Evaluation of the characteristics of 14 cover crops used in a soil rehabilitation trial

Abstract

Many of the soils in Santa Cruz Department, Bolivia, are degraded by serious weed infestation, subsoil compaction, and low organic matter and nitrogen contents. Fallow periods with cover crops are frequently used to recuperate the fertility of degraded soils, but little information exists on the desired characteristics of cover crops for this purpose. The aim of this study was to describe those characteristics, believed to be most relevant to the rehabilitation of degraded soils in Santa CNZ, of 14 cover crops, which included three grasses, nine legumes, and two winter cover crops sown after summer soybean (Gfycine m a ) . The cover crop characteristics, evaluated over two years, were ease of establishment, competitiveness against weeds, tolerance to drought, dry matter production and nutrient contents of the above-and below-ground residues, nodulation, rooting density and root diameters. The three grasses TobiatB (Panicum maximum var. TobiatB), Centenano (Panicum maximum var. Centenano) and Brizantha (Brachiaria brizantha) appeared to be the most promising for increasing soil organic matter contents, and the three grasses and groundnuts (Arachis hypogaea)/pigeon pea (Cajanus cajan) for the recuperation of subsoil structure. Mucuna deeringiana and Lablab (Dolichos lablab) were the most promising for increasing soil N status. All of these cover crops competed successfully with weeds. KEY WORDS Soil rehabilitation Degraded tropical soils Bolivia Cover crops Cover crop foliage and root characteristics Panicum maximum Brachiaria brizantha Cajanus cajan Dolichos lablab Mucuna deeringiana

Runoff, soil loss, and nutrient depletion under traditional and alternative cropping systems in the Transmexican Volcanic Belt, Central Mexico

“…In 2004, during rest in the AV treatment, erosion increased six-fold, much more than in the IT and TO treatments; nevertheless, the recorded value of (1.5 Mg ha À1 y À1 ) can be ranked as slight to moderate erosion. The latter result, and the increased surface runoff, strengthens the need for evaluating crops that favor soil rehabilitation during the fallow in Acrisols, as suggested by Barber and Navarro (1994), and demonstrated by Fuentes et al (2009) when the greatest effects on the soil's physical-chemical properties was produced by a maize-wheat rotation in Central Mexico.…”

“…Several authors have recognized the need for improving traditional fallow systems in degraded soils by the use of species that accumulate or recycle larger amounts of nutrients, or that better promote the restoration of the physical properties of soils (Barber and Navarro, 1994;Kass and Somarriba, 1999;Barrios et al, 2005). Assessments of alternative management methods such as crop rotations, intercropping systems, minimum-or zero-tillage approaches, and the management of crop residues for the restoration of soil quality, have been made in regions with predominance of traditional soil management systems (Huang et al, 2006;Fuentes et al, 2009).…”

Legume Cover Crops and Nutrient Cycling in Tropical Fruit Tree Production

“…During three months growth in a pot experiment, Joseph (1970) estimated the N fixation of Pueraria to 65 kg ha -1 . Despite the fact that the legume cover crops have a large biomass production and turnover, they are not likely to increase the soil organic matter content (Barber & Navarro, 1994a). However, Tian et al (1999) reported a lower soil organic matter decline with a Pueraria simultaneous cropping system than with conventional cropping in Nigeria.…”

“…Whereas ample information exists about cover crops in crop rotations (e.g. Barber & Navarro, 1994a), forage legumes (e.g. Cadisch et al, 1989) or intercropping with annual crops (e.g.…”

Modelling the effects of temperature on the rates of seedling emergence and leaf appearance in legume cover crops

“…There are many examples of their wide-spread use in intensive agriculture (Stivers et al, 1993;Reeves, 1994) and in increasing or sustaining the productivity of smallholder farming systems (Prinz, 1986). They have been particularly successful in combating soil degradation on sloping land; on land that was cleared and impoverished in slash and burn agriculture; and on land continuously cropped with cereals (Wilson et al, 1982;Barber and Navarro, 1994). Recent initiatives to increase the use of legume cover crops in agricultural practices worldwide have been discussed by Swift et al (1997).…”