An effective adaptive strategy for reducing climate change risks and increasing agro-system resiliency is broadening cropping system diversity, heightening the flexibility of cultivation and tillage methods. Climate change impacts on standard cultivation practices such as mineralisation and nitrate leaching due to mild and rainy winters, as well as frequent drought or water saturation, not only limiting fieldwork days, but also restricting ploughing. This calls for alternative methods to counteract these propensities. From 2010 to 2013, a farming system experiment was conducted on a distinctly heterogeneous organic farm in Brandenburg, Germany. With the intention of devising a more varied and flexible winter wheat cultivation method, standard organic farming practices (winter wheat cultivation after two years of alfalfa-clover-grass and ploughing in mid-October) were compared to four alternative test methods, which were then evaluated for their robustness and suitability as adaptive strategies. Two of the alternative methods, early sowing and catch crop, entailed moving up the date for alfalfa-clover-grass tilling to July. Instead of a plough, a ring-cutter was used to shallowly (8 cm) cut through and mix the topsoil. In the early sowing test method, winter wheat was sown at the end of August, after repeated ring-cutter processing. With the catch crop method, winter wheat seeding followed a summer catch crop and October tillage. The two oat methods (oat/plough; oat/ring-cutter) entailed sowing winter wheat in September, following oat cultivation. Overall, the cultivation methods demonstrated the following robustness gradation: standard practice = catch crop ≥ early sowing > oat/plough > oat/ring-cutter. When compared to standard procedures, the catch crop and early sowing test methods showed no remarkable difference in grain yields. Measured against early sowing, the catch crop test method was significantly more robust when it came to winterkill, quality loss, and weed infestation (40% lower weed-cover). High Nmin- values (up to 116 kg N ha-1) in autumn could have caused the chamomile and thistle infestation in both oat/ploughoat/ring-cutter test methods, which led to crop failure in the hollows. Compared to standard practices, the oat ring-cutter test method brought in over 50% less grain yield. This was attributed to ring-cutter processing, which reduced N mineralisation and caused high weed infestation. However, the ring-cutter effectively regulated alfalfa-clover-grass fields in both exceedingly wet and very dry weather; a temporal flexibility which increases the number of fieldwork days. The catch crop and early sowing test methods contributed most to boosting future agronomic diversity.
Farmers today face the challenge of adapting their crop cultivation methods to climatic changes. In the near future, farms with a high adaptive capacity will have a distinct advantage. The adaptive capacity of a farm is established first and foremost by expanding diversity and flexibility [
Winter wheat provides the economic foundation for the Wilmersdorf organic farm and has, thus far, been cultivated solely according to standard procedures. These standard organic farming procedures entail sowing winter wheat on fields prepared with a two-year multispecies legume-grass (LGS), which is mulched two to four times a year and ploughed under in autumn of the second harvest year. Directly following this virgin tillage (i.e. ploughing the sward without prior shallow soil processing), winter wheat is sown in mid-October. The subsequent crop is usually winter rye. This standard cultivation practice is practiced on large, rolling fields averaging 40 hectares, interspersed with
In view of these projected climate changes, the current standard cultivation practice reveals several weaknesses:
LGS virgin tilling in mid-October, followed by a mild and rainy winter, may lead to N-mineralisation, nitrate leaching and erosion, as the low development of winter wheat mass is unable to take up sufficient nitrogen at this time [
These issues are compounded by the influence dry periods and increased precipitation in late autumn and winter has on the
Since LGS processes great quantities of water via transpiration, increasing temperatures can potentially lead to a water shortage in the soil, inhibiting subsequent crop growth [
The extent of climate risks can be offset by increasing diversification within an agricultural ecosystem. This means not only introducing a greater diversity in crops and varieties, but also more flexibility in cultivation and tillage methods [
This work is therefore dedicated to the following questions:
In collaboration, the Wilmersdorf farm manager and the INKA BB field trial project a) developed new cultivation techniques and, b) tested the viability of these methods as alternatives to standard procedures. When evaluating various courses of action, i.e. cultivation methods, for their adaptability to uncertain climate change conditions,
A new agricultural tool, the ring-cutter, was used for the first time during the field tests in Brandenburg. This agricultural instrument has cutting rings running diagonally to the driving direction, allowing for an overall, non-turning, shallow tillage (see:http://www.heko-landmaschinen.de). The special ring-cutter construction is intended for soil processing when dryness or sogginess renders ploughing unsuitable. As opposed to the plough, the ring-cutter could be applied to both the dry hilltops and damp hollows on Wilmersdorf farm. The tool should also enable unploughed LGS processing, so that grain mulch seeding (
In the cultivation methods
In contrast to
In the
[-3]To keep future seeding on schedule despite higher winter precipitation (see Figure
The robustness of each cultivation method is tested based on the following hypotheses:
The ring-cutter effectively cuts and regulates LGS in both damp and dry soil conditions, where ploughing is restricted.
