冬油菜施氮的增产和养分吸收效应及氮肥利用率研究

 【目的】分析当前生产条件下长江流域冬油菜施氮增产效应及氮肥利用率,为冬油菜进一步增产和提高氮肥利用率提供依据。【方法】总结2004—2006年在长江流域10个省的73个油菜肥效田间试验数据,通过增产量、增产率、偏生产力、农学效率、生理利用率及表观利用率等指标分析长江流域冬油菜施氮增产效应及氮肥利用率。【结果】长江流域油菜施氮增产效果显著,当氮肥用量为180 kg?hm-2 时,平均增产油菜籽1 109 kg?hm-2,增产率为71.7%,地上部生物总量增加72.7%,但施氮对油菜收获指数无明显影响;施氮处理收获期地上部氮、磷和钾养分吸收量分别比不施氮处理增加90.0%、55.4%和59.8%,氮素收获指数随氮肥的施用而明显下降,磷及钾素收获指数则呈现上升趋势;氮肥偏生产力、农学效率、生理利用率及表观利用率分别为14.7 kg?kg-1、6.2 kg?kg-1、18.5 kg?kg-1和34.6%。【结论】在磷、钾及硼肥基础上施用氮肥,能明显提高油菜地上部生物量及氮、磷、钾养分吸收量,从而显著增加了油菜籽产量;油菜生产的氮肥利用率还不高,改进技术措施提高利用率的空间还很大。     

稻田不同供钾能力条件下秸秆还田替代钾肥效果

【目的】研究稻田不同土壤供钾能力条件下,秸秆还田配施钾肥对水稻产量、地上部钾素累积量以及钾肥利用率的影响,为秸秆还田水稻钾肥合理施用提供科学依据。【方法】2011-2012年在鄂中、江汉平原和鄂东地区的10个县（市）选择不同供钾水平田块布置水稻试验。根据湖北省第二次土壤普查制定的速效钾分级标准,本文将土壤速效钾含量＞150 mg•kg-1的试验点如钟祥和宜城归为高钾供应能力土壤（1级水平）,简称为高钾土壤,标记为High-K;土壤速效钾含量100-150 mg•kg-1的试验点如团风、仙桃、洪湖和枝江归为中钾供应能力土壤（2级水平）,简称为中钾土壤,标记为Middle-K;土壤速效钾含量＜100 mg•kg-1的试验点如麻城、广水、鄂州和蕲春归为低钾土壤,标记为Low-K。试验共设6个处理,分别为：（1）CK（-K）;（2）+K;（3）+S;（4）S+1/3K;（5）S+2/3K;（6）S+K,其中K和S分别表示钾肥和还田秸秆,以此来考查当前推荐钾肥用量（K2O 75 kg•hm-2）对水稻的增产效果以及轮作模式下麦秆或油菜秸秆还田钾素对钾肥的替代作用。【结果】结果显示CK处理（-K）,高钾、中钾和低钾土壤的稻谷产量分别为8 372、8 710和7 767 kg•hm-2,施钾和秸秆还田均可以不同程度地增加水稻产量和地上部钾素累积量。与CK相比,高钾、中钾和低钾土壤均以秸秆还田配施钾肥处理的增产效果最显著,增产量分别为633、1 098和814 kg•hm-2,增幅分别为7.7%、12.6%和12.5%;地上部钾素累积吸收增量分别为40.2、56.5和49.3 kg•hm-2,增幅分别为15.9%、21.3%和36.8%。在当前推荐钾肥用量条件下,秸秆还田会造成高钾土壤的钾肥吸收利用率下降,但可明显提高中钾和低钾土壤的钾肥吸收利用率;同时秸秆还田也会显著降低高钾土壤的钾肥农学利用率,但对中钾和低钾土壤的钾肥农学利用率没有明显影响。同钾肥利用率相比,钾素利用率均有所降低,但中钾土壤和低钾土壤的钾素利用率要显著高于高钾土壤的钾素利用率。通过对秸秆还田条件下钾肥用量与增产率、地上部钾素累积增幅的相关性分析得出高钾土壤和中钾土壤的推荐钾肥用量偏高。根据线性加平台肥效模型拟合得出,在秸秆还田条件下,高钾土壤田块（速效钾含量＞150 mg•kg-1）适宜钾肥用量平均为38.2 kg•hm-2,比推荐用量减少49.1%;中钾土壤田块（速效钾含量100-150 mg•kg-1）适宜钾肥用量平均为60.0 kg•hm-2,比推荐用量减少20.0%;而低钾土壤田块（速效钾含量＜100 mg•kg-1）,增产效果显著,推荐钾肥用量不足。【结论】因此,短期秸秆还田条件下,高钾和中钾土壤田块,秸秆还田钾素可不同程度地替代部分化学钾肥施用;而低钾供应田块推荐用量略显不足,增施钾肥仍有较大的增产空间。     

