Organic inputs for soil fertility management in tropical agroecosystems: Application of an organic resource database

Organic resources play a critical role in both short-term nutrient availability and longer-term maintenance of soil organic matter in most smaller holder farming systems in the tropics. Despite this importance, there is little predictive understanding for the management of organic inputs in tropical agroecosystems. In this paper, an organic resource database (ORD) is introduced that contains information on organic resource quality parameters including macronutrient, lignin and polyphenol contents of fresh leaves, litter, stems and/or roots from almost 300 species found in tropical agroecosystems. Data on the soil and climate from where the material was collected are also included, as are decomposition and nutrient release rates of many of the organic inputs. Examples of uses of ORD are provided in the paper: (1) nutrient contents (including median values and ranges) and other resource quality parameters of farmyard manure and crop residues are compared to that of alternative nutrient sources such as different plant parts and plant types; (2) nutrient stocks found in farm boundary hedges are estimated and evaluated as a source of nutrients for soil fertility management; (3) hypotheses regarding the indices and critical values of N, lignin, and polyphenol contents for predicting N release rates are tested; (4) organic materials for soil fertility management experiments are selected. This database, when coupled with models and decision support tools, will help advance organic matter management for soil fertility improvement from an empirical to a predictive practice.

[1]  J. Stoorvogel,et al.  Assessment of soil nutrient depletion in sub-Saharan Africa: 1983-2000. , 1990 .

[2]  John F. Muratore,et al.  Nitrogen and Lignin Control of Hardwood Leaf Litter Decomposition Dynamics , 1982 .

[3]  E. Smaling,et al.  Nutrient balances as indicators of productivity and substainability in Sub-Saharan African agriculture: Papers Presented during the conference Soil Fertility Management in Sub-Saharan Africa" held in Nairobi, February 1997 , 1998 .

[4]  A. Chesson,et al.  Plant degradation by ruminants: parallels with litter decomposition in soils. , 1997 .

[5]  W. Parton,et al.  Simulating regional patterns of soil C, N, and P dynamics in the U.S. central grasslands region , 1989 .

[6]  L. Bergström,et al.  Ecology of Arable Land — Perspectives and Challenges , 1989, Developments in Plant and Soil Sciences.

[7]  Graeme L. Hammer,et al.  APSIM: a novel software system for model development, model testing and simulation in agricultural systems research , 1996 .

[8]  J. Fownes,et al.  Nitrogen mineralization from leaves and litter of tropical plants: Relationship to nitrogen, lignin and soluble polyphenol concentrations , 1994 .

[9]  J. Fownes,et al.  Tissue‐to‐solvent ratio and other factors affecting determination of soluble polyphenols in tropical leaves , 1994 .

[10]  J. Anderson,et al.  Plant litter quality and decomposition: an historical overview , 1997 .

[11]  W. Schlesinger,et al.  DECOMPOSITION OF CHAPARRAL SHRUB FOLIAGE: LOSSES OF ORGANIC AND INORGANIC CONSTITUENTS FROM DECIDUOUS AND EVERGREEN LEAVES' , 1981 .

[12]  J. Diels,et al.  Residue Quality and Decompostion : An unsteady relationship ? , 1996 .

[13]  P. Sánchez,et al.  Nitrogen release from the leaves of some tropical legumes as affected by their lignin and polyphenolic contents , 1991 .

[14]  E. Paul.  Dynamics of Soil Organic Matter in Tropical Ecosystems , 1991 .

[15]  J. Anderson,et al.  Decomposition in Terrestrial Ecosystems , 1979 .

[16]  Ken E. Giller,et al.  Effect of multipurpose trees, age of cutting and drying method on pruning quality. , 1997 .

[17]  P. Saffigna,et al.  Nitrogen supply to no-tillage crops, as influenced by mulch type, soil type and season, following pasture leys in the semi-arid tropics , 1996 .

[18]  K. Giller,et al.  Driven by Nature: Plant Litter Quality and Decomposition , 1996 .

[19]  K. Giller,et al.  Driven by nature: a sense of arrival or departure? , 1997 .

[20]  K. Giller,et al.  Regulating N mineralization from plant residues by manipulation of quality. , 1997 .

[21]  L. Brussaard,et al.  An index for assessing the quality of plant residues under humid tropical conditions. , 1995 .

[22]  F. J. Stevenson.  HUmus Chemistry Genesis, Composition, Reactions , 1982 .

[23]  D. Coleman,et al.  Dynamics of Soil Organic Matter in Tropical Ecosystems , 1989 .

[24]  B. H. Janssen,et al.  Soil fertility in Africa is at stake , 1997 .

[25]  J. Tanner,et al.  Implications of livestock feeding management on soil fertility in the smallholder farming systems of sub-Saharan Africa , 2001 .