调亏灌溉对玉米生理指标及水分利用效率的影响

依据在漯北黄土高原地区的大田玉米调亏灌溉试验资料，分析了不同亏水处理对光合速率、气孔导度，蒸腾速率、根冠比、产量与耗水量以及水分利用效率等因素的影响，从亏水处理引起的气孔反应能提高光合与蒸腾之比，提示了调亏灌溉的节水增产机理。最后，从即提高产量又提高水分利用效率的双重目的出发，得到了苗期土壤含水率为５０％￣６０％田间持水量１拔节期土壤含水率为６０％￣７０％田间持水量是最佳调亏灌溉方案。     

调亏灌溉对棉花生长,生理及产量的影响

通过盆栽试验在棉花不同生育时期进行不同程度的调亏灌溉试验。结果表明,调亏灌溉对棉花株高、蕾铃脱落、成桃数等影响较显著;苗期和吐絮期重度水分亏缺、蕾铃期中度水分亏缺均有利有棉花产量的形成。棉花的光合速率和气孔阻力随土壤含水量变化的阈值约在１４％土壤含水量水平,该阈值相当于田间持水量的６０％～６５％。合理的棉花调亏灌溉制度是苗期控制水分供应,土壤含水量维持在田间持水量的５５％～６０％;蕾期和花铃期是棉     

调亏灌溉对苜蓿水分利用效率和品质的影响

从高产、优质和高效的三重目标出发，在甘肃秦王川灌区通过大田试验研究了调亏灌溉对苜蓿水分利用效率和品质的影响。结果表明：轻度水分亏缺下(土壤含水率为60%～65%田间持水量)苜蓿产量较充分灌溉(土壤含水率为65%～70%田间持水量)没有显著差异，而苜蓿的水分利用效率、粗蛋白含量与其余各处理间存在显著差异，其值均达到了最大，分别达2.10 kg/m³和13406.7 ug/g。     

调亏灌溉对棉花生长、生理及产量的影响

通过盆栽试验在棉花不同生育时期进行不同程度的调亏灌溉试验。结果表明,调亏灌溉对棉花株高、蕾铃脱落、成桃数等影响较显著;苗期和吐絮期重度水分亏缺、蕾铃期中度水分亏缺均有利于棉花产量的形成。棉花的光合速率和气孔阻力随土壤含水量变化的阈值约在14％土壤含水量水平,该阈值相当于田间持水量的60％～65％。合理的棉花调亏灌溉制度是苗期控制水分供应,土壤含水量维持在田间持水量的55％～60％;蕾期和花铃期是棉花的需水关键期,土壤含水量应分别保持在田间持水量的65％和70％左右;吐絮期应控制水分供应,土壤含水量维持在田间持水量的50％～55％。     

调亏灌溉对干旱环境下春小麦产量与水分利用效率的影响

试验研究调亏灌溉对干旱环境下春小麦产量与水分利用效率的影响结果表明,干旱环境下调亏灌溉春小麦拔节~孕穗后土壤水势低于未进行水分调亏的对照,且全生育期比对照多利用土壤水分14.3~66.5mm。调亏处理小麦产量、穗粒数、水分利用效率与充分供水对照间差异显著,并未因土壤水分亏缺而降低,甚至有较大幅度提高。试验条件下春小麦调亏的适宜土壤水分亏缺水平为营养生长期(拔节)重度水分亏缺(45%~50%田间持水量),其他生育期(孕穗、抽穗、灌浆期/生理成熟前)充分供水(65%~70%田间持水量),而最佳调亏灌溉定额为330~350mm。干旱环境下调亏灌溉春小麦产量和水分利用效率与全生育期耗水量间均呈二次抛物线关系。     

