Responses of Crop Yields and Soil Fertility to Long-term Nutrient Lacking

[Objective] Long-term （over 18 years） fertilization experiments were con- ducted to study the responses of crop yields and soil fertility to long-term nutrient lacking at Zhengzhou in China. [Method] The present study consisted of five treat- ments： 1 CK （no fertilizer or manure）, （2） NP （nitrogen and phosphorus fertilizer applied）, 31 NK （nitrogen and potassium fertilizer applied）, 4 PK （phosphorus and potassium fertilizer applied） and ：5 NPK （nitrogen, phosphorus and potassium fertil- izer applied）. [Result] Lacking of nitrogen or phosphorus led to a low yield; however, there was no significant difference in grain yields between the NP and NPK treat- ments which maintained a higher yield. Receiving no phosphorus, soil available phosphorus content declined to about 2.5 mg/kg. The concentration of soil ex- changeable potassium remained constant at a level of 60 mg/kg under the treat- ments without potassium fertilizer addition. Soil potassium spontaneous supply ca- pacity fluctuated around 100%.[Conclusion] In fluvo-aquic soil, nitrogen and phos- phorus were two key limiting factors to grain yields, biomass and yield component factors of wheat and maize, while potassium was not. However, potassium defi- ciency may occur in the future if there was still no potassium fertilizer applied.

Effects of level soil bunds and stone bunds on soil properties and its implications for crop production: the case of Bokole watershed, Dawuro zone, Southern Ethiopia

Level soil bunds (LSB) and stone bunds (SB) have been widely implemented in the Bokole watershed since 2000 through support of the World Food Program (WFP). However, the performance of them against the target of the structure has not been studied. This study analyzed the effect of LSB and SB on selected soil properties, when compared with nonterraced cropland. The Bokole watershed was divided into two units. From upper watershed, three croplands with LSB (aged 4, 6, and 9 years) and three nonterraced croplands each adjacent to one of the LSB were selected. Similarly, in lower watershed, SB aged 4, 6, and 8 years and three nonterraced croplands each adjacent to one of the SB were selected. From each cropland with LSB and SB, three composite soil samples (rep licates) were collected systematically in X designed rectangular plot. From each nonterraced cropland, three composite soil samples (replicates) were collected in X designed square plot. A total of 36 soil samples were analyzed for Soil Organic Carbon (SOC), Total Nitrogen (TN), Available Phosphorus (AP), Available Potassium (AK), pH, and Cation Exchange Capacity (CEC) following standard laboratory procedures. Most soil parameters were not significantly different in cropland with LSB and SB compared to nonterraced. However, in LSB aged 4 years and SB aged 6 years AP and pH were significantly less than their adjacent-nonterraced cropland. In SB aged 8 years, SOC, AP, AK, and pH were also significantly less than adjacent-nonterraced cropland. Past erosion, and past land uses are likely factors contributed to the observed result. It was inferred that the mean con tribution of LSB and SB alone for crop production with regard to analyzed soil parameters was not significant in the considered sites. Additional soil fertility management practices should be incorporated for better effect.

Effect of Different Levels of Water Soluble Phosphorus in Complex Fertilizers on Crop Productivity and Soil Health

Field experiments were undertaken on sandy soils with three cropping systems at Giridih,Jharkhand,India for two years during 2012-2014.The experiments were executed in split plot design by assigning water soluble phosphorus(WSP)fertilizers in main-plot and recommended dose of phosphorus(RDP)in sub-plot with three replications.The maximum economical yield of rice(4705 kg/ha),baby corn(842 kg/ha)and Chickpea(920 kg/ha)were recorded with the application of 30%WSP.The maximum economical yield of successive crops-wheat(3185 kg/ha),mustard(1720 kg/ha)and groundnut(1578 kg/ha)were recorded with the application of 30%WSP and 100%RDP treatment.Almost similar trends were noticed in terms of by-product yield,nutrient uptake and residual soil fertility status.All the levels of WSP(30%-89%)in complex fertilizers were found to be equally effective for grain yield,straw yield,nutrient uptake,and residual soil fertility.

