Quality of field work
Quality of field work — the degree to which the quality parameters and timing of actual performance of individual operations conform to the requirements of standards or agrotechnical requirements. The quality of field work determines crop yield. The quality of field work depends on the technical condition of tillage and sowing units, correct adjustment, the quality of preceding treatments, soil conditions, the timing of operations, and other conditions.
Violation of agrotechnical requirements for soil tillage leads to:
- worsening of conditions for the growth and development of cultivated plants;
- reduced yield;
- decreased fertilizer efficiency and chemical plant protection products;
- reduced efficiency of reclamation;
- possible development of soil erosion;
- reduced fertility.
Therefore, constant monitoring of the quality of field work must be organized, in particular monitoring of the quality of individual tillage operations.
The quality of performing an individual operation of tillage, sowing, and others is determined by a set of indicators characterizing the suitability of the soil for optimal plant growth and for carrying out subsequent technological operations. Evaluation can be performed using a three- or five-point system. Each operation is evaluated separately, and the total score determines the overall quality of field work. In production conditions, work is rated good when it is performed within the established time and in compliance with all agrotechnical requirements. Work is considered satisfactory when it is performed on time and in compliance with the main agrotechnical requirements, but individual quality indicators may slightly exceed permissible deviations without significantly affecting yield. Work is rated poor when it is performed with a gross violation of deadlines or agrotechnical rules, causing a significant reduction in yield. In this case, the work is rejected and redone.
Evaluation of work quality can be carried out during the operations, which makes it possible to identify and eliminate deficiencies in advance.
Evaluation of soil tillage quality
Stubble cultivation
The main indicators for evaluating the quality of stubble cultivation include:
- timing of the work;
- loosening depth and its uniformity;
- degree of cutting of weeds and cutting of rhizomes of perennial weeds;
- soil ridging;
- crumbling of the treated layer;
- absence of skips and untreated strips.
Additionally, observance of straightness of movement and the depth of the open furrow at the junction of the middle gangs are taken into account; it should not exceed the specified stubble cultivation depth.
The permissible deviation of loosening depth from the specified value is no more than 10%. Loosening depth is measured at the beginning of the unit’s operation and during performance. It is recommended to make at least 25 measurements on an area equal to the shift assignment of the unit and to calculate the average stubble cultivation depth. Depth is determined with a ruler or a graduated metal rod as the distance from the surface of untreated soil to the bottom of the furrow. When measuring the depth of a stubbled field, the obtained average value must be reduced by a loosening coefficient of 10–15%. The loosening coefficient is the ratio of the average depth of the loosened layer to the average stubble cultivation depth.
The degree of weed cutting is determined by counting the number of uncut plants on a 1 m2 plot. Accounting plots are established along the diagonal of the field at the rate of one plot per 10 ha of field area.
The presence of skips and untreated strips is determined visually when inspecting the field.
Plowing
The quality of plowing depends on the condition of the field during treatment, its size, configuration, soil moisture, technical condition of the unit, and other conditions. Before plowing, the field must be cleared of straw, stones, and coarse plant residues; if necessary, the field must be leveled. The best quality of loosening and crumbling is achieved when treating soil in a state of physical ripeness; treating dry soil leads to severe cloddiness and requires high energy costs.
Soils differing in technological properties must be treated with different plow working parts. For plowing cohesive soddy soils, plows with helical moldboards or front plows equipped with helical working surfaces are used. All types of plowing of old arable lands, except replowing of fallow and bare fallow and incorporation of organic fertilizers, are performed with plows having cylindroidal moldboards with skimmers. In areas of insufficient moisture and on soils subject to wind erosion, plows with moldboardless bodies are used.
In production conditions, plowing quality is evaluated at the beginning of the work and during its performance.
The main indicators of plowing quality:
- plowing time;
- depth;
- uniformity;
- degree of soil crumbling;
- cloddiness;
- ridging;
- quality of the back-furrow ridge and open furrow;
- straightness of plowing;
- degree of incorporation of plant residues, fertilizers, and weeds;
- absence of untreated strips.
