Ratooning rice has the advantages of saving production costs and improving grain yield. However, there are less reports on the effect of the combination of nitrogen fertilizer and organic materials on the soil in the ratooning rice mode. This study compared the effects of different nitrogen fertilizer combinations with organic materials on the soil properties of ratooning rice paddy fields to provide a reference for the sustainable development of ratooning rice models. A two-year (2020–2021) single-factor experiment was conducted in Jingzhou, Hubei, China. The experiment included five base fertilizer treatments: no nitrogen fertilizer (N0), base fertilizer nitrogen from conventional urea (CK), 50% base fertilizer nitrogen from conventional urea and 50% from slow-release urea (T1), biochar (T2), or animal manure (T3). The fertilization mode of T2 was only conducted in 2020, which was the same as that of CK in 2021; The fertilization modes of the other treatments were the same for both years. Compared with N0, the bulk density (BD) in the 0–20 cm soil layer at the heading stage of the main season rice and at the heading stage of the ratooning season rice decreased by 3.92%–6.15% in CK and by 4.38%–6.74% in T1, whereas the BD at the 0–40 cm soil layer during the whole growth period decreased by 9.82%–17.87% in T2 and by 9.48%–14.21% in T3. The order of soil pH in 2020 was T2>T3>N0>T1>CK. Compared with CK, pH in 2020 increased by 0.51−0.68 in T2. The order of soil pH in 2021 was T3>T2>N0>T1>CK. Compared with CK, the pH in 2021 increased by 0.14−0.32 in T3. The content of soil organic carbon (SOC) and total nitrogen (TN) in the 0–20 cm and 20–40 cm soil layers were T2>T3>T1>CK>N0. Compared with N0, other treatments increased the content of SOC and TN in the 0−20 cm soil layer by 4.79%−29.12% and 11.36%−28.49%, respectively; and they increased the contents of SOC and TN in the 20−40 cm soil layer by 5.43%−30.79% and 6.08%−20.02%, respectively. The contents of NH4+ and NO3− at the tillering and heading stages of the main season rice and the heading stage of the ratooning season rice were the highest under the CK, T1, and T3 treatments. Compared with N0, the contents of NH4+ and NO3− at the tillering stage of the main season rice increased by 131.26% and 153.59% under the CK treatment, respectively; the contents NH4+ and NO3− at the heading stage of the main season rice increased by 217.15% and 153.91%, respectively, under the T1 treatment; and the contents of NH4+ and NO3− at the heading stage of ratooning season rice increased by 246.76% and 126.70%, respectively, under the T3 treatment. Microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and urease (UR) activity in T2 and T3 were higher than in the other treatments. Compared with N0, MBC content increased by 18.29%−45.18% in T2 and 21.46%−46.10% in T3, MBN content increased by 49.25%−140.37% in T2 and 59.62%−142.57% in T3, and UR activity increased by 31.45%−225.04% in T2 and 60.83%−246.65% in T3. The β-glucosidase (BG) activity was the highest in the T3 treatment. Compared with N0, the BG activity increased by 21.26%−44.87% under the T3 treatment. A comparative analysis showed that the effect of animal manure on reducing BD and improving SOC and TN was similar to that of biochar, and its effect on improving inorganic nitrogen, microbial biomass, and soil enzyme activity was better than that of biochar. Therefore, animal manure and chemical fertilizers should be used as base fertilizers, and animal manure should replace 50% of the chemical fertilizer nitrogen.

