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Soil Nitrate and Water Dynamics in Sesbania Fallows, Weed Fallows, and Maize
Author(s) -
Hartemink Alfred E.,
Janssen B.H.,
Buresh R. J.,
Jama Bashir
Publication year - 1996
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1996.03615995006000020033x
Subject(s) - sesbania , subsoil , agronomy , weed , sesbania sesban , crop rotation , biology , soil water , crop , ecology
We hypothesized that the integration of trees into agricultural land‐use systems can reduce NO 3 leaching and increase subsoil N utilization. A field study was conducted on a Kandiudalfic Eutrudox (Ochinga site) and a Kandic Paleustalf (Muange site) in the subhumid highlands of Kenya to measure changes in soil NO 3 and water to 200‐cm depth for one rainy season in four land‐use systems (LUS): (i) planted tree fallow using Sesbania sesban (L.) Merr., (ii) unfertilized maize ( Zea mays L.), (iii) weed fallow, and (iv) bare fallow. Subsoil (50‐200 cm) NO 3 ‐N at the start of the season ranged from 58 to 87 kg ha ‐1 for the four LUS and two sites. In maize, subsoil NO 3 ‐N differed by <5 kg ha ‐1 between planting and harvest at both sites. In sesbania, subsoil NO 3 ‐N decreased by 22 kg ha ‐1 at both sites, whereas in weed fallow subsoil NO 3 ‐N decreased by 26 and 38 kg ha ‐1 at Ochinga and Muange, respectively. At both sites, subsoil water contents at the start of the season were similar in the four LUS; but at the end of the season, soil water at 100 to 200 cm was significantly lower for sesbania than for maize. Adsorption of NO 3 increased with soil depth. Sorbed NO 3 at 100 to 200 cm was about 60% in the Kandiudalfic Eutrudox and about 15% in the Kandic Paleustalf. Rotation of maize with either a sesbania fallow or a weed fallow can result in more effective subsoil NO 3 and water utilization than maize monoculture.