Effects of legumes on soil physical quality in a maize crop

Abstract

The effect of intercropped legumes and three N fertilizer rates in a continuous maize (Zea mays L.) cropping system on the physical properties of two soils were investigated for three years. The legumes, being a mixture of alfalfa, clover and hairy vetch, had a significant cumulative effect on some physical properties of both soil. The lowest stability and smallest mean weight diameter of soil aggregates were associated with monoculture maize plots. Aggregate size and stability were not affected by N fertilization at any of the rates of 0, 70, and 140 kg ha f in intercropped plots, except that aggregate stability was actually reduced by N fertilization in one soil, the Ste. Rosalie clay. In maize plots in both soils, stability and size of soil aggregates were significantly increased with increased added N. Intercropped legumes significantly decreased dry bulk density and soil penetration resistance. Added N had no measurable influence on these compaction factors. Soil water properties were not significantly affected by either intercropping or N fertilization. Positive effects noted on soil aggregation and other physical properties in intercropped plots are the result of enhanced root activity, or incorporation of legumes as green manure, or both. Improvement of soil structure in maize plots associated with increasing N application was the result of increased maize-root residues.

Increases in Soil Aggregation Following Phosphorus Additions in a Tropical Premontane Forest are Not Driven by Root and Arbuscular Mycorrhizal Fungal Abundances

“…As reported here, P additions have been shown to increase soil aggregation (Nobrega et al, 2001;Gil et al, 2009;Alguacil et al, 2010;Ortas and Lal, 2012), but also N additions (Latif et al, 1992;Tripathi et al, 2008;Wilson et al, 2009;Guo et al, 2012) as well as the application of multi-component fertilizers Hati et al, 2006;Huo et al, 2008). As proposed here, many studies focused on the indirect impact of AMF hyphal length and root abundance in this context.…”

“…By contrast, to our knowledge only very few experiments have been conducted in natural systems, covering a limited range of ecosystem types like temperate grasslands (Van Groeningen et al, 2002;Wilson et al, 2009) or dry tropical savanna (Tripathi et al, 2008). The majority of these studies report positive effects of nutrient additions on soil aggregation, often accompanied by increases in root and arbuscular mycorrhizal fungal (AMF) hyphal abundance (Latif et al, 1992;Nobrega et al, 2001;Wilson et al, 2009;Alguacil et al, 2010). The latter are important factors in the process of aggregate formation, though abiotic factors likewise may play an important role: Fertilization studies focusing on abiotic soil parameters also demonstrated interrelations with pH and the proportion of exchangeable cations and electrostatic binding agents Graham et al, 2002).…”

Soil structure, organic matter and earthworm activity in a comparison of cropping systems with contrasting tillage, rotations, fertilizer levels and manure use

“…During the first period of the experiment, the clover content in the conventional (CS4) and the organic (CS5) leys were 12-24% and 16-63%, respectively (Korsaeth and Eltun, 2000). Favourable effects on soil structure have been reported for several legumes grown together with maize (Latif et al, 1992). On the other hand, Breland (1995) found that ryegrass sown as a catch crop had a better effect on soil structure than did white clover, probably because its roots bound the soil well and provided carbon-rich material that stimulates microbial activity.…”

Living Mulch as a Tool to Control Weeds in Agroecosystems: A Review

“…In addition to providing adequate cover to reduce soil erosion (Wall et al 1991) and increase soil water infiltration (Bruce et al 1992), legume living mulches improve soil nutrient status through addition of organic nitrogen (N) (Holderbaum et al 1990;Brown et al, 1993) via fixed atmospheric nitrogen which improves soil physical properties (McVay et al 1989;Latif et al 1992). Incorporating legume living mulches can also increase the yield of the succeeding crop (Bollero and Bullock 1994;Decker et al 1994).…”