Evaluation of a power driven residue manager for no-till drills

The main operational problem in direct drilling of paddy straw residue is the accumulation and wrapping of loose straw within/on the tines and frame of no-till drills and traction problems with the ground wheel. A residue management equipment (RME) is developed to cut and remove paddy straw away from furrow openers of the no-till drill. The equipment consisted of nine parts; each part consisted of two powered wheels, one wheel for cutting the residue and the other wheel for removing them away from no-till drill furrow openers. This equipment was attached with the no-till drill with inverted "T" type furrow opener and the experiments have been conducted to compare the no-till drill with RME and same no-till drill without RME. No-till drill with RME increased the fuel consumption and time required by 29.6 % and 13.14 %, respectively. Adding RME to the no-till drill decreased the amount of residue clogged by 33% and increased the percentage of cut hill from 14.9 to 63.7%. The average numbers of effective tiller, spike length and plant heights were more for no-till drill with RME. Furthermore, the grain yield was increased by 12.4% for fields with no-drill with RME.


Introduction 
Crop residues on the soil surface makes uniform seedling establishment difficult in conservation tillage systems, in addition high levels of crop residues present a constraint to the adoption of conservation tillage because residues mechanically interfere with seeding operations. Improved seeding equipment or residue removal may be necessary for successful direct drilling practices (Carter, 1994; Manjeet andShukla, 2006 andWilkins, 2006).
The collection of straw after paddy harvesting is uneconomical and its end use is not yet wide spread. So either residue is incorporated in the soil or burnt in the field. Incorporation of straw in soil has got some advantages in improving the soil fertility and yield. But this process needs many operations which involves both time and money of the farmers and it delays sowing of wheat crop. The wheat production is adversely affected if crop is not sown in time. It has been reported that wheat yield decreases by 35-40 kg/ha per day, when wheat is not sown before November 30 (Singh and Singh, 1995). There may be several reasons for delayed sowing, but using direct drilling systems can reduce most of those reasons. In addition Indian economy would gain around 1 800 million dollar in net present value over the next 30 years from the adoption of no-till in the rice-wheat areas of north-western India (Vincent and Quirke, 2002).
In heavy crop residue or when row spacing is narrow, Hoe, chisel, winged chisel, and inverted "T" type drills are prone to blockages between adjacent openers (Wilkins et al. 1983 andSlattery, 1998), causing operator frustration and reducing field capacity. They also tend to cause large clumps of residue to form (Slattery and Riley, 1996), which cover the crop row and choke out young seedlings. Another problem with these types used in drills is that the furrow opening shank disturbs the soil with sufficient force that the uncontrolled soil is thrown out of the seed furrow and occasionally onto the adjacent seed row. This adversely affects seeding depth uniformity, which is important for optimum seedling emergence and maximum yield of many crops, including cereals (Morrison and Gerik, 1985).
Equipment modifications to overcome these problems have included mounting a residue cutting coulter ahead of each furrow opener, increasing the spacing between openers by either increasing row spacing and/or adding ranks of toolbars to improve residue flow, utilizing row cleaning devices to move residue away from the furrow, and adding rolling shields next to each furrow opener to reduce soil throw. But many drawbacks include being prone to damage in rocky soils and significantly increasing draft forces and therefore tractor power requirements, they also increase cluttering within the implement frame and therefore promote drill plugging when used in high residue densities.
An approach that has not been well explored is the use of powered devices to move the residue. One of existing power residue cutting system is a powered-disc ridge till with no-till planter, it was designed to solve the problems of straw blocking, high energy consumption of strip rototilling and unstable operation on ridges in current no-tillage maize planting in ridge tillage areas of northeast China. The machine used the combined device of powered-disc and depth control wheel to cut the stubble, open seed furrow and stabilize in planting, and the key parameters of the device were analyzed and determined. The powered-disc ridge till and no-till planter reduced fuel consumption by 8.5% and soil disturbance by 50%, respectively compared to the strip rototilling ridge till and no-till planter (Wang et al., 2008).
From above mentioned review, more studies are required to highlight the advantage of using power residue managers.

