發(fā)布時(shí)間：2018-04-30 08:07

  本文選題：甜高粱 + 干物質(zhì)產(chǎn)量��； 參考：《南京農(nóng)業(yè)大學(xué)》2016年博士論文

【摘要】：農(nóng)區(qū)種草是實(shí)現(xiàn)我國(guó)畜牧業(yè)現(xiàn)代化,促進(jìn)糧食、經(jīng)濟(jì)、飼用作物三元種植結(jié)構(gòu)協(xié)調(diào)發(fā)展的重要途徑。長(zhǎng)江下游農(nóng)區(qū)地處亞熱帶,降水豐沛、熱量充足,發(fā)展農(nóng)區(qū)種草有很大的潛力。但這一地區(qū)是典型的“稻-經(jīng)”二元種植模式地區(qū),在飼草生產(chǎn)方面缺少適宜的品種和栽培技術(shù)。此外,該地區(qū)高溫多雨,干草的加工調(diào)制受到限制,青貯成為保證全年粗飼料供應(yīng)的重要手段。所以,篩選研究適于當(dāng)?shù)厣鷳B(tài)環(huán)境下種植的青貯飼料作物并研發(fā)配套的高產(chǎn)栽培利用技術(shù),對(duì)長(zhǎng)江下游農(nóng)區(qū)種草養(yǎng)畜的持續(xù)發(fā)展有重要意義。甜高粱(Sorghum bicolor)為多用途C4植物,抗逆性強(qiáng)、適應(yīng)性廣、生物產(chǎn)量高、再生性好,是干旱地區(qū)的優(yōu)良飼用作物。我國(guó)長(zhǎng)江下游農(nóng)區(qū)傳統(tǒng)上將其作為嗜好作物零星種植。能否利用甜高粱抗逆和再生的優(yōu)良特性,在潮濕多雨氣候條件下用作青貯作物栽培利用?國(guó)內(nèi)外少有報(bào)道。本研究以青貯玉米為參照,研究了甜高粱(cv.Hunnigreen)的干物質(zhì)生產(chǎn)性能、營(yíng)養(yǎng)價(jià)值、青貯品質(zhì)和利用價(jià)值,論證了甜高粱在長(zhǎng)江下游農(nóng)區(qū)用作青貯作物的可行性。另外,通過(guò)系列的田間試驗(yàn)和實(shí)驗(yàn)室分析,研究了施氮水平和刈割次數(shù)對(duì)甜高粱生產(chǎn)性能、氮素利用率、光合作用、營(yíng)養(yǎng)價(jià)值、青貯發(fā)酵品質(zhì)和干物質(zhì)體外瘤胃發(fā)酵特性的影響,提出了甜高梁在長(zhǎng)江下游農(nóng)區(qū)高產(chǎn)栽培和青貯利用的關(guān)鍵技術(shù)。主要研究結(jié)果如下:1.長(zhǎng)江下游農(nóng)區(qū)農(nóng)田生態(tài)條件下,甜高粱的干物質(zhì)(DM)、粗蛋白(CP)和可消化干物質(zhì)產(chǎn)量遠(yuǎn)高于青貯玉米,分別為青貯玉米的1.54, 1.47和1.73倍。甜高粱的營(yíng)養(yǎng)價(jià)值和青貯發(fā)酵品質(zhì)與青貯玉米相當(dāng);青刈飼用及青貯品質(zhì)的穩(wěn)定性?xún)?yōu)于青貯玉米。甜高粱在長(zhǎng)江下游農(nóng)區(qū)用作青貯作物栽培利用潛力巨大。2.兩年的施氮試驗(yàn)表明,長(zhǎng)江下游農(nóng)區(qū)甜高粱適宜的施氮量為200～400 kg N·hm-2,在該施氮范圍內(nèi),DM產(chǎn)量高,氮素利用率高,氮素流失少。多元回歸和通徑分析表明,株高是決定DM產(chǎn)量的主要農(nóng)藝性狀,且不受施氮水平影響。莖葉比和葉面積指數(shù)對(duì)DM產(chǎn)量的影響在不同施氮水平下存在差異。施氮水平低于100 kg N·hm-2時(shí),莖葉比對(duì)DM產(chǎn)量的直接作用最大(P=0.925),葉面積指數(shù)對(duì)DM產(chǎn)量的直接作用最小(P=0.162);施氮水平為200kgN·hm-2和300kgN·hm-2時(shí),莖葉比對(duì)DM產(chǎn)量的影響降低(P=0.073 ),葉面積指數(shù)對(duì)DM產(chǎn)量的直接作用增加(P=0.797);而施氮水平為400 kg N·hm-2和500 kg N·hm-2時(shí),莖葉比和葉面積指數(shù)對(duì)DM產(chǎn)量的直接作用均為負(fù)值(P=-0.125, P=-0.040)。這表明,高氮水平下的合理密植對(duì)甜高粱高產(chǎn)更為關(guān)鍵;而在較低施氮水平下,收獲時(shí)間對(duì)飼草產(chǎn)量和品質(zhì)的平衡作用更加突顯。3.施氮水平和刈割次數(shù)對(duì)甜高粱光合作用有顯著影響。葉片的凈光合速率(Pn)隨施氮量和刈割次數(shù)的增加而增加,在300 kg N·hm-2施氮水平,刈割3次處理下達(dá)最大值。葉片的表觀量子效率(AQY),光飽和點(diǎn)(LSP)和羧化效率(CE)也均在刈割3次處理下達(dá)最大值,且顯著高于其他處理組合。說(shuō)明適當(dāng)提高施氮量和增加刈割次數(shù)有利于提高甜高粱的光合能力。但是,高氮和高頻刈割處理下暗呼吸速率(Rd)增大。因此,甜高粱干物質(zhì)產(chǎn)量并沒(méi)有與Pn同時(shí)在刈割3次處理下達(dá)到最大值,說(shuō)明施氮水平與刈割次數(shù)的適當(dāng)平衡,是提高甜高粱光合生產(chǎn)能力的關(guān)鍵。此外,隨著生長(zhǎng)期內(nèi)刈割次數(shù)的增加,葉片硝酸還原酶活性(NRA)有增大的趨勢(shì)。4.施氮水平和刈割次數(shù)對(duì)甜高粱飼草營(yíng)養(yǎng)價(jià)值和青貯發(fā)酵品質(zhì)有顯著影響。結(jié)果表明,CP和可溶性碳水化合物(WSC )含量均隨施氮量的增加而增加,分別在300 kg N·hm-2和225 kg N·hm-2處理下達(dá)最大值。兩者對(duì)氮肥的不同響應(yīng),導(dǎo)致最終青貯發(fā)酵品質(zhì)的不同。施氮量≥225 kg N·hm-2時(shí),青貯甜高粱的pH值和乳酸含量無(wú)顯著增加,丁酸和NH3-N含量均顯著高于其他施氮處理。刈割2次處理下的CP含量最大,且有較高的WSC含量和適宜的含水量,因此在青貯過(guò)程中CP損失最小(9.7%),青貯后NH3-N含量最低,pH值低于刈割3次處理,費(fèi)氏得分較高。雖然青貯后丁酸含量高于刈割3次處理,但兩者無(wú)顯著差異。因此刈割2次處理的甜高粱更適于青貯利用。5.干物質(zhì)體外瘤胃消化特性的試驗(yàn)結(jié)果表明,增施氮肥對(duì)甜高粱飼草干物質(zhì)降解率(DMD)無(wú)顯著影響,但中性洗滌纖維降解率(NDFD)隨施氮量的增加而降低。最大產(chǎn)氣量在300 kg N·hm-2處理下達(dá)最大,但與150 kg N·hm-2和225 kg N·hm-2處理無(wú)顯著差異。