【作者】 文石林；

【导师】 刘强； 荣湘民；

【作者基本信息】 湖南农业大学 ， 植物营养， 2012， 博士

【摘要】 南方红壤丘陵区水热条件优越,牧草发展潜力巨大,大量的荒山荒地及幼龄林果园等待开发利用,然而这些土地酸化严重,需要选择耐酸的牧草品种和采用适当的施肥管理措施才能使牧草良好建植并获得高产。针对这一目的,开展了一系列研究,布置了田间试验筛选适宜于酸性红壤上栽培的牧草品种,通过盆栽试验研究了一些当家牧草品种生长的适宜土壤pH范围,通过水培试验研究了它们的抗铝毒的能力及机理,采用盆栽和田间试验研究了这些牧草的合理施肥及混播栽培技术,建立了大型径流观测场,研究了将耐酸牧草纳入林果园生态系统中对控制水土流失、培肥酸性红壤、调节水热状况的效果。获得的主要结论如下：1、马唐、扁穗牛鞭草、桂牧1号、矮象草、狗尾草、罗顿豆、圆叶决明和大翼豆等暖季型品种极其耐酸,在不施肥和石灰的情况下也能良好生长,如施用适当肥料,则产量更高。鸡脚草、多花黑麦草和白三叶等冷季型品种只有在施用适当肥料和石灰情况下才能生长良好。一年生禾本科牧草品种墨西哥玉米产量很高,但不太耐酸,且必须在施用较多肥料情况下才能获得高产。2、豆科牧草中圆叶决明极其耐酸,适宜生长在土壤pH5以下的土壤中；罗顿豆和大翼豆也比较耐酸,在土壤pH4.5时也能生长良好,但最适宜生长的土壤pH在5-5.5之间；白三叶不耐酸,适合于种植在pH5.5-6.5的土壤上；禾本科牧草中马唐的耐酸能力非常强,在土壤pH4.5-5范围内生长最好；狗尾草的耐酸性能力比马唐稍差,适宜生长在pH5-6的土壤上；墨西哥玉米的适宜pH范围为5.5-6.5；鸡脚草在酸性土壤中生长很差,适宜种植的土壤pH范围为5.5-6.5。3、在测试的8个牧草品种中,抗铝毒能力排序为圆叶决明>马唐>大翼豆=罗顿豆>狗尾草>墨西哥玉米>鸡脚草>白三叶,铝胁迫对根系伸长的影响则刚好相反。4、在AlCl3浓度为30μmol·L-1条件下,去除牧草幼根根尖吸附的粘胶物质对圆叶决明、马唐和狗尾草等耐铝能力强的牧草品种的根系伸长影响最大,而对耐铝能力差的白三叶和鸡脚草影响很少,说明根系分泌粘胶是圆叶决明、马唐和狗尾草等牧草品种抵抗铝毒的机制之一。5、在铝诱导下,圆叶决明、罗顿豆、大翼豆、狗尾草、墨西哥玉米等品种根系分泌出柠檬酸,其分泌量反映其耐铝性能。根系分泌柠檬酸是这些品种耐铝的原因之一。6、在不施磷肥情况下,施用低量石灰(0.7-1.4g·kg-1)可快速提高白三叶、墨西哥玉米和大翼豆的产量,继续增施石灰,白三叶产量缓慢提高,而大翼豆和墨西哥玉米产量下降,施用磷肥可减缓下降趋势。施用磷肥可减轻土壤酸度对牧草的毒害,施用低量石灰(0.7-1.4g·kg-1)下,配施磷肥可大幅提高白三叶、大翼豆和墨西哥玉米的产量；圆叶决明非常耐酸,施用石灰反而抑制其生长,但施用磷肥可大幅提高其产量。7、耐酸豆科牧草罗顿豆与马唐、狗尾草、牛鞭草等耐酸禾本科牧草混种均能良好生长,罗顿豆与它们混种时的生物产量和粗蛋白质产量均明显高于禾本科牧草单播。在3种禾本科牧草中,马唐分蘖能力强,竞争能力强,罗顿豆与马唐以2：1比率混播最好。牛鞭草茎多叶少,对罗顿豆生长的影响小,提高牛鞭草混种比率对罗顿豆产量的影响不大,罗顿豆与牛鞭草1：2混播时生物产量和粗蛋白质产量最高。狗尾草的叶片较大,但分蘖扩展能力比马唐差,竞争能力介于马唐和牛鞭草之间,狗尾草与罗顿豆1：1比率混播(条播或撒播)最好。8、在红壤丘陵区经济林果园中种植耐酸耐瘠的豆科牧草能明显减少水土流失,并减少土壤有机质和土壤全氮、全磷、全钾、速效氮、速效磷、速效钾等养分的流失；种植豆科牧草4年后,土壤有机质和土壤全氮、碱解氮、速效磷、速效钾等养分的含量都有明显增加,因而培肥了土壤,土壤交换性Ca2+和Mg2+的含量增加,交换性Al3+的含量减少,从而减轻了酸害；种植牧草还可调节土壤水热状况,提高土壤表层水分含量,降低高温干旱期土壤温度,改善了林果园的生态条件。更多还原