冬小麦调亏灌溉制度田间试验研究初报

大田试验结果表明，拔节期为冬小麦水分最敏感的生育时期，其次为孕穗期和抽穗～开花期，而返青～起身期充分供水则造成冬小麦明显减产。拔节期最大调亏程度为0～50cm土层土壤含水量≥田间持水量的65%，过小则导致明显减产；孕穗～抽穗期、抽穗～灌浆前期最大调亏程度为0～80cm和0～100cm土层土壤含水量≥田间持水量的60%；灌浆后期最大调亏程度为0～100cm土层土壤含水量≥田间持水量的50%，由此建立了冬小麦调亏灌溉制度。     

矿山废弃地人工草地调亏灌溉试验研究

[目的] 以草原矿产资源开发形成的排土场为研究对象，研究不同调亏灌溉处理排土场边坡人工栽培牧草生长状况、土壤含水率和坡面侵蚀的变化，为完善草原矿区废弃地植被恢复灌溉技术提供科学依据。 [方法] 设置5种调亏灌溉处理，以充分灌溉为对照(CK)，通过对比试验分析不同调亏灌溉处理对边坡人工牧草群落总盖度、地上生物量、坡面径流及水分利用效率的影响，采用秩和比法确定废弃地边坡人工草地最佳补水方案。 [结果] 草原矿区废弃地边坡人工草地建设过程中，随着亏水程度的加重，植物生长发育受到限制，当土壤含水率在土壤田间持水率的45%以下时，植物地上生物量和群落盖度下降明显(p＜0.05)；植物生长初期，坡面产沙量和径流量随着灌水量的增加显著增加(p＜0.05)，快速生长期和生长旺盛期各处理之间的产沙量、径流量变化不明显；对比各灌溉处理水平，轻度、中度调亏灌溉(土壤水分含量分别达到土壤田间持水率的55%，45%时)水分利用效率较高。 [结论] 人工草地建植效果、蓄水保土能力、灌溉水利用效率综合评价结果表明，轻度调亏灌溉(土壤水分含量达到土壤田间持水率的55%)在人工草地建植效果与水分利用效率方面结合较好，水土流失防控效果明显，可作为草原区矿山废弃地建设人工草地主要节水灌溉模式优先选择。     

不同灌溉上限对温室黄瓜结瓜期生长动态、产量及品质的影响

对不同土壤灌溉上限处理、不同栽培季节温室黄瓜结果期生长发育动态、产量、品质及水分利用效率进行了研究。结果表明，90％田间持水量为黄瓜结果期较适宜的节水灌溉上限指标，较100％田间持水量灌溉上限处理而言，春茬和秋茬均单瓜重增加、品质好、产量和水分利用效率高。     

夏玉米调亏灌溉的生理机制与指标研究

在人工控制试验条件下，采用子母盆栽土培法，以夏玉米为材料进行了调亏灌溉试验研究。结果表明，玉米调亏灌溉是可行的，可以实现节水、高产和高效的目标。适时适度地水分亏缺显著抑制蒸腾速率，而光合速率下降不明显，复水后光合速率又具有超补偿效应，光合产物具有超补偿积累，且有利于向籽粒运转与分配；抑制营养生长，增大作物根冠比，提高了根系传导力，增强了植株抗旱性。玉米节水高产的调亏灌溉指标是：调亏时段为三叶一心—拔节（七叶一心），调亏度为４５％～６５％的田间持水率（θ_ｆ），历时２１天；或拔节～抽穗调亏，调亏度为６０％～６５％，历时２１天；平均比对照增产２５．２４％，节水１５．４１％，水分利用效率提高４５．０５％。     

作物调亏灌溉的适宜时间与调亏程度的研究

作物调亏灌溉是建立在作物与水分关系基础上的一种节水高产灌溉技术。根据陕西长武、甘肃民勤等地的田间试验资料分析了适度缺水对作物产量的有益效应,表明调亏灌溉的适宜时段应该在作物的早期生长阶段。陕西长武和甘肃民勤小麦和棉花的试验结果表明,其水分亏缺程度可达到田间持水量的45%～50%,而对作物的产量没有不利影响,但可明显提高作物水分利用效率。并且讨论了调亏灌溉目前存在的一些问题。     

