Short communication
Description standards of primary tillage implements
J.R. Marques da Silva
*, J.M.C.N. Soares
Departamento de Engenharia Rural, Universidade de EÂ vora, PO Box 94, P-7002-554 EÂvora, Portugal
Received 2 November 1999; received in revised form 22 June 2000; accepted 29 August 2000
Abstract
Recent research has shown that different types of tillage implements have a different impact on soil translocation. Tillage experiment descriptions in the bibliography are usually incomplete in their description of the implements and the experimental tillage conditions, which makes some difference if one wants to compare different experiments through time and space. The aim of this paper is to present a diagnostic of the problem, showing the importance of describing the implements and at the same time to present a proposal for a standard description of mouldboards, disc harrows and cultivators that should be taken into account when tillage experiments are carried out.#2000 Elsevier Science B.V. All rights reserved.
Keywords:Tillage implements description; Tillage experiments; Mouldboard; Disc harrow; Cultivators
1. Introduction
Implement description is important in tillage research to understand and compare different experi-ment results. It is also important because it allows replication of the experiment to be used in other studies. From Table 1 we can verify that tillage implement descriptions are usually incomplete.
This paper will focus on the tillage implement description and will not consider the implement adjustment because for each tillage experiment the implement is adjusted to the tractor for a perfect tillage performance. The objective of this study is to diagnose the problem and at the same time present a description proposal for mouldboard ploughs, disc harrows and cultivators.
2. Diagnostic and discussion
The relevant literature was scanned for studies with tillage implements and the description of the imple-ments was analysed taking into consideration the characteristics presented in Table 1. Based on Cedra (1993) we consider these characteristics to be the principal ones that have to be taken into account whenever describing a speci®c tillage implement.
2.1. Mouldboard plough
The mouldboard plough is usually used to embed residues, weeds, minerals and organic fertilisers, facil-itate the seed-bed preparation and improve the phy-sical soil condition.
Several studies do not describe the share width and the number of shares (Table 1), which are important, because they in¯uence the total work width of the mouldboard and together with the soil depth de®ne the total volume of the disturbed soil. Other studies do not describe the mouldboard form, which is known to Soil & Tillage Research 57 (2000) 173±176
*Corresponding author. Tel.:351-66-749823;
fax:351-66-711189.
E-mail address: jmsilva@uevora.pt (J.R. Marques da Silva).
Table 1
Implements description within different tillage experiments (N and Y represent parameter not described and parameter described, respectively)
in¯uence the type of turning furrow. Some studies do not describe the support mode and it is known that this in¯uences the soil movement, e.g. in a trailed harrow disc we can regulate the power draught of the tractor to mobilise deeper but in a mounted one it is not possible to do so.
The reversion mode and the turning mode of the mouldboard are not extremely important because they do not in¯uence the type of soil movement, but they are characteristics of the implement which should be described.
2.2. Cultivator
The cultivator is an implement that is used to fragment the soil without turning the furrow and is used for seed-bed preparation, weed control and soil segregation.
Table 1 shows how different studies have described different cultivators in experiments. The number of rows and the space between them, the number of tines and the space between them, the type of tines, the type of shares, the support mode, the work speed and the work depth are the factors that in¯uence any soil tillage experiment. The work width is a characteristic of the implement, which should be described.
Omitting the description of the characteristics pre-sented in Table 1 can lead to dif®culties in comparing cultivator experiments, as it is not possible to compare the type of work done by a ¯exible tine chisel with that of a rigid tine chisel, because the former segregates the soil and the latter does not.
2.3. Disc harrow
The disc harrow is an implement that is used to cut and mix soil, for a large number of applications, such as seed-bed preparation after the mouldboard plough, or as a complete replacement of the mouldboard plough in the minimum tillage systems. In this parti-cular case, the disc harrow will embed residues, weeds, minerals and organic fertilisers in the soil in the same way as the mouldboard, but at different depths.
Table 1 shows how different studies have described different disc harrows. The type and number of discs, the disc diameter, the space between discs, the disc angles, the support mode, the working speed and the
working depth, in¯uence the results of any tillage experiment.
In the different studies presented in Table 1 one can hardly compare two implements with each other because the necessary information for comparison is not available. It is necessary to make a standard description of the implements.
The standard description that we would like to propose is presented in Table 1, for the three different implements. For complex implements or components of complex implement, we propose that the authors should present at least a photograph where one can see the different dimensions and forms, for possible com-parison with others of the same category.
3. Conclusions
More information on tillage implement description is needed in cultivation studies. Present implement and experiment descriptions are often incomplete and prevent adequate comparison among studies.
The description of a mouldboard should at least present the share width, the number of shares, the mouldboard form, the work width, the reversion mode, the turning mode, the support mode, the working velocity and the working depth. If possible the description should also present the angle of penetra-tion (share pitch), body pitch angle (downward incli-nation of a body), the cutting angle and the lead to land angle (side suction).
The description of a cultivator should at least pre-sent the number of rows and the space between them, the number of tines and the space between them, the type of tines, the work width, the type of shares, the support mode, the working velocity and the working depth.
The description of a disc harrow should present the number of discs, the type of discs and the space between them, the discs diameter, the work width, the support mode, the disc angles, the working velo-city and the working depth.
References
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