To investigate the effects of growth-promoting bacteria and growth regulators on the salinity variations,rice yield and rice quality of the beach paddy,a rice planting experiment was conducted from June to November of 2020 in the coastal beach area of Nantong,Jiangsu Province.A two-factor split zone design was adopted,and the main zone was treated with seed immersion by growth-promoting bacteria,including clean water(CK),and growth-promoting bacteria of Rudong(RD)and Ningbo(NB).The second zone was treated by growth regulator spray,including clean water(W),"BiHu(0.136%Gibberellic Acid·indol-3-ylacetic Acid·brassinolide)"(T1)and"sodium nitrophenate"(T2).As the results,the salinity of irrigation water during rice cultivation ranged from 0.78 to 1.12 g·kg-1,and the soil salinity variations ranged from 1.11 to 1.87 g·kg-1 during the rice growth season in the CK,RD,and NB plots.Compared with CK,the rice yield increased by 4.65%and 1.83%in the RD and NB plots,respectively;and compared with W,the rice yield increased by 5.50%and 1.05%in the T1 and T2 plots,respectively.Compared with CK-W,the rice yield in RD-T1 increased the most by by 11.66%(P＜0.05),and the values of grain number per panicle and solid grain number were increased by 13.45%and 13.85%,respectively(P＜0.05).Compared with CK,the brown rice rate,amylose,and protein contents of rice in the RD plots were significantly reduced,but no significant effect was found on other quality indexes.According to the results of two-factor analysis,the growth regulator factor had a significant influence on panicle length,grains per panicle,filled grains per panicle and yield,while the growth-promoting bacteria factor had a significant influence on 1 000-grain weight.Moreover,a significant interaction was found between the growth regulators and growth-promoting bacteria specifically on 1 000-grain weight.In conclusion,growth-promoting bacteria combined with growth regulators had significant effect on the yield increase.Growth regulators mainly increased the number of grains per panicle and the number of solid grains,and growth-promoting bacteria mainly improved the 1 000-grain weight.This study provides a technical reference for exploring appropriate agronomic management measures to achieve the purpose of increasing rice yield in tidal flats areas.

为探明盐胁迫下缓释肥和氮肥减量对水稻生长、产量以及土壤特性的影响,以南粳5055为试材进行盆栽模拟试验,设置2个盐分水平S0(0 g/kg)和S1(1.5 g/kg)和5个氮肥处理:不施氮肥处理(CK)、常规尿素(CF)、缓释水稻专用肥(FS)、缓释水稻专用肥处理减氮10％和20％(FSA和FSB),调查分析水稻茎蘖动态、产量及其构成因素,并测定土壤基本理化性质.结果表明:(1)与S0条件相比,在S1条件下CF、FS、FSA和FSB处理的最大茎蘖数分别减少了11.86％、17.39％、14.14％和8.43％,且在S1条件下各氮肥处理的水稻达到分蘖盛期的时间相比S0条件下晚10～14 d;(2)与S0条件相比,S1条件下CF、FS、FSA和FSB处理的水稻株高、生物量、穗数、每穗粒数、千粒质量及产量均显著降低(P<0.05);在等氮施肥条件下,每穗粒数和产量在CF处理和FS处理之间没有显著差异;在化肥氮减量条件下,每穗粒数和产量FSB处理较FS、CF处理均显著降低,而FSA处理与FS、CF处理没有显著差异;(3)与S0条件相比,S1条件下CF、FS、FSA和FSB处理的氮肥农学利用率分别显著降低了32.08％、30.70％、30.85％和38.71％,氮肥偏生产力分别显著降低了18.98％、18.22％、18.20％和22.87％;无论S0还是S1条件下,FSA和FSB处理的氮肥农学利用率和氮肥偏生产力均显著高于CF和FS处理;(4)与CK相比,S1条件下CF、FS、FSA和FSB处理的电导率显著增加了54.35％、65.22％、43.48％和45.65％,速效钾含量分别显著增加了22.60％、39.57％、26.05％和31.53％.可见,盐胁迫下施用缓释肥减氮10％处理的水稻穗粒数和产量没有明显下降,且化肥氮减量10％有助于提高化肥利用效率,今后在滩涂盐碱地合理施用缓释肥并增加有机肥或通过绿肥轮作等方式可能是缓解水稻生长不利影响及土壤盐分积累的重要途径.