Coupling Effect of Water and Phosphate on Economic Traits of Sugarcane

[Objective] The aim was to study the coupling effect of water and phosphate on economic traits of sugarcane. [Method] Taking sugarcane variety ROC22 as tested material,coupling effects of different levels of water supply quantity and different levels of phosphorus fertilizer on the yield and quality of sugarcane were studied. Among them,water supply quantity had 3 levels,that was,the water supply quantity per 10 days from the early tillering stage of sugarcane to the end of elongation was 199.5 m3/hm2 (A1),400.5 m3/hm2 (A2) and 600.0 m3/hm2 (A3),respectively; Phosphorus fertilizer as basic fertilizer had 4 levels:P2O5 0 kg/hm2 (B1),120 kg/hm2 (B2),240 kg/hm2 (B3) and 360 kg/hm2 (B4). [Result] Treatment A3B2 in water-fertilizer coupling was more suitable to improve economic traits of sugarcane. [Conclusion] The research results provide theoretical basis for the efficient utilization of water and phosphorus fertilizer in production of Guangxi sugarcane and the cultivation of high-yield and high-glucose sugarcane.

Soil Test Based Fertilizer Prescriptions through Inductive cum Targeted Yield Model for Sesamum on Alfisol

Studies on Soil Test Crop Response Based Integrated Plant Nutrition System(STCR-IPNS)were conducted for three years adopting the Inductive cum Targeted Yield Model,on alfisols of Unified Andhra Pradesh,Southern India during summer 2016-2018 in order to develop fertilizer prescriptions through IPNS for the desired yield targets of Sesamum under field conditions.The bases for making the fertilizer prescriptions viz.nutrient requirement(NR),contribution of nutrients from soil(Cs),fertilizer(Cf)and vermicompost(CVC)were computed using the field experimental data.Making use of these basic parameters,the fertilizer prescription equations were developed under NPK alone and under IPNS for the desired yield targets of Sesamum for a range of soil test values.The quantity of fertilizers contributed by the application of vermicompost was assessed.Nutrient requirement to produce 100 kg of sesame seed was worked out to be 10.20 kg N,3.90 kg P2O5 and 5.22 kg K2O.In the present investigation,the requirement of N was higher which is followed by K2O and P2O5.The requirement of N was 2.62 times higher than P and 1.95 times higher than K.The percent contribution of N,P and K was 12.25,15.75 and 6.00 from soils,41.68,22.85 and 59.97 from fertilizer and 9.87,6.74 and 18.65 from organic manures,respectively.Thus the Inductive cum Targeted Yield Model used to develop fertilizer prescription equations provides a strong basis for soil fertility maintenance consistent with high productivity and efficient nutrient management in farming for sustainable and enduring agriculture.

不同耕作方式和前茬作物对冬小麦水肥利用效率及产量影响

【目的】探讨不同耕作方式和前茬作物对冬小麦土壤养分、产量及水肥利用效率的影响。【方法】设置2个主处理:旋耕(RT)和免耕(NT),2个副处理:玉米前茬(MW)和大豆前茬(SW),共4个处理,分别记为RTMW、RTSW、NTMW、NTSW,研究不同耕作方式和前茬作物对冬小麦土壤养分、水肥利用效率及产量的影响。【结果】同一前茬作物下,免耕处理土壤含水率高于旋耕处理;同一耕作方式下,玉米前茬处理土壤含水率高于大豆前茬;冬小麦季各处理有机碳量、全氮量、速效磷量、速效钾量、铵态氮量、硝态氮量均随土层深度增加而降低。0~50 cm土层,NTSW处理均有利于冬小麦麦田土壤有机碳、全氮、硝态氮量的积累,较RTMW处理分别提高了4.14%~13.54%、35.51%~54.44%、55.75%~112%;10~50cm土层,RTMW处理后茬麦田速效磷、速效钾量较高;0~50 cm土层,RTSW处理后茬麦田铵态氮量最高,较RTMW处理高13.39%~20.64%;NTSW处理穗数、穗粒数、千粒质量显著高于其他处理,且冬小麦产量也高于其他处理,较RTMW处理增产16.62%;NTSW处理水分利用效率及氮磷钾利用效率均最高。【结论】NTSW处理有利于冬小麦田的养分积累,且水肥利用效率最高,增产效果较好。

