盐渍化农田调控根层磷生物有效性提高棉花产量和养分效率的研究

发布时间：2018-04-29 00:35

本文选题：棉花 + 盐渍化土壤　；参考：《中国农业大学》2015年博士论文

【摘要】：盐渍化荒地是耕地的后备土地资源,合理开发盐渍化荒地而不造成环境风险成为保障耕地面积的可行性途径之一,新疆棉花产区存在大量盐渍化土壤,淡水资源不足严重限制新疆盐渍化上地开垦和利用,同时众多限制因子制约着盐渍化农田的改良和利用,包括根际土壤磷有效性、土壤盐渍化程度和pH、根层土壤温度以及土壤微生物活性等,这些因子相互制约,消除这些限制因子,改善根系生长环境,提高根际土壤磷有效性是提高棉花养分吸收效率、促进棉花增产的有效途径。本文利用多种微生物细胞特异性大分子化合物测定方法定性和定量研究了新疆盐渍化土地开垦和利用过程中土壤盐分、养分含量及微生物群落的变化,原位条件下定量研究了盐渍化土壤中土著AM真菌对作物生长、养分吸收和耐盐性的贡献,并研究了节水滴灌模式下改善栽培措施和肥料调控技术对棉花生长和养分吸收的影响,主要结论如下： (1)盐渍化农田中,土壤盐分、养分含量和微生物群落显著受土地利用方式和利用年限的影响。盐渍化荒地开垦为农田后,土壤盐分显著降低,盐渍化荒地开垦后pH由8.9降至7.9,土壤有机碳和养分含量均显著增加,土地利用方式转变一定程度上抑制土壤微生物量生长,土壤细菌(胞壁酸)和真菌(氨基葡萄糖)生物量都降低30%,磷脂脂肪酸体现相同趋势。土地转化为棉田后,土壤盐分、养分和微生物生物量经历2个阶段,棉田种植前3年为快速改良阶段,棉田产量快速增加,盐分快速降低,土壤养分含量和微生物生物量均快速增加,真菌所占比例和革兰氏阴性细菌和阳性细菌比值增加,盐分是此阶段主要限制因子；棉田种植5年后为稳定阶段,土壤盐分、养分含量和微生物生物量均保持稳定,探寻棉花生长限制因子是棉花增产的可行途径。磷脂脂肪酸主成分分析结果表明,土地利用方式和利用年限对微生物群落结构无显著影响。 (2)盐渍化农田中,土著AM真菌能够促进作物生长和养分吸收,提高作物耐盐性。通过本研究发现,由尼龙网和PVC管组成的装置,能够较好的用于原位条件下研究土著AM真菌对植物生长和耐盐性的效应,振动对PVC装置内非菌根作物甜菜无显著影响说明此装置不会抑制装置内作物生长,不同处理间差异源于土著AM真菌对装置内宿主作物的生长和养分吸收的贡献,振动和静止处理建立了棉花和玉米两种作物低侵染率对照和高侵染率处理,土著AM真菌能够显著促进作物生物量积累和磷、氮养分的吸收,对可溶性糖和脯氨酸等渗透物质的积累也有一定的促进作用,有利于提高作物耐盐性。研究结果表明：土著AM真菌能够缓解盐渍化土壤对作物生长的抑制作用,促进作物生长和养分吸收。 (3)双膜覆盖提高根层土壤温度,促进棉花出苗。通过2011和2013年研究发现,双膜覆盖能够有效提高播种期和苗期根层土壤温度,起到良好的增温保温的作用,结合适时早播促进棉花提早1天出苗,种植20天后早播和常规播种出苗率显著提高14%和40%,能够有效延长棉花生长季,有利于棉花生长,但双膜覆盖对土壤盐分和棉花产量均无显著影响。 (4)磷肥和氮肥形态和施肥方式调控,能够促进棉花生长和养分吸收,提高棉花产量。试验结果表明：增施磷肥能够促进苗期棉花地上部生物量增加,但对棉花后期生长和产量无显著正效应,磷肥施用量相同时,磷肥形态对棉花生长无显著影响,而磷肥和氨态氮肥条施能够酸化根际土壤,促进苗期棉花生长和养分吸收,但其正效应随生育期延长而消失,蕾期和花铃期棉花将更多养分运移至地上部营养器官和生殖器官中,棉花养分吸收量显著增加,结合花铃期滴施氨态氮肥,棉花产量显著增加,磷肥和氨态氮肥调控在促进棉花生长和养分生物有效性方面具有重要的作用。通过以上研究,主要得到以下结论：①土壤盐分、养分含量和微生物群落显著受土地利用方式和利用年限的影响；②盐渍化农田中,土著AM真菌促进作物生长和养分吸收,提高作物抗盐性,合理改善栽培措施,提高土著AM真菌功能有利于进一步提高养分利用效率和作物产量；③膜下滴灌模式下,双膜早播能够通过提高地表土壤温度促进棉花出苗,促进棉花苗期生长；④盐渍化土壤中,适量磷肥和氮肥调控促进棉花生长和提高养分生物有效性,增加棉花产量。这些结果为合理改善栽培措施提高盐渍化农田中作物生长和产量、以及利用土壤微生物评价盐渍化土地改良提供了直接证据。
[Abstract]:Salinized wasteland is a reserve land resource of cultivated land , and it is one of the feasible ways to rationally develop salinized wasteland without causing environmental risk to become a guarantee cultivated land . At the same time , there exist a large amount of salinized soil in the cotton production area of Xinjiang , which limits the soil salinity , soil salinity and pH , soil temperature of root layer and soil microbial activity .