To explore the effects of slow/controlled release fertilizer application on rice growth, yield and rice quality under salt stress, Nanjing 5055 was used as material to conduct pot experiments. Three salt levels and four nitrogen fertilizer types were set in the experiment, three soil salt levels including 0.0（S0）, 1.5（S1） and3.0g/kg（S2）, and four nitrogen fertilizer types including urea（F1）, slow-release special fertilizer for rice（F2）,large granule urea（F3） and sulfur-coated urea（F4）. The amount of nitrogen, phosphorus and potassium fertilizer application in each treatment were the same. Treatment without nitrogen fertilizer were set up as control（CK）.The results showed that, the maximum tiller number, plant height and percentage of productive tillers of F2treatment were higher than those of other treatments under salt stress. Compared with F1 treatment, the yields of F2, F3 and F4 treatments were increased by 11.89%, 5.58% and 17.14% under S0 level, respectively. Under S1and S2 levels, the yield of F2 treatment were 30.28% and 37.20% higher than that of F1 treatment, respectively.But F3 and F4 treatments had poor yield increase. Under S1 and S2 levels, the increase of F2 yield were mainly due to the significant increase of effective panicle number and grain number per panicle and 1000-grain weight.The grain weight per panicle of F2, grain weight, 1000-grain weight and seed-setting rate of primary branch,grain weight and 1000-grain weight of the secondary branch of F2 treatment were higher than those of other treatments under salt stress. Under S1 and S2 levels, F2 treatment had higher brown rice rate, milled rice rate,gel-consistency and lower amylose and protein content. Under the conditions of this experiment, F2 treatment had the best yield increase, and had certain favorable effects on improving rice quality under salt stress. F2 treatment could alleviate the damage of salt stress to rice to a certain extent.

Plant growth-promoting rhizobacteria(PGPR) have an important contribution to the plants nutrients uptake from soil, but less research has mentioned that how function of PGPR in farmland soil of tidal flat. In this study, 5PGPR strains were isolated from topsoil of paddy and maize-wheat rotation field in reclamation areas of Nantong and Ningbo, respectively. The strains were identified by 16S rRNA gene sequence as follows: Massilia varians(M.varians), Brevundimonas nasdae(Brv.nasdae), Microbacterium flavescens(Mib.flavescens), Pseudomonas chlororaphis(Ps.chlororaphis) and Pseudomonas jessenii(Ps.jessenii). Five factors including carbon source, nitrogen source, C/N,pH and temperature were used to test the phosphorus solubilizing ability of the isolated strains. Results show that compared with the control group, Mib.flavescens and Brv.nasdae show the best phosphorus-solubilizing activity under neutral conditions(80.27-85.51 mg/L), more phosphorus(13.59-81.94 mg/L) is released by Ps.jessenii at a wide range of temperature than other strains. These three strains have good potential application in microbial fertilizer, and provide a fundamental information for the development of microbial fertilizer in the future.

To investigate the effects of rice cultivation on the short-term changes of soil characteristics and rice yield performance in the reclamation area of tidal flat aquaculture， a field experiment including 0 year’s field derived from the adjacent reclaimed land （CK， 0Y）， 1 year’s field （1Y）， 2 year’s field （2Y） and 3 year’s field （3Y） for planting rice was conducted in the reclamation area of tidal flat aquaculture. The results showed as follows. （1） In the 0-20cm surface layer， soil EC， pH， porosity， NH 4 + ， NO 3 ? ， available K and WSOC/SOC showed the decreasing trend， while soil bulk density， SOC， TN， WSOC and C/N showed the increasing trend. In the 20-40cm soil layer， EC， NH 4 + ， NO 3 ? ， SOC， TN， WSOC， WSOC/SOC and C/N showed similar trends as in the 0-20 cm soil layer. （2） In 0-20cm soil layer， SOC， WSOC， available P and C/N increased， while AK and WSOC/SOC decreased with the increase of planting years. Meanwhile， compared with those in 0Y plots， the SOC and WSOC concentrations in 1Y， 2Y and 3Y plots were increased by 32.18% and 15.90%， 34.67% and 11.82%， 111.03% and 22.72%， respectively. And 3Y plots were significantly higher than those in 1Y and 2Y plots; （3） Rice yield in 2Y and 3Y plots increased by 26.33% and 42.89% compared with 348.3kg/667m 2 in 1Y plots （P ＜ 0.05）; Correlation analysis showed that rice yield was significantly positively correlated with grain number per panicle （P ＜ 0.01）. Therefore， we concluded that cultivation of reclaimed rice in the short term could improve the soil quality， especially the content of organic carbon and water-soluble organic carbon. Meanwhile， the increase of grain number per panicle was the main reason for the increase of rice yield in tidal flat.

