甘肃省不同旱作区全膜双垄沟播玉米增产效果研究

对甘肃省不同旱作区全膜双垄沟播玉米增产效果的研究结果表明,在不同旱作区,全膜双垄沟播的增产效果均极显著高于半膜双垄沟播,半膜双垄沟播显著高于半膜平铺穴播;以秋季覆膜的增产效果最好,顶凌覆膜次之,播前覆膜最低。不同旱作区全膜双垄沟播玉米的增产效果从大到小依次为半干旱偏旱区、半干旱区、半湿润偏旱区。     

不同抗旱性玉米苗期叶片活性氧代谢对水分胁迫的响应

［目的］抗旱性玉米栽培和育种提供理论依据。［方法］以耐旱品种掖单13和不耐旱品种丹玉13为试材,通过盆栽试验研究了水分胁迫对玉米苗期叶片活性氧代谢水平的影响。［结果］ 与正常供水处理相比,水分胁迫下掖单13和丹玉13苗期叶片O2产生速率分别升高了28.9%、36.1%（WS 50%）和31.3%、41.9%（WS 35%）,叶片H2O2含量分别升高了16.1%、25.4%（WS 50%）和23.7%、29.8%（WS 35%）。中度水分胁迫下掖单13和丹玉13的叶片SOD和POD活性分别比对照提高了22.8%、29.9%和22%、21.7%。与正常供水处理相比,丹玉13和掖单13的叶片MDA含量分别比对照增加了22.7%、14.5%（中度胁迫）和40.2%、15.6%（重度胁迫）。重度水分胁迫下掖单13和丹玉13的AsA和GSH含量分别比对照降低了12.6%、14.2%和33.3%、44.1%。［结论］耐旱性较强的玉米品种在水分胁迫下维持活性氧代谢平衡的能力较强。     

超声波/稀H_2SO_4预处理对玉米秸秆液体发酵产纤维素酶的影响

[目的]研究超声波强化稀H2SO4预处理对玉米秸秆液体发酵产纤维素酶的影响,探索超声波强化稀H2SO4预处理玉米的最优条件。[方法]利用正交试验法研究超声波强化稀H2SO4预处理玉米秸秆,并以预处理后的秸秆为唯一碳源进行发酵,测定胞外发酵液的纤维素酶活性。[结果]当酸浴时间3h、酸浓度3．5％、超声功率150w、超声时间5h时,胞外发酵液中的纤维素酶活性最高,分别为FPA15．82 U／ml、Cx39．9U／ml、β—Glu55．94U／ml。[结论]在该组合条件下,胞外产纤维素酶具有较高的稳定性。     

甘肃中部干旱地区生活污水灌溉可行性分析

以国家级贫困县——甘肃省榆中县夏关营村农业灌溉为研究对象,通过田间试验分析比较了污水灌区与井水灌区灌溉用水成分、土壤理化性状以及玉米长势和产量,分析了榆中县生活污水灌溉农田的可行性。结果表明,生活污水氨氮、COD、总磷含量远高于井水。长期用生活污水灌溉的土壤碱解氮、有机质含量比井水灌溉土壤分别提高了106.4%和6.4%,速效磷含量减少了7.9%,污灌对土壤养分含量总体有所提高。污水灌区土壤容重小,含水率高,盐分含量小于0.1 g/kg,污灌在有效改善土壤环境的同时并未引起盐渍化。污水灌区玉米的长势优于井水灌区,污水灌区玉米干重比井水灌区高7.4%,有效提高了玉米的产量。干旱区生活污水灌溉具有一定的可行性。     

控释肥对农田氮磷流失的影响研究

[目的]研究控释肥对农田氮磷流失的影响。[方法]通过选取巢湖流域水田作物水稻和旱地作物玉米进行大田试验,分别研究了施用普通复合肥、控释复合肥和减量20%控释复合肥对农田氮磷径流流失与淋溶流失的影响。[结果]水稻和玉米氮磷的径流与淋溶流失主要发生在施肥初期,其中径流流失量均占总流失量的98%以上,而淋溶流失部分所占比例均不到2%,说明水稻和玉米营养盐的流失主要通过径流流失。相对于普通复合肥处理组,减量20%控释复合肥处理组水稻田氮磷的总流失量分别降低了60%和63%,玉米地分别降低了27.8%和34%,表明施用控释复合肥能维持作物生长后期较高的土壤养分,提高氮磷的利用效率,有效地减少雨季水稻和玉米的氮磷流失,降低农业面源污染。[结论]该研究结果表明控释肥对农田作物养分流失具有减缓作用,为控释肥的大面积推广及减轻农业面源污染等提供了科学依据和技术支撑。     

紫花苜蓿青贮为主的混合发酵饲料研究

以分别晾晒4h、8h、12h和24h后调制的紫花苜蓿青贮为主要原料,添加8％豆粕和22％玉米粉后进行二次青贮,室温贮藏45d后取样分析.结果表明：添加豆粕和玉米粉能显著改善晾晒4h、8h后青贮的紫花苜蓿青贮饲料再次青贮的发酵品质（P＜0.05）,而对于晾晒12h、24h后青贮的紫花苜蓿青贮饲料,添加组的发酵品质普遍较差;第二次青贮后,氨态氮占总氮的百分含量随着晾晒时间增加而显著降低（P＜0.05）.晾晒4h、8h后青贮的紫花苜蓿青贮饲料再添加玉米粉和豆粕调制混合发酵饲料是可行的,其中以晾晒4h后青贮的紫花苜蓿青贮饲料为原料效果最佳.     

