Evaluating the Effects of Aquaculture Wastewater Irrigation with Fertilizer Reduction on Greenhouse Tomato Production,Economic Benefits and Soil Nitrogen Characteristics

The utilization of aquaculture wastewater as irrigation is an effective way to recycle and reuse water and nitrogen fertilizer resources because it contains numerous nutrients.However,it is still unclear that the pattern of substituting aquaculture wastewater irrigation for fertilizer supplementing is conducive to improving the soil nitrogen status,fruit yield and water-fertilizer use efficiency for tomato production.In this context,the experiment was intended to establish the appropriate irrigation regime of aquaculture wastewater in tomato production for freshwater replacement and fertilizer reduction to ensure good yields.Pot experiments were conducted with treatments as farmers accustomed to irrigation and fertilization used as control(CK),1.75 L aquaculture wastewater with base fertilizer(W1),2 L aquaculture wastewater with base fertilizer;and 2.25 L aquaculture wastewater with base fertilizer(W3).We examined the effects of aquaculture wastewater irrigation on soil nitrogen distribution,Nrelated hydrolases,tomato yield,and economic benefits.The results showed that the control treatment had the highest N input,about 24.68%higher than the W3 treatment,while the yield was only about 7.81%higher than W3.This indicated that the overuse of chemical fertilizer was present in the current tomato production.Although the reduction of fertilizer in aquaculture wastewater irrigation caused a decrease in tomato production,this economic loss can be compensated by cost savings in the wastewater disposal.Among aquaculture wastewater treatments,the W3 treatment had the highest overall benefit,achieving 62.63%freshwater savings,37.50%fertilizer input reduction,and an economic return of approximately 19,466 Yuan per hectare higher than the control.Additionally,increasing the irrigation volume of aquaculture wastewater could provide more available nutrients to the soil,which were more prevalent in the form of organic nitrogen.The lower soil nitrate reductase activities(NR)under aquaculture wastewater treatments after harvesting also proved that this pattern was beneficial to reduce soil nitrate nitrogen residues.Overall,the results demonstrate that aquaculture wastewater irrigation alleviates the soil nitrate residues,improves nutrient availability,and results in more economic returns with water and fertilizer conservation for the greenhouse production of tomatoes.

Physiological Basis of Photosynthetic Function and Senescence of Rice Leaves as Regulated by Controlled-Release Nitrogen Fertilizer

The physiological mechanism of photosynthetic function and senescence of rice leaves was studied by using early rice variety Baliangyou 100 and late rice variety Weiyou 46, treated with controlled-release nitrogen fertilizer （CRNF）, urea and no nitrogen fertilizer. CRNF showed obvious effects on delaying the senescence and prolonging photosynthetic function duration of rice leaves. Compared with urea, CRNF could significantly increase the chlorophyll content of functional leaves in both early and late rice varieties, and this difference between the treatments became larger as rice growth progressed; CRNF increased the activities of active oxygen scavenging enzymes super oxide dismutase （SOD） and peroxidase （POD）, and decreased the accumulation amount of malondialdehyde （MDA） in functional leaves during leaf aging; Photosynthetic rate of functional leaves in CRNF treatment was significantly higher than that in urea treatment. The result also indicated that CRNF could effectively regulate the contents of indole-3-acetic acid （IAA） and abscisic acid （ABA） in functional leaves; IAA content was higher and ABA content was lower in CRNF treatment than those in urea treatment. Therefore, application of CRNF could increase the rice yield significantly due to these physiological changes in the functional leaves.

Studies on the Mechanism of Single Basal Application of Controlled-Release Fertilizers for Increasing Yield of Rice (Oryza sativa L.)

This paper was to explore the mechanism of single basal application of controlled-release fertilizers for increasing yield of rice （Oryza sativa L.）. Pot trials and cylinder trials were carried out from 2002 to 2005 to study the influences of single basal application of 3 controlled-release fertilizers on the changes of soil available N, root development, senescence and lodging resistance at late growth stages. Results showed that at 30 days after fertilization, single basal application of controlled-release fertilizers coated with vegetal-substance （CRF1） and polymer materials （CRF3） increased soil available N to 12.0 and 147.9%, respectively, in comparison to split fertilization of rice-specific fertilizer （RSF1）. Treatments of the two CRFs obviously benefited the development of root system, resulting in greater rice root weights with extensive distribution and higher root activity. In addition, the two CRF treatments, in comparison to RSF1, enhanced chlorophyll consents of the flag leaves to 9.5 and 15.5%, and soluble protein up to 89.7 and 108.0% respectively. Application of the two CRFs also made the base of rice stems strong and large, declined the proportion of shoot and root, increased root depth index. Though relatively low K rate, single basal application of the CRF3 coated with NH4MgPO4 could also promote the development of root system, enhance root activity and some physiological functions of flag leaves. Based on these results, it was concluded that major mechanisms for increasing rice yield by single basal application of the CRFs should be attributed to grater soil available N supply, superior development of root systems, better nutrient absorption capacity, slower senescence and enhancement of lodging resistance at late stages.