Compared to the standard practice, winter wheat test methods ploughed in autumn,
The unploughed winter wheat test methods
The stockless organic farm Wilmersdorf (Bioland growers’ association member) is located in the north German lowlands in the northeast of Brandenburg (Uckermark; community Angermünde, district of Wilmersdorf: 53.11431
Wilmersdorf, located in the upper moraine region, is dominated by a hilly to undulating landscape of hills and hollows (40 to 75 meters above sea level) [
The Wilmersdorf climate is characterised by low annual rainfall and frequent dry periods in early summer and autumn. With 517 mm annual rainfall and an average annual temperature of 8.8
In 2010, high precipitation in summer (August: 117 mm; annual rainfall: 640 mm), made most fields impassable during both harvest and autumn sowing. 2011 was marked by a very warm and dry April and heavy rains in July (203 mm). Annual rainfall was 693 mm. Winter 2012 brought black frost and a succession of frost/thaw cycles, leading to considerable winterkill. The
The field trial was designed as a three-year serial experiment. Complying with crop rotation, the experiments were carried out on a different field each year. Two homogeneous fields (one hilltop, one hollow) were selected on each of these fields by interfacing digital plot, soil and yield maps. The trial cultivation systems were set upon the two sites in fully randomised blocks. Each block contained four plots divided into five sub-plots (20 sub-plots per site/40 sub-plots total). Except for reaping, the 15 m long by 5 m wide plots were worked with the customary
combine harvester. The individual steps, deadlines and applied techniques are listed in Table
Trial No. | Plot No. | pH |
C |
CaCO |
Gravel % | Sand % | Silt % | Clay% | Field Cap.% Vol. |
Texture class* |
5 | 401-405 | 7.07 | 2.27 | 4.2 | 60.2 | 29.6 | 10.2 | 18.8 | SaL | |
406-410 | 6.91 | 2.54 | 2.3 | 60.3 | 28.3 | 11.4 | 19.6 | |||
411-415 | 6.95 | 2.5 | 5.7 | 60.7 | 27.9 | 11.4 | 19.6 | |||
416-420 | 6.99 | 2.89 | 4 | 56.9 | 29.7 | 13.4 | 21.7 | |||
6 | 421-425 | 7.43 | 3 | 3.9 | 52.1 | 28.2 | 19.7 | 26.2 | SaL | |
426-430 | 7.4 | 2.82 | 3.51 | 4 | 57.6 | 28 | 14.4 | 22.4 | ||
431-435 | 7.13 | 2.71 | 1.3 | 59.9 | 28 | 12.1 | 20.3 | |||
436-440 | 7.5 | 3.51 | 2.16 | 1.4 | 52.8 | 26.9 | 20.3 | 26.6 | ||
245 | 481-485 | 6.72 | 2.64 | 3.3 | 55.9 | 33.8 | 10.3 | 20.9 | SaL | |
486-490 | 7.03 | 2.97 | 1.6 | 54.3 | 33.8 | 11.9 | 22.1 | |||
491-495 | 6.01 | 2.39 | 1.6 | 58.7 | 27.5 | 13.8 | 21.2 | |||
496-500 | 6.69 | 2.84 | 1.5 | 57 | 31.6 | 11.4 | 20.7 | |||
246 | 501-505 | 7.49 | 2.89 | 7.41 | 1.9 | 53.6 | 31.8 | 14.6 | 23.6 | SaL |
506-510 | 7.56 | 3.14 | 4.86 | 2.7 | 51.8 | 30.8 | 17.4 | 24.6 | ||
511-515 | 7.73 | 2.65 | 6.97 | 3.1 | 55.2 | 31.6 | 13.2 | 21.8 | ||
516-520 | 7.59 | 2.69 | 7.92 | 4.3 | 54.6 | 29.9 | 15.5 | 22.9 | ||