秦州区复种甜玉米品种比较试验

对引进的11个甜玉米品种进行比较,试验结果表明:绿色超人、甜美9号、黑宝、美珍206其鲜穗长分别为19.5cm、17.0cm、18.0cm、19.4cm,达J级、L级、L级、J级标准;鲜穗粗分别为5.3cm、5.3cm、5.2cm、4.9cm;鲜穗重分别为394g、280g、269g、254g,达K级、J级、L级、L级标准。这4个甜玉米品种商品性表现较好,其中绿色超人、美珍206、黑宝表现最好。     

Container and Installation Time Effects on Soil Moisture,Temperature, and Inorganic Nitrogen Retention for an in situ Nitrogen Mineralization Method

Mineralization contributes significantly to agronomic nitrogen (N) budgets and is difficult to accurately predict. Models for predicting N‐mineralization contributions are needed, and development of these models will require field‐based data. In situ mineralization methods are intended to quantify N mineralization under ambient environmental conditions. This study was conducted to compare soil moisture and temperature in intact soil cores contained in cylinders to those in adjacent bulk soil, compare the effect of two resin‐bag techniques on water content of soil within cylinders, and assess the effect of installation duration on inorganic N retention by resins. The study was conducted at a dryland conventionally tilled corn (Zea mays L.) site and an irrigated no‐tillage corn site in eastern Nebraska. Soil in cylinders was slightly wetter (<0.05 g g^?1) and warmer (<1 °C) than adjacent soil. Soil water content was <80% water‐filled pore space (WFPS) at all sampling times and differed little between the two resin‐bag techniques. Greater soil water content and temperature conditions (though small) observed during most of the study period likely enhanced N mineralization within the cylinder compared to N mineralization in adjacent bulk soil, but the magnitude is likely much less than core‐to‐core variation normally observed in a field. Installing cylinders for more than 60 days resulted in loss of inorganic N from resins. Care is needed during installation to ensure that compaction of soil below the cylinder does not impede water movement through the intact soil core. The in situ method utilizing intact soil cores and resin bags replaced at 28‐ to 40‐day intervals is a viable method for measuring N mineralization.     

Effects of Inorganic Fertilizer Inputs on Grain Yields and Soil Properties in a Long‐Term Wheat–Corn Cropping System in South China

Abstract

A long‐term double cropping wheat (Triticum aestivum L.) and corn (Zea mays L.) experiment was conducted at Qiyang, Hunan, China, to study the effects of inorganic fertilizers on grain yields and soil properties and to identify the possible causes of yield trends. Six treatments of unfertilized control, N, NP, NK, PK, and NPK were included. The treatments (N, NP, NK, and NPK) where inorganic nitrogen (N) was added showed significant (P<0.05) yield declines of 76 to 114 kg ha^?1 yr^?1 for wheat and 94 to 260 kg ha^?1 yr^?1 for corn, respectively, except for corn yield in the NPK treatment in which the decline was not significant during a 15‐yr (1990–2005) period. Comparatively, the decline amounts in corn were much higher than in wheat. The yields of wheat and corn remained unchanged in the PK treatment. The total organic carbon (C), total N, phosphorus (P), and available P, potassium (K), copper (Cu), and zinc (Zn) contents of soil were either increased or decreased during the study period. Both the decreases of exchangeable calcium (Ca²⁺) and magnesium (Mg²⁺) and increases of exchangeable hydrogen (H⁺) and Al³⁺ contents of soil in the treatments where inorganic N was applied were significant (P<0.05). The same four treatments showed significant pH declines ranging from 0.07 to 0.12 yr^?1. Several lines of evidence point to decline of soil pH due to inorganic N fertilizer added as leading to the overall yield decline of wheat and corn. However, the yields of both crops increased significantly after lime application. In the long term, the farmers should be encouraged to use adequate lime based on a balanced approach to ensure sustainable productivity.     

收获期对中单9409和中原单32玉米秸秆主要化学成分的影响

[目的]研究收获期对中单9409和中原单32玉米秸秆主要化学成分的影响.[方法]选用玉米品种中单9409和中单元32作为试验材料,研究收获期对其秸秆主要化学成分的影响.[结果]中单9409品种秸秆在1/4乳线期营养价值最高,其他收获期营养价值差异不明显;中原单32品种秸秆在3/4乳线期营养价值最高,1/4乳线期次之,4/4乳线期最差.[结论]中单9409在冻死时收获最佳,这更有利于籽粒中营养物质的积累.