Assignment help

英国地理学essay代写:农业种植

水分胁迫也被证明会导致植物养分胁迫,如养分有效性、养分的吸收和通过植物系统的运输。虽然肥料一般是用来帮助植物吸收养分的,但它被放置在较浅的深度,在有压力的情况下,这些深度会变得干燥。这就限制了植物从土壤中吸收养分的数量,从而影响植物的生长。土壤条件也是决定干旱胁迫条件的关键因素。土壤条件差导致根系发育浅,从而导致养分有效性降低,造成养分胁迫。正确的早期根系发育的重要性不可低估(爱荷华州立大学,2017)。“与根系较短的作物相比,根系较深的作物能更好地承受更长时间的水分胁迫,因为它们能在更大的土壤中寻找资源。”作物对干旱胁迫的响应是通过水分亏缺的过程来进行的,而与之相关的株系如不同植物发育水平的卷叶,玉米的干旱往往通过卷叶的方式表现在叶片上。然而,在严重的胁迫条件下,叶片组织会变灰。在观察玉米的干旱相关胁迫症状时,一天中叶片滚动发生的越早或滚动时间越长,作物所受的胁迫越大(爱荷华州立大学,2017)。爱荷华州立大学的推广和延伸得出结论:“当干旱连续四天或更长时间发生时,产量损失估计是假定的(爱荷华州立大学,2017年)。“话虽如此,但很明显,我们为什么要减少作物处于压力下的时间,以减少潜在的减产。每一发展阶段都将以不同的方式受到干旱的影响,因此了解和能够确定作物处于哪个阶段以及在这个阶段可能受到干旱相关压力影响的情况是很重要的。对于玉米来说,灌浆期是最关键的时期,而对于大豆来说,花期和结荚期是最受影响的时期,因此在这些时期的任何干旱都会大大降低产量.

英国地理学essay代写:农业种植

Moisture stress has also been shown to lead to plant nutrient stress such as nutrient availability, uptake and transport through the plant system. While fertilizer is generally placed to assist the plant in nutrients, it is placed at shallow depths and under stressful conditions these depths can become dry. This then limits the amount of nutrients the plant can uptake from the soil and could affect growth. Soil conditions are also a key role in determining drought-related stress conditions. Poor soil conditions cause shallow root development, which contributes to nutrient stress by decreased nutrient availability. “The importance of proper early root development cannot be underestimated (Iowa State University, 2017).” Crops that exhibit deep root systems are able to better withstand moisture stress conditions longer than those who exhibit short root systems, because they explore a greater volume of soil for resources. Crops respond to drought stress are conducted through the process of water deficit and correlated strains such as leaf rolling at various levels of plant development Drought in corn is often exhibited in the leaves by leaf rolling. However, in severe stress conditions greying of the leaf tissue has been observed. When observing for drought-related stress symptoms in corn, the earlier the leaf rolling occurs in the day or the longer the rolling is observed the greater the stress the crop is under (Iowa State University, 2017). Iowa State University Extension and Outreach concluded that “yield loss estimates are assumed when drought stress occurs for four consecutive days or more (Iowa State University, 2017).” With that being said, it is obvious why we want to reduce the amount of time the crop is under stress to also reduce the potential yield reductions. Each stage of development will be influenced by drought in a different way, so it is important to understand and be able to determine which stage the crop is in and what is going on during that stage that might be influenced by drought-related stress. For corn, the grain filling period is the most critical stage, while for soybean the stages of blooming and pod setting are most influenced so any drought during these stages can reduce yields considerably

本位摘自网络,并非来自ENLUNWEN的写手,仅供一些没有idea的同学阅读 请勿直接copy使用!一旦复制,TURNITIN 100%剽窃检测 切记切记。如需代写请联系我们的QQ7878393 微信同号 ,ENLUNWEN作为英国老牌靠谱代写机构有能力为同学们保驾护航!