253 | 5101-5105 | 7.32 | 2.39 | 2.5 | 64.9 | 23.9 | 11.2 | 18.7 | SaL | |
5106-5110 | 7.44 | 2.83 | 2.7 | 56.8 | 30.5 | 12.7 | 21.5 | |||
5111-5115 | 7 | 3.07 | 1.7 | 58 | 29.9 | 12.1 | 21.7 | |||
5116-5120 | 7.38 | 3.23 | 1.7 | 55 | 29.1 | 15.9 | 22.1 | |||
254 | 5121-5125 | 7.5 | 3.24 | 4.11 | 2.7 | 56.8 | 29.2 | 14 | 22.4 | SaL |
5126-5130 | 7.64 | 2.86 | 7.35 | 2.5 | 52.5 | 33.4 | 14.1 | 23.2 | ||
5131-5135 | 7.62 | 2.27 | 9.19 | 3.7 | 56.1 | 29.5 | 14.4 | 21.6 | ||
5136-5140 | 7.57 | 2.8 | 4.73 | 2.2 | 60.2 | 26.6 | 13.2 | 21 | ||
* estimated with the soli texture triangel USDA; |
Year | 2010 | 2011 | 2012 | ||||||||||||
Variant | Sp | ESr | CCp | Op | Or | Sp | ESr | CCp | Op | Or | Sp | ESr | CCp | Op | Or |
Ploughing* | 04-04 | 28-03 | 26-03 | ||||||||||||
Ring-cutter+ | 30-03 | 24-03 | 23-03 | ||||||||||||
04-04 | 28-03 | 26-03 | |||||||||||||
Oat sowing+ | 05-04 | 29-03 | 05-04 | ||||||||||||
Oat harvest |
06-08 | 04-08 | 20-08 | ||||||||||||
Mulching LGS-Mixture |
31-05 | 31-05 | 31-05 | 15-06 | 15-06 | 15-06 | 24-05 | 24-05 | 24-05 | ||||||
09-07 | 09-07 | 09-07 | 22-07 | 22-07 | 22-07 | 06-07 | 06-07 | 06-07 | |||||||
09-08 | 23-08 | ||||||||||||||
14-10 | |||||||||||||||
Ring-cutter+ | 13-07 | 13-07 | 12-08 | 30-03 | 26-07 | 26-07 | 17-08 | 17-08 | 09-07 | 09-07 | 23-08 | 23-03 | |||
16-07 | 16-07 | 17-09 | 04-04 | 28-07 | 28-07 | 29-08 | 29-08 | 12-07 | 12-07 | 17-09 | 26-03 | ||||
19-07 | 19-07 | 12-08 | 17-08 | 24-09 | 03-08 | 23-08 | |||||||||
12-08 | 17-09 | 29-08 | 23-08 | 17-09 | |||||||||||
02-10 | |||||||||||||||
Catch crop sowing |
22-07 | 02-08 | 16-07 | ||||||||||||
Ploughing* | 19-10 | 19-10 | 20-09 | 24-10 | 24-10 | 24-09 | 16-10 | 16-10 | 02-10 | ||||||
Winter wheat sowing |
19-10 | 26-08 | 19-10 | 22-09 | 22-09 | 25-10 | 31-08 | 25-10 | 27-09 | 27-09 | 18-10 | 23-08 | 18-10 | 18-10 | 18-10 |
Intercrop sowing |
26-08 | 31-08 | 23-08 | ||||||||||||
Year | 2011 | 2012 | 2013 | ||||||||||||
Winter wheat harvest | 04-08 | 20-08 | 01-08 | ||||||||||||
Winter rye sowing |
05-10 | 05-09 | 20-09 | ||||||||||||
Winter rye harvest | - | 01-08 | 24-07 | ||||||||||||
* Lemken Opal 90: Mounted reversible plough with four bodies (working depth 25 cm); | |||||||||||||||
+Ring-cutter (working width 3 m; working depth 6-8 cm); | |||||||||||||||
The yields of oat, winter wheat, and subsequent winter rye (2012 and 2013) were assessed by documenting the number of ears per square meter, the thousand kernel weight and the grain yield. The crude protein content in winter wheat, an indication of grain quality, was measured as well as the oat hectolitre weight. The development and structure of crops were determined by visually appraising cultivated plants, weeds and catch crop mixture coverage [
Biomass growth was compiled by taking manual cuts (0.5 m
