M. Kroulík

The impact of topography on soil properties and yield and the effects of weather conditions

Quantitative knowledge of the factors and interactions affecting yield is essential for site-specific crop management. One of the factors that frequently affects yield is topography. The aims of this study were to compare elevation data obtained from a combine harvester yield monitor and a hand RTK-GPS, and to evaluate the relationships between the spatial variation of cereal yield, selected crop nutrient concentration and topographic attributes derived from the two sources of elevation data. Simple models of elevation, slope and flow accumulation were created from the data of an experimental field in the Czech Republic, and the relations between yield and soil nitrogen and organic carbon contents and topography were determined over a four-year period. The models of elevation, slope and flow accumulation were compared with the yield, and soil nitrogen and organic carbon contents during the growing seasons of 2004, 2005, 2006 and 2007 in relation to total precipitation and temperature. The relationship between yield and topographic attributes was evaluated with the help of geostatistical methods. The results of correlation analysis among the variables were evaluated statistically by forward stepwise linear regression. No significant differences between elevation data from the combine harvester yield monitor and RTK-GPS were found. There was a significant relation between yield and crop nutrient concentration with topography. The correlation coefficients between flow accumulation and yield were weak for the wetter years and strong for the drier years.

Procedures of soil farming allowing reduction of compaction

Evaluation of new technologies using guidance systems is very important and can help producers with choosing the right equipment for their applications. Without using satellite navigation during field operations, there is a tendency for passes to overlap. That results in waste of fuel and pesticides, longer working times and also environmental damage. When utilising satellite guidance for field operations, there is a close connection with controlled traffic farming (CTF) as well. CTF is currently a quite quickly developing farming system based on fixed layout of machinery passes across a field. Tracks precisely set out for a machine’s tyres in the field could be a tool for minimising soil compaction risk which is another threat to the environment. The purpose of this paper was to evaluate the accuracy of currently available guidance systems for agricultural machines. Real pass-to-pass errors (omissions and overlaps) in a field were measured. Consequently, comparison between observed guidance systems was made regarding final working accuracy. Further, intensity of machinery passes, percentage of wheeled area and repeated passes in fields were monitored. These measurements were made in fields under real operating conditions using a conventional tillage system with ploughing and also a conservation tillage system, both systems with randomly organized traffic. Finally, the same parameters were monitored in fields where fixed machinery tracks were used for all operations and passes but only under a conservation tillage system. Pass-to-pass accuracy was measured for the evaluation of different guidance systems. Size of missed areas or overlaps was evaluated statistically. Concerning intensity of machinery passes and total field area affected by machinery passes, the following facts were found out. The experiments with randomized traffic showed a significant difference of the parameters mentioned above between a conventional tillage system with ploughing and a conservation tillage system. Wheeled area was 86 and 64%, respectively which proves benefits of conservation tillage. The experiments with a fixed track system showed that the total run-over area by machinery tyres decreased even more (up to 31%) in comparison to randomized traffic in a field (only fields under conservation tillage system were monitored and evaluated). The following statements based on our results can be made. The navigation and therefore possibility for better accuracy of machinery passes in fields together with permanent machinery tracks utilization could help with soil condition improvement and also energy savings which would result from that. The CTF system will help with further development of a system for soil compaction protection which is currently a real necessity.

Spatial Variability and Pattern of Selected Properties of Agricultural Soils in the Czech Republic Measured by Indirect Proximal and Remote Sensing

Spatial and temporal variabilities of soil properties were monitored within a 12-ha field over several consecutive years. Particle-size distribution, total carbon content (Ct), and pH were monitored. Soil samples were taken from points on a regular square grid. Additionally, the variability of soil properties was evaluated by proximal measurement methods including draft force measurements, soil electrical conductivity (ECa), and crop yield mapping. Remotely sensed bare-soil satellite images were obtained and digital elevation models were made. All the observed variables showed spatial variability, but the spatial patterns of Ct, pH, EC, and crop yield were temporally stable. Results were processed using statistical and geostatistical methods. Variograms and their parameters were used to describe spatial dependencies between observed variables. Significant dependencies were observed between monitored soil properties and indirect methods, indicating utility in the proximal approach.