滨海盐土稻作改良是江苏沿海滩涂开发利用的主要技术之一.本文概述了江苏省滨海盐土稻作改良方面的研究进展,在耐盐水稻鉴定方面,筛选出了'盐稻10号'、'盐稻12'、'通粳981'、'南粳5055'、'南粳9108'、'淮稻5号'等耐盐性较强的品种;在1.5 g/kg盐胁迫下,水稻产量为非胁迫的65％～85％,在3 g/kg的盐胁迫下产量为非胁迫的40％～45％;盐胁迫对稻米加工、外观、蒸煮和食味品质均存在一定程度的不利影响;定位观测表明微咸水灌溉条件下滩涂稻田土壤盐分最高点出现在抽穗前后.在此基础上对今后滩涂稻作改良研发工作提出了3个方面的建议:(1)耐盐水稻种质筛选与品种改良;(2)滩涂稻田地力提升技术研发;(3)滩涂水稻栽培关键技术研发.

为明确不同粳稻品种在江苏沿海滩涂地区的产量和品质表现,以近期育成的23个新品种(系)为材料、其中盐稻12号为对照,在中低盐分(2g/kg)复垦滩涂地块,微咸水(矿化度0.94～2.44g/L)灌溉,比较滩涂实地盐胁迫下粳稻产量和品质的表现.结果 表明,参试品种(系)平均产量8.21 t/hm2,变幅6.19～11.74t/hm2,为邻近无盐胁迫老垦区产量的85％左右;主要的穗粒结构表现为穗多而粒少,增加穗粒数是滩涂水稻高产栽培途径之一.就稻米品质而言,滩涂中低度盐胁迫对糙米率、精米率、长宽比和食味值的影响不大,对整精米率有一定的影响,影响最大的是稻米外观品质指标垩白粒率和垩白度,在耐盐品种选育与筛选中要加强对垩白度的选择.

探明不同盐逆境水平对耐盐水稻穗部性状及产量构成因素的影响,旨在为沿海滩涂水稻种植和耐盐水稻高产育种提供科学依据.以'扬农稻1号'(V1)、'南粳5055'(V2)和'通海粳18-2'(V3)为试材,利用盐池设施设置O g/kg(S0)、1.5 g/kg(S1)、3 g/kg(S2)3个不同盐分水平,采用裂区试验,测定分析水稻穗长、稳重、每穗粒数、枝梗数、结实率等穗部性状及产量性状差异.结果 表明:(1)不同盐逆境下,S1水平下的每穗粒数和千粒重显著低于S0水平下,S2水平下的水稻产量、有效穗数、每穗粒数、千粒重及结实率均低于或显著低于S0、S1水平下;与S0水平相比,在S2水平下一次枝梗的枝梗数、总粒数、实粒数和总粒重分别降低了9.10％、8.69％、10.03％和14.47％,S2水平下二次枝梗的枝梗数、总粒数、实粒数、结实率、总粒重、千粒重分别降低了14.69％、18.05％、22.49％、8.04％、17.21％、5.95％.(2)不同水稻品种间,与非盐逆境相比,盐逆境下水稻品种的产量、每穗粒数、一二次枝梗数、一二次枝梗的总粒数、一二次枝梗的实粒数均表现为V3＞V1＞V2.(3)盐逆境对水稻的相对抑制率影响结果表明,盐逆境主要抑制水稻V1、V2的每穗粒数,特别是二次枝梗数和二次枝梗总粒数;而盐逆境对V3的水稻穗部性状的相对抑制率均较低.(4)相关性分析表明,水稻产量与每穗粒数、二次枝梗数呈极显著正相关,与二次枝梗总粒数呈显著正相关;盐逆境下水稻产量与水稻穗长、稳重、一次枝梗性状(枝梗数和总粒数)、二次枝梗性状(枝梗数、总粒数、千粒重和结实率)之间呈显著正相关.盐逆境对水稻产量会产生不利的影响,且盐逆境下水稻产量降低的主要是每穗粒数明显减少引起的,特别是水稻二次枝梗数、二次枝梗总粒数和二次枝梗总粒重明显减少引起的.