Biochar-compost-based controlled-release nitrogen fertilizer intended for an active microbial community

Nitrogen(N) fertilizers in agriculture suffer losses by volatilization of N to the air, surface runoff and leaching into the soil, resulting in low N use efficiency(NUE)( 50%) and raising severe environmental pollutions. Controlledrelease nitrogen fertilizers(CRNFs) can control the release of N nutrients to NUE in crop production. Different methods were used to develop new CRNFs.However, different CRNF technologies are still underdeveloped due to inadequate controlling on N releasing time and/or unsustainable diffusion. The study on the influences of CRNF processing parameters on microbial conditions are lacking when the CRNFs composed of various bio-ingredients such as biochar, composts, and biowaste. The complexity of processing methods, material biodegradability, and other physical properties make current CRNFs of questionable value in agricultural production. This research aims to develop a novel biochar-compost-based controlled-release urea fertilizer(BCRUF) to preserve microbial properties carried by the compost. The BCRUF was synthesized by pelletizing the 50:50(dry, wt/wt) mixture of biochar and compost. BCRUF was loaded with urea and then spray-coated with polylactic acid(PLA). The releasing time of two types of BCRUFs, coated and uncoated with PLA, for 80% of N release in water was up to 6 h at three different temperatures(4, 23, and 40 °C), compared to conventional urea fertilizer and commercial environmentally smart N(ESN) fertilizer. The releasing time of coated BCRUF for 80% N release in soil was up to 192 h(8 days). Fourier-transform infrared spectroscopy(FTIR) analysis revealed that no new functional groups were found in the release solution, indicating no new chemical hazards generated. The differential scanning calorimetry(DSC)tests also verified that its thermal stability could be up to 160 °C. The microbe populations in the BCRUF pellets were reduced after the pelleting and drying processes in BCRUF fabrication, but a few bacteria can endure in the air-drying process. BCRUF pellets soaked in water for 4 days retained some bacteria. The BCRUF showed very promising characteristics to improve NUE and sustainability in agricultural production.

Effects of Grape Balanced Nutrition Fertilizer on Yield and Quality of Wine Grapes

In this study,the wine grapes balanced nutrient fertilizer(BNF)was designed according to the wine grape nutritional requirements in different growth stages,and objected to reduce fertilizer application rate of wine grape cultivation,improve fertilizer utilization rate,achieve stable yield and improve the quality of wine grapes.The experiment was carried out at the Great Wall Sanggan Winery,and the Aristocratic Winery.The experiment was designed with two treatments:Namely BNF treatment,and the traditional fertilization(CK).We investigated the effects of BNF on the quality of wine grapes by examining the plant traits of wine grapes in different experimental areas during the growing season,the fruit traits at maturity,and determined the contents of VC,organic acids,amino acids,flavonoids,soluble total sugars,soluble solids,tannins,total phenols and catechins.The results show that:①The application of grape BNF greatly reduced the application amount of nitrogen,phosphorus and potassium,while the vine had no fertilizer deficiency phenomenon;②It increased the single fruit weight,the ear weight and yield to varying degrees,and the yield increase range was between 12% and 41%;③The wine grapes with BNF had the following characteristics:tight infructescence,even color,small fruit less,no fruit dropped,strong fruit colloid feeling,better aroma and taste;④It greatly improved the quality of wine grapes,and increased the content of soluble solids,soluble total sugar,organic acids,VC,total phenols,flavonoids,amino acids and tannins in fruits;⑤It greatly increased the total catechin content of"Riesling"and"Syrah",and had no significant effects on the catechin content of"Merlot"and"Cabernet Sauvignon".In summary,the application of grape BNF has certain practical significance for guiding the production of local wine grapes,ensuring the yield while improving the quality,increasing the income and reducing the environmental pollution caused by excessive fertilization.