生物质缓释土壤保水增肥剂对宁夏盐池县土壤及其作物的影响

为探讨生物质缓释土壤保水增肥剂对农田土壤水温环境、土壤养分吸收和作物产量的影响,在宁夏回族自治区吴忠市盐池县以玉米、马铃薯、燕麦等为供试作物,生物质缓释土壤保水增肥剂为供试材料,采用田间试验,设置生物质缓释土壤保水增肥剂不同梯度的施用量,测定土壤含水量、酸碱度、电导率、容重和土壤养分等,研究其对试验地区土壤理化性质、土壤养分以及不同作物产量的影响。结果表明:在施用量不同的情况下,所种植的作物总体上产量都有所增加。苏丹草和燕麦草增产率最高,分别达到36.26%和24.35%。荞麦在生物质缓释土壤保水增肥剂施用量为120kg/hm^(2)时产量增产率达到23.19%,而马铃薯在生物质缓释土壤保水增肥剂施用量为120kg/hm^(2)时产量增产率最高,达到了77.78%,增产效果显著。但玉米产量变化趋势有所不同,在生物质缓释土壤保水增肥剂施用量为60kg/hm^(2)时产量反而有所下降,当施用量增加至120kg/hm^(2)时产量有所上升,但增产率只有0.69%,主要是由于地块所处位置、地势以及土壤组分存在一定程度的差异性,导致生物质缓释土壤保水增肥剂施用量对玉米产量影响不大。

Response of upland rice agronomic parameters to variable water supply

Rice response to water application is necessary for increased productivity;hence,this study was aimed at establishing the agronomic responses of rice crop to differential water supplies.A two-year dry season experiment was conducted on the research farm of International Institute of Tropical Agriculture(IITA),Ibadan,Nigeria.Two upland rice varieties(NERICA 2 and NERICA 4)were planted on a 5 m×5 m plot in a randomized complete block design with four treatments and two replicates based on different water application.Irrigation scheduling was designed as 100%ET,75%ET,50%ET and 25%ET for the treatments weekly.Agronomic parameters such as plant height,root depth,canopy shading(CS),leaf area index(LAI),panicle and tiller configuration,biomass and grain yield in relation to crop water use were obtained and the results were subjected to statistical analysis.Average values of highest plant height(89.0 and 100.3 cm),deepest root depth(22.1 and 23.8 cm),panicle diameter(3.9 and 4.5 cm),panicle length(26.1 and 25.7 cm),LAI,3.27 and 3.95,CS,0.22 and 0.99 were obtained for both NERICA 2 and NERICA 4 respectively.Leaf width(1.3 and 1.4 cm),total tillers(14 and 12)and leaf length(36.9 and 38 cm)were also observed for the two varieties respectively.The highest total grain and biomass yields of 1.94 t/ha and 1.95 t/ha were observed in 100%ET treatment for NERICA 2 while the least values of 0.29 t/ha and 1.09 t/ha were observed in 25%ET treatment.As for NERICA 4,the highest values(1.90 t/ha and 2.27 t/ha)were from 100%ET and the least(0.38 t/ha and 2.29 t/ha)in 25%ET.The result of ANOVA showed significant differences in biomass and grain yield,LAI,CS,plant height and root depth among treatments(P<0.05)stressing the domineering influence of water in agronomic response of rice.

优化管理对小麦-玉米轮作系统植株干物质积累、转运与产量的影响

针对小麦-玉米轮作种植系统中因秸秆处理不当、肥料施用不合理造成的农田土壤退化、作物减产等问题,本研究设置6种水肥结合秸秆优化管理模式,探究其对小麦、玉米干物质积累、转运和产量的影响,以期为改善小麦-玉米轮作系统田间管理提供科学依据。试验以农民常规管理模式(漫灌+常规施肥+秸秆还田)为对照(CK),设两种水肥优化方案———滴灌+增效复混肥+稳定尿素(水肥优化Ⅰ,SS)、水肥一体+增效复混肥(水肥优化Ⅱ,SF),每种水肥优化方案下设3种秸秆处理方式———秸秆还田、秸秆还田+腐解剂(D)、秸秆不还田+秸秆炭(C),共组合为6个处理,分别标记为SS、SSD、SSC、SF、SFD和SFC。研究发现,SSC处理可有效提升玉米干物质积累和转运,花前干物质转运量、转运效率和花前干物质对籽粒的贡献率较CK分别显著提高56.6%、7.14个百分点和10.93个百分点;SS处理下小麦干物质积累量最高,其花后干物质积累量较其他处理显著增加23.2%(SSD)~115.1%(SF);SFD处理可有效促进干物质转运,其花前干物质转运效率、对籽粒的贡献率分别较CK显著提高3.04个百分点和7.08个百分点。SSC、SFD处理的玉米、小麦产量均显著高于其他处理,分别较CK显著提升21.8%、16.2%(SSC)和14.2%、23.6%(SFD)。综上,各优化措施处理中,SSC和SFD模式均能有效提升植株干物质积累并协调其向籽粒转运,提高成熟期籽粒干物质分配比例,提升小麦-玉米轮作系统下作物产量,可在生产中推广应用。