Yield and Yield Components of Dry Bean Genotypes as Influenced by Phosphorus Fertilization

Dry bean is an important legume for South American population, and phosphorus (P) deficiency is the most yield-limiting nutrient for crop production in South American soils. A greenhouse experiment was conducted with the objective of evaluating influence of P fertilization on grain yield and yield components of 30 dry bean genotypes. The P levels used were 0 mg P kg^?1 (natural level of the soil) and 200 mg P kg^?1 applied with triple superphosphate fertilizer. Yield and yield components were significantly influenced with P as well as genotype treatments. The P?×?genotype interactions were significant for yield as well as yield components, indicating different responses of genotypes at two P levels. Root dry weight and maximum root length were also significantly increased with the addition of P fertilization. There were also significant differences among the genotypes in the growth of root system. Based on grain yield efficiency index (GYEI), genotypes were classified as P efficient, moderately efficient, and inefficient. Among 30 genotypes, 17 were classified as efficient, 12 were classified as moderately efficient, and 1 was classified as inefficient. Yield components such as pods per plant and seeds per pod were having significant positive association with grain yield. In addition, grain harvest index (GHI) was also having significant linear association with grain yield. Hence, it is possible to improve grain yield of dry bean in Brazilian Oxisol with the addition of adequate rate of P fertilization as well as use of P-efficient genotypes.     

Root growth,nutrient uptake and use efficiency by roots of tropical legume cover crops as influenced by phosphorus fertilization

The root is an important organ which supplies water and nutrients to growing plants. Data related to root growth and nutrient uptake by tropical legume cover crops are limited. The objective of this study was to evaluate root growth of tropical legume cover crops and nutrient uptake and use efficiency under different phosphorus (P) levels. The P levels used were 0 (low), 100 (medium) and 200 (high) mg kg^?1 of soil and 5 cover crops were evaluated. Root dry weight, maximum root length, specific root length were significantly influenced by P and cover crop treatments. Maximum values of these root growth parameters were achieved with the addition of 100 mg P kg^?1 soil. The P X cover crops interaction for all the macro and micronutrients, except manganese (Mn) was significant, indicating variation in uptake pattern of these nutrients by cover crops with the variation in P rates. Overall, uptake pattern of macronutrients was in the order of nitrogen>calcium>potassium>magnesium>phosphorus (N > Ca > K > Mg > P) and micronutrient uptake pattern was in the order of iron>manganese>zinc>copper (Fe > Mn > Zn > Cu). Cover crops which produced maximum root dry weight also accumulated higher amount of nutrients, including N compared to cover crops which produced lower root dry weight. Higher uptake of N compared to other nutrients by cover crops indicated that use of cover crops in the cropping systems can reduce loss of nitrate (NO₃^?) from soil-plant systems. Increase in root length and root dry weight with the addition of P can improve nutrient uptake from the soil and less loss of macro and micronutrients from the soil-plant systems.     

基于驻波率原理的土壤水分传感器的测量敏感度分析

土壤水分测量方法中,有效测量范围(即测量敏感区域)是一个重要问题。该文运用探针的静电场分布,分析由基于驻波率(SWR)原理的快速土壤水分传感器的测量敏感度,分析了SWR型土壤水分传感器的有效测量土体,输出电压与土壤体积含水率之间的最大线形区域,得出了SWR型土壤水分传感器的最佳结构     