降氮增施有机肥对烤烟生长发育和产量的影响

为了提高烤烟质量和经济效益,以龙江986为供试品种进行随机区组试验,设置5个处理,对不同处理烤烟农艺性状、干物质积累、叶绿素含量及经济性状进行测定,以此分析不同施肥配比条件下烟株生长发育及经济性状的变化情况。结果表明,施用肥料的处理其各项农艺性状指标均优于未施肥的对照处理,其中F3(硝酸钾+精制有机肥)和F5(硝酸钾+烟秆有机肥)处理效果最好。增施有机肥及仅施硝酸钾均能够促进烟株的生长,但仅施硝酸钾的效果没有配合施用有机肥的效果好。有机肥与硝酸钾配合施用有利于增加烟株根、茎、叶的干物质积累,与F2(只施硝酸钾)处理相比,团棵期效果最好的为F4(硝酸钾+蚯蚓有机肥)处理,根增加0.40 g,茎增加0.86 g,增加叶重2.25 g;始采期效果最好的为F3处理,茎增加6.64 g,叶增加3.67 g。有机肥与硝酸钾配合施用能够提高烟株叶绿素含量,与F2处理相比,F3处理SPAD值增加1.0,F4处理增加1.6,F5处理增加0.9。此外,有机肥与硝酸钾配合施用能够提升烟株的产量及品质,与F2处理相比,F4处理的单叶质量最大,为5.71 g;产量最高,为1 465.95 kg·hm^(-2),对提高烟株的单叶质量及增产作用效果较好;F5处理的上等烟率最高,为7.05%,可明显改善烟株的品质。综合来看,降氮增施有机肥对烤烟生长发育和产量存在正向促进的作用。F3处理有利于改善烟株农艺性状,F4处理在干物质积累、提高叶绿素含量、单叶质量和产量方面存在一定优势,F5处理有利于提高上等烟率。在生产过程中可以结合具体需求筛选合适的处理或者搭配使用。

施肥方式和减施氮肥对寒地水稻抗倒性的影响

为明确施肥方式和减施氮肥的主效及互作效应对寒地水稻产量及抗倒性的影响,以水稻‘垦粳8’为材料,比较不同施肥方式和减施氮肥对寒地水稻产量、株高、以及各节间长度、直径、鲜重、茎壁厚度及抗折力的影响差异。结果表明:侧深施肥产量、第三节间长度、重心高度分别显著或极显著高于全层施肥7.49%、7.02%、2.54%。侧深施肥第一节间直径、茎壁厚度、鲜重、抗折力分别显著或极显著低于全层施肥7.85%、14.18%、4.13%、2.03%;第二节间直径、茎壁厚度、抗折力分别显著或极显著低于全层施肥8.15%、9.18%、18.61%;第三节间茎壁厚度和抗折力分别极显著低于全层施肥16.00%、16.15%。侧深施肥的抗倒伏指数极显著低于全层施肥16.60%。减施氮肥条件下重心高度、各节间长度、茎壁厚度、节间鲜重及节间抗折力变化多利于提高水稻抗倒性,减氮15%和减氮30%处理的抗倒伏指数较常规施氮分别极显著提高6.19%和9.52%。全层施肥条件下抗倒伏指数随施氮量下降呈增加趋势,而侧深施肥的减氮施肥水平间差异不显著。

减氮和侧深基施缓混肥对‘南粳5055’产量、品质及氮素吸收利用的影响

旨在探讨减氮和侧深基施缓混肥对水稻产量、品质和氮素吸收利用的影响,本研究以当地主推粳稻‘南粳5055’为材料,设置不施氮肥(0N)、当地常规施肥(CK)、一次性侧深基施缓混肥(S1)、侧深基施缓混肥+追施速效氮肥(S2) 4个处理,分别在如皋市东陈镇和白蒲镇两地的水稻田开展试验。两地的试验结果均表明:与CK相比,在减氮25%情况下,S1和S2均明显改善了稻米的外观品质和蒸煮食味品质,但两者的水稻产量和总吸氮量均有所降低,平均分别减少了5.12%、1.27%和9.53%、2.77%。其中S1明显减产主要由于每穗粒数的显著降低,而S2则与CK无显著差异。另外,S2也较CK显著提高了氮肥的吸收利用率、农学效率和偏生产力。表明在氮肥大幅减少的情况下,采用侧深基施缓混肥+追施速效氮肥更有利于实现水稻的绿色优质高效生产。