膜下滴灌制度与生物炭用量对玉米生长及水氮利用效率的影响

为探明干旱地区盐碱地膜下滴灌不同灌水下限施用生物炭对玉米产量和水肥利用效率的响应差异及相互影响关系,提出较优的灌溉制度和生物炭用量。连续2年在河套灌区盐渍化农田玉米生长阶段进行小区控制试验,设计3个灌水下限[土壤基质势为-15(W15),-25(W25),-35(W35)kPa,灌水定额为22.5 mm]和3个生物炭用量水平[0(B0),15(B15),30(B30)t/hm^(2)],2因素完全随机试验设计,共9个处理。测定并分析玉米全生育期0—15 cm土壤理化性状、作物生长特征和水氮利用效率。结果表明:不同灌水下限施用生物炭整体提高玉米全生育期土壤含水率、有机质和碱解氮含量,同一灌溉水平下生物炭用量越高,各指标提升的幅度越大。施用生物炭提高玉米地上部干物质积累量和产量,灌溉水利用效率和氮肥偏生产力显著提高,且生物炭施用当年的效果普遍优于翌年。相较于不施用生物炭的对照,W15、W25、W35条件下,B15使玉米产量平均增加12.8%,10.3%,14.2%,灌溉水利用效率提高14.2%,10.4%,12.9%,氮肥偏生产力提升12.8%,10.4%,14.0%,其节水增产提效的作用普遍优于同一灌水处理的B30。建议河套灌区盐渍化农田玉米生育期的膜下滴灌灌水下限为-35 kPa,生物炭施用量为15 t/hm^(2)。

春小麦叶片气体交换与产量对干旱响应的阈值差异

叶片气体交换过程是作物干物质及产量形成的基础,在干旱发展过程中作物叶片气体交换对水分胁迫存在阈值响应,众多相关生理指标也以此为基础用于监测作物受旱状况。然而作物叶片气体交换过程与产量对干旱的响应阈值是否具有同步性,目前尚不清楚,这在一定程度上影响了利用作物生长期叶片气体交换相关生理指标监测农业干旱的准确性。本研究通过控制试验确定春小麦叶片气体交换对干旱的响应阈值,并利用该阈值特征参数化春小麦生长模型,从而设计水分控制模拟试验,分析春小麦产量对干旱的阈值响应特征及其与叶片气体交换指标阈值的差异。结果表明:春小麦气孔导度对土壤有效含水量的响应阈值为0.50,大于蒸腾速率与净光合速率的响应阈值(0.40)。用净光合速率对土壤有效含水量的响应阈值参数化春小麦生长模型,能够准确模拟春小麦地上部生物量和产量的变化。春小麦地上部生物量与产量对根系层土壤有效含水量的响应阈值为0.18,明显小于叶片气体交换指标对土壤有效含水量的响应阈值。证明了利用作物生育期间叶片气体交换等生理指标表征作物受旱状况,反映作物最终产量降低程度会存在一定问题。本研究结果可为农业干旱监测、预测及干旱影响评估提供参考依据。