浙江省油菜主产区氮、磷、钾肥效应与土壤测试值关系

对浙江省2006—2008年油菜“3414”试验结果进行了分析,结果表明,油菜预设最佳施肥处理(N₂P₂K₂)产量从1 665 kg/hm²至3 200 kg/hm²间变异,较低产量水平试验土壤pH偏酸、土壤速效钾含量较低。浙江省油菜施肥平均增产率氮(117.5%)>磷(45.1%)>钾(7.3%),单位N,P₂O₅,K₂O平均增产油菜籽以P₂O₅(7.0 kg) >N(4.7 kg)>K₂O(1.7 kg),不同土壤类型氮、磷、钾肥的效应有较大差异。油菜缺素处理相对产量与土壤测试值相关分析结果表明,缺氮区相对产量与土壤有机质、土壤全氮有显著的相关性,土壤有机质和全氮测试值可作为氮肥推荐施肥的指标,而土壤有效磷、速效钾与缺磷区相对产量、缺钾区相对产量相关性较差,只有50%试验点土壤有效磷与缺磷区相对产量有相关关系,70%的试验点土壤速效钾含量与缺钾区相对产量呈显著相关性,表明现有土壤有效磷、土壤速效钾测试方法对指导施肥有一定的局限性,进一步的研究需对不同土壤类型制订相应的指标体系。     

苏丹草-黑麦草轮作制中氮、磷、钾肥施用效果研究

【目的】为苏丹草-黑麦草轮作制中合理利用养分、水分及培肥土壤提供理论依据。【方法】连续3年盆栽试验研究苏丹草(Sorghum sudanense)-黑麦草(Lolium L.)轮作制中氮、磷、钾肥对饲草产量、养分吸收、水分利用及土壤养分的影响。【结果】氮、磷、钾肥配施显著增加饲草产量,2005/2006、2006/2007、2007/2008年度的饲草总量分别为1690.0、2091.3、1770.7g/pot。与CK处理(NPK配施)相比,不施氮处理(PK)的饲草产量分别减少700.7%、1256.9%、856.3%,不施磷处理(NK)分别减少426.3%、384.9%、792.3%,不施钾处理(NP)分别减少15.9%、4.4%、10.6%。氮、磷、钾肥配施促进饲草的养分吸收,3个年度NPK处理的总吸氮(N)量分别为6.36、4.91、6.85g/pot,总吸磷(P)量分别为0.79、1.01、0.82g/pot,总吸钾(K)量分别为11.58、6.36、5.62g/pot,养分利用效率显著高于其它处理。3个年度NPK处理水分生产率分别为16.5、16.1、16.2kg·m-3,明显高于其它处理。轮作体系下,土壤有机质,NP、NK、NPK处理的全氮,NP、PK、NPK处理的速效磷,NK、PK处理的缓效钾、速效钾均上升;土壤pH,NP、NPK处理的缓效钾、速效钾下降,而PK处理的全氮、NK处理的速效磷基本稳定。【结论】苏丹草-黑麦草轮作体系下,合理配施氮、磷、钾肥能持续获得高产、促进饲草养分吸收和有效改善土壤肥力。     

