R. Holle and H. Untiedt
Ökoring Schleswig-Holstein, Kielerstrasse 26, 24582 Bordesholm, Germany
Summary
The usual crop rotation in Northern Germany includes 25% to 33% grass-clover. Because there is not enough nitrogen for all the cereals in these rotations it is of the utmost importance to grow undersown legume crops to increase nitrogen fixation. But for grass-clover grown in the customary manner there always is a problem of little exposure to light and because of this it tends to be of inferior quality and size. On the other side, in case of successful grass-clover cultivation the following wheat often has too low a content of crude protein. An interesting solution to the complex problems associated with this dilemma has been the use of wide row spacings, hence called the wide row system. The development of this system led to a considerable strengthening of the clover grass. Furthermore it allows for relatively high levels of grain biomass and protein yields, which for wheat is of fundamental value. As far as the farms of our investigation are concerned the row spacing varied from 0.3 to 0.5 m. For organic farmers the wide row system seems to be a promising way of producing wheat with a protein quality, which meets the needs of the market.
Introduction
The usual crop rotation in Northern Germany includes 25% to 33% grass-clover. The common rotations use 25% grass-clover undersown in the cereals, because this gives a higher yield over the whole rotation. In normal rotations the following problems often occur:
• On heavy soils with enough water there are high yields of wheat, but the quality of protein is
reduced.
• The cereals furthest away from the grass-clover may not have a sufficient nitrogen supply, because the undersown legume does not supply nitrogen to the crop.
• If the farmer tries to grow undersown legumes very frequently, there will be less stubble breaking and as a result perennial weeds like thistle and couch grass becomes prevalent.
A method of growing grain and grass-clover permanently is originated by the organic farmer Joachim Stute and is now commonly known as the wide row system. The wide row system allows cereals and grass-clover to be intercropped, increasing the protein-content of the wheat to a higher level. Wheat with a crude protein below 10.5% can only be marketed for feed. If the crude protein is above 10.5% it can be sold as baking wheat.
The procedure of the wide row includes:
• Drilling of the grains in single rows, seldomly in double rows.
• Amount of seeding 33% lower than the standard seeding rates.
• Width of row spacing about 0.3 to 0.5 m.
• Drilling of underseeds after the last hoeing.
Because the price difference of feeding wheat and baking wheat is approximately 10 EURO per 100 kg, the organic farmers are interested in producing wheat with a higher crude protein content. The evaluation of wheat analyses from organic farmers of the last years demonstrates that only half of the wheat samples were of baking wheat quality, although wheat was grown mostly in the year following grass-clover.
Materials and methods
The wheat fields of 33 organic farms, members of product organisations BIOLAND, NATURLAND or DEMETER, were assessed during the harvest of 1997. The exact yield, the protein content and water content of their harvests were recorded and samples of crude protein and gluten were taken. The test areas were spread over the three geologically different regions of Schleswig-Holstein (Table 1). Items important for assessing the production methods were ascertained by a survey.
On the farm "Brock" at the east coast several cultivation methods were tested. The spring-wheat variety "Combi" was used. The cultivation methods included:
For standard seeding (0.125 m row spacing):
• without maintenance works
• with use of curry-comb
For the wide row system (double row, 0.375 m row distance)
• with use of hoe
• with use of field cultivator
Table 1 Distribution of the farms and fields in the regions of Schleswig-Holstein .
Region Numbers of farms Numbers of fields
East coast 20 53
Fehmarn 5 17
West coast 8 21
Sum 33 91
Results and discussion
Table 2 shows the results of the yield and quality ratings of wheat from farms in different areas of Northern Germany. These values show a very high variation and therefore exact interpretation requires division in three categories depending on site, variety an production method:
1. "region" (East coast, Fehmarn, West coast) 2. "variety" (spring-wheat, winter-wheat)
Table 2 Overview of mean and minimum and maximum values and standard deviation of the key variables yield, crude protein, gluten and N-uptake. Numbers of samples: 91.