基于响应面法的多砾石砂土滴灌春小麦水肥条件优选

【目的】研究多砾石砂土土质条件下不同水肥处理对滴灌春小麦生长发育的影响,为阿勒泰地区小麦的水肥施用提供指导。【方法】设置30 mm(W_(1))、45 mm(W_(2))、60 mm(W_(3))3个灌水水平及尿素施用0 kg/hm^(2)(N_(0))、300 kg/hm^(2)(N_(1))、600 kg/hm^(2)(N_(2))3个施肥水平,利用方差分析及响应面法进行结果优选。【结果】同一灌水水平下,N_(0)处理相比N_(1)、N_(2)处理春小麦株高及干物质积累量较低,其中N_(0)处理与N_(2)处理株高和干物质积累量差异显著(P<0.05);同一施肥水平下春小麦株高及干物质积累量随着灌水量增加逐渐增加。灌水量对有效穗数有显著影响(P<0.05),对千粒重无显著影响(P>0.05)。施肥量对千粒重和有效穗数无显著影响(P>0.05)。灌水量与施肥量对每穗粒数和产量有极显著影响(P<0.01),水肥交互仅对产量有极显著影响(P<0.01)。【结论】利用响应面法优选后的最佳水肥条件为灌水60 mm,施肥388 kg/hm^(2),该条件下小麦产量为6923.1 kg/hm^(2);W_(3)N_(1)处理(灌水量60 mm,施肥量300 kg/hm^(2))下小麦的干物质积累、产量构成及产量表现较好,最终产量为7040.93 kg/hm^(2),选取W_(3)N_(1)为较好的水肥处理。

河套灌区耕地土壤性质与作物产量空间分布特征之间的关系

【目的】阐明内蒙古河套灌区耕地土壤性质与作物产量空间分布特征之间的关系,提出灌区耕地水肥管理优化对策。【方法】基于经典统计学与地统计学方法,研究河套灌区耕地土壤理化性质和作物产量的空间变异性与分布特征,剖析主要作物产量与土壤性质之间的关系,基于土壤盐渍化程度和主要作物产量的空间分布格局提出水肥优化管理对策。【结果】巴彦淖尔市土壤盐渍化程度总体偏高,土壤体积质量较大,作物产量普遍较低,有机质和氮素贫乏,有效磷适量、速效钾富余。土壤含盐量属于强变异,有机质、全氮、有效磷、速效钾和作物产量系数属于中等变异,体积质量和pH值属于弱变异。在空间分布特征上,土壤含盐量呈中部高、四周低的空间格局;作物产量系数呈自西南向东北的递减趋势;有机质量自西向东递增;体积质量、pH值、全氮量、有效磷量呈中部高,东、西部低的空间格局;灌区东南部速效钾量贫乏。土壤含盐量是制约内蒙古河套灌区作物产量的突出因子。【结论】兼顾土壤培肥与作物增产,建议深施氮肥和有机肥,重度盐渍化和盐土区域建议尿素、有机肥施用量为225、3393.7 kg/hm^(2);中度盐渍化区域为295.4、2332.8 kg/hm^(2);轻度和非盐渍化区域为365.1、1280.9 kg/hm^(2)。建议重点完善灌区西北、南部和东南地区的排水系统,提高中部和东部地区排水、排盐效率。

水肥优化配施腐解剂对小麦-玉米轮作体系土壤养分含量和作物产量的影响

本试验以小麦‘烟农24’、玉米‘郑丹958’为材料,全量秸秆还田条件下,以农民常规水肥管理(漫灌+常规施肥)为对照(CK),设置常规水肥管理+腐解剂(CKD)、优化水肥管理Ⅰ(滴灌+缓控释肥,SS)、优化水肥管理Ⅰ+腐解剂(SSD)、优化水肥管理Ⅱ(水肥一体,SF)、优化水肥管理Ⅱ+腐解剂(SFD)5个处理,探究水肥优化配施腐解剂对小麦-玉米轮作体系土壤养分和作物产量的影响。结果表明,在玉米季,各处理土壤速效养分含量呈不规律的波动变化趋势,大喇叭口期追肥可有效缓解土壤养分下降,维持土壤肥力。小麦季,随生育期的推进,氮磷钾速效养分含量呈逐渐降低趋势。成熟期,水肥优化配施腐解剂(SSD和SFD)处理显著提高玉米季0~20 cm土层碱解氮和有效磷含量,较SS和SF分别提升27.9%、35.9%和12.5%、19.5%。CKD处理玉米产量最高,为10.0 t/hm^(2),其次为SFD、SF处理,较CK分别显著增产16.3%、11.6%、9.3%;SFD处理小麦产量最高,为8.6 t/hm^(2),其次为SS、SF处理,较CK分别显著增产19.4%、18.1%、15.3%。相关性分析表明,玉米产量与苗期0~20 cm土层和成熟期20~40 cm土层碱解氮及有效磷含量呈显著负相关,与大喇叭口期20~40 cm和灌浆期0~20 cm土层速效钾含呈显著正相关;而小麦产量主要与返青期土壤速效养分相关。综上,相同水肥管理下,配施腐解剂有助于维持土壤速效养分含量,对小麦、玉米产量有积极影响。玉米季以滴灌+缓控释肥和水肥一体配施腐解剂、小麦季以滴灌+缓控释肥配施腐解剂土壤速效养分含量较高,常规水肥管理配施腐解剂的玉米产量和水肥一体管理配施腐解剂的小麦产量较高。