發(fā)酵產(chǎn)物中,除異丁酸(IBA)和異戊酸(IVA)外,總揮發(fā)性脂肪酸(TVFA)及其組分均隨施氮量的增加而增加,在300 kg N·hm-2下達(dá)最大,但與225 kg N·hm-2處理無(wú)顯著差異,乙酸/丙酸(A/P)在225 kg N·hm-2處理下達(dá)最大。(CO2/CH4(CCP)則隨施氮量的增加而減小,說(shuō)明增施氮肥雖然會(huì)增加CH4產(chǎn)量,但同時(shí)也有利于提高乙酸濃度。DMD和NDFD隨刈割次數(shù)的增加而增大,但最大產(chǎn)氣量卻隨刈割次數(shù)的增大而減小。發(fā)酵產(chǎn)物中除IBA外,TVFA及其組分均隨刈割次數(shù)的增加而降低,但刈割2次處理下的AA和A/P均顯著高于其他刈割處理,且CCP高于其他刈割處理。施氮處理對(duì)青貯飼料體外瘤胃發(fā)酵特性的影響與青貯原料基本一致,但刈割處理對(duì)青貯飼料體外瘤胃發(fā)酵特性的影響與青貯原料稍有不同。刈割2次處理下的青貯原料,其發(fā)酵產(chǎn)生的PA與其他刈割處理無(wú)顯著差異,而青貯飼料發(fā)酵產(chǎn)生的PA顯著低于其他別割處理,說(shuō)明刈割2次處理的甜高粱青貯后,其瘤胃發(fā)酵類(lèi)型更趨向于乙酸型。綜合分析發(fā)酵酸和產(chǎn)氣量,施氮量150 ～ 225 kgN·hm-2,全生長(zhǎng)季內(nèi)刈割2次處理下的甜高粱,更有利于瘤胃微生物的發(fā)酵。綜上所述,甜高粱在長(zhǎng)江下游農(nóng)區(qū)可以用作青貯作物進(jìn)行栽培利用,在其生長(zhǎng)期內(nèi)施氮225 kgN·hm-2,刈割2次可獲得較高的生物產(chǎn)量和較好的飼草品質(zhì)。
[Abstract]:Farming area grass planting is an important way to realize the modernization of animal husbandry in China and to promote the coordinated development of three yuan planting structure for grain, economy and forage crops. The lower reaches of the Yangtze River are located in subtropical zone, rich in precipitation and abundant in heat, and have great potential for developing agricultural grass planting. In addition, there is a lack of suitable varieties and cultivation techniques. In addition, the region has high temperature and rain, and the processing and modulation of hay are limited. Silage is an important means to ensure the supply of coarse feed for the whole year. Therefore, the selection of silage crops suitable for local ecological environment and the development of a matching high-yield cultivation and utilization technology are developed for the farmers in the lower reaches of the Yangtze River. The continuous development of planting grass and raising livestock is of great significance. The sweet sorghum (Sorghum bicolor) is a multipurpose C4 plant with strong resistance, wide adaptability, high biological yield and good regeneration. It is a fine feeding crop in arid areas. In this study, the dry matter production performance, nutritional value, silage quality and utilization value of sweet sorghum (cv.Hunnigreen) were studied with silage corn as reference. The feasibility of sweet sorghum used as a silage crop in the lower reaches of the Yangtze River was demonstrated. In addition, through a series of field experiments and laboratory analyses, the effects of nitrogen application level and cutting times on the production performance, nitrogen utilization rate, photosynthesis, nutrient value, silage fermentation quality and the fermentation characteristics of dry matter in vitro were studied. The key techniques for high yield cultivation and silage utilization of Sweet Sorghum in the lower reaches of Changjiang River were put forward. The main results are as follows: (1.) the dry matter (DM), crude protein (CP) and digestible dry matter yield of sweet sorghum are much higher than silage corn, 1.54, 1.47 and 1.73 times of silage corn, respectively. The stability is better than silage corn. The nitrogen application test of sweet sorghum