为探明沿海滩涂种植水稻对土壤微生物量碳(MBC)和水溶性有机碳(WSOC)含量的影响,并探讨滩涂稻田土壤MBC、WSOC含量与土壤因子之间的相互变化关系,在江苏沿海如东县方凌垦区,设置种稻0年(CK)、种稻2年(2Y)和种稻5年(5Y)田块处理,2017年水稻收获后进行土壤采样,测定土壤MBC含量、WSOC含量及土壤因子的变化.结果表明:(1)CK田块0～10、10～20、20～30 cm土层中MBC含量分别为126.60、113.05、98.03 mg/kg,WSOC含量分别为71.46、48.19、53.98 mg/kg;与CK田块相比,2Y和5Y田块各土层MBC含量分别显著提高了35.61％和42.59％、34.23％和43.68％、31.72％和44.64％(P<0.05),2Y和5Y各土层WSOC含量分别显著提高了20.75％和46.81％、69.14％和73.02％、30.34％和35.31％(P<0.05).(2)2Y田块0～10 cm土层有机碳(SOC)含量显著提高(P<0.05),且各土层SOC分别提高了28.16％、2.97％、8.95％;5Y田块0～30 cm土层SOC含量均显著提高(P<0.05),且各土层分别提高了82.44％、46.81％、40.71％;且MBC/SOC在滩涂土壤中均在2.05％～3.18％之间变化,WSOC/SOC均在1.04％～1.73％之间变化.(3)土壤MBC、WSOC、MBC+WSOC及SOC含量之间均存在极显著的正相关关系(P<0.01),且WSOC、MBC、WSOC+MBC含量与全氮、碱解氮和有效磷含量均呈极显著正相关(P<0.01),与速效钾含量均呈显著负相关(P<0.05);MBC、WSOC+MBC含量与电导率呈显著负相关(P<0.05).可见,滩涂土壤MBC、WSOC含量与土壤肥力变化密切相关,且滩涂种植水稻有利于提高土壤MBC和WSOC含量,这将为沿海滩涂发展水稻种植改善土壤质量提供科学依据.

缓/控释肥料是21世纪肥料发展的重要方向,对维护中国粮食安全、提高肥料利用率,实现农业生产与生态协调发展、节本增效和节能减排等方面均具有十分重要的意义.本文在总结缓/控释肥定义、作用机制、研究现状的基础上,阐述了缓/控释肥在农业生产中的应用效果和在应用及推广中存在的问题,提出了相应的对策和建议,展望了缓/控释肥的发展前景,以期为缓/控释肥的研究提供理论依据.

沿海滩涂是江苏省主要的土地后备资源,滨海盐土的开发、利用和保护已得到各级政府的高度重视.基于盐平衡指数的概念,归纳出滨海盐土的三大脱盐技术,即雨水/微咸水淋洗脱盐技术、阻止毛管水上升减少根区聚盐技术和生物脱盐技术.在具体的滩涂脱盐改土实践中江苏省通过这3种技术的集成,已形成各具特色的滨海滩涂脱盐改土技术体系,包括养鱼改土技术、稻作改土技术、秸秆覆盖旱作改土技术和秸秆覆盖造林改土技术.预计这些技术将对江苏沿海滩涂资源的开发利用提供有效的技术支撑.