Soil physical properties,nutrients,and crop yield with two-year tillage rotations under a winter wheat-summer maize double cropping system

Winter wheat and summer maize were planted from 2015-2017 to study the effects of different rotational tillage patterns on soil physicochemical properties,crop yield,water content,and fertilizer utilization.The tillage treatments were designed as wheat subsoiling-maize no tillage(WS-MN),wheat rotary tillage-maize subsoiling(WR-MS),wheat subsoiling-maize subsoiling(WS-MS),and conventional wheat rotary tillage-maize no tillage(WR-MN)as a control.Among the four treatments,WS-MN and WR-MS were single-season subsoiling treatments,and WS-MS was a two-season subsoiling treatment.The average soil bulk density decreased by 7.6%in the single-and double-season subsoiling groups compared to the WR-MN group,and the total porosity and noncapillary porosity increased by 10.7%and 12.2%,respectively.Single-or double-season subsoiling treatment was not conducive to water storage in the 0-20 cm soil layer but increased the water content of the 20-140 cm soil layer,and the average soil water content of the 0-140 cm layer was increased by 11.6%in the two-growing season treatment groups compared with the WR-MN group.In WS-MS and WS-MN groups compared with the WR-MN group,the soil ammonium nitrogen content was increased by an average of 18.6%in 0-20 cm soil and 16.8%in 20-100 cm soil;soil nitrate-nitrogen content was decreased by 13.5%in 0-100 cm soil;total organic carbon and microbial carbon contents in the 15-30 cm soil were increased by 18.1%and 12.7%,respectively;and soil urease,catalase,and alkaline phosphatase activities were increased by 46.1%,15.2%,and 23.1%,respectively.Annual crop yield and water use efficiency increased by 8.9%and 15.0%,respectively,in both the single-and double-season subsoiling treatment groups.This study demonstrated the advantages of subsoiling tillage and suggested that it is suitable for crop cultivation in the Haihe Plain,China.

不同供肥条件下水分分配对旱地玉米产量的影响

通过盆栽试验和田间试验，研究了不同供肥条件下不同生育期水分状况对玉米产量的影响。结果表明，任何生育期的土壤干旱胁迫均会导致玉米减产，肥料供应充足时减产幅度较小；干旱胁迫越严重，肥料的这一作用越显著。无论正常供肥还是低肥，玉米对抽雄期土壤水分最敏感，防止这一时期干旱胁迫对保证玉米产量具有重要意义。拔节期是旱地玉米有限灌溉的另一个关键时期，水分的增产潜力很大，低肥时增加拔节期土壤水分供应效果更显著。玉米苗期并不耐旱，尤其是低肥时苗期干旱显著影响玉米的籽粒产量。在相对含水量45％～90％范围内。玉米产量随土壤含水量的增加而增加，但增加幅度与肥料供应和生育期有关。玉米获得最高产量的土壤水分条件与肥料供应密切相关，与正常供肥相比，低肥时所需土壤含水量较低。玉米增产的肥效大于水效，产量随肥料投入的增加显著提高，水分胁迫条件下增加肥料供应同样具有增产作用。肥料供应不足时水分的增产作用会受到限制。在现有的水资源条件下，提高肥料供应水平是旱地玉米增产的主要途径。

