Abstract:

To evaluate the effects of co-incorporation of rice straw and Chinese milk vetch on photosynthetic characteristics， yield and quality of rice， the conducting randomized field experiments were carried out with 6 treatments of different cultivation practices， including no fertilizer （CK）， normal nitrogen fertilizer （N）， normal nitrogen fertilizer+rice straw return （RN）， normal nitrogen fertilizer+Chinese milk vetch return （MN）， normal nitrogen fertilizer+rice straw+Chinese milk vetch return （MRN）， 60% nitrogen fertilizer+rice straw+Chinese milk vetch return （MRN60%）. The chlorophyll content （SPAD value）， net photosynthetic rate （P_n）， stomatal conductance （G_s）， intercellular CO₂ concentration （C_i） and transpiration rate （T_r）， dry matter accumulation， yield and rice quality were measured under different treatments. The results showed that， compared with CK， N， RN， MN， MRN and MRN60% treatments could significantly increase the SPAD value， P_n， G_s， yield， brown rice rate， head rice rate and protein content， and decreased the amylase content. Compared with N treatment， MRN treatment significantly increased SPAD value， P_n and G_s by 2.36%， 5.95%， 7.80%， respectively. Meanwhile， MRN treatment significantly increased dry matter accumulation at tillering stage， heading stage and milk-ripe stage by 14.77%， 3.52%， 4.95%， respectively. Especially， MRN treatment significantly improved the effective spike number， grain number and rice yield by 7.38%， 3.08% and 15.96%， respectively. Additionally， MRN treatment significantly increased the head rice rate by 4.63% and significantly reduced amylase content by 6.54%. However， MN treatment only significantly increased P_n by 4.75% compared to N treatment， MRN60% treatment only significantly reduced amylase content by 7.00% compared to N treatment. The correlation analysis showed that SPAD value， P_n and G_s extremely significantly positively correlated with effective spikes， grains per panicle， yield， brown rice rate and head rice rate. However， the SPAD value， P_n and G_sextremely significantly negatively correlated with amylase content. The SPAD value and P_n extremely significantly positively correlated with protein content， and G_ssignificantly positively correlated with protein content. In conclusion， with conventional nitrogen application， the co-incorporation of rice straw and Chinese milk vetch could significantly improve SPAD value， P_n， G_s， yield and cooking quality. With 60% nitrogen application， the co-incorporation of rice straw and Chinese milk vetch could stabilize the photosynthetic characteristics and maintain the yield and quality of rice， which could provide reference in high quality rice production.

Key words: rice straw, Chinese milk vetch, photosynthetic characteristics, yield, quality

摘要：

为评价稻秸-紫云英联合还田对水稻光合特性、产量及稻米品质的影响，采用田间随机试验，以不施氮肥为对照（CK），设置常规氮肥（N）、稻秸还田+常规氮肥（RN）、紫云英还田+常规氮肥（MN）、稻秸还田+紫云英还田+常规氮肥（MRN）、稻秸还田+紫云英还田+60%氮肥（MRN60%），共计6个处理。对不同处理下的叶绿素含量（SPAD值）、净光合速率（net photosynthetic rate，P_n）、气孔导度（stomatal conductance，G_s）、胞间CO₂浓度（intercellular CO₂ concentration，C_i）、蒸腾速率（transpiration rate，T_r）和干物质积累量、产量及稻米品质进行比较。结果表明，与CK相比，N、RN、MN、MRN和MRN60%处理均可显著提高水稻剑叶的SPAD值、P_n、G_s、稻谷产量及稻米糙米率、整精米率和蛋白含量，并显著降低直链淀粉含量。与N处理相比，在光合特性方面，MRN处理剑叶的SPAD值、净光合速率、气孔导度分别显著提高2.36%、5.95%、7.80%；在干物质积累量方面，MRN处理分蘖期、孕穗期、乳熟期的干物质积累量分别显著提高14.77%、3.52%、4.95%；在产量及构成因素方面，MRN处理的有效穗数、穗粒数、稻谷产量分别显著提高7.38%、3.08%、15.96%；在稻米品质方面，MRN处理的整精米率显著提高4.63%，直链淀粉含量显著降低6.54%。与N处理相比，MN处理仅净光合速率显著提高4.75%；MRN60%处理仅直链淀粉含量显著降低7.00%。相关分析结果表明，剑叶SPAD值、P_n和G_s均与有效穗数、穗粒数、产量、糙米率、整精米率呈极显著正相关，与直链淀粉含量呈极显著负相关；SPAD值和P_n与蛋白含量呈极显著正相关；G_s与蛋白含量呈显著正相关。综上，在常规施氮下，稻秸-紫云英联合还田可显著提高水稻剑叶的SPAD值、P_n、G_s等光合指标及水稻产量和蒸煮品质；在60%氮肥施用下，稻秸-紫云英联合还田有利于稳定水稻剑叶光合特性，保持水稻增产和品质特征，可应用于优质水稻生产。

关键词: 稻秸, 紫云英, 光合特性, 产量, 稻米品质