used as a silage crop in the lower reaches of the Yangtze River for.2. for two years shows that the suitable nitrogen application amount of Sweet Sorghum in the lower reaches of the Yangtze River is 200~400 kg N. Hm-2. In the range of nitrogen application, the yield of DM is high, the utilization rate of nitrogen is high and the nitrogen loss is less. Plant height is the main agronomic character determining DM yield and is not affected by nitrogen application level. The effect of stem leaf ratio and leaf area index on DM yield is different at different nitrogen application levels. When nitrogen application level is lower than 100 kg N. Hm-2, the direct effect of stem and leaf ratio on DM yield is the most (P=0.925), and the direct effect of leaf area index on DM yield is minimal (P=0). .162); when the level of nitrogen application was 200kgN hm-2 and 300kgN. Hm-2, the effect of stem and leaf ratio on the yield of DM decreased (P=0.073), and the direct effect of leaf area index on DM yield increased (P=0.797), while the direct effect of stem leaf ratio and leaf area index on the yield of DM was negative when the nitrogen level was 400 kg N. The results showed that reasonable planting at high nitrogen level was more critical for high yield of sweet sorghum, while at low nitrogen level, the balance of harvest time on Yield and quality of forage forage showed that.3. nitrogen level and mowing times had significant effect on Photosynthesis of sweet sorghum. The net photosynthetic rate (Pn) of leaves increased with the increase of nitrogen application and mowing times. Addition, at 300 kg N hm-2 nitrogen application level, mowing 3 times the maximum value. The apparent quantum efficiency (AQY) of leaves, light saturation point (LSP) and carboxylation efficiency (CE) also reached the maximum value under the 3 treatment, and significantly higher than other treatment combinations. However, the dark respiration rate (Rd) increased under high nitrogen and high frequency mowing. Therefore, the dry matter yield of sweet sorghum did not reach the maximum value at the same time with Pn at the same time of cutting 3 times, indicating that the proper balance between the nitrogen level and the mowing times is the key to improve the photosynthetic capacity of the sweet sorghum. The nitrate reductase activity (NRA) increased, and the nitrogen level and cutting times of.4. had a significant effect on the nutritional value of sorghum forage and the quality of the silage fermentation. The results showed that the content of CP and soluble carbohydrate (WSC) increased with the increase of nitrogen application, and reached the maximum value at 300 kg N hm-2 and 225 kg N. Hm-2 respectively. The different response to nitrogen fertilizer resulted in the difference of the final silage fermentation quality. When the amount of nitrogen fertilizer was more than 225 kg N hm-2, the pH value and lactic acid content of the silage sweet sorghum were not significantly increased, and the content of butyric acid and NH3-N was significantly