( 1 ) In salinized farmland , soil salinity , nutrient content and microbial community were significantly affected by land use pattern and service life . After reclamation of salinized wasteland into farmland , the soil salinity decreased significantly , and the soil organic carbon and nutrient contents decreased significantly .
After five years of cotton field planting , the soil salinity , nutrient content and microbial biomass were stable . The cotton growth restriction factor was the feasible way to increase the yield of cotton . The main component analysis of phospholipid fatty acid showed that the land use pattern and the service life had no significant effect on the structure of microbial community .

( 2 ) In salinized farmland , indigenous AM fungi can promote crop growth and nutrient absorption , improve the salt tolerance of crops .

( 3 ) The double - film mulching increased the soil temperature of the root layer and promoted the emergence of cotton . Through the research in 2011 and 2013 , the double - film mulching can effectively improve the soil temperature of the root layer in the seedling stage and the seedling stage , play a good role of warming and keeping warm , combine the early sowing to promote the seedling emergence rate of the cotton early 1 day , increase the growth season of the cotton and facilitate the growth of the cotton , but the double - film mulching has no significant effect on the soil salt content and the cotton yield .

The results showed that the phosphorus fertilizer and ammonia nitrogen fertilizer could promote the growth and nutrient absorption of cotton in the seedling stage , but the positive effects of phosphorus fertilizer and ammonia nitrogen fertilizer could acidify the rhizosphere soil and promote the growth and nutrient absorption of cotton .

Through the above research , the following conclusions are mainly obtained : ( 1 ) The soil salinity , nutrient content and microbial community are obviously affected by land use pattern and service life ;
( 2 ) In salinized farmland , the indigenous AM fungi promote crop growth and nutrient absorption , improve the salt tolerance of crops , improve the cultivation measures reasonably , and improve the function of the indigenous AM fungi to further improve the nutrient use efficiency and crop yield ;
( 3 ) Under the mulch drip irrigation mode , the double - film early sowing can promote the cotton seedling emergence by increasing the surface soil temperature and promote the growth of the cotton seedling stage ;
The results provide direct evidence for improving the growth and yield of crops in salinized farmland and using soil microorganisms to evaluate the improvement of salinized land .

【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：S562

【参考文献】