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Die Wirksamkeit von Boden

Die Wirksamkeit von Boden

Performance of farmland

Performance of farmland terraces in maintaining crop productivity Pair-wise comparisons showed a similar trend in most crops, where yields decreased towards the up-terrace position. However, the differences among crop types were nonlinear (Table 6.2 and Figure 6.3). Accordingly, the grain yields of five crops (barley, maize, teff, field pea and horse bean) significantly (P < 0.02) decreased towards terrace position C. Similarly, all crops except wheat had significantly (P � 0.002) higher biomass yield on the terrace position A. The biomass on average measured 4.2 t h -1 , 3.5 t h -1 and 3.0 t h -1 on terrace position A, B and C, respectively (Table 6.2). Crop yields without significant differences also tended to decrease towards position C. Although terrace position B had higher grain yields for all crops except field pea than terrace position C, the differences were statistically insignificant for all crops except teff and horse bean. On the other hand, terrace position B had significantly higher barley, wheat, teff and horse bean biomass than position C, while the biomass of the other crops showed non-significant differences. Generally, low yields were measured on terrace position C for most crops except field pea, and the magnitude of the differences varied with crop type (Table 6.2). Table 6.2 Average crop yield (t ha -1 ) on three terrace positions Crop Grain yield (t ha -1 ) Biomass yield (t ha -1 ) A B C F -Value A B C F -Value Barley 2.20 aa 1.88 d 1.61 44.88 *** 4.8 aa 4.0 b 3.4 13.82 *** Wheat 1.17 1.24 1.03 0.76 ns 3.4 db 3.3 c 2.8 2.51 * Maize 2.51 aa 1.64 d 1.24 17.07 *** 6.7 aa 4.9 d 4.1 11.80 *** Teff 1.60 ba 1.52 b 1.16 13.59 *** 92 3.6 da 3.4 a 2.8 9.17 *** Emmer wheat 1.84 db 1.55 d 1.44 5.04 * 4.0 ba 3.4 d 3.0 7.01 *** Field pea 1.28 ab 0.92 d 0.92 5.99 *** 3.3 aa 2.4 d 2.4 9.11 *** Horse bean 1.89 ba 1.67 b 1.37 9.44 *** 3.4 da 3.1 b 2.6 8.25 *** Note: Terrace positions: A= low-, B= mid- and C = up-terrace. See Table 6.1for abbreviations and superscripts. Higher grain yield differences were observed between position A and C than between position A and B or between position B and C (Table 6.3). The overall grain yield on the terrace position A was 0.53 t ha -1 higher than terrace position C; however, the differences varied with crop type (Figure 6.3a). The grain yield differences between position A and C varied from 0.14 t ha -1 in case of wheat to 1.27 t ha -1 in the case of maize. Similarly, the grain yield differences between position A and B varied from nil in case of wheat to 0.87 t ha -1 in the case of maize, while between position B and C yields ranged from 0 t ha -1 in the case of field pea to 0.4 t ha -1 in the case of maize

Performance of farmland terraces in maintaining crop productivity (Table 6.3). Generally, average grain yield differences were 0.53 t ha -1 between position A and C, 0.3 t ha -1 between position A and B, and 0.24 t ha -1 between position B and C. Higher grain yield differences were observed in case of maize, while the differences for wheat were the lowest. The biomass yield gradient within a terrace followed the same trend as that of the grain yield (Figure 6.3b). The highest biomass difference was between terrace position A and C followed by between position A and B and between position B and C, respectively (Table 6.3). Biomass and grain yield showed similar differences within a terrace (Figure 6.3). Table 6.3 Crop yield differences (t ha -1 ) between terrace positions Crop Grain yield differences (t/ha) Biomass yield differences (t/ha) A - B A - C B - C A - B A - C B - C Barley 0.32 0.59 0.27 0.8 1.4 0.6 Wheat -0.07 0.14 0.21 0.1 0.6 0.5 Maize 0.87 1.27 0.40 1.8 2.6 0.8 Teff 0.08 0.44 0.36 0.2 0.8 0.6 Emmer wheat 0.29 0.40 0.11 0.6 1.0 0.4 Field pea 0.36 0.36 0.00 0.9 0.9 0.0 Horse bean 0.22 0.52 0.30 0.3 0.8 0.5 Average 0.30 0.53 0.24 0.7 1.1 0.5 Note: See Table 6.2 for abbreviations Note: Terraces positions: A = low-, B = mid- and C = up-terrace position Figure 6.3 Grain (a) and biomass (b) yield (t ha -1 ) on the three terrace positions 93