Effect of row width on splash erosion and throughfall in silage maize crops

Brant V., Zábranský P., Škeříková M., Pivec J., Kroulík M., Procházka L. (2017): Effect of row width on splash erosion and throughfall in silage maize crops. Soil & Water Res., 12: 39−50. Line width is one of the major factors affecting arable soil erosion. The aim of the study was to assess the effects of different row spacing on splash erosion and throughfall in maize crops. Field measurements of the throughfall (Pth, mm) and splash erosion (MSR, g/m 2) were carried out in silage maize crops (row spacing 0.45 and 0.75 m) in 2012–2014. The BBCH growth stages for the crops, plant length (L, m), and leaf area index (LAI) were evaluated. Positive correlation was observed between the aerial precipitation (P, mm) and the Pth values. With increasing P-values, higher levels of Pth were identified in the 0.75 m compared to the 0.45 m row spacing. The value of this proportion was decreasing from the centre of the inter-row (0.75 m) to the row of the plants direction. Statistically significant lower values of splash erosion were observed in the 0.45 m compared with the 0.75 m wide rows, especially within the years 2012 and 2014. The experiments proved the positive influence of the length of plants and LAI on P/Pth values. A decrease of Pth in relation to precipitation values with height of plants and LAI values was observed. This dependency was then confirmed from the beginning of the stem elongation (BBCH 30) to the end of flowering (BBCH 70). Tighter dependency between the plant length (L) and the values of P/Pth ratio in the 0.75 m wide crop rows was determined. Conversely, a more important influence of LAI on the values of P/Pth ratio was estimated in the 0.45 m wide crop rows. The experiments proved the positive influence of the 0.45 m wide rows on the decrease of splash erosion as well as throughfall compared with the 0.75 m row spacing.

Splash erosion in maize crops under conservation management in combination with shallow strip-tillage before sowing

Brant V., Kroulík M., Pivec J., Zábranský P., Hakl J., Holec J., Kvíz Z., Procházka L. (2017): Splash erosion in maize crops under conservation management in combination with shallow strip-tillage before sowing. Soil & Water Res., 12: 106−116. Soil under maize cropping is among the most endangered by erosion. The effect of conservation tillage management on values of splash erosion when using shallow strip tillage before sowing maize was evaluated in the Central Bohemian region (Czech Republic) during the period 2010–2012. The following types of tillage management using conventional technology and shallow tillage were evaluated: ploughed plots with mulch formed by weed biomass (PLW), ploughed plots with mulch from perennial ryegrass plants (PLPR), ploughed plots without mulch (PL) and shallow tillage (ST) where the mulch was formed by cereals straw. Furthermore, values of the splash erosion, plants and plant residues coverage ratio of soil by image analysis and the stability of soil aggregates were monitored during the whole experiment. The average value of splash erosion (MSR) was higher by 18.7% in the variant of PLW, lower by 35.9% in PLPR, and lower by 39.5% in ST, than in the control treatment PL (MSR value for PL = 100%) for the whole evaluated period (2010–2012). The average values of the soil surface plant coverage ratio in the plots with mulch ranged from 1.5 to 43.0% at the beginning of the vegetation period, and from 4.9 to 85.5% in the second half of the vegetation period. A positive correlation was observed between the average values of the stability of soil aggregates and the plant coverage ratio of the soil surface in 2010 and 2011.

