Our previous study conducted in a wasted mulberry plantation showed significant decline of leaf productivity of mulberry (Morns sp.) by cattle grazing in three years (Ogura et al., 2009). This means t㏊t improvement of understory vegetation is essential to use such wasted areas as grazing lands. In this study, the mixture of seeds (Dactylis glomerata, Lolium perenne, Poa pratensis and Trifolium repens, 15:15:5:2) was seeded on 18 Sep. 2007, in nine experimental plots (6 m × 6 m each) with different seeding rates (L: 37 ㎏/㏊, M: 56㎏/㏊ and H: 74㎏/㏊, three replications) in the wasted mulberry plantation described in the previous paper (paddock A) (Ogura et al., 2009). Two cows were grazed in the paddock for 42 and 54 days in 2007 and 2008, respectively. No fertilizer nor herbicides were applied in the paddock. The coverage of the sown species and weeds, and the proportion of bare area were recorded on 19 Sep. 2007, 16 Nov. 2007, 21 May 2008 and 21 May 2009. T. repens rapidly covered the understory; the coverage ranged 49.4-71.7% in 2008-2009 (Fig. 1). D. glomerata and L. perenne also increased to 10.6-18.3% and 20.6-33.9% in 2009, respectively, regardless to the seeding rates. In contrast, the proportion of bare area rapidly decreased. The quick establishment of the sown plants probably due t㏊t defoliation and trampling of cows suppressed the growth of native plants. In conclusion, the seeding rate of 3.7 ㎏/㏊ is sufficient to establish herbage plants in wasted mulberry plantations under cattle grazing.

Mulberry (Morus sp.) plantations have been deteriorating in Japan due to decline of silk industry. In mountainous areas, large part of the mulberry plantations has been wasted. Cattle grazing in the wasted mulberry plantations is a practical system to reuse the wasted areas for food production, because mulberry leaves are highly nutritive (Ezenwa and Kitahara, 2001), productive (Kitahara et al., 2002) and palatable to cattle (Ogura et al., 2008). In this study, the productivity and quality of mulberry leaves were investigated for 3 years in a wasted mulberry plantation grazed with beef cows, in Minamisanriku town, Miyagi, Japan. Cattle grazing started in September 2005 (paddock A, 44 a) and June 2006 (paddock B, 96 a). For each paddock, two pregnant cows were grazed from June to August-October in 2006-2008. In the paddocks A and B, four mulberry trees were chosen and the leaf mass and chemical composition were measured in mid-June and late August (pre-grazing leaf mass) during 2006-2008. A non-grazed paddock was also measured in 2007-2008. Leaf productivity of mulberry trees significantly decreased with cattle grazing; pre-grazing leaf mass changed from 246.8 g to 10.4 g DM/tree and 286.2 g to 17.6 g DM/tree in the paddock A and B, respectively (Fig 1). In contrast, 149.2-365.1 g DM/tree of leaves was produced in the non-grazed paddock. Chemical composition was stable during the three years in all paddocks. It is concluded that cattle grazing gives severe damage to leaf production of mulberry trees in three years.