Determining fertilizer phosphorus requirement of upland rice

Abstract

Assessing the fertilizer phosphorus requirement (FPR) of crops is an important component of research for efficient and rational use of fertilizers. Soil and plant tests are used to determine the FPR of crops. Two methods were evaluated for determining the FPR of upland rice grown on an Ultisol in the humid forest zone of Cote d'Ivoire. The first method used a simple model based on P uptake using the equation: FPR=(Up‐U0)/PRF, where Up is P uptake at a given yield, Uo is P uptake from unfertilized soil, and PRF is the P recovery fraction of applied P. The parameters, U0, Up, and FPR were determined in field experiments for the rice cultivars grown on an Ultisol under rainfed upland conditions. The second method was based on the P applied, P uptake, and grain yield relationships for upland rice. First, P uptake at a given rice yield was determined from the relationship between total P uptake and grain yield. The amount of fertilizer P applied for the given P uptake and grain yield was then, determined from the relationship between P applied and P uptake. There was a good agreement between the observed values of FPR and the predicted values of FPR determined by the two methods. The results suggest that the simple model based on P uptake can be utilized for determining the fertilizer P requirements of crops.     

真空降水预压及水泥搅拌桩在桥坡加固中的应用

为有效治理桥头跳车现象,减小桥坡工后沉降,针对填土速率、桥台侧向位移、总沉降及分层沉降等技术参数,提出了相应的技术措施,重点对真空降水预压和水泥搅拌桩进行比较分析.分析结果认为,对软土层较薄、填土高度较低的路段,可只做浅层处理,采取换土法、石灰短桩法,辅以砂垫层、复合土工布等减小不均匀沉降;对于深层处理方法,在桥坡填土较高、填土速率较快的条件下,真空降水预压法较经济但侧向位移相对较大,水泥搅拌桩加固法侧向挤压力较小但费用较大,结合工程实践对上述问题进行了改进和探索.     

喷蒸真空热压水溶性酚醛胶杨木大片刨花板

我国防水人造板生产目前普遍采用酚醛树脂胶（PF），热压周期长，生产效率低。笔者采用南京林业大学饱和蒸汽喷蒸试验压机，压制水溶性PF胶杨木大片刨花板。结果表明，采用喷蒸真空热压（SIVP）技术，热压时间可缩短到传统热压的35％左右；板的吸水厚度膨胀率（TS）缩小33％；在相同施胶量下，板的内结合强度（IB）提高的15％，同时甲醛释放量降低约24％；但板的抗弯性能有较大幅度的下降；此外，板材芯层最低密度值比传统热压的板增高，断面密度分布趋于均匀。     

Effect of steam explosion treatments on drying rates and moisture distributions during radio-frequency/vacuum drying of larch pillar combined with a longitudinal kerf

This study was carried out to investigate the effects of steam explosion treatment on drying rates, moisture distribution, shrinking, and checking during radio-frequency/vacuum drying of Korean larch pillar combined with a longitudinal kerf. All the pillars except the nonkerf/control with high initial moisture content (MC) could be dried within 89 h from the green condition to about 15% MC. In pillars with high initial moistures or in the early stage of drying, the drying rates were sharply accelerated by steam explosion treatments. The final moisture gradients along the transverse direction were gentler for the steamexploded pillars and for pillars with a longitudinal kerf, respectively, than for the unexploded pillars and for pillars without a longitudinal kerf. The moisture gradients along the longitudinal direction on all the layers were gentler for the pillars with a longitudinal kerf than for those without the kerf. Formation of checking was significantly controlled in the pillars with a longitudinal kerf. All the steam-exploded pillars except the kerf/1-cycle, however, were more severely damaged by checks than the unexploded pillars. A prong test revealed an extremely low level of residual stress for all the dried pillars.     

喷蒸真空热压刨花板板坯内部的温度场特性

研究了喷蒸真空热压杨木大片刨花板坯内部的温度分布特征。实验结果表明,平行于热压板的板坯中心平面内的温度分布比较均匀,沿板坯厚度方向各点的温度分布差异较大。在喷蒸真空热压过程中,板坯内部的温度上升速率比传统热压快得多。     

Connect Technique of Laminated Object Manufacturing Using Metallic Materials as Modeling Materials

To solve some key problems existed in the manufacturing of metallic functional part via Laminated Object Manufacturing (LOM), a new technique using vacuum solid-state pressure diffusion weld technique to connect the metallic slice sheets is presented in this paper. The following conclusions can be draw from the experiments introduced specially: the size in the stack direction shrink at the rate of less than 1% and the shrinking is owed to regularly error, the atom-diffusion between two combined interface occurred clearly and new crystallites shaped meanwhile, shearing intension of well connected diffusion section is more than 100 MPa and micro hardness of well-knit portion is the same to matrix's. It can be proved from the result above that the vacuum solid-state pressure diffusion technique weld is a perfect technique for connecting metallic slice sheets used in the manufacturing of metallic functional part via LOM.     

延长低温牛肉制品货架期方法的研究

低温牛肉西红柿肠用可食性壳聚糖和Nisin作为涂膜保鲜液处理后,结合真空包装,分别置于常温(20℃左右)和冷藏(0￣4℃)两种不同温度下贮藏,测定不同贮藏期细菌总数、大肠杆菌、TVB-N和H2S等指标及进行感官评定。结果表明,经处理贮藏的牛肉西红柿肠的货架期均优于对照组;在20℃时,各处理组的货架期分别为30,30和60d;在4℃条件下,各处理组的货架期分别为60,60和120d以上。     

小径柞木真空干燥应力的试验研究

在真空干燥条件下,分析小径级柞木板材的应力与含水率、时间的关系,结果表明:在低温条件下,由于真空负压作用,水分蒸发速度得到了加快,干燥应力由于干燥前板材内的初始应力的差异,导致干燥过程中应力的发生、发展有所差异。根据应力表现的差异应当在干燥不同阶段及时进行调湿处理,预防板材开裂产生。     

真空糖制雪莲果的工艺优化

以雪莲果块根为原料,研究了护色、热烫、硬化、糖浓度、果胶和柠檬酸的添加量、真空度、抽空时间、抽空温度、烘制温度等因素对果脯品质的影响。通过试验得到适宜的工艺条件为:柠檬酸护色液0.5%,热烫时间2 min,氯化钙硬化液0.3%,糖质量分数60%,果胶0.25%+柠檬酸0.2%,真空度0.06 MPa,抽空时间20 min,抽空温度60℃,并在60℃下烘制24 h。该工艺条件下制作的产品质量好。     

猕猴桃—苹果复合果丹皮加工工艺研究

为了拓宽猕猴桃产品的开发途径,以猕猴桃、苹果为原料,研制猕猴桃—苹果复合果丹皮,最佳工艺配方为苹果与猕猴桃的质量比为2∶8,每100 g混合果浆里配料的添加量为:蔗糖30 g,柠檬酸4.5 g,果胶0.7 g,植物油0.5 g;最佳工艺条件为:50℃真空浓缩至可溶性固形物含量为50%左右,摊片厚度3~4 mm,50~55℃烘烤14~16 h。