In accordance with test method design, the same LGS seed mix was sown on all plots over all three years. Over all three years, no substantial differences in the quantity of biomass growth on hilltops and hollows could be discovered (Table
In 2010 and 2011 until mid-October, catch crop test plots achieved growth between 2.5 and 3.9 t DM ha
Site | Year | Test method | Cut 1 | Cut 2 | Cut 3 | CC |
Hollow | 2010 | SP | 4.1 | 3.3 | 2.2 | |
ESr | 4.7 | 4 | ||||
CCp | 4.5 | 3.3 | 3.7 | |||
HSD | 2.2 | 0.9 | ||||
p-value | 0.7179 | 0.0947 | ||||
2011 | SP | 5.7 | 5.3 | 4.1 | ||
ESr | 5.4 | 5.9 | ||||
CCp | 5.7 | 5.9 | 2.8 | |||
HSD | 1.3 | 1.4 | ||||
p-value | 0.7125 | 0.3542 | ||||
2012 | SP | 5 | 2.4 | 4.4 | ||
ESr | 4.8 | 2.5 | ||||
CCp | 5.1 | 2.7 | ||||
HSD | 1.4 | 1.1 | ||||
p-value | 0.8631 | 0.7744 | ||||
Hill | 2010 | SP | 4.7 |
4.3 | 2.5 | |
ESr | 4.7 |
3.5 | ||||
CCp | 5.8 |
4.6 | 3.9 | |||
HSD | 1 | 2.3 | ||||
p-value | 0.0318 | 0.3774 | ||||
2011 | SP | 4.9 | 4 | 3 | ||
ESr | 5.2 | 3.6 | ||||
CCp | 5.7 | 4.5 | 2.5 | |||
HSD | 2.1 | 3.3 | ||||
p-value | 0.571 | 0.6816 | ||||
2012 | SP | 4 | 1.7 |
2 | ||
ESr | 4 | 2.3 |
||||
CCp | 4.7 | 2.4 |
||||
HSD | 1.5 | 0.5 | ||||
p-value | 0.3866 | 0.0067 | ||||
HSD (honestly significant difference); | ||||||
Different letters indicate significant
differences ( |
Site | Year | Alfal. | WC | RC | Grass/herb. |
Hollow | 2010 | 9 | 66 | 25 | |
2011 | 49 | 4 | 47 | ||
2012 | 38 | 15 | 47 | ||
Hill | 2010 | 62 | 23 | 14 | |
2011 | 76 | 1 | 23 | ||
2012 | 63 | 5 | 1 | 32 |
In 2010 and 2012, oat yields were 21% and 54% higher in the
Site | Year | Test | Ears | tkw | Grain yield | Hectolitre |
method | (m |
(g) | (t ha |
weight (kg) | ||
Hollow | 2010 | Op | 270 | 36.2 | 5.1 |
45.8 |
Or | 211 | 35.8 | 2.9 |
45.9 | ||
HSD | 76 | 12 | 1.5 | 0.7 | ||
p-value | 0.0829 | 0.5128 | 0.0214 | 0.1001 | ||
2011 | Op | 307 | 47.3 | 5.3 | 51.5 | |
Or | 280 | 49.1 | 4.6 | 51.4 | ||
HSD | 41.7 | 4.2 | 2.4 | 2.1 | ||
p-value | 0.1266 | 0.2744 | 0.4132 | 0.8299 | ||
2012 | Op | 145 | 41.4 | 3.9 |
48.2 | |
Or | 178 | 39.9 | 1.8 |
48.1 | ||
HSD | 76 | 2.9 | 0.2 | 3.5 | ||
p-value | 0.2612 | 0.2177 | <.0001 | 0.9349 | ||
Hill | 2010 | Op | 243 |
36.2 | 4.2 |
43.9 |
Or | 181 |
36.1 | 3.3 |
45.2 | ||
HSD | 21.4 | 3.2 | 0.4 | 3.8 | ||
p-value | 0.0027 | 0.9624 | 0.0076 | 0.3451 | ||
2011 | Op | 285 | 46.1 | 3.6 | 49.5 | |
Or | 274 | 48 | 4.1 | 50.3 | ||
HSD | 73.8 | 6.2 | 1.6 | 0.9 | ||
p-value | 0.668 | 0.3883 | 0.3302 | 0.0657 | ||
2012 | Op | 209 | 41.2 | 4.2 | 47.8 | |
Or | 165 | 41.6 | 2.3 | 48.2 | ||
HSD | 61.8 | 2.3 | 2.3 | 1.6 | ||
p-value | 0.1082 | 0.6804 | 0.0882 | 0.4824 | ||
HSD (honestly significant difference); | ||||||
Different letters indicate significant
differences ( |
Among test methods, the winter wheat grain harvest varied considerably. This variance was most pronounced in the years with extreme weather conditions (2011 and 2012; see Section 2.3.).