微生物菌剂与氮肥配施对紫花苜蓿生长及土壤性质的影响

为获得河西地区紫花苜蓿(Medicago sativa L.)人工草地上的最佳施肥组合。以‘惊盛’紫花苜蓿品种为试验材料,研究微生物菌剂与氮肥减量配施对紫花苜蓿植株生长、营养品质及土壤理化性质的影响,结果表明:与全量氮肥(CK)相比,微生物菌剂与氮肥减量处理的紫花苜蓿株高、干草产量无显著差异;与CK相比,C8,G8,C7和G7处理的紫花苜蓿粗蛋白、粗脂肪、中性和酸性洗涤纤维含量无显著差异,其中G7处理的紫花苜蓿粗蛋白含量最高;微生物菌剂与氮肥减量处理增加了土壤铵态氮含量(P<0.05),而土壤有机质、速效磷、含水率和pH值差异不显著;与CK相比,G7处理显著增加了土壤碱性磷酸酶活性(P<0.05)。通过对不同施肥处理的紫花苜蓿生长、营养和土壤指标的综合分析,综合表现最好的为G7(根瘤菌剂与氮肥减量30%),有利于减少河西地区氮肥用量,为河西地区紫花苜蓿的科学施肥提供依据。

有机肥部分替代氮肥的盐碱土壤改良与水稻增产效应研究

本研究旨在揭示利用有机肥部分替代氮肥实现作物增产和土壤改良的可能性及其机理。以南粳9108为供试水稻品种,设置4个处理:常规施肥(T1),低量自配有机肥部分替代氮肥(T2),高量自配有机肥部分替代氮肥(T3),不施肥(CK),T1、T2和T3采用等氮量设计(315 kg/hm^(2)),开展田间试验。研究结果表明:较常规施肥,有机肥部分替代氮肥能够显著降低土壤pH、提升土壤有效磷和速效钾、增强脲酶和碱性磷酸酶活性、增加土壤有机质和碱解氮;能够显著增加收获时的水稻干物质积累量,一定程度地提升水稻株高,促进水稻分蘖并且增加穗粒数、结实率和千粒重。有机肥部分替代氮肥能够实现土壤改良和水稻增产。

“紫云英×油菜”混播还田及减施氮肥对双季稻田温室气体排放的影响

为探究绿肥“紫云英×油菜”混播还田及氮肥减施对双季稻田温室气体排放的影响,在冬季种植“紫云英×油菜”并还田的条件下,设双季稻不施氮肥(CK)、施100%氮肥(150 kg·hm^(-2),N1MR)、减施20%氮肥(120 kg·hm^(-2),N2MR)、减施40%氮肥(90 kg·hm^(-2),N3MR)和减施60%氮肥(60 kg·hm^(-2),N4MR)共5个处理。在双季稻生育期内平均每7 d采用静态暗箱—气相色谱法测定稻田温室气体排放,分析绿肥混播还田条件下氮肥减施对双季稻田水稻产量、温室气体排放通量、累积排放量、全球增温潜势(GWP)及温室气体排放强度(GHGI)的影响。结果表明,氮肥减施20%~40%能显著提高水稻产量,减施20%和40%处理水稻产量分别较CK显著提高24.2%和23.8%(P<0.05)。在双季稻生育期,所有施氮处理均较CK显著降低了CH_(4)排放,增加了N_(2)O排放(P<0.05)。氮肥减施20%处理的GWP和GHGI两季总量均为最低,且均显著低于CK、施100%、减施40%和减施60%氮肥处理(P<0.05),GWP分别降低57.9%、16.5%、23.4%和40.8%,GHGI分别降低63.9%、17.8%、24.6%和43.2%。综上,氮肥减施20%对水稻增产和温室气体减排效果最佳。因此,“紫云英×油菜”混播还田配合氮肥减施20%是一种适合当地推广的低碳稳产施肥管理模式。本研究结果为实现南方稻区农业绿色可持续发展提供了理论依据和决策基础。

