A comparison between seasonal changes in soil water storage and penetration resistance under conventional and conservation tillage systems in Aragón

Abstract

1 Low and extremely variable precipitations limit dryland crop production in the semi-arid areas of 2 Aragón (NE Spain). These areas are also affected by high annual rates of topsoil losses by both wind 3 and water erosion. A long-term experiment to determine the feasibility of conservation tillage in the 4 main winter barley production areas of Aragón was initiated in 1989 at four locations, three on loam to 5 silt loam soils (Xerollic Calciorthid) and one on a silty clay loam (Fluventic Ustochrept), receiving 6 between 300 and 600 mm of average annual rainfall. In this study, we compared, under both continuous 7 cropping and cereal-fallow rotation, the effects of conventional tillage (moldboard plow) and two 8 conservation tillage systems, reduced tillage (chisel plow) and no-tillage, on soil water content and 9 penetration resistance during the first two growing seasons. Whereas reduced and conventionally tilled 10 treatments generally had similar soil water contents during the experimental period, the effects of no-11 tillage were inconsistent. No-tilled plots had from 26% less to 17% more stored soil water (0-80 cm) 12 than conventional tilled ones at the beginning of the growing season. In contrast to the conventional and 13 reduced tillage treatments, penetration resistances were between 2 and 4 MPa after sowing in most of 14 the plow layer (0-40 cm) under no-tillage at all sites. Fallow efficiencies in moisture storage in the 15 cereal-fallow rotation, when compared with the continuous cropping system, ranged from -8.7 to 12%. 16The highest efficiencies were recorded when the rainfall in the months close to primary tillage exceeded 17 100 mm. Since this event is very unlikely, long fallowing (9-10 months) appears to be an inefficient 18 practice for water conservation under both conventional and conservation management. Our results 19suggest that, up to now, only reduced tillage could replace conventional tillage without adverse effects 20 on soil water content and penetration resistance in the dryland cereal-growing areas of Aragón.

Turbulent characteristics of a semiarid atmospheric surface layer from cup anemometers – effects of soil tillage treatment (Northern Spain)

“…The traditional farming system of cereal-follow rotation extends over 250 000 ha in Central Aragon (Lopez et al, 1996), and the soil during the fallow period is smooth and bare. The experimental field, located in an area called El Saso (41 • 36 N, 0 • 32 W, 285 m above mean sea level), 35 km away from Zaragoza in the Ebro Valley (Fig.…”

“…The CT treatment consisted of mould-board ploughing, at a depth of 30-35 cm, followed by the pass of a compacting roller to obtain a very flat ground: it constitutes the traditional practice in this area. The RT treatment, an alternative practice of conservation tillage (Lopez et al, 1996), consists of a unique pass of a chisel plough at a depth of about 15-20 cm, yielding a ground with furrows. In both cases, the tillages were done in the WNW direction.…”

Biological quality of a podzolic soil after 19 years of irrigated minimum-till kikuyu–ryegrass pasture

“…1. A stratification ratio of 1 indicates a uniform distribution to 300 mm deep, and when >2, it generally indicates an improvement in the system (López et al 1996). Stratification ratios of organic matter indicators of virgin soil remained <2, except for active C and PMN, but those of cultivated pasture soil were >2.…”

Profile of the horizontal wind variance near the ground in near neutral flow – K-theory and the transport of the turbulent kinetic energy

“…The CT treatment consisted of mouldboard ploughing, at a depth of 30-35 cm, followed by the pass of a compacting roller to obtain a very flat ground: it constitutes the traditional practice in this area. The RT treatment, an alternative practice of conservation tillage (Lopez et al, 1996), consists of a unique pass of a chisel plough at a depth of about 15-20 cm, giving a ground with furrows. In both cases, the tillages were done in the WNW direction.…”