不同密度异型莎草和水苋菜对水稻产量及稻米加工、外观品质的影响

Effects of different density of Cyperus difformis and Ammannia baccifera on rice yield,processing and appearance quality

异型莎草和水苋菜均为世界范围内水稻田危害性杂草,对水稻生产造成了严重影响。选用太湖地区常见水稻品种南粳46为材料,采用单因素试验设计,分别设计5个杂草密度,4组重复,研究不同密度异型莎草和水苋菜对水稻产量、稻米加工、外观品质及籽粒氮积累量的影响。结果表明,随着异型莎草和水苋菜密度增加,水稻的有效穗数、每穗粒数、千粒重和产量均逐渐下降,且籽粒氮积累量和稻米加工、外观品质也随之降低。当异型莎草密度为65株·m^(-2)时,水稻产量为3.28 t·hm^(-2),与空白对照相比,产量损失率达57.29%,且稻米加工、外观品质均显著下降。当水苋菜密度为250株·m^(-2)时,水稻产量为3.10 t·hm^(-2),与空白对照相比,产量损失率达59.16%,稻米加工和外观品质显著下降。异型莎草和水苋菜密度增加,均能使水稻产量、加工品质和外观品质显著降低。据试验结果可知,杂草主要通过影响水稻有效穗数、每穗粒数和千粒重影响水稻产量,而田间小气候、水肥竞争等可能是影响稻米加工和外观品质的重要原因。为保证水稻产量及稻米加工、外观品质,应当注意水稻田中下层杂草的防控。

Both Cyperus difformis and Ammannia baccifera were harmful weeds in rice fields worldwide and caused serious impacts on rice production.In this study,the common rice variety Nanjing 46 in Taihu area was selected as the material.The single factor experiment design was used to design five weed densities and four groups of repetitions.To investigate the effects of different densities of C.difformis and A.baccifera on rice yield,rice processing,and appearance quality and seed nitrogen accumulation.The results showed that the effective panicle number,grain number per panicle,1000-grain weight and yield of rice gradually decreased with the increase of density of C.difformis and A.baccifera,the seed nitrogen accumulation,processing and appearance quality of rice also decreased.When the density of C.difformis was 65 plants·m^(-2),the yield of rice was 3.28 t·hm^(-2),and the yield loss rate was 57.29%compared with the blank control.The rice processing and appearance quality were significantly decreased.When the density of A.baccifera was 250 plants·m^(-2),the yield of rice was 3.10 t·hm^(-2),and the yield loss rate was 59.16%compared with the blank control.Rice processing and appearance quality decreased significantly.Increasing density of C.difformis and A.baccifera could significantly reduce rice yield,processing quality and appearance quality.The results showed that weeds mainly affected rice yield by affecting the effective panicle number,grain number per panicle and 1000-grain weight of rice,and field microclimate,water and fertilizer competition may be an important reason for affecting rice processing and appearance quality.In order to ensure rice yield,rice processing and appearance quality,attention should be paid to the prevention and control of weeds in the middle and lower layers of rice fields.