长期施用含硫和含氯化肥对稻田杂草生长动态的影响

Effects of long-term applying sulfur-and chloride-containing chemical fertilizers on weed growth in paddy field

利用湖南祁阳红壤稻田长期定位试验,研究了在等量氮磷钾养分条件下,长期施用含Cl-、SO42-和Cl-+SO42-化肥水稻生育期间杂草种类和生物量的变化.结果表明:施肥34年后,施用含Cl-化肥处理水稻生育期间杂草的种类最多、总生物量(浮生杂草和湿生杂草的生物量之和)最大,早稻期间杂草平均总干物质量分别比含SO42-和Cl-+SO42-化肥处理增加了51.4%和17.6%,晚稻期间分别增加了144%和242%.含SO42-和Cl-+SO42-化肥处理稻田中浮生杂草生物量较大,而含Cl-化肥处理田间几乎没有浮生杂草生长.杂草总干物质量和湿生杂草干物质量均与土壤Cl-含量呈显著正相关(相关系数分别为0.764**和0.948**),与土壤SO42--S含量呈显著负相关(相关系数分别为0.849**和0.641*).土壤碱解氮和有效磷受土壤SO42--S、Cl-及pH的共同作用对杂草总干物质量产生影响.通过各种施肥措施维持土壤适宜pH及碱解氮、有效磷含量,提高土壤SO42--S含量、降低Cl-含量,能有效抑制南方红壤稻田中湿生杂草的生长,降低杂草总生物量.

An investigation was made at a double-rice paddy field in the Qiyang Red Soil Field Experimental Station,Hunan Province,China to study the species and biomass of weeds growing in rice（Oryza sativa L.） growth season after 34-year application of sulfur（SO42-） and chloride（Cl-）-containing chemical fertilizers under the same application rates of nitrogen（N）,phosphorus（P）,and potassium（K）.Long-term application of Cl--containing chemical fertilizer resulted in the greatest species number of weeds and the highest biomass of floating weeds and wet weeds,compared with long-term application of SO42-and Cl-＋SO42--containing chemical fertilizers.In early rice growth season,the biomass of weeds after applying Cl--containing chemical fertilizer was 51.4% and 17.6% higher than that after applying Cl-＋SO42-and SO42--containing chemical fertilizers,respectively;in late rice growth season,the increment was 144% and 242%,respectively.More floating weeds were observed after applying Cl-＋SO42-and SO42--containing chemical fertilizers,but few of them were found after applying Cl--containing chemical fertilizer.The total dry mass of weeds and the dry mass of wet weeds were positively correlated with soil Cl-content（r=0.764,P0.01 and r=0.948,P0.01,respectively）,but negatively correlated with soil SO42--S content（r=0.849,P0.01 and r=0.641,P0.05）.Soil alkali-hydrolyzable N and available P,under the co-effects of soil SO42--S,Cl-,and pH,had indirect effects on the total dry mass of weeds.By adopting various fertilization measures to maintain proper soil pH and alkali-hydrolyzable N and available P contents,increase soil SO42--S content,and decrease soil Cl-content,it could be possible to effectively inhibit the growth of wet weeds and to decrease the total biomass of weeds in double-rice paddy field.