Conventionally Tilled and Permanent Raised Beds with Different Crop Residue Management: Effects on Soil C and N Dynamics |
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Authors: | B Govaerts K D Sayre J M Ceballos-Ramirez M L Luna-Guido A Limon-Ortega J Deckers L Dendooven |
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Institution: | (1) Faculty of Applied Bioscience and Engineering, Laboratory for Soil and Water Management, Katholieke Universiteit Leuven, Vital Decosterstraat 102, 3000 Leuven, Belgium;(2) International Maize and Wheat Improvement Centre (CIMMYT), Apdo. Postal 6-641, 06600 Mexico, D.F., Mexico;(3) Departamento de Biotecnología y Bioingeniería, Cinvestav, Avenida Instituto Politécnico Nacional 2508, C.P. 07000 México, D.F., México;(4) INIFAP-CEVAMEX, AP10, Km 17.5 Carr. México-Lechería, 56230 Chapingo, CP, México |
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Abstract: | Conservation tillage in its version of permanent bed planting under zero-tillage with crop residue retention has been proposed
as an alternative wheat production system for northwest Mexico. However, little is known about the dynamics of C and N in
soils under wheat/maize on permanent beds (PB) where straw was burned, removed, partly removed or retained, as opposed to
conventionally tilled beds (CTB) where straw was incorporated. We investigated the dynamics of soil C and N and normalized
difference vegetative index (NDVI) crop values in zero-tilled PB and CTB after 26 successive maize and wheat crops. Organic
C and total N were respectively, 1.15 and 1.17 times greater in PB with straw partly removed and with straw retained on the
surface, than in CTB with straw incorporated. Organic C and total N were 1.10 times greater in soils with 300 kg N ha−1 added than in unfertilized soil. Cumulative production of CO2 was lower under CTB with straw incorporated than under PB treatments, and CO2 production increased with increments in inorganic fertilizer. The N-mineralization rate was 1.18 times greater than in unamended
soils when 150 kg inorganic N ha−1 was applied, and 1.48 times greater when 300 kg inorganic N ha−1 was added. The N-mineralization rate was significantly (1.66 times) greater in PB where the straw was burned or retained
on the surface than in CTB where the straw was incorporated, but significantly (1.25 times) lower than in PB with straw partly
removed. The NDVI values reached a maximum 56 days after planting and decreased thereafter. The NDVI for unfertilized soil
were similar for CTB with straw incorporated, PB with straw partly removed, and PB with straw retained on the surface, but
significantly lower for PB with straw burned and PB with straw removed. In soils to which 150 or 300 kg N ha−1 was added, NDVI was significantly lower for PB with straw burned than for other treatments. Among other things, this suggests
the utility of rotating maize or wheat with crops whose residues have lower C–N ratios, thus avoiding immobilization of large
amounts of N for extended periods. PB with residue burning, however, is an unsustainable practice leading to low crop performance
and soil and environmental degradation. |
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Keywords: | conventional and zero-tillage crop residue C and N dynamics NDVI nitrogen fertilizer permanent beds |
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