A study of mole drainage with simplified cultivation for autumn-sown crops on a clay soil

Abstract

A replicated, long-term field drainage experiment on a clay soil was started in 1978 to investigate the effects of mole drainage on land that had been direct-drilled or ploughed. We here describe the background and the need for this work, details of the experiment and summarize the results for the first 2 years. The main factors causing point-to-point variability in the soil at the experimental site and their relative contributions were assessed. Variations in inherent soil properties were small, except for depth to calcareous clay. Site hydrology was also generally uniform, especially soil water content, and was little affected by the presence of subsoil drainage schemes dating from the 19th century. There were some variations in micro-relief. The drained and undrained plots were hydrologically separated. Equipment was installed to measure separately surface runoff, lateral flow at the bottom of the cultivated layer (the interflow) and deep drainage from the mole and pipe system (in the drained plots only). The design and performance of that equipment is described. In both years much of the undrained soil became saturated in winter, but a residual cultivation pan limited the effect of the mole drains in 1978-9. In 1979-80, after disrupting the pan, the water table in the moledrained plots was about 25 cm deeper than in the undrained plots, root growth was greater and yield of winter wheat 11% heavier. About 90% of water and nutrients draining from the drained plots were carried in the mole and pipe system. The results on water balance, nutrient losses, crop growth and yield are fully reported in companion papers (Harris et al. 1984;Ellis et al. 1984).

Spatial variability in the degradation rates of isoproturon and chlorotoluron in a clay soil

“…The Brimstone Farm site is at Faringdon, Oxfordshire, UK, and is a heavy clay soil of the Denchworth series with 7% sand (60–2000 μm), 37% silt (2–60 μm), 56% clay (< 2 μm) and 4.5% organic matter (Cannell et al ., 1984). The field used for the drainage studies is divided into 20 plots each of 0.24 ha, plus an area (the southern discard) not used for the major experimental programme.…”

Effect of crop residue management and drainage on the persistence and movement of isoproturon in a structured clay soil over the growing season of a winter barley crop.

“…The site consists of 20 experimental plots, each subjected to different agricultural management practices. Comprehensive details of the original plot establishment are given by Cannell et al (1984) and subsequent modifications by Harris et al (1994). The overall dimensions of the plots are 59.0 m x 41.0 m. Each plot was hydrologically isolated to a depth of 1.1 m by installing a continuous sheet of polyethylene down the slope at the eastern and western boundaries of the plots.…”

Valley Bottom Clay Distribution and Adapted Drainage Techniques

“…The clay thickness and location are two of the most important factors that help in the choice of the type of subsurface drainage for the soil (Cannell et al 1984;Foth 1990). When the peak followed a more pervious layer such as in the downstream area (Pi4 and Pi10, Fig.…”

“…However, the persistence of a thick clay layer in the topsoil of the upstream and middle cross sections calls for application of alternative techniques such as "mole drainage" or permeability improvement practices (Schultz 1988). Mole drainage technique has been successfully applied against waterlogging and salt adversities for wide varieties of clay (Cannell et al 1984;Robinson et al 1987). Elsewhere, crack-making trenches were realized in the heavy, but non swelling clay (mainly illite) of the 165,000 ha agricultural land of IJsselmeerpolders in the Netherlands.…”