中国不同区域油菜氮磷钾肥增产效果

【目的】研究中国油菜氮、磷、钾肥增产效果,明确不同区域油菜施肥效果概况和区域特点,为区域推荐施肥提供理论基础。【方法】总结2005—2010年中国2 106个油菜田间试验数据,通过计算获得最高产量时氮、磷、钾肥的增产量、增产率和农学利用率,分析各油菜区域施用化肥的增产效果。【结果】中国油菜施用氮肥增产量和增产率均值分别为1 044 kg•hm-2和87.4%,主要分布在500—1 500 kg•hm-2和5%—100%范围内,99%的试验有增产效果;磷肥增产量和增产率均值分别为634 kg•hm-2和39.9%,主要分布在200—1 000 kg•hm-2和5%—40%范围内,94%的试验有增产效果;钾肥增产量和增产率均值分别为420 kg•hm-2和22.9%,主要分布在100—600 kg•hm-2和10%—40%范围内,88%的试验有增产效果。每千克氮肥（N）、磷肥（P2O5）、钾肥（K2O）平均增收油菜籽6.2、7.8和5.4 kg。长江下游冬油菜区氮、磷肥的增产效果最好,增产率均值分别为128.8%和51.3%,长江中游冬油菜区钾肥增产效果最好,增产率均值为24.6%,春油菜区氮磷钾肥施用增产效果较低,增产率均值分别为42.6%、31.6%和21.3%。【结论】中国油菜施用化肥增产效果显著,具体表现为氮肥＞磷肥＞钾肥,氮素是影响油菜产量的主要养分因素。春油菜区氮磷钾肥增产效果较差,长江下游冬油菜区氮、磷肥增产效果最好,长江中游冬油菜区钾肥增产效果最好。部分试验施用肥料不增产或肥料用量不合理,需要进一步改进施肥量,实现油菜施肥高产高效。     

Effects of Nitrogen Management on the Yield of WinterWheat in Cold Area of Northeastern China

A plot experiment including four treatments, CK (N 105 kg ha-1 as urea, including a basal N application of 35 kg ha-1 and a topdressing N 70 kg ha-1 at turned green stage) and optimized N management (OPT1, OPT2 and OPT3, applied two-thirds, one-third and two-fifths N at jointing stage, respectively, total N 60 kg ha-1), was conducted to evaluate the effects of nitrogen management on growth and N uptake of winter wheat (Triticum aestivum), Dongnong 1, which is the first highly cold tolerant winter wheat in China. Index of population quality, N uptake and yield were determined. The ear-bearing tiller rate was increased by above 12%, and the leaf area index, biomass and N uptake were significantly decreased (P<0.05) at jointing stage. OPT treatments increased the grain to leaf area ratio at heading stage, the dry matter weight and N uptake after heading by 14.3-27.9%, 11.6-28.7% and 118.1-161.8 %, respectively. The yield of the OPT treatments was increased by 14.2-37.5% compared with CK, and there was a significant difference (P<0.05) between CK and OPT1 treatments. Harvest index and N partial factor productivity (PFP, kg grain yield per kg N applied) was clearly enhanced from 0.4 and 35.6 kg, respectively for CK to an average of 0.48 (P<0.05) and 77.6 kg (P<0.05) in the OPT treatments. These results indicated that the optimized N management increased the harvest index, yield and N use efficiency by decreasing the N application rate and postponing N application time, improved wheat population quality, controlled excessive growth in the vegetative stages and increased dry matter and N accumulation rates after heading.     

Photosynthesis, Carbohydrate Storage and Remobilization During Grain Filling as Affected by Sulphur Application in Winter Wheat

Photosynthesis and carbohydrate storage and remobilization was investigated during grain filling of winter wheat (Triticum aestivum L., cv. Lumai 22) in sulphur application experiments where the available sulphur (S) content in the soil of 0-20 cm soil layer was 5.84 mg kg-1. Two levels of S were applied as S0 (0 kg S ha-1) and S1 (67.5 kg S ha-1). The results showed that net photosynthetic rate of flag leaf of S1 treatment was significantly higher than S0 treatment, and it increased gradually from anthesis to 35 DAA. Sucrose-phosphate synthase (SPS) activity and sucrose content of S1 treatment were significantly higher than those of S0 treatment. The contents of total soluble sugar, sucrose, fructose, glucose, DP3 and DP ≥ 4fructan in stem and sheath of S1 treatment were significantly higher than those of S0 treatment also. The amount of total soluble sugar and fructans remobilization from stem and sheath and the starch accumulating rate in grain of S1 treatment was significantly higher than those of S0 treatment. It is suggested that sulphur application increase photosynthate remobilization from stem and sheath to grain at later filling stage.     