Theoretical considerations and concepts for the residue management equipment
The residue management equipment (RME) was developed on the basis of cutting and removing of paddy straw away from the no-till drill. In order to facilitate the movement of straw, two processes are needed one for cutting the residue and the other for removing them.
The significance of the residue cutting include reducing the length of loose straw and cutting stand stable which may be laying in front of no-till drill but still connected with the soil. Removing the residue is necessary to reduce the amount of residue clogged on furrow openers and make the line of sowing clear and clean from residue which affects no-till drill performance. The residue management device was power driven to overcome the problems found with using passive devices.
The design of cutting wheel is based on the idea that using star shape wheel (teeth) would essentially work as a narrow tool, but with a forward and rake angle (McKyes, 1985). During soil-wheel contact, the wheel will be provided with greater momentum than that obtained with a smooth, waved, notched and ripple edged which commonly used to cut plant residues, beside reducing the amount of soil throw (Desbiolles, 2004). Besides, the wheel would penetrate the soil more easily and require less vertical force. The toothed wheel will cut the residues only if it penetrates the soil with little depth and rotates. This will happen only if there is enough vertical pressure from the wheel and a corresponding soil resistance to the draught force due to the action of the teeth. This can happen if we provide a power source to rotate the wheel with specific rotating speed and fixed position.
For adjust the suitable distance between two consecutive teeth, one tooth should touch the residue surface when the previous one penetrate the soil as shown in Figure 1 (Bianchini, 2002).     The fuel consumption varied from 10.88 to 11.60 l/ha for no-till drill with RME. In case of using no-till drill without RME fuel consumption varied from 7.82 to 8.10 l/ha as presented in Table 1.

Clogged Residue
The clogged residues are the amount of residue clogged (clumped residue) with the no-till drill or residue management device during sowing operation, this clogged residue is sticking to the wheels causing non-smooth rotations. Surface residue samples were collected before seeding from 1 m 2 area from the field.
The dry weight of residue was presented in terms of kg/ha. with RME compared to no-till drill without RME ( Figure   5). Statistical analysis showed that using no-till drill with the residue manager had significant effect on amount of clogged residue with standard deviation 96.08.

Cutting Standing Residue
Standing residues before seeding from 1 m 2 area from easily pass between furrow openers without being cut.
Statistical analysis showed that using no-till drill with the residue manager had significant effect on cutting standing residue with standard deviation 26.64.

Effective Tiller Count
The yield of the crop will be based on number of effective tillers/m length. The effective tiller count was measured at harvesting stage from three places of one meter row length in each plot.
Effective tiller count/m length varied from 92.73 to 93.08 and from 86.57 to 87.16 for no-till with RME and no-till without RME respectively ( Table 1). The average number of effective tiller was higher in case of no-till drill with RME. Analysis of variance showed that different sowing machines had significant effect on no. of effective tiller per meter length with standard deviation 3.36 (Table 1).  (Table 2). Using no-till drill with residue management device increased the yield by 12.4% Table 2 Effect of various treatments on grain yield more than using no-till drill without RME. Analysis of variance as presented in Table 3 showed that using no-till drill with the residue manager had significant effect on grain yield with standard deviation 337.20.

Conclusion
Adding the power driven residue manager as an attatchment for no-till drillls can increase their ability for working under diffucult field conditions. Using this unit under above mentioned expremints decreased the amount of residue clogged by 33%, which make sowing wheat in this condition more easly and reduce interface occured to the no-till drills. Using the residue manager with no-till drill also increased number of cut hill by 76.6%, which increase the possibility for uniform sowing in combine harvested rice fields. Effective tiller count, Spike length and plant height were high in case of using no-till drill with the residue manager , which increased the grain yield by 12.4% more than using no-till drill without this attachment. Allthough, using this attachment will increase fuel consumption and power reuired for sowing wheat, but it has many features related to crop response and yield, which will be more economically and has many benifites for farmers.