Table. Agrotechnical requirements for plowing.
| Evaluated indicator | Permissible deviation parameters |
|---|---|
| Deviation of average plowing depth from specified, % | ±10 |
| Uniformity of plowing depth, % | Not less than 90 |
| Soil crumbling (share of clods more than 5 cm in diameter), % | 10-15 |
| Height of back-furrow ridge, cm | 5-7 |
| Plowing depth under back-furrow ridge | Not less than half the specified plowing depth |
| Incorporation of plant residues, weeds, fertilizers | Complete |
| Straightness of plowing (deviation from straightness per 100 m of pass), cm | ±10 |
| Presence of untreated strips, wedges, and other defects | Not allowed |
Timeliness of plowing is determined by comparing the established agrotechnical deadline with the actual one. For example, in the central regions of the Non-Chernozem zone, plowing for winter cereals is carried out immediately after harvesting the predecessor within 5 days, no later than 2–3 weeks before sowing. Deviation from the established agrotechnical deadline leads to soil drying, excessive cloddiness, and weed infestation of the field.
A plow equipped with replaceable bodies with helical moldboards must turn the furrow slice by 140…180° at a plowing depth of 25 cm. Front and linear plows must ensure a full 180° turn of the slice.
The permissible deviation of plowing depth from the specified value is no more than 10%, and it must be uniform. An exception is made for the first two passes of the unit in the back-furrow section. According to other recommendations (Klenin, Khalansky), deviations are allowed on level areas of no more than 10–15%, and on uneven areas no more than 5–10%. The microrelief of the field surface is considered uneven if deviations exceed 15 cm. Plowing depth is measured with a furrow gauge or ruler by measuring the distance from the surface of untreated soil to the bottom of the furrow. For evaluation, 25 measurements are made along several plow passes along the diagonal of the field. The deviation of the actual plow working width from the design width should be no more than ±10%.
When plowing, care is taken to ensure that the width and thickness of the slices are the same.
Open furrows and back-furrow ridges must be straight and barely noticeable. The deviation from straightness should not exceed ±10 cm per 100 m of pass. The plowing depth under the back-furrow ridge must be not less than half the specified depth. Open furrows at the end of plowing are filled in.
Soil crumbling is determined as the ratio of the mass of clod fractions less than 5 cm in size to the total mass of the soil sample, expressed as a percentage. The size of the taken sample is 40×30×30 cm. The quality of slice crumbling is judged by cloddiness (G), that is, the share of clods more than 5 cm in diameter (100−G). Crumbling of the slice when plowing old arable soils with general-purpose plows should be not less than 75% (content of the fraction up to 5 cm).
Cloddiness is determined with a frame of 1 m2 divided into squares of 1 cm2. 8–10 placements are made along the diagonal of the plot. Clods more than 5 cm in diameter falling within the frame are measured by length and width, and their area is determined. Cloddiness is evaluated as the ratio of the total area of clods to the area of the frame, in percent. Cloddiness occupied by clods more than 10 cm in size is allowed to be no more than 15% of the arable area.
Movement of the unit when filling open furrows.
Continuity and ridging of plowing characterize the uniformity of the height of all ridges and the surface of the plowed field without hollows and elevations, and the absence of steps in individual passes of the unit. It is determined with a profilometer or a 10-meter measuring cord, placing it across the ridges so that it follows the field surface. The ratio of the elongation of the cord to its projection shows the ridging coefficient. Ridging during fall plowing under moist conditions and on sloping lands is positive. When plowing in arid regions, for winter crops, and for main plowing, ridges, on the contrary, are leveled. The height of ridges should not exceed 5 cm for plows with cylindroidal bodies, 10 cm for helical bodies, and 4 cm for front and linear plows.