In 2011 and 2012, winter wheat on the
In 2012 and 2013, winter rye was a subsequent crop to winter wheat, bringing in high grain yields, especially in the hollows. With the exception of the thousand kernel weight in the hollows in 2013 there was no discernible difference between the test methods (Table
Site | Year | Test | Ears | tkw | Grain yield | Crude |
method | (m2) | (g) | (t ha-1) | protein (%) | ||
Hollow | 2011 | SP | 256 | 41.9 | 4 | 13.6 |
ESr | 262 | 41.3 | 3.6 | 11.0 |
||
CCp | 243 | 43.7 | 3.8 | 12.4 |
||
Op | - | - | - | - | ||
Or | - | - | - | - | ||
HSD | 84.3 | 3.4 | 2 | 1.3 | ||
p-value | 0.7886 | 0.1727 | 0.807 | 0.0025 | ||
2012 | SP | 197 | 46.6 | 3.1 | 13.9 | |
ESr | * | * | * | * | ||
CCp | 189 | 47 | 2.9 | 13.9 | ||
Op | - | - | - | - | ||
Or | - | - | - | - | ||
HSD | 127.4 | 5.4 | 2.4 | 1.7 | ||
p-value | 0.8544 | 0.8314 | 0.7934 | 0.9942 | ||
2013 | SP | 166 | 43.9 |
2.8 |
13 | |
ESr | 185 | 48.2 |
2.8 |
12.6 | ||
CCp | 191 | 42.9 |
2.8 |
12.7 | ||
Op | 187 | 42.2 |
2.3 |
12.7 | ||
Or | 181 | 38.4 |
1.0 |
12.7 | ||
HSD | 74.1 | 3.3 | 0.8 | 1 | ||
p-value | 0.851 | <.0001 | <.0001 | 0.7514 | ||
Hill | 2011 | SP | 270 | 43.9 |
4.6 |
12.8 |
ESr | 237 | 41.1 |
3.5 |
10.3 |
||
CCp | 250 | 45.8 |
4.5 |
11.4 |
||
Op | 176 | 41.8 |
3.6 |
9.9 |
||
Or | 158 | 42.5 |
1.9 |
9.9 |
||
HSD | 157.3 | 2.9 | 2 | 1.5 | ||
p-value | 0.1647 | 0.0018 | 0.0078 | <.0001 | ||
2012 | SP | 170 |
42 | 2.6 |
13.6 |
|
ESr | * | * | * | * | ||
CCp | 153 |
40 | 2.5 |
13.7 |
||
Op | 93 |
40 | 1.3 |
12.6 |
||
Or | 85 |
44.7 | 1.2 |
11.6 |
||
HSD | 68.6 | 7.5 | 1.3 | 1.1 | ||
p-value | 0.0082 | 0.359 | 0.0172 | 0.0009 | ||
2013 | SP | 218 | 41.7 |
2.6 |
11.5 | |
ESr | 177 | 47.1 |
2.6 |
11.9 | ||
CCp | 188 | 42.6 |
2.9 |
11.7 | ||
Op | 234 | 40.5 |
2.2 |
11.6 | ||
Or | 171 | 37.5 |
1.2 |
11.4 | ||
HSD | 87 | 3.1 | 0.4 | 0.8 | ||
p-value | 0.1562 | <.0001 | <.0001 | 0.3644 | ||
Different letters indicate significant differences ( |
||||||
*Winterkill damage; HSD (honestly significant difference); |
Site | Year | Test | Ears | tkw | Grain |
method | (m |
(g) | yield (t ha |
||
Hollow | 2012 | SP | 400 | 34.1 | 6.2 |
ESr | 403 | 33.4 | 6 | ||
CCp | 351 | 35 | 6.4 | ||
Op | 370 | 33.9 | 5.9 | ||
Or | 426 | 35.3 | 6.2 | ||
HSD | 111.3 | 2.6 | 2.2 | ||
p-value | 0.2842 | 0.2873 | 0.9548 | ||
2013 | SP | 438 | 31.9 |
4.9 | |
ESr | 438* | 34.1* |
6.0* | ||
CCp | 485 | 32.2 |
5 | ||
Op | 476 | 32.3 |
6.3 | ||
Or | 430 | 35.4 |
5.3 | ||
HSD | 152.2 | 2.3 | 2.4 | ||
p-value | 0.6883 | 0.0015 | 0.2964 | ||
Hill | 2012 | SP | 294 | 35.4 | 5.2 |
ESr | 357 | 33.4 | 5.1 | ||
CCp | 306 | 34.7 | 4.8 | ||
Op | 244 | 34.9 | 4.1 | ||
Or | 278 | 35.1 | 4.6 | ||
HSD | 124.9 | 3.2 | 2.2 | ||
p-value | 0.1238 | 0.3836 | 0.5357 | ||
2013 | SP | 244 | 35 | 3.7 | |
ESr | 223* | 37.3* | 2.9* | ||
CCp | 269 | 36.8 | 4.2 | ||
Op | 221 | 36.2 | 2.5 | ||
Or | 269 | 34.7 | 3.3 | ||
HSD | 180.37 | 5.3 | 5 | ||
p-value | 0.8397 | 0.6058 | 0.8433 | ||
*Preceding crop summer wheat; | |||||
HSD (honestly significant difference); | |||||