探究复合肥、缓/控施肥、有机无机互混肥和不施氮肥对传统中稻模式和稻虾共生模式下水稻生长动态及产量的影响,为不同稻作模式下优化氮肥管理和提高水稻产量提供理论依据.采用裂区设计,2种稻作模式为主区,4种氮肥施用类型为裂区,于水稻主要生育期内调查水稻叶面积指数(LAI)和光合势(LAD)、干物质积累量(DW)和生长速率、光合特征,成熟后测定产量及产量构成因子,计算收获指数和氮肥偏生产力.结果表明:稻虾共生模式下水稻生育期延长,抽穗期LAI、抽穗期和成熟期DW、生长速率、抽穗期SPAD值和净光合速率、产量显著降低,抽穗期至成熟期LAD显著增加.常规中稻模式下未施氮处理的生殖生长期和全生育期短于3个施氮处理,稻虾共生模式下未施氮处理的营养生长期和全生育期长于3个施氮处理.有机无机互混肥的各时期LAI、LAD、抽穗期光合能力和千粒重最高,复合肥的分蘖期光合能力和抽穗期至成熟期生长速率最高,缓/控释肥的各时期DW、分蘖期至抽穗期生长速率、有效穗数、产量和氮肥偏生产力最高.缓/控释肥是两种稻作模式下水稻产量和氮肥偏生产力最高的最佳氮肥类型.

为研究不同栽培措施对江汉平原中稻的影响,采用L9(34)正交试验设计,对中稻"黄华占"连续两年采用播种期、施氮量、基本苗、水层进行不同栽培因素组合试验,探索不同栽培措施对中稻"黄华占"生长和产量的影响.结果表明,播种期和施氮量能显著影响生育期,播种期每推迟1期生育期缩短1.7～2d,施氮量每增加50kg/hm2生育期延长0.3～2d;施氮量与基本苗对产量关系密切,施氮量为150kg/hm2和移栽的基本苗60×104株/hm2时产量最高,平均达到8898.30kg/hm2;施氮量与基本苗主要通过影响单位面积有效穗进而影响产量,单位面积有效穗与产量呈显著正相关(R2=0.6859,P＜0.05).综合考虑,"黄华占"最佳的栽培因素组合为播种期4月25日,施氮量纯N 150kg/hm2,基本苗60×104株/hm2,移栽后7d内统一灌水5cm.

针对江汉平原早稻-再生稻模式不利种植越冬作物的突出问题,研究中稻-再生稻模式培肥增效可为提高土地利用率提供科学依据.以水稻品种两优1208为试验材料,针对头季稻进行施肥处理,以施磷钾肥不施氮肥为对照(CK),设置3种基肥与追肥组合处理,各处理的总有效养分相同(N-P2O5-K2O=120-63-135 kg/hm2),钾肥作基施和穗肥分2次等量施用,氮肥作基肥、分蘖肥和穗肥分3次施用,其施用比例对于处理CRF(基施缓控释复合肥)为8:0:2,对于处理CF(基施复合肥)和OCF(基施有机无机复混肥)为5:3:2.结果表明,两优1208作为再生稻用种,全生育期为156～157 d;通过观测不同施肥处理下水稻叶面积指数、SPAD值和干物质积累发现,基施复合肥可促进头季稻前期至中期生长,基施缓控释复合肥可促进头季稻后期和再生稻的生长,基施有机无机复混肥可促进再生季水稻生长.

水稻稻纵卷叶螟是我国水稻产区的主要害虫之一,生产中通常采取化学方法进行防治.然而,化学方法有残留,对环境有影响,特别是在稻虾共生模式下化学防治增加了小龙虾健康养殖的风险,因此探索利用生物多样性防治水稻病虫害十分必要.针对稻虾共生模式和传统的一季中稻模式,本研究开展了不同水稻品种混作田间试验,观察了4个品种单作(Y两优911、黄华占、美香占2号和象牙香占)和2组2个品种混作(Y两优911+美香占2号,美香占2号+象牙香占)下水稻稻纵卷叶螟发生情况,测定了水稻主要生长代谢指标.结果 表明:与稻虾共生模式相比,在传统中稻模式下,水稻卷叶率增加了173.93％,水稻的株高、茎蘖数、叶面积指数(LAI)和地上部分干物重(DW)分别高5.82％、16.44％、19.51％和15.84％;叶片的蜡质含量、SPAD和净光合速率(Pn)分别高11.09％、3.36％和6.50％;有效穗和产量分别高17.58％和20.69％.与水稻单作相比,品种混作整体上降低了卷叶率,增加了茎蘖数、LAI和DW;当叶片硅含量、蜡质含量和Pn差异较大的品种混作时,混作群体数值在两个混作品种单作的数值之间,而混作群体的SPAD通常低于两个混作品种单作的数值;混作后,有效穗数和每穗粒数处于两个混作品种单作的数值之间,而结实率和千粒重无显著差异;混作对产量的影响因品种自身和环境而异.因此,可将水稻品种混作作为稻纵卷叶螟绿色防控的有效手段.