Molybdenum Requirements of Dry Bean with and without Liming

Molybdenum (Mo) is an essential micronutrient for crop plants, and its deficiency has been reported in many parts of the world. Two greenhouse experiments were conducted with the objective to determine Mo requirements of dry bean (Phaseolus vulgaris L.) grown on a Brazilian Oxisol with and without liming. The Mo treatments were 0, 5, 10, 15, and 20 mg kg^?1. In one experiment dolomitic lime was added at the rate of 2.5 g per kg of soil before the application of Mo treatments and incubated 5 weeks before sowing. In other experiments, Mo treatments were same as the lime-added experiment but no lime was added. Most of the growth, yield, and yield components were significantly increased with the addition of Mo in both the experiment. Growth, yield, and yield components were increased in a quadratic fashion when Mo was applied in the range of 0 to 20 mg kg^?1. Maximum shoot dry weight was obtained with the addition of 17 mg Mo kg^?1 in the experiment with Mo rates without lime and 9.69 mg Mo kg^?1 in the experiment of Mo rates with lime application. Maximum seed yield was obtained with the application of 10.48 mg Mo kg^?1 in the experiment that did not receive lime along with Mo treatments and 10.28 mg Mo kg^?1 in the experiment that received lime along with Mo treatments. Similarly, the maximum number of pods per plant was obtained with the addition of 9.33 mg Mo kg^?1 in the experiment that did not receive lime and 8.83 mg Mo kg^?1 in the experiment that did receive lime. Maximum root length was obtained with the addition of 12.38 Mo kg^?1 in the experiment that did not receive lime and 9.75 mg Mo kg^?1 in the experiment that received lime. Maximum root dry weight was obtained with the addition of 11.67 mg Mo kg^?1 in the experiment that did not receive lime and 9.28 mg Mo in the experiment that received lime. Soil properties determined after harvest of dry bean plants were not influenced significantly with the addition of Mo in the Oxisol under investigation.     

Growth of Tropical Legume Cover Crops as Influenced by Nitrogen Fertilization and Rhizobia

Tropical legume cover crops are important components in cropping systems because of their role in improving soil quality. Information is limited on the influence of nitrogen (N) fertilization on growth of tropical legume cover crops grown on Oxisols. A greenhouse experiment was conducted to evaluate the influence of N fertilization with or without rhizobial inoculation on growth and shoot efficiency index of 10 important tropical cover crops. Nitrogen treatment were (i) 0 mg N kg^?1 (control or N₀), (ii) 0 mg N kg^?1 + inoculation with Bradyrhizobial strains (N₁), (iii) 100 mg N kg^?1 + inoculation with Bradyrhizobial strains (N₂), and (iv) 200 mg N kg^?1 of soil (N₃). The N?×?cover crops interactions were significant for shoot dry weight, root dry weight, maximal root length, and specific root length, indicating that cover crop performance varied with varying N rates and inoculation treatments. Shoot dry weight is considered an important growth trait in cover crops and, overall, maximal shoot dry weight was produced at 100 mg N kg^?1 + inoculation treatment. Based on shoot dry-weight efficiency index, cover crops were classified as efficient, moderately efficient, and inefficient in N-use efficiency. Overall, the efficient cover crops were lablab, gray velvet bean, jack bean, and black velvet bean and inefficient cover crops were pueraria, calopo, crotalaria, smooth crotalaria, and showy crotalaria. Pigeonpea was classified as moderately efficient in producing shoot dry weight.     

Nutrient Uptake and Use Efficiency of Dry Bean in Tropical Lowland Soil

Dry bean is an important source of protein for the population of South America, and yield of this legume is very low in this continent. Knowledge of nutrient uptake and use efficiency of a crop is fundamental to improve yield. A greenhouse experiment was conducted to evaluate growth, nutrient uptake, and use efficiency of dry bean (Phaseolus vulgaris L., cv. BRS Valente) during the growth cycle. Plant samples were collected at 15, 30, 45, 60, 73, and 94 days after sowing. Root dry weight, maximum root length, shoot dry weight, and number of trifoliates were significantly increased in a quadratic fashion with the advancement of plant age. Root dry weight and number of trifoliates had significant positive association with shoot dry weight. Uptake of nutrients in the grain was in the order of nitrogen (N) > potassium (K) > calcium (Ca) > magnesium (Mg) > phosphorus (P) > iron (Fe) > manganese (Mn) > zinc (Zn) > copper (Cu). Hence, it can be concluded the N requirements for bean is greatest and Cu is minimal compared to other essential nutrients for grain yield. Uptake efficiency for root, shoot, and grain production was in the order of P > Mg > Ca > K > N > Cu > Zn > Mn > Fe. The greatest P-use efficiency among macro- and micronutrients can be considered a positive aspect of mineral nutrition of bean, because recovery efficiency of P in acidic Inceptsols is less than 20%.     