Different letters indicate significant differences ( |
The N-dynamic in cultivation methods was estimated based on the LGS N-input, N-up-take in the grains and N
In late summer 2010 (Table
In the autumn of 2011 and 2012,
Site | Year | Test | Input | Uptake | Uptake | Uptake | Balance |
method | LGS | Oat | WW | WR | |||
Hollow | 2010–2012 | SP | 259 | 83.8 | 83.7 | 0.32 | |
ESr | 191 | 59.5 | 78.2 | 0.31 | |||
CCp | 180 | 71.2 | 80.3 | 0.4 | |||
Op | 105.8 |
74.6 | |||||
Or | 56.2 |
76.2 | |||||
HSD | 43.7 | 43.5 | 26.5 | ||||
p-value | 0.0447 | 0.3031 | 0.8273 | ||||
2011–2013 | SP | 267 | 65.4 | 52 | 0.24 | ||
ESr | 184 | 66 | |||||
CCp | 211 | 60.3 | 54.4 | 0.29 | |||
Op | 100.4 | 66.6 | |||||
Or | 83 | 54.4 | |||||
HSD | 40.4 | 47.5 | 25 | ||||
p-value | 0.2642 | 0.7571 | 0.2373 | ||||
2012–2013 | SP | 206 | 55.4 |
0.27 | |||
ESr | 145 | 53.2 |
0.37 | ||||
CCp | 146 | 54.6 |
0.37 | ||||
Op | 73.2 a | 43.4 |
|||||
Or | 31.7 b | 18.8 |
|||||
HSD | 9.2 | 14.3 | |||||
p-value | 0.0007 | <.0001 | |||||
Hill | 2010–2012 | SP | 352 | 87.4 |
69.2 | 0.25 | |
ESr | 265 | 54.2 |
65 | 0.2 | |||
CCp | 278 | 77.8 |
60.2 | 0.28 | |||
Op | 79.0 |
53.8 |
49.5 | ||||
Or | 59.0 |
29.1 |
57.5 | ||||
HSD | 10.53 | 32.3 | 27.4 | ||||
p-value | 0.0091 | 0.0008 | 0.255 | ||||
2011–2013 | SP | 222 | 52.9 a | 47.9 | 0.24 | ||
ESr | 228 | 37.6 | |||||
CCp | 226 | 52.3 |
55.5 | 0.23 | |||
Op | 66.2 | 24.8 |
29.7 | ||||
Or | 78 | 20.6 |
38.5 | ||||
HSD | 32 | 25.7 | 64.2 | ||||
p-value | 0.3229 | 0.0047 | 0.7404 | ||||
2012–2013 | SP | 149 | 45.1 |
0.3 | |||
ESr | 156 | 46.0 |
0.29 | ||||
CCp | 145 | 51.3 |
0.35 | ||||
Op | 69.8 | 37.6 |
|||||
Or | 39.1 | 20.6 |
|||||
HSD | 43.4 | 7.4 | |||||
p-value | 0.1094 | <.0001 | |||||
Different letters indicate significant differences ( |
|||||||
HSD (honestly significant difference); |
N |
|||||||||
Date of sampling | Site | Sp | ESr | CCp | Op | Or |
|
HSD | p-value |
11-08-2010 | Hollow (2010) | 35.8 |
109.8 |
96.9 |
42.4 |
22.5 |
61.4 | 28.1 | <.0001 |
Hill (2010) | 34.6 |
89.5 |
73.5 |
43.0 |
20.0 |
52.1 | 32.9 | <.0001 | |
Different letters indicate significant differences ( |
N |
||||||||||
Date of sampling | Site | Sp | ESr | CCp | Op | Or |
|
HSD | p-value | |
05-04-2011 | Hollow (2010) | 79.7 |
36.7 |
48.6 |
25.0 |
22.2 |
42.4 | 22.4 | <.0001 | |
Hill (2010) | 48.7 |
16.9 |
36.0 |
15.4 |
15.6 |
26.5 | 15.4 | <.0001 | ||
01-11-2011 | Hollow (2011) | 66.9 |
73.9 |
77.5 |
115.6 |
90.3 |
84.8 | 39.5 | 0.0153 | |
Hill (2011) | 49.0 |
79.2 |
53.0 |
106.6 |
98.7 |
77.3 | 38.5 | 0.0262 | ||
24-04-2012 | Hollow (2011) | 99.5 |
* | 114.7 |
42.9 |
42.0 |
74.8 | 51.5 | 0.0003 | |
Hill (2011) | 101.8 |
* | 119.3 |
78.3 |
73.7 |
93.3 | 55 | 0.0258 | ||
22-10-2012 | Hollow (2012) | 46.4 |
61.1 |
33.7 |
77.4 |
54.1 |
54.5 | 22.8 | 0.0007 | |
Hill (2012) | 34.0 |
48.1 |
39.7 |
74.2 |
59.0 |
51 | 26.4 | 0.0029 | ||
06-03-2013 | Hollow (2012) | 76.1 |
38.8 |
47.3 |
38.6 |
34.0 |
46.9 | 21.7 | 0.0003 | |
Hill (2012) | 51.6 | 41.5 | 52.6 | 37.3 | 36.2 | 43.8 | 21.8 | 0.0897 | ||
