Infiltration Rate as Affected by an Alfalfa and No-till Cotton Cropping System

Abstract

Previous studies measured a long-term increase in infiltration rate in a sandy loam soil with time when alfalfa (Medicago saliva L., cv. WL514) was grown. Cotton (Gossypium hirsutum L.) was directplanted into alfalfa to determine if the high infiltration rates measured under alfalfa culture could be maintained in cotton under either a till or no-till system. Treatments were no-till or tillage to the 0.15 -m depth just before the cotton was planted. Prior compaction levels created by harvest traffic applied to the alfalfa made the soil loose or compacted. Cotton was planted flat and irrigated as a basin. Infiltration rates measured 2 h after water was applied and averaged for the season were 101 (no-till, loose), 56 (till, loose), 82 (no-till, compacted), and 42 mm/h (till, compacted). All the infiltration rates were much higher than normally measured for cotton in these soils. Water flow in the 5-yr-old alfalfa was determined to be mainly through the soil macropore system. High infiltration rates measured in the no-till cotton were also probably the result of flow through the macropores.

Infiltration Rate of a Sandy Loam Soil: Effects of Traffic, Tillage, and Plant Roots

“…Pits were dug by hand to the 600-mm depth in each of 24 plots in the adjacent field and no earthworms were found. Meek et al (1990) found that this increase in infiltration rate caused by alfalfa could result in a higher infiltration rate for the next crop under no-till or shallow tillage. Pores that conducted the methylene blue solution past the 150-mm depth had an average diameter of 4 mm and many were partially filled with plant material (Table 1).…”

“…Shallow tillage to the 150-mm depth was done in one-half of the plots when the cotton was planted in 1988. Detailed procedures are given in Meek et al (1990). Bulk density was measured in October 1988.…”

Effect of root systems on preferential flow in swelling soil

“…Meek and his co-workers (Meek et al, 1989;1990), in studies of cropping and tillage systems on a sandy loam, observed yearly increases in infiltration rate which corresponded to decreases in alfalfa stand density over a 4-year alfalfa trial. Their dye studies showed that the decayed-root macropores extended to the soil surface and increased infiltration even on plots that were frequently trafficked during multiple harvests.…”

Impact of water quality, cultivation, and cropping systems on infiltration and physical properties of an arid clay soil

“…Sauer et al (1990) indicated that even though NT soils had higher bulk density than tilled ones; infiltration was higher in these soils due to more stable soil structure and increased number of continuous earthworm channels. In addition, higher infiltration in NT could be attributed to water flow through macropores and reduced surface sealing (Meek et al 1990). Furthermore, the lower infiltration rates in tilled treatments were probably due to the collapse of aggregates and the formation of surface crusts caused by direct raindrop impact.…”