With moldboard plowing, all weeds, crop residues and plant residues, fertilizers, and sod must be buried. At a plowing depth of 22–30 cm, the plant mass should be incorporated to a depth of 10–15 cm by traditional plows and to 12–15 cm by front and linear plows. The incorporation depth is determined using a soil cross-section 40 cm wide (or the plow working width) across the ridges to the plowing depth.
Moldboardless plowing should ensure preservation on the field surface of 40–50% stubble and crop residues. Crumbling of soil into particles less than 1 mm is not allowed.
One of the walls of the cross-section is made vertical, and along it the upper and lower boundaries of the buried sod or plant residues are determined. From the obtained data, a cross-section profile is constructed indicating the location of the incorporated sod.
In production conditions, the quality of incorporation of plant residues is determined visually by estimating the amount of unincorporated stubble and sod per 100 m2 or 1 ha, which should be no more than 5%.
The plowing depth of field edges and headland strips must correspond to the plowing depth of the main area. Skips between adjacent passes of the unit, unplowed wedges, and plowing along the slope, except for waterlogged lands, are not allowed.
Flat-cutting tillage
The quality of flat-cutting tillage is evaluated by the following indicators:
- timing;
- treatment depth;
- uniformity;
- degree of soil crumbling;
- preservation of stubble on the field surface;
- observance of overlaps in adjacent passes of the unit;
- surface ridging;
- straightness of treatment.
Table. Agrotechnical requirements for flat-cutting tillage.
| Indicator | Loosening depth, cm | |
|---|---|---|
| 8-16 | 25-27 | |
| Deviation of average treatment depth from specified, % | ±10 | ±10 |
| Soil crumbling (share of clods 3-5 cm in diameter for shallow treatment and 3-10 cm for deep treatment), % | 80 | 80 |
| Degree of stubble preservation (per one sweep pass), % | 85-90 | 70-80 |
| Height of ridges formed by loosener tines, cm | 6 | 5 |
| Width of furrows formed by loosener tines, cm | 15 | 15 |
| Weed cutting | Complete | Complete |
| Overlap of adjacent passes of the unit, cm | 10 | 10 |
Timeliness of the work, selection of implements, and depth of flat-cutting tillage are determined taking into account zonal features, soil type and moisture, biological characteristics of the crop, risk of erosion, and organizational and production conditions.
Soil loosening is carried out at optimal times: shallow loosening with sweep cultivators such as KPSH-9 and KPSH-11 to a depth of 8–16 cm, and deep loosening with deep-loosening sweeps, for example KPG-2-150, KPG-250, PG-3-100, to 25–27 cm. The share of clods characterizing the degree of loosening, 3–5 cm for shallow treatment and 3–10 cm for deep treatment, should constitute the predominant part of the treated layer at optimal soil moisture.
The treatment depth must correspond to the specified depth and be uniform. The permissible deviation of the average treatment depth from the specified value should not exceed ±1–2 cm for shallow treatment and no more than ±2–3 cm for deep treatment. The treatment depth is determined across the entire working width of the unit with a graduated metal rod. Measurements are made no closer than 30 cm from the trace of the sweep tine pass. For an objective evaluation, 25–30 measurements are made along the diagonal of the field, on an area equal to the shift assignment, usually 10 ha.
The degree of stubble preservation on the surface should be 85–90% for shallow treatment and not less than 80–85% for deep treatment. To account for undamaged stubble on the soil surface, a plot 10 m long and as wide as the working width of the unit is marked out, on which the width of all furrows left by each working part of the sweep is measured. All measurements are summed up and the width of the sweep tine traces is determined, expressed as a percentage of the total length (10 m).
For example, on a plot 10 m long, the total width of damaged stubble strips is 1.5 m; then the degree of stubble preservation is:
The roots of weeds during flat-cutting tillage must be cut at the depth of travel of the working parts, and the treated surface must be leveled. Ridges at the junction of passes of loosening tines should be no higher than 5 cm, and the width of furrows at the places where tine shanks pass should be no more than 15 cm.
Gaps between adjacent passes of the unit, as well as skips and untreated strips and wedges, are not allowed. Headland strips are also treated to the specified depth.