*Winterkill damage; Different letters indicate significant differences ( |
N |
||||||||||
Date of sampling | Site | Sp | ESr | CCp | Op | Or |
|
HSD | p-value | |
08-11-2011 | Hollow (2010) | 120 | 94.5 | 84.0 | 125.7 | 148.5 | 114.5 | 111.5 | 0.4086 | |
Hill (2010) | 130.4 | 99.7 | 137.3 | 96.3 | 122.5 | 117.2 | 82.9 | 0.4461 | ||
22-10-2012 | Hollow (2011) | 97 | 70.6 | 87.3 | 50.3 | 66.2 | 74.2 | 64.5 | 0.2293 | |
Hill (2011) | 104.1 | 121.3 | 116.8 | 66.5 | 97.1 | 101.1 | 75.3 | 0.2184 | ||
02-08-2013 | Hollow (2012) | 41.1 | 35.3 | 40.5 | 38 | 33.4 | 37.6 | 12.3 | 0.2672 | |
Hill (2012) | 28.5 | 29.9 | 30.2 | 31.1 | 24.6 | 28.8 | 9.8 | 0.306 |
Weed distribution varied on the different sites and test method plots. In all experimental years, the weed population in oats and winter wheat was more pronounced in the hollows than on the hilltops.
On average, the standard practice and
The prior LGS crops generated weed flora—alfalfa (
The experimental cultivation methods were carried out from 2010 to 2013 and were at times subject to extreme weather conditions. Only 2013 came close to long-term averages and predicted climate changes, such as pre-summer drought (see Figure
The hypothesis that the ring-cutter can effectively kill and regulate LGS in both wet (spring) and dry (summer) soils was confirmed—LGS secondary growth coverage on unploughed oat and wheat plots was the same height as on ploughed plots. The tool’s cutting technique - a shallow, vertical undercutting of the upper topsoil - separates the alfalfa sprout shaft below the root crowns, effectively impeding regrowth. In contrast to the plough, ring-cutter tractive power requirements are low and operating speed (11 km h
Bearing all this in mind, it becomes clear that the results of reduced tillage are highly dependent on the time of ring-cutter processing, on crop rotation selection and on weather conditions, as confirmed by the completely unploughed
Weed coverage % | ||||||||||
Date | Site | Zadoks scale | Sp | ESr | CCp | Op | Or |
|
HSD | p-value |
27-04-2011 | Hollow (2010) | 30–37 | 11 |
71 |
16 |
71 |
94 |
53 | 29.7 | <.0001 |
Hill (2010) | 32–39 | 19 |
64 |
19 |
26 |
75 |
41 | 32.8 | 0.0002 | |
28-06-2011 | Hollow (2010) | 77–83 | 34 |
64 |
48 |
91 |
99 |
67 | 25.5 | <.0001 |
Hill (2010) | 77–83 | 29 | 50 | 34 | 24 | 50 | 37 | 49.1 | 0.3428 | |
03-05-2012 | Hollow (2011) | 30–34 | 51 |
* | 48 |
97 |
93 |
72 | 36.1 | <.0001 |
Hill (2011) | 30–34 | 12 |
* | 11 |
8 |
54 |
21 | 39.4 | 0.0036 | |
16-07-2012 | Hollow (2011) | 83–87 | 73 |
* | 71 |
95 |
90 |
83 | 21.5 | 0.0021 |
Hill (2011) | 83–87 | 49 | * | 40 | 45 | 43 | 44 | 42.1 | 0.5208 | |
23-04-2013 | Hollow (2012) | 29–31 | 12 |
73 |
6 |
8 |
34 |
26 | 15.9 | <.0001 |
Hill (2012) | 29–31 | 9 |
71 |
5 |
6 |
21 |
22 | 15.4 | <.0001 | |
24-05-2013 | Hollow (2012) | 41–49 | 31 |
68 |
38 |
36 |
59 |
46 | 24.5 | 0.0017 |
Hill (2012) | 41–49 | 20 |
66 |
17 |
10 |
33 |
29 | 21.3 | <.0001 | |
*Winterkill damage; Different letters indicate significant differences ( |
Weed DM t ha |
||||||
Date | Site | Op | Or | HSD | p-value | |