不同水肥条件对小麦生长及养分吸收的影响

采用盆栽试验研究了不同水肥条件对小麦地上部分和根系生物量、养分吸收状况及产量的影响。结果表明 :随着水肥条件的改善 ,小麦地上部及整体植株生物量均呈明显增加趋势 ,而根系生物量在水肥条件适宜时较小 ,次适宜时较大 ;当水分进一步亏缺时 ,根系生长受阻 ,其生物量下降。水肥条件对小麦成穗率及穗粒数均有不同程度的影响 ,从而导致了籽粒产量在不同水肥条件下的差异 ;千粒重受水肥条件影响不大。适宜的水肥条件有利于作物对养分的吸收和运输 ,有利于植株的协调生长 ;而当水分供应不足时 ,根系与地上部分存在对养分和光合产物的竞争 ,根系成为光合产物的优势库 ,根系养分含量增加 ,根 /冠亦增大。当土壤水分严重亏缺时 ,根系及茎秆中的养分向穗粒部运输受阻 。

有机—无机肥配施的增产效应及对土壤肥力影响的定位研究

本文根据１３年的定位研究资料，较系统的阐述了不同量有机肥与氮、磷化肥配合施用，及关中灌区两熟制粮食产量、土壤肥力和养分平衡的影响。初步揭示了关中楼土的基本生产力持续时间较短；土壤的供肥能力是玉米高于小麦。作者认为采用有机肥与氮、磷化肥配施，才是该区粮田持续高产和土壤培肥的有效措施。

适宜微喷灌灌水频率及氮肥量提高冬小麦产量和水分利用效率

为明确微喷水肥一体化条件下灌溉次数和氮肥用量对冬小麦产量形成和水分利用的影响,该试验在灌水定额1 500 m3/hm2下设置微喷2次（拔节期750 m3/hm2＋开花期750 m3/hm2）、3次（拔节期450 m3/hm2＋开花期750 m3/hm2＋灌浆期300 m3/hm2）、4次（拔节期450 m3/hm2＋孕穗期300 m3/hm2＋开花期450 m3/hm2＋灌浆期300 m3/hm2）和氮肥追施45、90、135 kg/hm2处理,N肥随灌水等量分次施入,考察群体光合特性、物质生产和水分利用特征。结果表明：微喷3次和4次相比于微喷2次,产量提高了5.3%～18.9%,水分利用效率提高了5.3%～27.8%,但微喷3次与4次之间差异不显著。适当增加微喷次数提高了开花期和灌浆期群体绿色叶面积指数,延缓了叶片衰老,提高了生育后期干物质积累,增加了千粒质量,进而提高了籽粒产量;多次微喷（3次或4次）降低了总耗水量和开花前耗水比例,提高了开花后耗水比例;适当增施氮肥能进一步提高花后物质积累和花后耗水比例。综合来看,1 500 m3/hm2灌溉定额下微喷4次,追施氮肥90 kg/hm2产量和水分利用效率较高。

适宜灌水施氮方式利于玉米根系生长提高产量

为研究不同灌水方式和施氮方式对玉米根系生长分布的影响，2011年在大田条件下采用垄植沟灌技术，设交替灌水、固定灌水、均匀灌水和交替施氮、固定施氮、均匀施氮2因素3水平的随机完全组合试验方案。分抽雄期、灌浆期和成熟期对0～100 cm土层监测植株正下方、植株正南侧和植株正北侧的根系生长状况。结果表明，灌水方式对各位置根长及根系总量影响均达显著水平，施氮方式只对植株南侧根长和根系总干质量影响显著，二者的交互作用只对植株北侧根长和总根长影响显著。交替灌水均匀施氮在监测时期内维持了较大总根长，并使得灌浆期植株不同位置根长、总根量（总根干质量除外）均较大，并最终获得较大的产量（11524 kg/hm^2）。而固定灌水固定施氮总根长最小，产量最低。各处理下0～40 cm土层根长所占整个土层根长比例均较高，该比值以交替灌水均匀施氮最大。对比发现，根系生长分布对灌水方式更加敏感，通过不同灌水与施氮调控玉米根系生长分布应集中在0～40 cm土层，交替灌水均匀施氮最有利于根系的生长和产量的提高，为垄植沟灌下较好的灌水施氮方式。该研究为通过不同灌水施氮方式调控作物根系生长并获得高产提供了一定理论依据。