higher than that of other nitrogen treatments. The content of CP under the mowing treatment was the largest, and the content of WSC and the suitable water content were higher, therefore, the content of WSC and the appropriate water content were higher. In the process of silage, the loss of CP was the lowest (9.7%), the content of NH3-N was the lowest after silage, and the value of pH was lower than that of mowing 3 times. Although the content of Fermor was higher than that of 3 times of mowing, there was no significant difference between the two treatments. Therefore, the sweet sorghum which was mowing 2 times was more suitable for the experiment of the digestion characteristics of the rumen in the silage using.5. dry matter in vitro. There was no significant effect on the dry matter degradation rate (DMD) of the sweet sorghum forage, but the degradation rate of neutral detergent fiber (NDFD) decreased with the increase of nitrogen application. The maximum gas yield reached the maximum at 300 kg N. Hm-2 treatment, but no significant difference was found between the 150 kg N. Hm-2 and 225 kg N. Hm-2. The total volatile fatty acid (TVFA) and its components increased with the increase of nitrogen application, reaching the maximum at 300 kg N. Hm-2, but there was no significant difference from 225 kg N hm-2 treatment. Acetic acid / propionic acid (A/P) reached the maximum under 225 kg N. Hm-2 treatment. The concentration of.DMD and NDFD increased with the increase of mowing times, but the maximum gas yield decreased with the increase of mowing times. Except for IBA, the TVFA and its components decreased with the increase of mowing times, but the AA and A/P under 2 treatments were significantly higher than other mowing treatments, and CCP was higher than the other mowing. The effect of nitrogen treatment on the fermentation characteristics of silage in vitro was basically the same as that of silage, but the effect of Mowing on the rumen fermentation characteristics of the silage was slightly different from the silage material in vitro. There was no significant difference between the PA and the other mowing treatments of the 2 times of mowing, but the fermenting of the silage was fermented. The production of PA was significantly lower than other cutting treatments, indicating that the rumen fermentation type was more inclined to acetic acid after the 2 treatment of sweet sorghum silage. The fermentation acid and gas yield, the nitrogen application amount of 150~225 kgN. Hm-2, and the sweet sorghum under 2 treatments in the whole growing season were more beneficial to the fermentation of the rumen microorganism. Sorghum can be used as a silage crop for cultivation and utilization in the lower reaches of the Yangtze River, with 225 kgN hm-2 nitrogen applied during its growth period, and high biological yield and better forage quality can be obtained by cutting 2 times.

【學(xué)位授予單位】：南京農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：S54
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本文編號(hào)：1823758