为探明滩涂围垦区气候因子对不同盐分水平下土壤盐分的变化规律,于2014年5月-2015年5月在江苏如东滩涂开展试验,设低、中、高3个盐分水平,监测了土壤盐分和气候因子的动态变化.结果 表明:(1)在中-高盐水平下,表层盐分均表现为在9-12月有明显积盐作用,且在10月达到最大值分别为26.66 g/kg和14.13g/kg;在低盐下,表层和亚表层盐分均无明显的季节性变化规律,而分别在0.50～2.00 g/kg和1.20～2.90 g/kg之间波动;(2)在中-高盐水平下,表层盐分变化均与降雨量有显著的负相关,与蒸降比有极显著的正相关;在低盐下,土壤盐分与大气温度有明显的正相关.因此,若采取适当的人为措施如种植植被、覆盖等加剧降雨量对土壤盐分变化的影响,充分利用沿海降雨量比较集中的特点,可能是未来沿海滩涂降盐改土的重要措施.

为探明不同水平盐胁迫对稻米品质的影响,以耐盐性较好的常农粳8号和南粳9108为试验材料,利用盐池设施设置不同水平土壤含盐量(S0,0 g/kg;S1,1.5 g/kg;S2,3.0 g/kg;S3,4.5 g/kg;S4,6.0 g/kg)试验,研究不同水平盐胁迫对不同水稻品种的加工品质、外观品质、营养品质、稻米淀粉黏滞谱特征值以及食味品质的影响.结果表明,糙米率和精米率随着盐胁迫强度的增加而逐渐降低,而整精米率则表现为V字型变化;盐胁迫对稻米垩白度、透明度无显著影响,但强胁迫处理(S4)下垩白粒率表现为显著下降.随着盐胁迫强度的提高,RVA谱特征值并未表现为线性的增加或减少,而是表现为V型(峰值黏度、热浆黏度、崩解值)或倒V型(消减值、回复值和起始糊化温度)的变化,最低值或最高值出现在S2处理.盐胁迫对食味值和相关参数的影响方面,盐胁迫以及盐胁迫与品种互作均达显著或极显著水平,而品种的影响未达显著水平.随盐胁迫强度的增加,稻米的食味值和相关参数表现为V型(食味值、外观、黏度和平衡度)和倒V型(硬度)变化.相关分析表明,稻米食味值与峰值黏度、热浆黏度、崩解值呈显著或极显著正相关,与糙米率、蛋白质含量、消减值、回复值、起始糊化温度呈极显著负相关.

研究沿海滩涂种植水稻对土壤有机碳和碳库管理指数的影响,探讨滩涂稻田土壤有机碳与盐分变化之间的相关关系,将为评价沿海滩涂稻田土壤质量变化提供科学依据.2016年水稻收获后,在江苏沿海滩涂如东方凌垦区,设置种稻0年(CK,0-Y)、种稻1年(1-Y)和种稻4年(4-Y)田块处理进行土壤采样,测定土壤盐分、土壤有机碳(SOC)及活性有机碳(AOC),并计算碳库指数(CPI)、碳库活度指数(AI)和碳库管理指数(CMI).结果表明:(1)与CK相比,1-Y和4-Y田块在0～10、10～20和20～30 cm土层盐分均显著降低,且1-Y和4-Y田块在各土层分别降低了94.38％和92.77％、86.57％和85.94％、77.48％和77.91％(P<0.05),同时1-Y和4-Y田块之间盐分在0～30 cm土层均没有显著的差异(P>0.05);(2)1-Y和4-Y田块在0～10、10～20和20～30 cm土层有机碳均显著提高,且各层分别提高了36.11％和69.17％、37.64％和69.20％、36.42％和57.50％(P<0.05);1-Y和4-Y田块在各土层活性有机碳也均显著提高,且各层分别提高了85.63％和101.20％、89.26％和110.04％,158.70％和243.59％(P<0.05);(3)沿海滩涂种植水稻后对CPI、AI和CPMI提高均有明显的积极作用,且相比1-Y田块,4-Y田块的稻田耕层0～30 cm的CPI和CPMI均有一定的提高;(4)沿海滩涂稻田0～30 cm土层中,土壤盐分与有机碳及活性有机碳之间均具有极显著的幂函数相关(P<0.01).可见,沿海滩涂种植水稻后能降低稻田土壤盐分,提高土壤有机碳、活性有机碳及碳库管理指数,进而改善沿海滩涂稻田土壤质量和提高土壤肥力.