减氮下不同肥料配施对麦玉复种体系作物氮素积累分配及产量的影响

为探索陕西关中地区冬小麦-夏玉米复种体系氮肥减量增效潜力,构建适宜的作物养分管理体系,于2018-2019年采用田间试验研究了减氮并配施不同肥料对麦玉复种体系作物生长状况、植株氮素积累分配、作物产量以氮素利用效率的影响。试验设置5个处理:常规施氮(225 kg·hm^(-2),N 100);减氮20%(180 kg·hm^(-2),N 80);减氮配施生物炭(180 kg·hm^(-2),生物炭22500 kg·hm^(-2),N 80+BC);减氮配施缓释肥(180 kg·hm^(-2),尿素∶缓释肥=1∶1,N 80+S);减氮配施微生物菌肥(180 kg·hm^(-2),微生物菌肥3600 kg·hm^(-2),N 80+BF)。结果表明:减氮及其配施不同肥料对夏玉米大喇叭口期后株高、干物质和氮素积累没有显著影响;而N 80+BF促进了夏玉米氮素向籽粒中的分配;N 80+BC提高了夏玉米产量和收获指数,且较N 80处理分别显著提高8.3%和20.1%;减氮下三种配施处理均能提高夏玉米氮农学利用率和氮肥偏生产力,且以N 80+BC处理表现最佳,较N 100分别显著提高43.3%和29.0%,较N 80分别显著提高45.8%和8.3%;N 80+BC和N 80+BF还能显著提高夏玉米氮肥表观表观回收率,二者较N 100显著增加18.1%和10.7%,较N 80处理显著增加26.9%和19.0%。与N 80相比,N 80+BF有效提高了冬小麦扬花期和成熟期分蘖数、茎蘖成穗率以及成熟期干物质和氮素积累量,并能显著提高冬小麦穗数和产量,增幅分别为13.7%和16.2%。减氮下3种配施处理均能提高冬小麦氮农学利用率、氮肥偏生产力和氮素利用率,其中氮农学利用率和氮肥偏生产力在N 80+BF处理表现最佳,较N 100分别显著提高了31.2%和28.4%,较N 80分别显著提高了33.7%和16.2%,氮素利用率在N 80+S处理表现最佳。综上所述,减氮及其配施处理中,180 kg·hm^(-2)配施生物炭(22500 kg·hm^(-2))和180 kg·hm^(-2)配施微生物菌肥(3600 kg·hm^(-2))更有利于作物生长,促进氮素积累与分配,提高作物产量和氮素利用效率,实现关中地区麦玉复种体系氮肥管理的“减量增效”。

绿肥还田结合减氮对麦田土壤呼吸及其温度敏感性的影响

研究绿肥还田结合氮肥减施对麦田土壤呼吸动态及小麦产量的影响,以期为干旱绿洲灌区农田碳减排技术研发提供理论依据。试验于2021—2022年在甘肃河西绿洲灌区开展,以常规施氮无绿肥还田(N100)为对照,设施用15000 kg∙hm^(−2)绿肥+85%氮肥(G_(1)N_(85))、22500 kg∙hm^(−2)绿肥+85%氮肥(G_(2)N_(85))、30000 kg∙hm^(−2)绿肥+85%氮肥(G_(3)N_(85))、15000 kg∙hm^(−2)绿肥+70%氮肥(G_(1)N_(70))、22500 kg∙hm^(−2)绿肥+70%氮肥(G_(2)N_(70))和30000 kg∙hm^(−2)绿肥+70%氮肥(G_(3)N_(70))共7个处理。探讨小麦生育期的土壤呼吸速率、碳排放量、产量及碳排放效率,分析土壤呼吸对土壤温度的响应。结果表明:不同处理下麦田土壤呼吸速率均呈先升高后降低的单峰趋势,全生育期内变化范围为0.8~6.2μmol∙m^(−2)∙s−1。绿肥还田结合氮肥减施显著提高麦田土壤呼吸速率及土壤碳排放总量,与N100相比,平均增幅分别为7.2%~19.8%和5.7%~18.8%;其中G_(3)N_(85)和G_(3)N_(70)较其他处理土壤呼吸速率分别增加2.3%~16.0%和3.3%~19.8%,土壤碳排放总量分别增加2.9%~15.2%和3.1%~18.8%;与G_(3)N_(85)相比,G_(3)N_(70)处理两年平均土壤呼吸速率及土壤碳排放总量分别增加3.3%和3.1%(P<0.05)。绿肥还田结合氮肥减施处理显著降低土壤呼吸温度敏感性(Q10),与N100相比,Q10值降幅为10.4%~18.1%(P<0.05)。绿肥还田结合氮肥减施显著影响了小麦产量和土壤碳排放效率,其中G_(3)N_(85)处理分别显著高于其他处理4.2%~45.6%和0.3%~26.4%(P<0.05)。可见,绿肥还田结合氮肥减施在增强麦田土壤呼吸的同时,显著降低土壤呼吸温度敏感性,提高小麦产量和碳排放效率,其中翻压绿肥30000 kg∙hm^(−2)配合氮肥减量15%处理(G_(3)N_(85))是河西绿洲灌区小麦田节氮减排和提高农田土壤生产力的有效途径。