【Abstract】 The potential of developing forages is tremendous due to the high rainfall, long sunshine and high temperature in red soils hilly region. Plentiful wasteland and new developed orchard are suitable to develop forage. However, the soil is very acid in these lands, thus seriously affects forages growth. Therefore, selecting suitable aciduric forages and using suitable fertilizing and planting management measures are necessary to get better establishment and higher yield. In this study, filed experiment was set up to select aciduric forages for acid red soil, suitable soil pH range of forages growth was determined by pot experiments, the tolerant ability and mechanism of forages to aluminium toxicity were studied by a series of water culture experiments, the effects of lime and phosphorus fertilizer on forages growth were studied by pot experiments, suitable combination ratio of forage legume Lotononis bainesii and3grasses was studied in a filed experiment. Runoff plots were set up to study the effects of forage on erosion control, improving soil and ecological condition in forest plantation or orchard. The main conclusions are as follows:(1) Some of Warm season grasses such as Digit aria eriantha cv Premier Hemarthria compressa, Pennisetum purpureum, Pennisetum purpureum cv Mott, Setaria sphacelata cv Soland, and legumes such as Chamaecrista rotundifolia cv Wynn, Lotononis bainesii and Macroptilium atropurpureum cv Siratro had high acid tolerance ability. They grew well in the acid soil (pH is4.5) even no fertilizer and lime were applied. Some of cool season species such as Trifolium repens cv Haifa, Dactylis glomerata cv Porto and Lolium multiflorum cv Tetila grew poorly in the acid soil if no ferilizer and lime, however they grew well if ferilizers and lime were applied.(2) Chamaecrista rotundifolia cv Wynn was the most acid tolerant legume species which grew best in the soil with pH less than5. The suitable soil pH was5-5.5for Macroptilium atropurpureum cv Siratro and Lotononis bainesii. Trifolium repens cv Haifa was not acid tolerant which was suitable to grow in the soil with pH5.5-6.5. Digitaria eriantha cv Premier had high ability of acid tolerance and grew best in the soil with pH4.5-5. The soil pH ranges of Setaria sphacelata cv Soland, Zea Mexicana and Dactylis glomerata cv Porto were5-6,5.5-6.5and5.5-6.5, respectively.(3) The order of acid tolerant ability of8forages tested to aluminium toxicity was Chamaecrista rotundifolia cv Wynn, Digitaria eriantha cv Premier, Macroptilium atropurpureum cv Siratro, Lotononis bainesii, Setaria sphacelata cv Soland, Zea Mexicana, Dactylis glomerata cv Porto and Trifolium repens cv Haifa.(4) The effects of wiping off mucilage glue absorbed on radicle of Chamaecrista rotundifolia cv Wynn, Digitaria eriantha cv Premier and Setaria sphacelata cv Soland on radicle elongation were the highest, and the lowest for Dactylis glomerata cv Porto and Trifolium repens cv Haifa, when these forages were planted in a solution with AICl3concentration of30μmol·L-1. It shows that the radicles excreting mucilage glue is one of mechanisms of forage forbearing aluminium toxicity.(5) The roots of Chamaecrista rotundifolia cv Wynn, Setaria sphacelata cv Soland, Lotononis bainesii, Macroptilium atropurpureum cv Siratro and Zea Mexicana excreted citric acid in the solution with high concentration of Al3+. The amount of excreting citric acid was relative with the ability of forbearing aluminium toxicity of these forages. It shows that root excreting citric acid is one of reasons of forbearing aluminium toxicity of these forages.(6) Applying0.7-1.4g·kg-1lime could increase quickly the yield of Trifolium repens cv Haifa, Macroptilium atropurpureum cv Siratro, and Zea Mexicana. The yield of Trifolium repens cv Haifa increased slowly when applying2.1-2.8g·kg-1lime, however the yields of Macroptilium atropurpureum cv Siratro, and Zea Mexicana decreased, applying phosphorus could slow down the decrease trend of yield. Applying phosphorus could alleviate the damage of soil acid to forage. Applying phosphorus and0.7-1.4g·kg-1lime could increase hugely the yields of Trifolium repens cv Haifa, Macroptilium atropurpureum cv Siratro, and Zea Mexicana. The ability of Chamaecrista rotundifolia cv Wynn forbearing aluminium toxicity was very high, applying lime restrained its growth, but applying phosphorus increased its yield.(7) Lotononis bainesii could grow well when it was mixed sowing with Digitaria eriantha cv Premier or Setaria sphacelata cv Soland or Hemarthria compressa. The biomass and crude protein yields in the mixed sowing treatments were higher significantly than that in grass monoculture treatments. Mixed sowing could promote the growth of grass, sustain pasture productivity. The competitive ability of Digitaria eriantha cv Premier was the highest among3grass species. The best mixed ratio of Digitaria eriantha cv Premier and Lotononis bainesii was1:2. The competitive effect of Hemarthria compressa on growth of Lotononis bainesii was little as it has little leaf. The biomass and crude protein yield were the highest when it was mixed sowing with Lotononis bainesii as a ratio of2:1. The competitive ability of Setaria sphacelata cv Soland was middle, the best ratio sown with Lotononis bainesii was1:1(broadcast or row sowing).(8) Planting aciduric forage legume in the forest plantation or orchard could reduce soil erosion significantly, and reduce the loss of nutrients and organic matter. Soil organic matter, total N, Available N, available P and available K increased after planting forages for4years, thus improved soil fertility. Soil exchangeable Ca+and Mg2+increased and Al3+decreased, thus alleviated aluminium toxicity in the soil. Planting forages in orchard could temper the soil moisture and temperature, increase soil water content in surface soil, decrease soil temperature during hot and dry season, thus improve the ecological condition of orchard.更多还原