湖北省油菜施硼效果及土壤有效硼临界值研究

【目的】从区域角度研究湖北省油菜主产区硼肥施用对油菜（Brassica napus L.）生长及产量的效果,确定目前生产条件下土壤有效硼临界值,为油菜科学施肥提供依据。【方法】2005～2006年在湖北省布置30个田间试验研究油菜施硼产量效应,结合土壤有效硼含量确定缺硼临界值。【结果】施硼对油菜的营养生长及产量构成因素均有促进作用,30个试验点施硼平均增产油菜籽428 kg•ha-1,平均增产率19.2%,70%的试验增产效果显著,增产量超过500 kg•ha-1的试验点占26.7%;土壤有效硼含量与施硼效果呈极显著负相关;按照不施硼产量相对于施硼处理的90%作为判断标准,土壤有效硼临界值比20年前第二次土壤普查时确立的临界值有所提高。【结论】湖北省油菜施用硼肥增产效果显著,现阶段油菜种植的土壤有效硼临界值为0.58 mg•kg-1,大约80%的地块在种植油菜时需要施硼。     

不同氮钾用量对旱地春油菜生长发育的影响及肥料效应的研究

[目的]确定青海省东部农业区春油菜的最佳氮、钾肥配比,为春油菜的配方施肥提供科学依据。[方法]以青杂305为供试品种,施肥方案采用＂3414＂不完全设计,包含氮、磷、钾3个因素,氮、钾肥各设4个水平,磷肥设1个水平,共9个处理。[结果]各施肥处理中,处理N2P2K1（N 133.80 kg/hm2、K2O 101 kg/hm2）春油菜产量最高,为5 780.67 kg/hm2;其次是处理N2P2K2（N 133.80 kg/hm2、K2O201.00 kg/hm2）,产量为5 669.50 kg/hm2。通过＂3414＂肥效试验,获得该地区春油菜肥效回归方程,得出理论氮、钾最佳施肥量,即纯N170.71 kg/hm2,K2O 88.14 kg/hm2,总施肥量258.85 kg/hm2,最佳产量为5 746.59 kg/hm2。试验区土壤氮素含量为中肥力水平,土壤钾含量为高肥力水平。氮肥农学利用率在处理N2P2K2下达到最大值;钾肥农学利用率在处理N2P2K1下达到最大值。在处理N2P2K1下获得的纯收入最高,为24 210.95元/hm2。[结论]综合分析不同施肥方法的推荐施肥量,并结合青海东部农业生产实际,建议氮、钾的施肥量分别为N 170.00 kg/hm2、K2O 85.00 kg/hm2。     