生物炭和间作鲜食豌豆对氮肥减量下玉米产量的促进效应

于2022—2023年进行裂区试验,主区为玉米‖鲜食豌豆(M‖P)和单作玉米(SM),裂区为地方推荐施氮量(N1,360 kg·hm^(-2))和减量30%施氮(N2,250 kg·hm^(-2)),裂裂区为施用生物炭(C)和不施用生物炭(A),探究生物炭和间作鲜食豌豆对玉米光合源、干物质积累以及产量的影响。结果表明,在减量30%施氮水平下,间作鲜食豌豆配施生物炭可以使玉米出苗后45~90 d保持较高的叶面积指数,且较SMN1A处理有效减缓了玉米出苗后90~150 d的叶面积指数降低,显著提高了玉米全生育期叶日积(P<0.05)。M‖PN2C处理玉米干物质积累量和干物质积累速率较SMN1A处理在玉米出苗后60~90 d分别提高13.0%和15.3%,在玉米出苗后90~150 d分别提高16.2%和19.5%。M‖PN2C处理玉米籽粒产量较M‖PN1A和SMN1A处理分别显著增加6.3%和17.8%(P<0.05),与M‖PN1C处理无显著差异。间作玉米千粒重较单作玉米平均提高5.2%,且施用生物炭在减量30%施氮水平下较地方推荐施氮量不施用生物炭可提高玉米的穗粒数和千粒重,间作鲜食豌豆配施生物炭处理的玉米穗粒数和千粒重在N2与N1之间无显著差异。通径分析结果表明,间作鲜食豌豆配施生物炭通过提高玉米千粒重,使间作玉米在氮肥减量下能获得较高的籽粒产量。因此,玉米‖鲜食豌豆下减量30%施氮配施生物炭可作为干旱绿洲灌区节氮高效种植的参考技术。

绿洲灌区密植对氮肥减量玉米产量的补偿潜力

【目的】针对绿洲灌区玉米生产氮肥用量过高的问题,探究通过密植补偿氮肥减量对玉米产量负效应的可行性。【方法】2019—2021年,以施氮水平为主区,设地方习惯施氮(N_(2),360 kg·hm^(-2))、减量25%施氮(N_(1),270 kg·hm^(-2))两个水平;以种植密度为副区,设传统(M_(1),7.8万株/hm^(2))、中(M_(2),10.4万株/hm^(2),增密33%)、高(M3,12.9万株/hm^(2),增密66%)3个密度水平,进行裂区试验,重点研究氮肥减量条件下增密对玉米产量及其构成因素的影响。【结果】(1)氮肥减量导致玉米籽粒产量、生物产量分别降低4.0%、4.9%。减氮条件下,中密度可以产生籽粒产量补偿效应,N_(1)M_(2)较对照N_(2)M_(1)提高4.1%;高密度处理N_(1)M3生物产量补偿效应最大,较对照提高14.2%。(2)通过回归分析模拟得到:减氮条件下,当种植密度提高至8.4万株/hm^(2)可以与对照N_(2)M_(1)籽粒产量持平,并在10.6万株/hm^(2)时获得最大产量13537kg·hm^(-2),较对照提高4.9%。(3)氮肥减量引起穗数、穗粒数和千粒重分别降低5.0%、3.3%和3.4%;中、高密度分别较传统密度提高穗数27.9%、49.7%,降低穗粒数3.8%、8.4%,降低千粒重5.2%、8.9%。中密度较传统密度对收获指数无显著影响,而高密度使收获指数降低14.2%。N_(1)M_(2)较对照N_(2)M_(1)通过穗数增加补偿了减氮引起穗数、穗粒数及千粒重的下降,从而实现丰产。(4)氮肥减量降低拔节期至抽雄吐丝期的玉米生长率7.2%—8.4%;中、高密度较传统密度提高苗期至大喇叭口期玉米生长率27.3%、60.3%。(5)氮肥减量条件下,N_(1)M_(2)较对照提高叶、茎和鞘干物质转运量达9.6%、13.6%和3.7%,提高叶和茎对籽粒产量的贡献率5.3%和9.0%。【结论】通过合理密植可以补偿减氮引起的玉米产量下降,在施氮量270 kg·hm^(-2)的基础上增密至10.4万株/hm^(2),能够最大化产量补偿效应,是绿洲灌区玉米节氮稳产丰产的可行措施。

