Establishment and production of common sainfoin (Onobrychis viciifolia Scop.) in the UK. 2. Effects of direct sowing and undersowing in spring barley on sainfoin and sainfoin-grass mixtures

The dry matter (DM) yield and herbage quality of swards of sainfoin ( Onobrychis viciifolia ), meadow fescue ( Festuca pratensis ,) and tetraploid perennial ryegrass ( Lolium perenne ) grown in monocultures and in four sainfoin:grass mixtures (0·33 sainfoin:0·66 meadow fescue, 0·66 sainfoin:0·33 meadow fescue, 0·33 sainfoin:0·66 perennial ryegrass and 0·66 sainfoin:0·33 perennial ryegrass), established by direct sowing or undersowing in spring barley, were investigated over 3 years in a field experiment in the UK. Direct sowing produced a mean yield across all species and mixtures of 1·8 t DM ha⁻¹ in the establishment year, whereas undersowing produced no measurable yield except for that of the spring barley. Undersowing reduced the yields of sainfoin and sainfoin-grass mixtures in the first full-harvest year but not in the second. The annual yield of a monoculture of sainfoin was 7·53 t DM ha⁻¹ and that of sainfoin-grass mixtures was 8·33 t DM ha⁻¹ averaged over 3 years. Both sainfoin and the sainfoin-grass mixtures had higher annual DM yields than the grass monocultures. The mixture of 0·66 sainfoin:0·33 meadow fescue gave the highest mean annual yield (9·07 t DM ha⁻¹) over the 3 years. There was a higher proportion of sainfoin maintained in mixtures with perennial ryegrass than with meadow fescue. The proportion of sainfoin in sainfoin–meadow fescue mixtures declined from 0·62 in the first year to 0·32 in the third year, whereas the proportion in sainfoin–perennial ryegrass increased from 0·48 in the first year to 0·67 in the second year and remained stable in the third year.     

柑桔园套种黄豆的试验研究

报道了在柑桔园套种黄豆的播种期、株行距、穴保留株数及施肥技术。试验结果表明种黄豆可明显地改善果园小气候,改良土壤肥力和水热状况,有利于幼树的生长发育和产量的提高。     

稻田三熟制油菜谷林套播技术研究初探

为了克服江西三熟制稻田季节矛盾,确保三熟制稻田的三熟高产,通过采用二晚稻田油菜谷林套播栽培方法,研究这一栽培方法对油菜生长发育及产量的影响。结果表明：与二晚接茬油菜相比,谷林套播油菜尽管个体发育受到抑制,植株比较瘦弱、总角果数、每角粒数较少、千粒重也较小,但其每公顷株数最多,在一定范围内充分发挥了群体生长优势,因而产量最高,为1680.59 kg/hm²,比前者增产30.49%;每公顷的净收益也最大,为3044.95元/hm²,是前者的2.3倍。     

杉木幼林套种大豆的技术和效益

在杉木幼林地套种大豆试验中,作了大豆的品种选择、施肥和除草剂试验,并相应地进行了土壤分析和小气候观察,调查了杉木幼林的年生长量。研究结果表明:套种大豆早熟品种以坎山白最好,在4月5日播种为宜,株行距采用50cm×50cm,每穴3株最佳;迟熟品种以野猪戳最好,在5月15日前后播种为宜,株行距采用33cm×33cm为宜,每穴2～4株都可。以钙镁磷肥作基肥有显著的增产效果,以尿素、草木灰作追肥,则增产效果不明显。除草剂以来草克8ml/hm~2除草效果最佳,除草率达82.46％,并且对杉苗、豆苗安全无害,比人工除草省工省钱。另外,杉木幼林地套种大豆,可以明显改善小气候,改良土壤,促进杉木生长,杉木幼树株高当年生长量约可增加34.6％。     

Effect of Sowing Technique on Growth of Undersown Crop and Yield of Spring Barley

Undersowing a main crop enables establishment of a catch crop in areas characterized by a short post-harvest period before the onset of winter. Techniques with lower costs than conventional undersowing by separate drilling are often regarded as unreliable. Undersowing by drilling after sowing spring barley ( Hordeum vulgare L.) was compared with broadcast sowing simultaneously with drilling barley. Various implements were coupled behind the combined drill in cases where seed was broadcast: a press-wheel attachment, a long-tined harrow and a cage roller. A fourth treatment did not include an implement coupled behind the drill. The undersown crop was sown as a seed mixture of 3 kg ha^–1 red clover ( Trifolium pratense L.) and 6 kg ha^–1 meadow fescue ( Festuca pratensis Hudson). The numbers of plants and weeds and the plant height were measured five times during the growing season. Above-ground biomass of the undersown species was determined at barley harvest and in late autumn. Grain yield of spring barley was recorded. Drilling resulted in the highest yield of undersown crop when an early summer drought occurred, but broadcasting in combination with use of seed covering equipment led to the least variation in biomass production over the 4 years the experiment was conducted. The relative proportion of meadow fescue in the crop was low in three years, and lower when broadcast than when drilled. Barley grain yield was highest when the seed was broadcast and seed covering equipment was used. Use of a cage roller increased weed biomass, but press-wheels and a long-tined harrow did not. Separate rolling after undersowing increased undersown crop yield in one year, but decreased grain yield in some cases.