This experiment was carried out in the University of Miyazaki, southern Kyushu, Japan (31˚49’N, 131˚24’E) in May 2013 to May 2015. Table 1 showed sowing and harvesting seasons in the present triple cropping system. In the first year, we cultivated maize (cv. Snow dent 110), teff (cv. Tiffany) and barley (cv. Wasedori-nijyou). In the second year, the same cultivar of maize was used as in the first year, while cultivar of teff was changed to cv. Moxie and winter grass crop was changed to wheat (cv. Chikugoizumi and Minaminokaori). Maize was sown in a spacing of 20 cm intra-row and 75 cm interrow at a density of 6.67 plants・m⁻². Teff and barley were broadcast-sown uniformly at 1.3 and 3.0 g・m⁻², respectively. Both wheat cultivars were broadcast-sown at 3.0 g・m⁻² in November. Plot size was 9 m², with 0.5 m space between plots. The plot was arranged in a completely randomized block design with three replications. Plant growth attributes measured were plant length, tiller number, heading tiller number and SPAD index (SPAD 502 meter, Minolta, Osaka, Japan). Plants were fractionated to leaf blade, stem, and dead leaves. Fresh matter and dry matter (DM) weights were determined at monthly intervals. Plant parts were ground to pass through a 1 mm screen and were analyzed for in vitro dry matter digestibility (IVDMD) [9] , total nitrogen, total carbon and general component composition. Crude protein (CP) was determined by calculating total nitrogen content × 6.25. Crude ash (CA), crude fat (EE) and crude fiber (CF) were determined by dry ash method, ether extract method and ANKOM Technology-9/99 using a filter bag method, respectively. TDN content for all crops, except for the first-year maize was estimated by the following equation:

TDN (%) = {CP(%) × IVDMD (%) + 2.25 × EE (%) × IVDMD (%) + nitrogen free extract (NEF, %) × IVDMD (%) + CF (%) × IVDMD (%)} × 0.01,

and that for the first-year maize was estimated by the corresponding regression equation:

TDN (%) = ratio of ear × 0.885 + (100 − ratio of ear) ×0.528 − 3.2 [10] .

Maize cultivar “Snow dent 110” has high DM yield with lodging resistance. Teff cultivar “Tiffany” is now a leading variety in the U.S. and “Moxie Teff” is a high yielding with highly palatable cultivar. Since seed size of Teff is very small, therefore Teff needs soil compaction at the sowing to maintain good establishment. In the second year, Teff variety “Moxie” is adopted since it is sold as coated seed, which should facilitate the establishment. Barley cultivar “Wasedori-nijyo” is an extremely early-maturing type with lodging resistance. The cultivars of wheat are used to edible varieties for bread and noodles. Wheat cultivar “Chikugoizumi”, is an early-maturing type with disease tolerance to abnormally early-ripening season and leaf rustfungi [11] . Wheat cultivar “Minaminokaori”, has high crude protein content [12] with disease tolerance to wheat yellow mosaic virus.

Analysis of variance (ANOVA) was performed using Excel Statistics (OMS Co. Ltd., Saitama) by one-way analysis procedures for growth attributes of maize, Teff and wheat in a randomized complete design. Mean separation was tested using the Tukey-Kramer method at the 5% level. Student’s t-test at the 5% level was applied to analyze the differences in yield attributes of each crop between two growing seasons.

Monthly precipitation in July and August in the first growing season (2013) was lower than in the normal year averaged in 1980-2010, while the mean air temperature in the corresponding months was higher by 2˚C than in the normal year (Figure 1), showing that the summer weather condition had high temperature with low precipitation. In the second season (2014), mean air temperature was the same as in the normal, while precipitation in February and August was higher than in the normal year.