有机肥替代氮肥对银北灌区盐化灌淤土理化性质及玉米生长的影响

次生盐渍化已成为宁夏银北灌区灌淤土壤退化的主要形式,制约着宁夏农业持续高质量发展。为了给宁夏地区盐化灌淤土的施肥管理及提高作物产量提供科学依据,以银北灌区典型盐化灌淤土为研究对象、玉米品种先玉335为指示品种,研究了不同施肥水平对盐化灌淤土土壤理化性质及玉米生长的影响。结果表明,各施肥处理均能有效地增加盐化灌淤土的速效养分含量,进而优化玉米产量构成要素,提高玉米产量。各施肥处理除常规施肥处理(施N 375.0 kg/hm^(2)、P_(2)O_(5)100.0 kg/hm^(2)、K_(2)O 100.0 kg/hm^(2))的玉米总根长、根表面积最高外,有机肥替代常规施肥量50%氮肥(施N 187.5 kg/hm^(2)、P_(2)O_(5)100.0 kg/hm^(2)、K_(2)O 100.0 kg/hm^(2)、有机肥7.3 t/hm^(2))处理的土壤理化性质及玉米生长指标最高。与对照不施肥相比,该处理下土壤有机质、速效氮、速效磷、速效钾分别增加了34.5%、25.9%、120.5%、23.7%,玉米穗长、穗粗、穗粒数、产量分别增加了40.5%、15.2%、80.5%、104.8%,秃尖长降低了78.0%;与常规施肥处理相比,该处理下土壤有机质、速效氮、速效磷、速效钾分别增加了36.5%、21.4%、13.7%、8.6%,玉米穗长、穗粗、穗粒数、产量分别增加了0.6%、1.9%、5.3%、3.1%,秃尖长降低了57.7%。综合分析,不同施肥水平均可改善盐化灌淤土理化性质进而提升玉米产量,且以有机肥替代部分氮肥施用的处理效果较好,其中以有机肥替代常规施肥量50%氮肥的施肥水平效果最好。

水肥一体化减氮对陇中地区马铃薯产量和水分利用效率的影响

于2022—2023年在陇中地区开展马铃薯水肥一体化试验,共设置4个种植模式,包括农户旱作高肥模式(T1,基施氮肥260 kg·hm^(-2),生育期不灌溉)、合作社高水高肥模式(T2,基施氮肥260 kg·hm^(-2),生育期灌水150 mm)、水肥一体化模式Ⅰ(T3,基施氮肥102 kg·hm^(-2)+追施氮肥98 kg·hm^(-2),生育期灌水90 mm)和水肥一体化模式Ⅱ(T4,基施氮肥42 kg·hm^(-2)+追施氮肥98 kg·hm^(-2),生育期灌水90 mm),探究补灌减氮水肥一体化技术对马铃薯产量和水分利用效率的影响。结果表明:补灌减氮水肥一体化显著促进了马铃薯叶面积指数增长、地上部和块茎干物质积累,显著增加了商品薯率,T2处理下马铃薯生育后期干物质积累速度放缓。2022和2023年,T3处理马铃薯块茎产量较T1处理分别显著提高100.7%和229.1%,较T2处理分别显著提高30.4%和38.6%;T4处理马铃薯块茎产量较T1处理分别显著提高94.4%和216.2%,较T2处理分别提高26.3%和33.1%;T3和T4处理间差异不显著。2022—2023年,各处理间WUE表现为T3>T4>T2>T1;相较于T1处理,T3处理两年WUE分别显著提高46.2%和146.4%,T4处理分别显著提高44.0%和135.7%;与T2处理相比,T3处理两年WUE分别显著提高51.1%和55.1%,T4处理分别显著提高48.9%和48.3%。综上,水肥一体化显著提高了马铃薯产量和水分利用效率,水肥一体化处理下基施氮肥42 kg·hm^(-2)、追施氮肥98 kg·hm^(-2)、生育期补灌90 mm的栽培措施,可作为陇中半干旱地区马铃薯高产高效生产的推荐模式。

巢湖流域新型肥料氮素减量施用对水稻产量、氮肥利用效率及经济效益的影响

为统筹考虑作物丰产与面源污染防控,避免过量施肥和盲目减肥,推进巢湖流域水稻生产和水环境生态协调发展,于2022年在巢湖流域开展新型肥料(普通复合肥和氨基酸复合肥)减肥田间试验,设置不施氮(CK,施氮量0 kg·hm^(–2))、农户常规模式(FP,施氮量281 kg·hm^(–2))、减氮20%(OP1,施氮量225 kg·hm^(–2))、减氮40%(OP2,施氮量169 kg·hm^(–2)),分析水稻籽粒产量及其构成因素、氮素吸收利用、氮肥利用效率、氮损失情况和经济效益。结果表明,在产量水平及产量构成要素方面,与FP相比,OP1产量无显著差异,但OP2施用普通复合肥处理的产量显著降低,OP1和OP2处理的穗数和穗粒数均无显著差异;在氮肥利用效率方面,与FP相比,OP1和OP2处理两种肥料的氮素农学利用率分别显著提高50.82%和53.79%,氮肥偏生产力分别显著提高29.29%和64.51%,OP2氨基酸复合肥处理的氮肥吸收利用率显著提高37.54%;在经济效益和环境效益方面,与FP相比,OP1和OP2处理两种肥料氮损失总量分别显著降低39.12%和60.93%,生产成本分别降低13.37%和18.26%,净利润分别增加8.25%和3.63%,并且与普通复合肥相比,施用氨基酸复合肥还可减少氮肥用量12.60%。因此,巢湖流域稻田氮肥减量20%有助于提高水稻氮肥利用率,增加水稻地上部氮素养分的吸收和转运,提升环境和经济效益,且推荐施用氨基酸复合肥(180 kg·hm^(–2))为宜,实现环境效益与经济效益的双赢。

