种稻年限对盐碱土微量元素及水稻产量和品质的影响

Effects of Rice Planting Years on Saline-alkali Soil Trace Elements, Rice Yield and Quality

为加快推进种稻改良盐碱地示范推广,以宁夏银北前进农场盐碱地稻田为研究区域,试验设计种植1、2、5、10、15 a水稻处理,研究不同种稻年限对盐碱土壤pH值、全盐和有机质、5种微量元素(Fe、Mn、Cu、Zn、B)含量及水稻产量和品质的影响。结果表明:与种稻1 a相比,连续种稻5-10 a对水稻成熟期土壤pH值和全盐量的下降幅度、有机质含量的增加幅度影响较大。种稻1 a条件下土壤pH值和全盐量较种植前仅下降了0.09、0.03%,有机质含量较种植前仅增加了2.0 g·kg^?1,而种稻5-10 a条件下,对应的pH值和全盐量下降了0.22-0.24、0.07%-0.1%,有机质含量增加了3.9-5.0 g·kg^?1;不同种稻年限对盐碱土壤中5种微量元素含量的影响程度不同,连续种稻2 a条件下水稻成熟期土壤Fe和Cu含量较种植前分别提高51.7%、68.7%,连续种稻15 a下两种元素含量的增幅为46.9%、59.3%,连续种稻15 a较连续种稻2 a土壤Fe和Cu的增幅下降了4.8%、9.4%。连续种稻5 a下水稻成熟期土壤B、Mn和Zn含量较种植前分别增加240%、24.6%和82.2%,但连续种稻15 a下的增幅分别为150%、20.6%和69.5%,连续种稻15 a较连续种稻5 a土壤B、Mn和Zn含量的增幅分别下降了90%、4%和13.7%;不同种稻年限影响水稻产量及其构成因素,连续种稻5 a显著增加水稻产量(P<0.05),产量高达11 475 kg·hm^?2,种稻年限过长(15 a)显著降低产量(P<0.05),相比连续种稻5 a,减产率达24.8%;此外,不同种稻年限对稻米品质的影响主要体现在整精米率、垩白度、垩白粒率上,连续种稻5 a稻米整精米率较种植1 a增加5.2%,垩白粒率和垩白度分别较种植1 a下降20%、2.4%,稻米品质达到2级,连续种稻15 a对垩白粒率和垩白度的影响不明显(P<0.05),但明显降低稻米精米率和整精米率(P<0.05),精米率和整精米率较种稻5 a分别下降4.7%和37.8%,稻米品质降为等外级别。综上,连续种稻5 a土壤微量元素含量及水稻产量和品质表现最优。研究结果可以为盐碱地改良种稻年限的确立和合理配施微肥提供科学依据。

To accelerate the demonstration and extension of the reclamation of saline-alkali soil by rice cultivation,this study selected paddy field of saline-alkali soil of Qianjin farm in Ningxia Yinbei Region and chose saline-alkali soil that had been planted with rice for 1 year(as control),2 years,5 years,10 years and 15 years as research objects,analyzing the changing of soil pH value,total salt content,organic matter content,five selected microelements(Fe,Mn,Cu,Zn and B)contents,and rice yield and quality under different planting years.The results showed that continuous rice planting for 5?10 years had a greater impact on the decrease of soil pH value and total salt content and the increase of organic matter content in the mature stage of rice compared with that of rice planting for 1 year.Under the condition of planting rice for one year,the soil pH value and total salt decreased by only 0.09 and 0.03%,and the organic matter content increased by only 2.0 g·kg^?1 compared with that before planting.Under the condition of planting rice for five to ten years,the corresponding pH value and total salt decreased by 0.22?0.24,0.07%?0.1%,and the organic matter content increased by 3.9?5.0 g·kg^?1.Different rice planting years have different effects on the content of 5 microelements in saline-alkali soil.Under the condition of continuous rice planting for 2 years,the Fe and Cu content in soil in the mature stage of rice increased by 51.7%and 68.7%respectively compared with that before planting.Under the condition of continuous rice planting for 15 years,Fe and Cu content in soil increased by 46.9%and 59.3%respectively,and the growth rate of Fe and Cu content in soil decreased by 4.8%and 9.4%respectively compared with that in the continuous rice planting for 2 years.The content of B,Mn and Zn in soil at the mature stage of continuous rice planting increased 240%,24.6%and 82.2%,respectively,compared with that before rice planting for 5 years.However,the increase of B,Mn and Zn in soil after continuous rice planting for 15 years was 150%,20.6%and 69.5%,respectively,and the growth rate of B,Mn and Zn in soil after continuous rice planting for 15 years decreased by 90%,4%and 13.7%,respectively,compared with that after continuous rice planting for 5 years.Different years of rice planting had an effect on rice yield and its components.Continuous rice planting for 5 years significantly increased rice yield(P<0.05),with yield as high as 11 475 kg·hm^?2;long rice planting years(15 years)significantly reduced rice yield(P<0.05),and the yield reduction rate reached 24.8%compared with continuous rice planting for 5 years.In addition,the effects of different planting years on rice quality were mainly reflected in the head rice rate,chalky rate and chalky degree.Compared with that of planting rice for one year,head rice rate increased by 5.2%in 5 consecutive years,while the chalky rate and chalky degree decreased by 20%and 2.4%respectively,and the rice quality reached level 2.The effect of continuous rice planting for 15 years on chalky rate and chalky degree was not obvious(P<0.05),but it reduced significantly the milled rice rate and head rice rate(P<0.05),and the milled rice rate and head rice rate decreased by 4.7%and 37.8%respectively compared with that of rice planting for 5 years,and the quality of rice was reduced to an extra level.The results showed that the content of soil microelements and the yield and quality of rice were the best under continuous rice planting for 5 years.This study provides scientific basis for the establishment of rice planting years in the reclamation of saline-alkali soil and the reasonable supplement and application of micro-fertilizer.