According to the amount of no3 ( superscript - ) - n in the deep layer soil during the growth of winter wheat , irrigation and fertilization help to no3 ( superscript - ) - n leaching , so it was very easy to seep into groundwater and pollute the environment 在冬小麦的整个生育期中，拔节期的追肥灌水有助于硝态氮向土壤深处移动，甚至有可能淋洗出根层，对地下水产生影响。
The elongation stage is the key and sensitive stage , the n fertilizer applied at this stage could not only increase the yield of winter wheat but also increase the content of free amino acid and protein of grain , and improve the quality of grain protein 冬小麦水氮高效的关键期和敏感期在拔节期，这个时期施氮可以增加子粒中游离氨基酸及蛋白质含量，提高其质量。
Based on 2 - d - optimum orthogonal design field experiment in the jointing - heading period of phleum pratense l . , the results show that potassium content is the most productive on the seed yield , phosphorus comes next and nitrogen the least 摘要采用二因素d -饱和最优设计，通过猫尾草拔节抽穗期的根氮、磷、钾和茎叶氮、磷、钾的含量对其种子产量和产量因子进行灰关联熵分析。
Results show that the growth of plants is limited , growth of root is enhanced , water consumption is reduced , water use efficiency increase apparently , yield has little reduce when reducing irrigation water and detaining irrigation time properly 结果显示：分蘖拔节期适当减少灌水量并推迟灌水时间，能抑制春小麦地上部分的生长，促进根系生长，减少总耗水量，提高水分利用率。
The maximum influence of drought stage upon rice yield is the jointing - booting stage ; the second influence stage is earing stage and the suitable water deficiency in tillering and filling stage can ' t bring tremendous effects on yield of rice 不同阶段的不同程度受旱对水稻生长发育的影响不尽相同，相同程度受旱对产量影响最大的阶段为拔节孕穗期；抽穗开花期次之，在分蘖期和灌浆期实施一定程度的水分亏缺不会对产量构成较大影响。
The results indicated : ( 1 ) during the jointing stage of winter wheat , the differences of catalase activity among different measures of soil water utilization are significant in shallow soil , in which the catalase activity of furrow planting with straw mulch is the highest and that of row - spacing - reduced and close planting is the lowest ; ( 2 ) the trends of catalase activity versus depth are almost the same for different treatments , looking like an inverse s ; ( 3 ) for furrow growing without mulch , the activity of soil catalase in the furrow is higher than that in the ridge ; ( 4 ) soil catalase activity reflects some effects from different techniques of soil water utilization and may be used as a indicator for micro - eco - environment in the fields 初步分析得出： ( 1 )冬小麦拔节期，采用不同土壤水利用技术的冬小麦田浅层土壤过氧化氢酶活性差异明显，以沟播不盖秸秆处理的过氧化氢酶活性最强，缩行密植处理的最弱； ( 2 )土壤过氧化氢酶活性随深度的变化趋势大体一致，呈反s形； ( 3 )沟播不盖秸秆处理沟中土壤过氧化氢酶活性明显高于垄上； ( 4 )土壤过氧化氢酶对于田间微生态环境具有指示作用，在一定程度上反映了土壤水利用技术对微生态环境的影响。
The result of experimentation on coupling effect of water and fertilizers on spring corn in the three gorges reservoir area indicate that water stresslead the effect low of highness and lai , and the most effect is made in shooting stage ; it has a significant positive correlation between the yield of corn and biomass , and hasn ' t none significant positive correlation between the yield of corn and the weight of roots ; the coupling effect of water and n is significant , but the coupling effect of water and k is not significant , the maximum yield of corn condition fitting - water and medium n , corn absorbs n has a threshold value during the growth , and using superfluous n is able to prick up soil drought and crop drought ; water is the leading factor which effects the yield of corn , next is n and k 摘要三峡库区春玉米盆栽水肥耦合试验研究结果表明，水分胁迫导致玉米株高和叶面积指数降低，以拔节期受到影响最大；玉米产量与生物量呈显著正相关关系，产量与根重无显著正相关关系；水氮耦合效应显著，适宜水分和中氮处理下玉米的产量最高，玉米生长发育对氮肥的吸收存在一定的阈值，过多施用氮肥会加剧土壤干旱和作物干旱，水和钾耦合效应对玉米产量影响不显著；水分是影响玉米产量的主导因素，其次是氮效应和钾效应。
Pot experiments materials were carried out to determine the cold hardiness of six varieties cultivated popularly in henan , named bainong aikang 58 , handan 6172 , yumai 49 , yumai 54 - 99 , yumai 18 , yumai 2 , under controlled temperature at seedling stage , over - wintering stage , green returned stage and jointing stage for identifying 摘要以河南省主推品种百农矮抗58 、邯郸6172 、豫麦49号、豫麦54 - 99系、豫麦18号、豫麦2号6个小麦品种为材料，通过控制各生育时期的生长温度，分别测定苗期、越冬期、返青期和拔节期各品种的抗寒能力。
Therefore , measurements of fertilization should ensure adequate n , p , k nutrient supply in the earlier and mid periods of maize growth , especially k application should be fully made before elongating stage , but a large amount of n fertilizer should be applied in tasseling and filling stages for uptake by plant to promote plump seeds so as to attain high maize yield 因此，施肥措施应保证在玉米生育早期和中期充足的氮磷钾养分供应，尤其施钾应在拔节前全部完成，但是在抽雄期和拔节期应施用大量氮促成饱满籽粒而获得玉米高产。
