5 Influence of permanent raised bed planting and residue management on physical and.pdf

ORIGINAL PAPER Influence of permanent raised bed planting and residue management on physical and chemical soil quality in rain fed maize/wheat systems B. Govaerts ? K. D. Sayre ? K. Lichter ? L. Dendooven ? J. Deckers Received: 15 August 2006 / Accepted: 24 November 2006 / Published online: 17 January 2007
Springer Science+Business Media B.V. 2007 Abstract Densely populated, intensively cropped highland areas in the tropics and sub- tropics are prone to erosion and declining soil fertility, making agriculture unsustainable. Con- servation agriculture in its version of permanent raised bed planting with crop residue retention has been proposed as an alternative wheat pro- duction system for this agro-ecological zone. A five years field experiment comparing permanent and tilled raised beds with different residue management under rainfed conditions was started at El Bata?n (Mexico) (2,240 m asl; 19.31N, 98.50W; Cumulic Phaeozem) in 1999. The objec- tive of this study was to determine the soil quality status after five years of different management practices. The K concentration was 1.65 times and 1.43 times larger in the 0–5 cm and 5–20 cm profiles, respectively, for permanent raised beds compared to conventionally tilled raised beds. The Na concentration showed the opposite trend. Sodicity was highest for conventionally tilled raised beds and for permanent raised beds it increased with decreasing amounts of residue retained on the surface. Permanent raised beds with full residue retention increased soil organic matter content 1.4 times in the 0–5 cm layer compared to conventionally tilled raised beds with straw incorporated and it increased signifi- cantly with increasing amounts of residue re- tained on the soil surface for permanent raised beds. Soil from permanent raised beds with full residue retention had significantly higher mean weight diameter for wet and dry sieving com- pared to conventionally tilled raised beds. Per- manent raised beds with full residue