秸秆还田条件下不同供钾能力土壤水稻、油菜、小麦钾肥减量研究

【目的】研究不同供钾能力土壤在秸秆还田条件下钾肥减量施用对水稻、油菜、小麦的产量、钾素吸收量及钾肥利用率的影响,计算秸秆还田条件下3种作物的钾肥适宜用量,为秸秆还田条件下钾肥资源的合理利用及农田钾素养分管理和调控提供理论依据。【方法】2013—2015年在湖北省38个县(市)的水稻、油菜及小麦3种作物上开展秸秆还田钾肥减量施用田间试验。试验设置6个处理,分别为(1)对照,不施钾(CK);(2)施用全量化学钾肥(+K);(3)秸秆还田处理(+S);(4)秸秆还田配施50%钾肥(S+1/2K);(5)秸秆还田配施75%钾肥(S+3/4K);(6)秸秆还田配施全量钾肥(S+K)。参考不施钾肥处理的作物相对产量(即CK处理产量/+K处理产量)将土壤供钾能力分为高、中、低3个水平。【结果】不同供钾水平土壤施钾和秸秆还田均能不同程度增加水稻、油菜和小麦的产量和地上部钾素吸收量。其中,高供钾能力的土壤水稻、油菜和小麦仅通过上季作物秸秆全量还田即可满足作物高产的钾素需求;中等供钾能力的土壤3种作物可在秸秆还田条件下减少50%钾肥用量;而低供钾能力的土壤,秸秆还田条件下水稻季可减少25%钾肥用量,油菜和小麦季可减少50%钾肥用量。从土壤钾素表观平衡来看,秸秆还田可缓解土壤钾素亏缺,其中油菜季平均盈余量为14.1—152.6kg K_2O·hm~(-2),小麦季平均盈余量为25.5—95.9 kg K_2O·hm~(-2),水稻季则仍表现为钾素亏缺。在考虑秸秆钾素投入量的情况下,通过一元二次方程和线性加平台方程拟合秸秆还田条件下钾肥用量与作物产量之间的关系,以+K处理产量为标准得到秸秆还田条件下的适宜钾肥用量。结果表明,在前茬作物秸秆全量还田的条件下,供钾能力为中、高等水平的土壤3种作物钾肥适宜施用量为20—33 kg K_2O·hm~(-2),油菜钾肥施用量低于水稻和小麦;而供钾能力低的土壤上,秸秆还田土壤钾肥适宜施用量为45—49 kg K_2O·hm~(-2),油菜钾肥推荐用量高于水稻和小麦。与目前钾肥经济施用量60 kg K_2O·hm~(-2)相比,3种作物在供钾能力为中、高等水平的土壤通过秸秆还田可节省钾肥45.0%—66.7%,供钾能力低的土壤也可节省钾肥18.3%—25.0%。【结论】秸秆还田条件下水稻、油菜及小麦可以在减少18.3%—66.7%钾肥用量的同时保证作物产量,钾肥施用量减少的比例应根据土壤供钾水平进行调整。     

浙东北油菜产区土壤肥力状况及其评价

于2010年测定了杭州市桐庐县514个油菜地土壤肥力。结果表明,桐庐县油菜地土壤的有机质含量为168～300 g·kg-1,平均233 g·kg-1,土壤全氮含量为093～234 g·kg-1,平均173 g·kg-1;碱解氮、速效磷和速效钾含量分别为(187～2680),(06～1331)和(1～238)mg·kg-1,平均含量分别为827,157和636 mg·kg-1。桐庐县油菜地土壤碱解氮和速效钾缺乏面积分别占总面积的681%和693%,速效磷缺乏面积占总面积的467%。油菜产量与土壤碱解氮含量极显著正相关(r=0851**,n=15),与速效磷含量显著正相关(r=0553*,n=15),而与土壤有机质、全氮和速效钾含量无显著相关性。     

基于ASI法的长江流域冬油菜区土壤有效磷、钾、硼丰缺指标研究

 【目的】为当前生产条件下长江流域油菜测土配方施肥技术的推广提供理论依据。【方法】2004-2006连续3个年度在长江流域10省布置油菜肥效田间试验,并用ASI法对基础土壤样品进行测试分析,以缺素区与推荐施肥区油菜籽相对产量＜60%,60%～75%,75%～90%,90%～95%和＞95%为标准,分别将土壤有效磷、钾和硼分成“严重缺乏”、“缺乏”、“轻度缺乏”、“适宜”和“丰富”5级。【结果】长江流域油菜区土壤有效磷“严重缺乏”指标为＜5.5 mg P?L-1,“缺乏”指标为5.5～12.5 mg P?L-1,“轻度缺乏”指标为12.5～28.5 mg P?L-1,“适宜”指标为28.5～38.0 mg P?L-1,“丰富”指标为＞38.0 mg P?L-1;本研究没有建立土壤有效钾及有效硼的“严重缺乏”指标,土壤有效钾 “缺乏”、“轻度缺乏”、“适宜”和“丰富”的指标分别是＜30 mg K?L-1、30～75 mg K?L-1、75～100 mg K?L-1和＞100 mg K?L-1;土壤有效硼“缺乏”、“轻度缺乏”、“适宜”和“丰富”的指标分别是＜0.25 mg B?L-1、0.25～0.95 mg B?L-1、0.95～1.50 mg B?L-1和＞1.50 mg B?L-1。【结论】在长江流域油菜主产区,运用ASI法测定的土壤有效磷、钾及硼含量高低分别与不施磷、不施钾及不施硼处理的油菜籽相对产量呈显著正相关关系,据此建立的土壤养分丰缺指标可以用来指导长江流域油菜的测土配方施肥工作。     