为确定油菜适宜的施硒方式和筛选具备富硒低镉或低铅能力的优势油菜品种,在大田条件下采用播前底施活化硒矿粉(XK)、始花期叶面喷施硒叶面肥(XY)、播前底施活化硒矿粉+始花期追施硒叶面肥(XKY)对6个油菜品种进行处理,研究了不同施硒方式对油菜生长、产量以及籽粒硒、镉、铅含量的影响.结果表明,与CK相比,XY、XKY处理油菜株高、茎粗、叶片SPAD值、产量增加.其中,产量分别增加3.88％、2.17％;施用硒叶面肥第21天,XY、XKY处理叶片SPAD值分别较CK和XK处理提高9.86％、7.38％和8.42％、5.97％.与CK相比,XK、XY、XKY处理油菜籽粒硒含量分别显著增加61.64％、253.42％、289.04％,籽粒镉含量分别降低9.24％、5.88％、12.61％,但籽粒铅累积量变化较小;楚油杂79在3种硒肥处理下的平均籽粒硒含量较CK增加182.40％,平均籽粒镉含量降低10.64％.综上,3种施硒方式中,XKY处理提高油菜籽粒硒含量且降低籽粒镉含量效果最佳,可应用于油菜富硒生产;在XY和XKY处理下,楚油杂79籽粒能较好地吸收硒肥且镉积累量较低,是具备富硒低镉潜力的优势良种.

对7个小麦(Triticum aestivum L.)品种(系)施用硒叶面肥,以空白为对照,探讨硒叶面肥对小麦农艺性状、产量和籽粒硒含量的影响.结果表明:①施用硒叶面肥对小麦结实率的影响显著(F=.15> F0.05); ②施用硒叶面肥对小麦产量影响不显著(F=3.84< F0.05).施用硒叶面肥后小麦单产均值为311.82kg/667m2,比对照增加4.2%; ③施用硒叶面肥可以增加小麦籽粒的硒含量,施用硒叶面肥后小麦籽粒的平均硒含量为0.316mg/kg,比对照增加0.263mg/kg.鄂麦18、鄂麦596对硒的吸收能力较强,籽粒硒含量分别达到0.487、0.357mg/kg;鄂麦398对硒的吸收能力较差,籽粒硒含量仅为0.195mg/kg.

从国际水稻所引进了296份籼稻微核心种质,分别在三亚、深圳、杭州和荆州考察了该套核心种质的外观品质和加工品质,并筛选出优质种质资源.结果表明,有8个品种在三亚表现为优质,36个品种在深圳表现为优质,32个品种在杭州表现为优质,24个品种在荆州表现为优质.其中,IR120982、IR122232和IR117277在多种环境条件下均表现为优质,为中国南方稻区优质稻品种选育提供了优质供体亲本.

农业是国民经济的基础，是人类的衣食之源、生存之本。农业的发展状况直接影响着、左右着国民经济全局的发展。地少人多是我国农业发展长期存在的问题，经济社会的发展，城镇化程度的加深，导致这一问题日益严峻。农业发展面临许多压力，中国农业的发展必须转型，通过高技术在农业上的投入使农业发展走向新型的可持续发展之路。