In the first growing season, plant length in maize increased rapidly from mid-June to mid-July and continued to increase consistently up to heading stage in early August (Figure 2). SPAD value in leaf blade of maize was determined at

40 in June, while it dropped to 30 due to drought stress under low precipitation in July. In early August, an amount of rainfall at 100 mm led to rise SPAD value to 42. In the second growing season, plant length and SPAD value in maize significantly increased with time up to early July to reach the maximum SPAD value at 42 (Figure 2). As for teff in both the first and second seasons, plant length increased with time from sowing to reach the peak around 85 - 88 cm in early September, and then decreased to 52 - 68 cm at the harvest in early October due to lodging (Figure 3). As for barley in the first season, plant length and tiller density were 95 cm and 2233 per m² at the harvest (Table 2). Among two cultivars of wheat in the second season, “Chikugoizumi” tended to be higher in plant length and tiller density at 103 cm and 344 per m², respectively at the harvest than “Minaminokaori” at 97 cm and 325 per m², respectively (Table 2). Tiller density in both cultivars of wheat peaked in the end of December, then dropped to early February, probably due to cold weather damage, recovered to early March, and then slightly thinned due to stem elongation (Figure 4).

In five cereal crops, even though teff was not fractionated, maize, barley and two cultivars of wheat were fractionated to plant parts and determined for compositions of general chemical components, IVDMD and TDN (Table 3), showing similar tendency in general chemical components among plant fractions (Table 3). Compared with the other plant parts, leaf blade had the highest composition

in CP, EE and CA among maize, barley and two cultivars of wheat, stem the highest in CF and ear the highest in NFE, except for CP composition in two cultivars of wheat having comparable composition in head. In whole plants, IVDMD was 77.2%, 86.1%, 73.8% and 72.4% in maize, barley, wheat cv. “Chikugoizumi” and “Minaminokaori”, respectively. Compared with data in Standard Tables of Feed Composition in Japan [13] , CF content was lower and EE content was higher in the current study. CP content in teff was 14.3% and 10.2%

*: p < 0.05.

in the first and second growing season, respectively, while IVDMD and TDN content of teff were higher in the second than in the first season due to the higher IVDMD (Table 3). In the current study, barley as a whole plant had the highest in CP, IVDMD and TDN content, followed by maize and wheat cv. “Chikugonoizumi” and “Minaminokaori”, while teff was variable from higher IVDMD and TDN content in the second season to the lower values in the first season (Table 3).

DM yield of each plant fraction was determined at the harvest in the two growing seasons (Table 4). As winter crop, barley and wheat were incorporated into the present triple cropping in the first and second season, respectively. As for spring maize, DM yield increased from the first to the second year mainly due to the doubled DM accumulation of ear fraction in the second year. Reduction in teff yield in the second year was due to the lower DM accumulation in the stem fraction than in the first year. Increase in wheat DM yield in the second season was due to DM accumulation in stem and ear fractions, compared with barley in the first season (Table 4).

CP: crude protein; EE: crude fat; CF: crude fiber; NEF: nitrogen free extract.

Annual total of DM and TDN yields of the two-year cropping were compared in Figure 5. Total DM and TDN yields in the second growing season were significantly higher than those in the first season. In the first and second seasons, DM yield of maize was 1,312 and 1,780 g・m⁻², respectively, however, teff cv. “Tiffany” and “Moxie” poorly yielded 317 and 92.9 g・m⁻², respectively, due to weed damage. “Moxie” is sold as coated seed and so the establishment under adverse conditions is improved, leading to increase in DM yield. However, in the present study, the germination of coated seed “Moxie” was slower than the pure seed “Tiffany”. Therefore, the early growth of “Moxie” was slower than that of “Tiffany”, leading to the suppression of growth of “Moxie” by summer weed. In winter crops, DM yield of wheat in the second season was higher than that of barley in the first season. In the current study, annual total of DM yield was higher in the second season at 2,637 g・m⁻² than in the first season at 2,044 g・m⁻² and TDN yield was in the same order at 1,749 g・m⁻² than in the first season at 1,270 g・m⁻². Compared with the statistical data [13] [14] , total DM and TDN

yields in the double cropping of maize with Italian ryegrass were reported at 2,189 and 1,885 g・m⁻², respectively, showing that the total DM and TDN yields in the second season of the current study achieved at about 20% and 11% higher than those in the statistical data.