Root Growth,Nutrient Uptake,and Nutrient-Use Efficiency by Roots of Tropical Legume Cover Crops as Influenced by Phosphorus Fertilization

Roots are important organs that supply water and nutrients to growing plants. Data related to root growth and nutrient uptake by tropical legume cover crops are limited. The objective of this study was to evaluate root growth of tropical legume cover crops and nutrient uptake and use efficiency under different phosphorus (P) levels. The P levels used were 0 (low), 100 (medium), and 200 (high) mg kg^?1 of soil, and five cover crops were evaluated. Root dry weight, maximum root length, and specific root length were significantly influenced by P and cover crop treatments. Maximum values of these root growth parameters were achieved with the addition of 100 mg P kg^?1 soil. The P?×?cover crops interactions for all the macro- and micronutrients, except manganese (Mn), were significant, indicating variation in uptake pattern of these nutrients by cover crops with the variation in P rates. Overall, uptake pattern of macronutrients was in the order of nitrogen (N) > calcium (Ca) > potassium (K) > magnesium (Mg) > P and micronutrient uptake pattern was in the order of iron (Fe) > Mn > zinc (Zn) > copper (Cu). Cover crops which produced maximum root dry weight also accumulated greater amount of nutrients, including N, compared to cover crops, which produced lower root dry weight. Greater uptake of N compared to other nutrients by cover crops indicated that use of cover crops in the cropping systems could reduce loss of nitrate (NO₃ ^?) from soil–plant systems. Increase in root length and root dry weight with the addition of P can improve nutrient uptake from the soil and lessen loss of macro- and micronutrients from the soil–plant systems.     

模拟CCS技术CO_2泄露对C_4作物生物量的影响

模拟CCS技术CO_2泄露对C_4作物生物量的影响,以期为CCS技术CO_2泄露后可能产生的环境影响提供基础性资料。利用CO_2人工气候箱,模拟CCS技术CO_2泄露产生的高浓度CO_2环境,研究在CO_2分别为正常大气CO_2浓度(对照组),10 000,20 000,40 000,80 000mg/kg时,对玉米、高粱、谷子、糜子4种C4作物植株干重、根冠比、干湿重比的影响。试验结果表明:当CO_2浓度为10 000,20 000mg/kg时,4种C4作物植株干重逐渐增加,根冠比、干湿重比均减小,但随着CO_2浓度持续增加到40 000,80 000mg/kg时,4种C_4作物植株干重逐渐减少,根冠比、干湿重比均增大,并且随着试验天数的增加,4种C_4作物的根冠比和干湿重比会逐渐减小。在CO_2浓度为20 000mg/kg时,4种C_4作物的干重值最大,根冠比和干湿重达到最小值,此时,更利于植物地上部分的生长,其水分利用率达到最高。     

种猪体重三维预估模型的研究

在利用图像处理技术实时预估活体猪体重中,选用的预估模型对能否获得较好精准性至关重要,同时也影响图像处理算法实现的复杂性、稳定性及高效性。该文在充分考虑猪的体形特点及其与猪体重影响因素的基础上,将猪体的头部和躯干分别近似为圆锥体和圆柱体,以此建立种猪体重的三维预估模型。经与实测数据比对,表明该预估模型具有较好的准确性,为实现猪体重的无损测量提供了一种新的方法。     

基于熵权法加权的模糊C均值聚类算法研究

针对模糊C均值聚类算法不能区分数据各属性之间的不平衡性,提出了一种基于熵权法加权的模糊C均值聚类算法。该算法首先应用熵权法计算各属性的权重系数,然后对标准化之后的原始数据进行加权,最后应用模糊C均值聚类算法对加权之后的数据进行聚类。实验表明,该算法聚类准确率要明显高于未加权的模糊C均值聚类算法。