, the differences in the limits were only 2 to 3%. The modulus of rupture values were lowered by addition of the animal manure. Decreases (p < 0.05) occurred for the silt loam and clay loam samples. The wet aggregate stability increased and the dispersible clay decreased in the manure-treated soils. Increases (p < 0. 05) in wet aggregate stability occurred for the sandy loam and silt loam samples, Decreases (p < 0.05) in dispersible clay were measured for the sandy loam and clay loam samples. Water retention was consistently, but only slightly, increased by manure addition. The increases, in the order of sample texture, were clay loam > sandy loam ~ silt loam. Ihcreases tended to be higher at the lower values of tension. Manure addition consistently increased the weight percentages of aggregates passing a given mesh size. Increases, in order of sample texture, were silt loam > clay loam > sandy loam. In their entirety, these results show that the manure produced measurable changes in the soil physical properties. The magnitude of the changes, in most cases, were small and depended on the soil texture. Given the high total amount of manure applied, the results indicate that manure-induced physical changes in the soil were small and evidently did not accumulate over time. Rapid microbial degradation of the manure could be responsible for the lack of marked changes in the soil physical properties.

Effects of cattle manure compost combined with chemical fertilizer on topsoil organic matter, bulk density and earthworm activity in a wheat–maize rotation system in Eastern China

“…Maintaining adequate amount of SOM is particularly important for sustaining the productivity of an agro-ecosystem (Lal et al, 1999;Carter, 2002;Ding et al, 2012). Numerous studies have found strong correlations among soil structure, soil aggregate stability and SOM content (Darwish et al, 1995;Haynes and Naidu, 1998). For instance, some studies have shown that increase in SOM improves soil's aggregation, total porosity, hydraulic conductivity, waterholding capacity, resistance to water and wind erosion, and lowers bulk density and the degree of compaction (Celik et al, 2004;Leroy et al, 2008).…”

Effect of organic and mineral fertilizers on soil P and C levels, crop yield and P leaching in a long term trial on a silt loam soil

“…Indeed, sufficiently high soil organic carbon levels have to be maintained as they may affect crop yield indirectly by modifying soil physical and chemical properties, offering an improved root environment (Darwish et al, 1995;Stratton et al, 1995;D'Hose et al, 2014). Krey et al (2013) observed a similar or even stronger impact of organic fertilizers applied every third year on plant traits and P availability, compared to the annual application of inorganic P fertilizers.…”

Comparison of Soil Physical Properties in Conventional and Organic Farming Apple Orchards

“…Organically managed soils typically differ substantively in fertility as well as a number of soil quality properties when compared to conventionally managed soils [6][7][8][9][10][11] . Organic farming systems have been found to have a greater soil organic matter than the conventional agricultural systems 12,13) , and it has a profound impact on soil quality 7,8,[14][15][16][17] . Organic matter encourages granulation, increases water storage, nutrient supply, and soil organism activity, and improves soil fertility and productivity.…”