Yield (t ha-1) Crude protein (%) Gluten (%) N-uptake (kg N ha-1) Mean 4.0 11.3 22.3 69 Minimum 2.2 9.7 14.1 36 Maximum 5.9 14.2 30.8 109 Standard deviation 8.5 1.3 3.7 17
This differentiation of the data according to the categories defined above allows conclutions to be drawn more easily, as can be seen from Table 3. The regions of Fehmarn and the West coast seem to be privileged places for a high yield with high values of gluten and crude protein. The category "variety" shows that spring wheat gives lower yield, but a higher quality than winter wheat. The quality effect of the wide row system may be seen from a content of crude protein of 11.7% and of gluten of 24.0% on average. Since the production method of the wide row system is more widely used at the West coast this leads to the complication that the quality effects of this system indicated by Table 3 may in part result from the different soils. But Table 4 shows comparison of the wide row and standard seeding in one region only. The yield of the wide row system is less but the crude protein is higher than of the standard seeding.
Table 3 Mean values of the variables yield, crude protein, gluten and N-extraction by the different categories. Values above the mean of the whole sample (see above table 1) are printed in bold.
Category (t haYield -1) Crude protein (%) Gluten (%) (kg N ha-1) N-uptake
Region East coast (n=53) 3.9 11.1 22.0 66 Fehmarn (n= 17) 4.2 10.9 22.6 71 West coast (n=21) 4.2 11.9 23.1 78 Variety S.-wheat (n=37) 3.9 11.9 23.4 71 W.-wheat (n=54) 4.1 10.9 21.3 69 Production method Wide row (n=44) 3.9 11.7 24.0 71 Normal seeding (n=47) 4.1 10.9 21.3 68
Table 4 Comparison of the quality effect of the wide row of the East coast region depending on the production method.
Production method (t haYield -1) Crude protein (%) Gluten (%) N-uptake (kg N/ha)
Standard seeding 4.2 10.8 20.9 70 Wide row 3.8 11.7 23.6 62
Table 5 Results of the wide row experiment on the farm "Brock".
Variety (t haYield -1) Crude protein (%) Gluten (%) N-uptake (kg N/ha)
Normal seeding (no maintenance) 2.3 10.4 19.4 37
Normal seeding (curry-comb) 3.2 10.8 20.5 54 Wide row (field cultivator) 3.3 12.0 24.8 61 Wide row (hoeing) 3.0 12.9 26.3 60
On average the difference between common seeding and the wide row system is about 0.2 t ha-1. For
the East coast region the difference is 0.35 t ha-1. These differences were, however, not significant.
The effect on quality of crude protein and gluten is confirmed by the experiment on the farm "Brock" at the east coast (Table 5). The normal seeding with a yield of 2,3 t ha-1 seems to be to low. The reason
was most probably presence of the cornflower weed. The use of curry-comb had no measurable effect to the quality of crude protein, whereas the wide row system resulted in a very high crude protein and gluten. The N-uptake (kg ha-1) is considerable, too. With the use of the field cultivator or the hoe more
nitrogen is mobilised.
39 of 44 grain samples (89%) analysed from the wide row system had a crude protein above 10.5%. Only five samples had less than 10.5% crude protein, an explanation for this may be their origin with heavy soils and high output and nitrogen being thinned out. For locations like these a greater width of row spacing (about 0.5 m) may prove sufficient to guarantee a high crude protein in the future.
The use of spring or winter wheat is also important for the effect on quality. Only 55% of winter wheat, but 95% of spring-wheat had more than 10.5% crude protein.
Acknowledgement
The project "Monitoring the wide row with regard to quality of organic-baking wheat" was kindly supported by the Department of Agricultre in Schleswig-Holstein, Germany, 1997. Part of this project´s findings are integrated in the following paper.
This investigation of the 1997 yield monitoring has been supported by the investigations of Jochen Hochmann, LWK Schleswig-Holstein, Futterkamp 1996-98.