间作及施氮量对宁南旱区马铃薯生理特性及品质的影响

于2019年5—10月在大田条件下，以马铃薯青薯9号和燕麦燕科1号为试验材料，设置2种种植模式（马铃薯单作、马铃薯燕麦间作，分别记为IP、JP），4种施氮水平（0、75、150、225 kg·hm^-2，分别记为N0、N1、N2、N3）的裂区试验，测定马铃薯叶片CAT、POD活性，MDA、脯氨酸、叶绿素含量及马铃薯品质。结果表明：施氮条件下，马铃薯CAT、POD活性均显著高于N0处理（P＜0.05），成熟期，JP在N3水平下CAT、POD活性及叶绿素含量较N0处理分别增高14.0%、22.5%、19.6%，N2水平下MDA及脯氨酸含量较N0处理分别降低2.1%、56.8%，现蕾期至块茎膨大期，JP的生理特性优于IP；间作和适宜的施氮量有益于马铃薯品质提高，N1、N2、N3较N0处理，IP直链淀粉含量分别增加15.9%、23.8%、12.3%，JP分别增加11.4%、45.6%、17.1%，IP支链淀粉含量分别增加3.2%、16.7%、22.8%，JP分别增加27.8%、64.6%、1.1%；可溶性糖含量在各施氮处理间无显著差异（P＞0.05）；粗蛋白含量随施氮量的增加呈先增后减的趋势，施氮量为N2时最高，IP、JP较N0分别增加3.0%、8.9%，且JP显著高于IP（P＜0.05）。由通径分析中剩余因子e=（1-R²）^1/2可知，马铃薯生理指标对支链淀粉形成的影响最大，对粗蛋白含量的影响最小，剩余因子分别为0.750、0.401。叶绿素对直链淀粉与支链淀粉形成的直接影响最大，直接通径系数分别为0.328、0.767，可通过叶绿素含量反映出块茎直链淀粉、支链淀粉及可溶性糖的含量。综上，马铃薯燕麦间作复合系统优化了马铃薯生长发育过程中的生理特性，从而达到改善品质的目标，在生产中建议的施氮量为150 kg·hm^-2（N2）。

Effects of intercropping and nitrogen application on physiological characteristics and quality of potatoes in arid areas of Southern Ningxia

This experiment used potato Qingshu 9 and oat Yanke 1 as study materials and took place from May to October 2019 under field conditions.The treatments included four nitrogen application levels of 0, 75, 150 and 225 kg·hm^-2(N0, N1, N2 and N3) and two planting modes of potato monoculture and potato\|oat intercropping (IP and JP).The activities of CAT and POD, MDA proline and chlorophyll content and quality of potato leaves were measured. The results showed that under the condition of nitrogen application, the activities of CAT and POD in potato were significantly higher than those in N0 treatment (P<0.05). At maturity, the activities of CAT, POD and chlorophyll content of JP at N3 level were 14.0%, 22.5% and 19.6% higher than those in N0 treatment respectively, and the contents of MDA and proline at N2 level were 2.1% and 56.8% lower than those in N0 treatment respectively. From budding stage to tuber expansion stage, the physiological characteristics of JP were better than that of IP. Intercropping and appropriate nitrogen application rate were beneficial to the formation of potato quality. Compared with N0 treatment, N1, N2 and N3 increased amylose content in IP by 15.9%, 23.8% and 12.3%, by 11.4%, 45.6% and 17.1% in JP, and amylopectin content by 3.2%, 16.7% and 22.8% in IP, by 27.8%, 64.6% and 1.1% in JP respectively. There was no significant difference in soluble sugar content among nitrogen application treatments (P>0.05). The content of crude protein increased first and then decreased with the increase of nitrogen application. When the amount of nitrogen application was N2, it was the highest with the increaseof 3.0% in IP and 8.9% in JP respectively compared with N0.The crude protein in JP was significantly higher than that in IP (P<0.05). From the path analysis, the remaining factor e=(1-R²)^1/2 showed that the physiological indicators of potato had the greatest impact on the formation of amylopectin and the least impact on the crude protein content. The remaining factors were 0.750 and 0.401, respectively. Chlorophyll had the greatest direct influence on the formation of amylose and amylopectin. The direct path coefficients were 0.328 and 0.767 respectively. The content of tuber amylose, amylopectin and soluble sugar was reflected by the level of chlorophyll. In summary, the potato\|oat intercropping compound system optimized the physiological characteristics of potato growth and development, thereby improving potato quality.The recommended nitrogen application rate in production is 150 kg·hm^-2 (N2).