Evaluation of pre-sowing tillage quality
Soil prepared for sowing (planting) must meet the following requirements: it must be fine-cloddy, well loosened to the depth of seed sowing, have a compacted seedbed, and be completely free of weeds.
Cloddiness, that is, the share of clods more than 3 cm in diameter, should be no more than 15–20% for moist regions and no more than 10% for arid regions. Clods with an area more than 10 cm2 in the sowing layer are not allowed.
The quality of pre-sowing soil preparation is usually evaluated as a whole, rather than by individual operations, immediately before sowing.
The quality indicators of pre-sowing treatment include:
- timing of performance;
- treatment depth;
- uniformity of treatment;
- cloddiness;
- soil crumbling;
- degree of weed cutting;
- absence of untreated headland strips and wedges.
Table. Agrotechnical requirements for pre-sowing tillage.
| Quality indicator of soil prepared for sowing | Permissible deviation parameters |
|---|---|
| Deviation of average treatment depth from specified, % | ±1 |
| Uniformity of soil treatment by depth, % | 90 and more |
| Cloddiness (share of clods more than 3 cm in diameter), % | For winter crops 15-20, for spring crops 5-10 |
| Height of ridges, cm | Not more than 4 |
| Soil surface | Leveled, fine-cloddy |
| Weed cutting | Complete |
| Presence of untreated strips, wedges, and other defects | Not allowed |
Pre-sowing treatment is carried out before sowing or on the day of sowing.
An important indicator of pre-sowing treatment is thorough loosening of the soil to the depth of seed placement and leveling of the surface. For this purpose, pre-sowing cultivations are used across or at an angle to the direction of plowing. Repeated treatments are carried out across the preceding ones for better crumbling and leveling; on sloping lands, across the slope or along the contour lines of the relief.
The depth of the loosened layer is determined with a metal ruler or a graduated rod. For an objective evaluation, 25–30 measurements are made along the diagonal of the field and the average value is calculated. Uniformity of depth is determined by the deviation of the average treatment depth from the specified value or by calculating the coefficient of field levelness.
Cloddiness and ridging are evaluated in the same way as for plowing.
The degree of weed cutting is determined by placing a frame of 1 m2 along the diagonal of the plot and counting uncut weeds. 10–15 counts are made per area; the presence of uncut plants is not allowed.
At the end of field treatment, headland strips and field edges are cultivated. Untreated areas, ridges, and depressions are not allowed.
The surface of a field treated by an erosion-control system must be wind-resistant with preservation of not less than 60% crop residues.
Evaluation of sowing quality
The indicators of sowing (planting) quality include:
- sowing time;
- seed sowing rate;
- established sowing depth;
- distance of butt row spacings;
- straightness of rows;
- absence of gaps.
Table. Agrotechnical requirements for sowing.
| Evaluated indicators | Permissible deviation parameters |
|---|---|
| Deviation of average sowing depth from specified, % | for cereals ±15 for small-seeded crops and grasses ±5 |
| Uniformity of seed placement depth, % | More than 90 |
| Deviation of seed sowing rate from specified, % | ±4 |
| Deviation of butt row spacing width, cm | for adjacent seeders ±2 for adjacent units ±4 |
| Straightness of rows (deviation from straightness per 100 m of pass), cm | ±10 |
Sowing (planting) must be carried out at times optimal for the crop, taking into account its biological characteristics. Early-sowing crops are sown when the soil temperature at the seed placement depth is 4–6 °C; late crops are sown at 10–12 °C.
Sowing must be performed uniformly, with the established sowing rate. Deviations of the sowing rate from the specified value must be no more than 4%. The uniformity of seed sowing by each sowing unit is determined by the number of seeds sown, for example, over a certain number of seeder wheel revolutions. Seeds must be uniformly distributed in the row at the specified depth in a compacted seedbed and covered with loose soil. The deviation of the average sowing depth for cereals should be no more than ±1 cm, and for small-seeded crops no more than ±0.05 cm. Seeds on the surface are not allowed.