为探明不同地面覆盖对滩涂围垦区土壤盐分变化和肥力性质的影响,于2014年5月～2015年5月,在江苏如东东凌垦区开展了秸秆和植被覆盖的田间试验,设置对照(CK,裸地)、15 t/hm2秸秆覆盖(SM)、植被覆盖(PC,田菁-野生芥菜种植)和植被覆盖结合7.5t/hm2秸秆覆盖(PC +1/2SM)4种试验处理.结果表明:(1)与CK处理相比,覆盖处理半年后(12月),SM处理0～～40 cm土壤含盐量下降了91.0％以上(P＜0.05),而PC和PC+ 1/2SM处理0～40 cm没有明显的降盐效果(P＞0.05);SM、PC和PC+ 1/2SM处理1年后滩涂围垦区0～100 cm各土层土壤含盐量均有明显地下降,SM、PC和PC+ 1/2SM处理0～40和40～ 100 cm土壤含盐量分别下降了97.0％和83.0％以上,40.0％和30.0％以上,54.0％和33.0％以上;(2)SM和PC+ 1/2SM处理0～ 100cm土壤pH值均显著高于CK和PC处理(P＜0.05),而CK与PC处理间pH变化没有明显差异;(3)PC和PC+ 1/2SM处理显著增加了表层(0～20 cm)土壤有机碳、全氮、碱解氮含量及孔隙度,显著降低了表层土壤容重(P＜0.05),但SM处理对土壤容重、有机碳、全氮、碱解氮、有效磷等均没有明显的影响.因此,相比PC和PC+ 1/2SM处理,虽然15∥hm2秸秆覆盖措施对滩涂围垦区土壤降盐效果更为明显,但综合考虑土壤培肥和降盐效果,种植耐盐植被结合适量秸秆覆盖(如15 t/hm2秸秆覆盖)是滩涂围垦区降盐改土的重要措施之一.

为促进沿海滩涂盐碱地脱盐和开发利用,研究了三个秸秆覆盖水平——0、1.5和3 kg m-2下滨海重盐土(EC15=4.18 dSm-1)土壤盐分的动态变化规律.结果表明2种秸秆覆盖量对0 ～ 40 cm表土均具有较好的快速脱盐效果,处理后3个半月0～20 cm和20～ 40 cm的土壤盐分分别降至0.18/0.15和0.80/0.41 dS m-1.0～40 cm土层脱盐率达90％以上.回归分析表明土壤盐分含量与累积降雨量、淋洗方程(ECa/ECi与Dw/Ds间的关系)均表现为指数函数关系,模拟的效果均较好(P＜0.01).1.5 kgm-2秸秆覆盖条件下0～20 cm和0～ 40 cm土壤剖面脱盐80％需要142 mm和324 mm的累积降雨量,而3 kg m-2秸秆覆盖条件下0 ～ 20 cm和0～ 40 cm土壤剖面脱盐80％需要186 mm和316 mm的累积降雨量.两种覆盖量脱盐效果的差别主要体现在1m剖面的60～ 100 cm.秸秆覆盖增加了雨季滨海重盐土的淋洗效果,秸秆覆盖条件下滨海重滩涂脱盐80％需要320 mm的累积降雨量,江苏沿海地区雨季(6～8月)的常年雨量可满足这一要求.

选取如东县东凌垦区经自然脱盐后的轻中度盐土为研究对象,以邻近中高度盐土为对照,2014年5月～2015年4月定期采集0～20、20～40 cm土样测定土壤盐分含量,探讨主要气候因子降水量、蒸发量、温度等对轻中度盐土盐分变化的影响.结果表明:与中高度盐土相比,轻中度盐土的土壤盐分含量无明显的季节性变化特点,且表现出缓慢的下降趋势.土壤盐分含量与降水量、蒸发量存在一定程度的相关性,其中相邻取样点间盐分含量的变化与这一期间的累积降水量在0～20 cm土层存在显著的负相关.另外,降水量和蒸发量对0～20 cm土层盐分含量的影响强度高于20～40 cm土层.就温度而言,无论是平均气温还是积温与0～20、20～40 cm土层盐分含量均存在显著的正相关,其回归方程可用y=a+bx拟合.