大气CO_(2)浓度升高背景下优化施氮对淹水稻田CH4排放的影响

为探讨未来气候变化条件下,合理管理氮肥以充分协调水稻产量与温室气体排放量之间的矛盾,实现低碳排放并保持水稻产量,本研究探讨了大气CO_(2)浓度升高120μmol·mol^(-1)与氮肥减施40%对淹水稻田水稻生产及CH4排放的影响及机理。利用开顶式气室(OTC)组成的CO_(2)浓度自动调控平台设置4个处理,即环境CO_(2)浓度+施氮250 kg·hm^(-2)(CK)、大气CO_(2)浓度升高120μmol·mol^(-1)+施氮250 kg·hm^(-2)(C+)、环境CO_(2)浓度+施氮150 kg·hm^(-2)(N-)、大气CO_(2)浓度升高120μmol·mol^(-1)+施氮150 kg·hm^(-2)(C+N-),分析了稻田CH4累积排放量(CAC)、水稻生物量及产量、土壤理化性质及酶活性等指标。结果表明:与CK处理相比,C+处理使CAC/产量显著提高了16.93%,N-处理使CAC/产量显著降低了13.33%,C+N-处理使CAC/产量降低了7.89%,但不显著;N-处理在一定程度上削弱了C+处理对CAC、CAC/产量、水稻生物量、土壤可溶性有机碳含量的促进作用;逐步回归分析表明,基于可溶性有机碳和硝态氮含量及土壤脲酶活性的线性模型,可解释稻田CH4累积排放64%的变异。综上,在大气CO_(2)浓度升高条件下,氮肥减施可通过影响土壤碳、氮基质及土壤脲酶活性来调节稻田CH4排放。

紫云英及氮肥减量下配施生物质炭对土壤理化性质和水稻产量的影响

【目的】为减少化学氮肥的使用,通过盆栽试验探究在紫云英还田条件下,氮肥减量配施生物质炭对稻田土壤养分提升、水稻增产的作用,旨在明确在紫云英替代部分氮肥的基础上,更有利于培肥和增产的最佳减氮量和生物质炭添加比例,以期为实际生产应用提供科学依据。【方法】采用双因素水稻盆栽试验,以冬闲+常规施肥(CK)为空白对照,设置了4个(0.25%、0.5%、1%、2%)生物质炭添加比例,在追肥时设置3个(减氮10%、减氮20%、减氮30%)减氮比例,共设置13个处理组合,每个处理重复4次,共计52盆,生长周期120 d,水稻成熟后比较各处理对土壤理化性质及水稻产量、性状的影响。【结果】在紫云英还田下,减氮30%配施2.0%生物质炭显著提高了土壤pH(P<0.01)与CK相比提高了12.02%;减氮20%配施2.0%生物质炭对土壤有机质(SOM)、有效磷(AP)、速效钾(AK)含量均具有极显著提升作用(P<0.01),显著提升了土壤全氮含量(P<0.05),比CK分别增加了38.8%、107.2%、25.4%、24.9%;减氮20%配施0.5%生物质炭时碱解氮含量显著提升了49.6%(P<0.01)。紫云英还田下减氮30%配施1.0%生物质炭时产量最高,与CK相比分别显著增产18.7%(P<0.01)。施加低量生物质炭(0.25%生物质炭)更有利于水稻地上部生物量积累,比CK显著增加了90.04%(P<0.01)。相关性分析表明,土壤有机质、有效磷、速效钾是提升水稻产量的主要土壤环境因子(P<0.05、r>0.5)。【结论】紫云英、氮肥减量及生物质炭联合施用的培肥增产效果显著,紫云英还田下减氮20%配施2.0%生物质炭更有利于提升稻田土壤养分含量,减少氮素流失,促进水稻生长增产,但施加过量生物质炭对水稻产量及生物量具有一定的抑制作用,在追肥时减氮30%配施1.0%生物质炭对水稻增产效果最佳。