Sowing depth is determined by opening 2–3 rows from the front and rear colters of seeders not following the tractor track. For this, the surface is first leveled and the distance from the soil surface to the sown seeds is measured. For an objective evaluation, at least 20 measurements are made along the diagonal of the field and over several seeder passes.
For a more precise determination of sowing depth, a cylinder with cutouts every 10 mm is used, into which gates are inserted. The cylinder is immersed into the row deeper than the seed sowing depth, removed, and the soil layers are separated by the gates every 10 mm. Seeds are separated from the soil on sieves and counted according to their depth.
The straightness of rows during sowing is evaluated visually or by measuring the distance from the row to a straight line. The deviation should be no more than ±10 cm per 100 m of pass, that is, the row should fit into a rectangle 100×0.2 m.
The permissible deviation of butt row spacings at adjacent seeders should be no more than ±2 cm, and the width of butt row spacings in two adjacent passes of the unit should not deviate from the established row spacing by more than ±5 cm.
Headland strips must be sown with the same sowing rate as the whole field. Gaps and overlaps are not allowed.
Evaluation of crop care work quality
The quality of inter-row cultivation is evaluated by the following indicators:
- treatment time;
- depth;
- uniformity;
- degree of soil crumbling;
- degree of weed cutting;
- absence of damage to cultivated plants.
The soil in the inter-row spaces must be treated to the required depth without damaging the root system of the crop, observing the protective zone in the rows.
The soil in the treated zone must be loosened, fine-cloddy, and leveled, except for crops requiring hilling. All weeds in the zone of passage of the cultivator working parts must be cut. Mineral fertilizers applied as top dressing must be incorporated into the soil at the established depth.
When hilling, moist soil must be earthed up to the plant stems. Damage to cultivated plants during treatments is not allowed. Quality control of care operations is carried out both at the beginning of the work and during its performance.
Productivity
The productivity of plowing and other units is the amount of work of specified quality performed by them over a time interval T. Productivity is divided into theoretical (calculated) and actual productivity.
Theoretical productivity W is calculated by the formula:
where
- B
- — design working width of the unit (plow), m;
- v
- — theoretical travel speed of the unit, km/h.
The actual productivity of the unit is always less than the theoretical one because of deviations of the working width B, actual travel speed vp, and net working time Tp from the calculated values.
The working width of the unit may differ from the design width because of incorrect connection of machines to the tractor, erroneous adjustment of working parts, inaccurate driving of the unit, overlap of the working width of individual machines included in the unit, poor technical condition, and malfunction of machines. The working speed of the unit differs from the theoretical one due to slipping of the running gear and poor technical condition of the tractor. The time during which the unit directly performs useful work (plowing, harrowing, etc.) differs from the calculated time, since part of the working time is spent on moves, turns, stops for adjustment, repair, cleaning and refilling of machines, and other organizational measures.
Therefore, actual productivity is determined taking into account the correction coefficient K by the formula
where
When organizing the work of units, efforts are made to ensure that actual productivity approaches theoretical productivity. For this purpose, the design working width is used to the maximum, work is performed at higher speeds, and shift time is used optimally; two- and three-shift work of units is also organized, especially during busy periods. Timely maintenance of machines, observance of the intervals for cleaning, lubrication, checking the condition of individual assemblies, working parts, transmissions, and their preventive adjustments is also of great importance.
To improve the maintenance of machines, group work of plowing units is used.
References
- Bazdyrev G. I., Loshakov V. G., Puponin A. I. et al. (2000). Agriculture. Textbook for universities. Moscow: Kolos Publishing House.
- Niklyaev V. S. (2000). Fundamentals of agricultural production technology. Agriculture and crop production. Moscow: Bylina.
- Klenin N. I., Kiselev S. N., Levshin A. G. (2008). Agricultural machines. Moscow: KolosS.
- Khalansky V. M., Gorbachev I. V. (2004). Agricultural machines. Moscow: KolosS.
