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以晋西黄土区典型的苹果-玉米间作系统为研究对象,设置了双因素三水平水肥耦合试验,分析不同水肥调控措施下玉米灌浆期穗位叶光合生理特性.本试验根据玉米及苹果适宜的水分和养分条件设置9(3×3)个处理(W_1F_1、W_2F_1、W_3F_1、W_1F_2、W_2F_2、W_3F_2、W_1F_3、W_2F_3、W_3F_3),设置的3个灌溉水平为:田间持水量(Fc)的50%(W_1)、65%(W_2)和85%(W_3),3个施肥量水平为:N 289 kg·hm~(-2)+P_2O_5118 kg·hm~(-2)+K_2O 118 kg·hm~(-2)(F1)、N412.4 kg·hm~(-2)+P_2O_5168.8 kg·hm~(-2)+K_2O 168.8 kg·hm~(-2)(F_2)、N 537 kg·hm~(-2)+P_2O_5219kg·hm~(-2)+K_2O 219 kg·hm~(-2)(F_3),另设一组无水肥补给的空白对照(C_K).结果表明:不同水肥调控方式对光合指标日变化趋势无明显影响,但水肥补给可提高作物净光合速率(P_n)的峰值,降低作物日水分利用效率(WUE)最大值,延长气孔开放时间,影响胞间CO_2浓度(C_i)最低值的出现及维持时间;各处理光合作用的限制因素均为非气孔因素.蒸腾速率(T_r)、气孔导度(g_s)均与距树行距离呈极显著负相关(P<0.01),水分利用效率则与距树行距离呈显著正相关(P<0.05);距树行距离平均每增加1 m,Tr可减少0.56~1.41 mmol·m~(-2)·s(-1),gs可减少0.028~0.093 mol·m~(-2)·s(-1),WUE可增加0.08~1.00μmol·mmol-1.灌水施肥可以显著提高净光合速率、蒸腾速率、气孔导度日均值;降低水分利用效率的日均值;W3F1拥有最高的净光合速率日均值(10.64μmol·m~(-2)·s(-1))、水分利用效率日均值(3.05μmol·mmol-1)、气孔导度日均值(0.295 mol·m~(-2)·s(-1))以及较低的蒸腾速率日均值(4.32 mmol·m~(-2)·s(-1)).多元回归分析结果显示,在拔节-灌浆期内,灌水总量为1300 m3·hm~(-2)、施肥总量为525 kg·hm~(-2)时,作物净光合速率最大,理论值为10.32μmol·m~(-2)·s(-1).因此,W_3F_1为最利于间作系统作物光合效率改善的水肥调控模式.
Taking the typical apple-corn intercropping system in the western Shanxi Province as the research object, a two-factor and three-level water-fertilizer coupling experiment was set up to analyze the photosynthetic characteristics of ear leaves under different water and fertilizer control measures. (3 × 3) treatments (W_1F_1, W_2F_1, W_3F_1, W_1F_2, W_2F_2, W_3F_2, W_1F_3, W_2F_3, W_3F_3) were used to set the three irrigation levels as follows: field water capacity (Fc) (W_1), 65% (W_2) and 85% (W_3) respectively. The three fertilizer levels were N 289 kg · hm -2 P 2 O 5 118 kg · hm -2 K 2 O 118 kg · hm ~ (-2) (F1), N412.4 kg · hm -2 (P 2 O 5 516.8.8 kg · hm -2 · K 2 O 168.8 kg · hm -2 · F 2 · N 537 kg · hm -2 and P 2 O 529kg · hm -2 and K 2 O 219 kg · hm -2 F_3, respectively, and a group of blank control (C_K) supplemented with no water was set up.The results showed that different water and fertilizer treatments Had no significant effect on the diurnal variation trend of photosynthetic index. However, the water and fertilizer supply could increase the peak value of net photosynthetic rate (P_n), decrease the maximum WUE, prolong the stomatal opening time and affect the intercellular CO_2 concentration ) The appearance of the lowest value and the maintenance time; each processing light The limiting factors for the co-operation were all non-stomatal factors.The transpiration rate (T_r) and stomatal conductance (g_s) were significantly and negatively correlated with the distance from the tree line (P <0.01), and the water use efficiency (P <0.05). For every 1 m increase in distance from tree row, Tr could be reduced by 0.56-1.41 mmol · m -2 · s -1, while gs could be reduced by 0.028-0.093 mol · m -1. (-2) · s (-1), and WUE increased by 0.08-1.00 μmol · mmol-1.Water fertilization could significantly increase daily net photosynthetic rate, transpiration rate and stomatal conductance, and decrease daily average water use efficiency. W3F1 The highest daily average net photosynthetic rate (10.64μmol · m -2 · s -1), daily average water use efficiency (3.05μmol · mmol -1) and average stomatal conductance (0.295 mol · m -1) ~ (-2) · s (-1)) and lower mean transpiration rate (4.32 mmol · m -2 · s -1), respectively.Multivariate regression analysis showed that during the jointing-filling stage , The total net photosynthetic rate was the highest when the total irrigation was 1300 m3 · hm -2 and the total fertilization was 525 kg · hm -2. The theoretical value was 10.32 μmol · m -2 · s (-1). Therefore, W_3F_1 is the most suitable water and fertilizer regulation mode for photosynthesis efficiency of cropping system.