Pneumatic conveying characteristics of seeds in a vertical ascending airstream

Kroulík M., Hůla J., Rybka A., Honzík I. (2016): Pneumatic conveying characteristics of seeds in a vertical ascending airstream. Res. Agr. Eng., 62: 56–63. Pneumatic conveying characteristics were measured in vertical tubes for seeds of selected varieties of cereals, wide-row crops, oil crops, legumes and catch crops. The measured values were used for graphical representation of variation curves for the chosen groups of seeds. The values of the critical air velocity for seeds (velocity of seed lift) were computed. Statistical significance of differences in the mean values of critical velocities of tested seeds was determined. The critical velocity of cereal seeds ranged from 8.03 to 10.54 m/s. Among the crops grown in wide rows the highest critical velocity of seeds was found out in maize (13.29 m/s), the lowest in sunflower seeds (8.38 m/s). In oil crop seeds, the lowest critical velocity was recorded in poppy (4.67 m/s), which was the lowest value of all seed samples of the tested crops. The highest value of the critical velocity was measured in pea seeds (14.85 m/s).

SOIL CHARACTERISTICS IN THE SYSTEM WITH PERMANENT TRAFFIC LANES AFTER TWO YEARS OF ITS BEGINNING

In a field experiment on a plot of 10 ha in sugar beet production area physical soil properties and the soils ability to absorb water from rainfall were evaluated thereafter two years since the system of controlled crossings had been applied. Soil conditions: calcaric Leptosols soil type, loamy soil, slope of 2.0 to 4.2 degrees. Therefore the benefits of controlled crossings system to protect the soil from excessive compaction have been confirmed. Concentration of wheel tracks into permanent lines improved conditions for the movement of machinery on the field. Bearing capacity of soil increased in the areas of wheel tracks – penetration resistance of the surface soil layer in summer was 2.7 to 4.4 times higher in the parts of wheel tracks than in areas outside of tracks. In the parts of the area with random traffic penetration resistance was measured 1.9 times higher than in the parts without wheel tracks. Concentration of wheel tracks also contributed to improve the quality of soil tillage – the area without wheel tracks accounted for 68% of the land area when the working width of 6 m module was used. When measuring surface water runoff by rain simulator the water runoff occurred at 10.0 minutes, respectively at 11.6 minutes in the parts with wheel tracks, while in areas without wheel tracks the surface water runoff occurred after 29.6 minutes and the rate of water runoff was significantly lower in the parts without traffic than in the wheel tracks. Concentration of wheel tracks into permanent traffic lines may be one of the ways to increase the soil ability to absorb water during intense rainfall. Keywords: controlled traffic farming, soil physical properties, surface water runoff. Article DOI: http://doi.org/10.15544/RD.2015.006

Evaluation Of Soil Physical Properties In System With Permanent Traffic Lanes Practised In 10 Ha Field

Abstract The paper deals with basic soil physical properties as affected by wheel traffic. Agricultural land is, in varying degrees, exposed to the pressures exerted by running parts of tractors, harvesting machinery and transport equipment. Damaging the soil by compaction increases the energy efficiency, deteriorates the quality of tillage, may reduce crop yields and is associated with environmental risks that accompany water erosion. The selection of results from field trials demonstrates the positive effect of the reduction of level crossings on the results of physical and mechanical properties of the soil.

Parallel Plate Mass Flow Sensor for Forage Crops and Sugar Beet

Measurements described in this paper were realized in order to find out whether there is some relationship between mass flow of plant material passing through a parallel plate capacitive sensor and its output signal. This possibility of mass flow determination could be useful for the aim of forage crops or sugar beet yield maps creation. A parallel plate capacitive throughput sensor was designed for that purpose. The capacitive sensor and the whole oscillating circuit were driven at 27 MHz frequency. The laboratory set-up consisted of a conveyer belt, carrying a measured quantity of material into sensor, equipped with an electronic measurement apparatus. Material passed through the sensor between its plates. Laboratory tests were carried out with forage crops and with sugar beet. Resulting coefficients of determination ranged from R2=0.95 to 0.97 for forage crops and around R2=0.98 for sugar beet. It was possible to conclude from our measurement that forage and sugar beet mass flow determination by means of the parallel plate capacitive sensor is a promising way. The results showed a strong linear relationship between the feed rates of plant material passing through the sensor and tested measuring capacitive sensor circuit output signal.