土壤磷钾供应能力研究

为给冬小麦-夏玉米高产提供合理施肥和培肥土壤的科学依据,采用田间试验法,在河北省宁晋县大陆村镇试验地,研究该地土壤磷钾供应能力。结果表明,冬小麦季,土壤磷素贡献率达100%,钾素贡献率为94.5%;不施肥处理的土壤供P、K量分别为55.4和139.2 kg/hm^2,NP配施土壤供K量比对照提高15.7%;NK配施土壤供P量比对照提高6.3%。施入钾肥改善了冬小麦的株高、基本苗数、分蘖数、总茎数、成穗数、穗粒数和最终产量,提高土壤的钾素营养。增施磷肥,不能增加冬小麦产量,只能增加生产成本,造成土壤中磷的残留增多。对照区土壤中的磷钾在支持6 750 kg/hm^2的小麦产量后,还能继续满足9 810 kg/hm^2的夏玉米需求,说明供试土壤补钾能显著提高冬小麦产量,土壤中的磷钾不是限制夏玉米产量的主要因素。     

A Preliminary Study on Dynamics and Models of N, P, K Absorption for High-Yield Cotton

The field experiments were carried out to investigate the dynamics and models of N, P and K ab-sorption for the cotton plants with a lint of 3 000 kg ha-1 in Xinjiang. The main results were as follows: Thecontents of N, P2O5, K2O in cotton leaves, stems, squares and bolls decreased obviously with the time over thewhole growth duration and the falling extent was greater in high-yield cotton than in CK. Contents of N inleaves, squares and bolls, in particular in the leaves of fruit-bearing shoot was higher in high-yield cotton thanin CK. Contents of P2O5 in squares and bolls and that of K2O in stems were higher in high-yield cotton than inCK during the whole growing period. The accumulations of N, P2O5 and K2O in the cotton plants could be de-scribed with a logistic curve equation. There was the fastest nutrient uptake at about 90 d for N, 92 d for P2O5and 85 d for K2O after emergence, respectively. Total nutrient accumulation of N, P2 O5 and K2O was 385.8,244.7 and 340.3 kg ha-1 , respectively. Approximately 12.5 kg N, 8.0 kg P2O5 and 11.1 kg K2O were neededfor producing 100 kg lint with the leaves and stems under the super high yield condition of 3 000 kg ha-1 inXinjiang.     

氮、磷、钾、硼肥施用对甘蓝型杂交油菜产量及经济效益的影响

 【目的】指导当前生产条件下江西油菜测土配方施肥技术的推广。【方法】2008—2009年在江西省设置12个田间试验,研究氮、磷、钾和硼肥施用对甘蓝型杂交油菜产量及其相关性状的影响,并对施肥经济效益进行分析。【结果】氮磷钾硼肥配施处理(NPKB)平均产量为2 015 kg?hm-2,与不施肥相比,NPKB、缺B(NPK)、缺P(NKB)、缺K(NPB)和缺N(PKB)分别增产1 121、839、758、746和249 kg?hm-2;NPKB配施处理下各主要经济性状表现较好,有利于对N、P、K、B素的吸收利用;效益分析表明,NPKB配施效益达到5 449.5元/hm2,比不施肥增收2 231.1元/hm2,其次是缺B(NPK)、缺P(NKB)、缺K(NPB),分别比不施肥增收1 298.4、1 280.7和1 541.1元/hm2,而不施氮肥的处理减收206.1元/hm2。【结论】NPKB配施对甘蓝型杂交油菜增产、增收效果显著,是保证高效生产的技术关键。     