以盐丰47、 珍珠糯、 甬优15号3个水稻品种种子为试验材料,在光照培养条件下添加1:15竹叶生物质炭水浸提液与0、10％、30％、50％、75％稀释液进行种子萌发,分别对种子发芽势、 发芽率、 发芽指数等指标进行测定.结果表明,高于30％浓度生物质炭水浸提液对3个水稻品种的种子萌发均存在一定的抑制作用,且随着浓度增加抑制越显著,但10％生物质炭水浸提液对水稻种子萌发具有一定的促进作用.因此,建议在稻田土壤改良和实际生产过程中合理添加生物质炭,不易过量施加生物质炭.

To elucidate the seasonal variations in soil salinity and its driving factors, and to explore the effects of planting Suaeda glauca and straw mulching on soil desalination and salinity controlling, a field experiment was conducted in extremely heavy saline soil of coastal areas in Rudong, Jiangsu Province. There were four treatments: control (bare land, CK), planting S. glauca (PS), straw mulching A (at 15 t·hm-2, SM-A), straw mulching 2A (at 30 t·hm-2, SM-2A). Climate factors (including rainfall, atmospheric temperature, sunshine duration, and atmospheric evaporation) and soil salinity dynamic changes were determined from May 2014 to May 2015. Results showed that: (1) The seasonal variation of soil salinity was obvious in the bare ground (CK), with the lowest (8.69 g·kg-1) during June-August and the highest (26.66 g·kg-1) during September-December. The changes of soil salinity in topsoil (0-20 cm) were more intense than that in sub-topsoil (20-40 cm), with the changes in sub-topsoil having somewhat time lag compared the topsoil. (2) Soil salinity in CK treatment had a significantly linear correlation with the cumulative rainfall and evaporation-precipitation ratio of the fifteen-day before sampling. The results from multifactor and interphase analysis indicated that the increases of rainfall would promote soil desalinization. The rise of atmospheric temperature could exacerbate soil salt accumulation in surface soil. The interaction between rainfall and atmospheric temperature would have a positive effect on soil salt accumulation. (3) PS treatment did not alter the seasonal variation in soil salinity, but it reduced soil salinity in topsoil. (4) In SM-A and SM-2A treatments, the relationship of soil desalinization rate (%, Y) and treatment time (days, X) was expressed as Logistic curve equation. Moreover, the soil desalination rate was over 95.0% in the topsoil after 90-100 days of straw mul-ching treatment and was over 92.0% in sub-topsoil after 120 days of straw mulching treatment. The soil salinity in SM-A and SM-2A treatments fluctuated below 0.60 g·kg-1 and 1.00 g·kg-1, respectively in topsoil and sub-topsoil. Considering the desalination and economic costs, a suitable amount of straw mulching (such as 15 t·hm-2) before rainy season was recommended, which would promote the soil desalinization and reclamation in extremely heavy saline soil of coastal areas.

[Objective]Rice growing is one of the widely utilized technologies for desalting, improving and exploiting tidal flat in Jiangsu coastal beach. The objective is to reveal the effects of salinity stress on rice yield, photosynthetic parameters, grain quality and starch viscosity, providing a reference and laying a theoretical basis for developing rice production in Jiangsu coastal beach.[Method]Four japonica rice varieties with better salt tolerance, Tongjing 981, Yandao 12, Yandao 10 and Nanjing 5055 were used to investigate the yield and its components, photosynthetic parameters, rice quality and starch viscosity under salinity stress (S1, 1.112 dS/m for EC1:5) and no salinity stress (S0, 0.207 dS/m, control).[Result]Compared with the control, rice yield decreased significantly under salinity stress, was only 40.5% of that of the control, panicle number per unit area had no significant difference, while grain number per panicle and 1000-grain weight also decreased significantly. The photosynthetic rate and intercellular CO2concentration decreased significantly, but stomatal induction and transpiration rate had no significant difference between S0and S1. The processing quality of rice, together with amylose content decreased significantly, the appearance quality almost remained unchanged, while protein content increased significantly. The peak viscosity, trough viscosity, final viscosity, breakdown value, consistence value showed no significant changes, the setback value and pasting temperature increased significantly.[Conclusion]Salinity stress had adverse effects on yield, photosynthetic parameters and grain quality of rice. During the critical period of salt stress on yield and quality, such as booting stage and filling stage, measures should be taken to alleviate salt stress.