30-06-2010 | Hollow (2010) | 1.2 |
2.5 |
1.8 | 1.2 | 0.0491 |
Hill (2010) | 0.7 | 1.6 | 1.2 | 0.7 | 0.1373 | |
09-06-2011 | Hollow (2011) | 0.9 | 1.3 | 1.1 | 1.4 | 0.4211 |
Hill (2011) | 0.7 | 0.3 | 0.5 | 0.7 | 0.216 | |
12-06-2012 | Hollow (2012) | 1.8 | 2.2 | 2 | 0.7 | 0.2211 |
Hill (2012) | 0.8 | 1 | 0.9 | 1.2 | 0.4896 | |
Different letters indicate significant differences ( |
Sp | ESr | CCp | Op | Or | |||||||||||||||||
Ca | Ms | Ca | Ms | Ca | Ms | Ca | Ms | Ca | Ms | ||||||||||||
Oat | |||||||||||||||||||||
n | Site | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. |
32 | Hollow (2010) | 12 | 38 | 29 | 84 | ||||||||||||||||
32 | Hill (2010) | 16 | 100 | 20 | 34 | 23 | 20 | ||||||||||||||
12 | Hollow (2011) | 5 | 8 | 12 | 100 | 12 | 58 | 8 | 100 | ||||||||||||
12 | Hill (2011) | 19 | 100 | 13 | 100 | ||||||||||||||||
4 | Hollow (2012) | 8 | 25 | 25 | 75 | 4 | 75 | ||||||||||||||
4 | Hill (2012) | 2 | 75 | 22 | 50 | 5 | 100 | ||||||||||||||
Winter Wheat | |||||||||||||||||||||
n | Site | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. | dom. | freq. |
20 | Hollow (2010) | 5 | 20 | 5 | 5 | 7 | 45 | 6 | 10 | 14 | 75 | 9 | 45 | 25 | 85 | ||||||
20 | Hill (2010) | 13 | 20 | 14 | 35 | 22 | 20 | 6 | 20 | 12 | 55 | 8 | 20 | 4 | 15 | 4 | 20 | 10 | 45 | 7 | 20 |
8 | Hollow (2011) | 13 | 25 | 15 | 25 | * | * | 17 | 88 | 5 | 13 | 6 | 13 | 25 | 100 | ||||||
8 | Hill (2011) | 20 | 100 | * | * | 14 | 100 | 3 | 25 | 8 | 13 | ||||||||||
8 | Hollow (2012) | 8 | 13 | 6 | 50 | 15 | 38 | 8 | 25 | 19 | 63 | 9 | 38 | 13 | 25 | 33 | 100 | 4 | 13 | ||
8 | Hill (2012) | 8 | 75 | 9 | 25 | 6 | 25 | 12 | 13 | 8 | 88 | 12 | 63 | 8 | 13 |
In the test methods
On the other hand, in 2010 and 2011,
Although the
Studies suggesting oat as a good LGS exploiter are confirmed by their results [
Despite summer crop cultivation after springtime LGS tilling, there may be an increased risk of nitrate leaching the following winter [
In the spring,
When it comes to adapting cultivation methods to climate changes, greater diversity is an effective risk management strategy for agricultural enterprises [
Ring-cutter processing proved to be overall practical, and particularly suited to organic farming needs (multiple-year LGS tillage). However, the denser weed growth, lower N mineralisation and lower grain yields, clearly proves it cannot replace the plough. Nonetheless, as a flexible, manageable tool, the ring-cutter is indeed an alternative on fields where site or weather conditions create severe ploughing risks, such as ploughing depth compaction and hilltop erosion. Climate changes are also changing the customary ploughing and/or soil processing dates [
This work was funded by the Federal Ministry of Education and Research (BMBF), Germany, by the Federal Ministry of Food, Agriculture and Consumer Protection (BMELV), Germany and by the Ministry of Science, Research and Culture (MWFK), Brandenburg. We thank Mr. Stefan Palme, organic farmer, for his expert advice and for allowing the experiments to be conducted on Wilmersdorf.