稻草与钾肥配合施用对冬作马铃薯土壤钾素的影响

为研究施钾肥和稻草还田对南方冬作马铃薯土壤钾素状况的影响,在施氮磷肥基础上设计了稻草与钾肥不同组合的盆栽试验。结果表明:相对于仅施氮磷肥,增施钾肥和稻草可显著增加土壤速效钾、有效钾、缓效钾含量,且以氮磷钾肥配施稻草处理对土壤钾素提高的效果明显好于氮磷肥基础上施用钾肥或稻草;至马铃薯成熟期,氮磷钾肥配施稻草处理的土壤速效钾、有效钾和缓效钾含量平均高180.13%、125.16%和10.62%,而且较种植前也有较大提升,土壤速效钾含量平均提高33.33%。钾肥与稻草不同配比中以T5(K3S2)、T8(K2S3)对土壤钾素影响比较明显,速效钾和缓效钾含量比种植前分别增加69.69%、14.09%和81.98%、10.76%。从节约资源和改善土壤钾素状况综合考虑,在南方早稻-晚稻-马铃薯种植模式下,钾肥和稻草施用量以199.7 kg/hm2和9 000 kg/hm2较佳。     

Modeling the Impacts of Soil Organic Carbon Content of Croplands on Crop Yields in China

This study quantified the impacts of soil organic carbon （SOC） content on the grain yield of crops using a biogeochemical model （DNDC, denitrification-decomposition）. Data on climate, soil properties, and farming management regimes of cropping systems were collected from six typical agricultural zones （northeast, north, northwest, mid-south, east and southwest regions of China, respectively） and integrated into a GIS database to support the model runs. According to the model, if the initial SOC content in the cropland was increased by 1 g C kg^-1, the crop yield may be increased by 176 kg ha^-1 for maize in the northeast region, 454 kg ha^-1 for a maize-wheat rotation in the north region, 328 kg ha^-1 for maize in the northwest region, 185 kg ha^-1 for single-rice in the mid-south region, 266 kg ha^-1 for double-rice in east region, and 229 kg ha^-1 for rice and wheat rotation in southwest region. There is a great potential for enhancing the crop yield by improving the SOC content in each region of China.     

长期施钾对东北春玉米产量和土壤钾素状况的影响

 【目的】为探明长期施钾对大田玉米产量和耕层土壤钾素状况的影响。【方法】本文通过在东北三省的代表性土壤上连续13年的定位施钾试验进行研究。【结果】东北3个定位试验点在施用氮磷肥基础上长期施钾对玉米产量的影响差异较大，辽宁13年间（1993～2005）施钾效应不稳定，吉林自第3年（1995年）开始施钾显著增产，黑龙江自定位开始施钾显著增产；辽、吉、黑3点长期施钾条件下作物产量13年平均分别增加9.9%～10.3%、12.6%～13.6%和17.5%～21.7%。辽宁、吉林两点施K2O 112.5 kg•ha-1时土壤-作物系统内钾素处于较明显的亏缺状况，而施K2O 225.0 kg•ha-1时3个定位点钾素均有较多的盈余。长期施钾均能显著增加土壤速效钾含量，且土壤速效钾含量随施钾量的增加而增加，而长期施钾对3个定位点缓效钾含量的影响有所不同。【结论】基于产量、效益和土壤钾素状况，3点的适宜钾（K2O）用量为112.5 kg•ha-1左右。     

北方麦区小麦产量与籽粒氮磷钾含量对监控施钾和土壤速效钾的响应

【目的】分析我国北方麦区监控施钾下小麦产量与养分吸收分配变化与土壤速效钾的关系,为节约钾资源,实现小麦丰产优质可持续发展提供理论依据。【方法】于2018—2020年在我国北方麦区43个地点进行田间试验,研究不同土壤速效钾水平下监控施钾对小麦产量、产量构成、籽粒氮磷钾含量及养分吸收分配的影响。【结果】北方麦区农户小麦施钾不足和过量问题同时存在。小麦产量随土壤速效钾含量升高显著增加,在土壤速效钾含量150—180 mg·kg^-1时,小麦产量达到最高,为6 340 kg·hm^-2。土壤速效钾过高并不能持续提高小麦产量,当土壤速效钾含量>180 mg·kg^-1时,小麦产量显著降低,平均为5 409 kg·hm^-2。与农户施肥相比,在土壤速效钾含量<90、90—120、120—150和>180 mg·kg^-1时采用监控施肥技术增加了钾肥用量,在速效钾含量150—180 mg·kg^-1时减少了钾肥用量,各土壤速效钾水平下采用监控施肥技术施用钾肥均提高了小麦产量,且在速效钾含量<90和>180 mg·kg^-1时显著增产。土壤有效磷含量>30 mg·kg^-1时,土壤速效钾含量120—150或>180 mg·kg^-1时,不施钾肥小麦产量有降低的趋势。土壤速效钾含量升高显著提高了小麦籽粒氮含量,农户施肥和监控施肥处理的籽粒氮磷钾含量无显著变化,速效钾含量>180 mg·kg^-1时不施钾肥的小麦籽粒磷钾含量显著降低。速效钾含量>150 mg·kg^-1时,监控施肥的钾肥偏生产力与钾肥吸收效率较农户施肥显著提高。【结论】在北方麦区,土壤速效钾含量150—180 mg·kg^-1时,合理施肥可使小麦产量达较高水平,但当土壤有效磷较高,超过30 mg·kg^-1时,不施钾肥小麦有减产风险。应根据土壤速效磷钾和小麦产量水平监控施肥,合理确定钾肥用量,实现北方麦区小麦丰产高效生产。     

Molecular Assisted Breeding and Adaptability Analysis of Zhongyouza 11 with Super High Oil Content

Using a three-line system of Shaan 2A cytoplasmic male sterility, a hybrid variety rapeseed, Zhongyouza 11, was developed by the combination of traditional methods and a molecular marker-assisted breeding technique. This hybrid variety had high grain yield, high oil content, wide adaptability, and good quality. The oil content of Zhongyouza 11 is steadily above 43% in the three ecological regions along the Yangtze River valley, which is the largest winter oilseed production area in China. The highest oil content of Zhongyouza 11 reached 46.68% in the upper reaches of the Yangtze River valley in 2003-2004, which was the highest among all lines involved in the national regional rapeseed variety trials. In the regional yield trials in Hubei Province, the average yield of Zhongyouza 11 reached 2 853 kg ha-1 (2002-2004), yielding more than the control variety Zhongshuang 6 by 11.34%. In the national trials, the yield of Zhongyouza 11 reached 2 405.7, 2 697.3, and 2 770.2 kg ha-1 in the upper, middle, and lower reaches of the Yangtze River valley, yielding more than the control varieties by 11.52, 12.9, and 14.92%, respectively, in 2003-2005. Both the high oil content and high grain yield contributed to the high oil yield of Zhongyouza 11. The oil yield of Zhongyouza 11 in the national trials reached 1083.3, 1210.2, and 1224.8 kg ha-1, yielding more than the controls by 29.42, 27.65, and 20.98%, respectively, in the upper, middle, and lower reaches of the Yangtze River valley. The highest oil yield reached 1369.65 kg ha-1 in the middle reach of the Yangtze River valley(2003-2004), with an increase of 46.21% compared to the control. The experimental sites distributed widely along the Yangtze River valley, cover most of the Chinese winter rapeseed production areas. Among the 89 experimental location/years, the yield of Zhongyouza 11 surpassed the controls at 77 location/years in the trials, indicating its wide adaptability.Zhongyouza 11 was the only one that passed the national regional trials in all three regions along the Yangtze River valley simultaneously in 2005. It is also the first rapeseed variety that contained seed oil exceeding 46% and passed the national regional trials. This study shows that heterosis prediction by the means of estimation of genetic distance between parental lines using single sequence repeat (SSR) and sequence related amplified polymorphism (SRAP) markers is an efficient way for the reduction of tedious field trials and the acceleration of breeding procedure.