基于留一交叉验证法的APSIM-Maize产量模拟

作物生长模型APSIM广泛应用于作物估产和农业生产管理中,在观测数据有限的情况下,开展留一交叉验证是提高模型模拟能力的关键途径。本研究以内蒙古十大孔兑地区春玉米为研究对象,量化分析了APSIM-Maize模型模拟2012—2019年间玉米产量对关键参数的敏感性,并根据参数敏感性强弱对APSIM-Maize模型进行交叉验证与参数率定,提高了模型模拟能力。主要结果为:(1)影响春玉米产量的敏感性参数由强到弱依次是:蒸腾效率系数、辐射利用效率、开花到成熟的积温、出苗到拔节的积温、开花到灌浆的积温、潜在灌浆速率、光周期和最大穗粒数;(2)交叉验证时,APSIM-Maize模型各参数变异系数在1.06%~23.32%之间波动,总体上模型参数变异性小,可靠性高;(3)APSIM-Maize模型经过参数率定后的模拟产量与实测产量具有较好的一致性(R^(2)=0.72,RMSE=401.5kg hm^(-2)),模型在十大孔兑地区春玉米产量的评估中表现出较好的适应性。本研究为在农田试验数据有限情况下提高模型率定参数的可靠性提供了新的研究思路和科学依据。

Effect of subsoil tillage depth on nutrient accumulation, root distribution, and grain yield in spring maize

A four-year field experiment was conducted to investigate the effect of subsoiling depth on root morphology, nitrogen(N), phosphorus(P), and potassium(K) uptake, and grain yield of spring maize. The results indicated that subsoil tillage promoted root development,increased nutrient accumulation, and increased yield. Compared with conventional soil management(CK), root length, root surface area, and root dry weight at 0–80 cm soil depth under subsoil tillage to 30 cm(T1) and subsoil tillage to 50 cm(T2) were significantly increased, especially the proportions of roots in deeper soil. Root length, surface area, and dry weight differed significantly among three treatments in the order of T2 > T1 > CK at the12-leaf and early filling stages. The range of variation of root diameter in different soil layers in T2 treatment was the smallest, suggesting that roots were more likely to grow downwards with deeper subsoil tillage in soil. The accumulation of N, P, and K in subsoil tillage treatment was significantly increased, but the proportions of kernel and straw were different. In a comparison of T1 with T2, the grain accumulated more N and P, while K accumulation in kernel and straw varied in different years. Grain yield and biomass were increased by 12.8% and 14.6% on average in subsoil tillage treatments compared to conventional soil treatment. Although no significant differences between different subsoil tillage depths were observed for nutrient accumulation and grain yield, lodging resistance of plants was significantly improved in subsoil tillage to 50 cm, a characteristic that favors a high and stable yield under extreme environments.

Tillage and straw mulching impacts on grain yield and water use efficiency of spring maize in Northern Huang–Huai–Hai Valley

A two-year field experiment(2012–2013) was conducted to investigate the effects of two tillage methods and five maize straw mulching patterns on the yield, water consumption,and water use efficiency(WUE) of spring maize(Zea mays L.) in the northern Huang–Huai–Hai valley of China. Compared to rotary tillage, subsoil tillage resulted in decreases in water consumption by 6.3–7.8% and increases in maize yield by 644.5–673.9 kg ha-1, soil water content by 2.9–3.0%, and WUE by 12.7–15.2%. Chopped straw mulching led to higher yield,soil water content, and WUE as well as lower water consumption than prostrate whole straw mulching. Mulching with 50% chopped straw had the largest positive effects on maize yield, soil water content, and WUE among the five mulching treatments. Tillage had greater influence on maize yield than straw mulching, whereas straw mulching had greater influence on soil water content, water consumption, and WUE than tillage. These results suggest that 50% chopped straw mulching with subsoil tillage is beneficial in spring maize production aiming at high yield and high WUE in the Huang–Huai–Hai valley.

Subsoiling and Ridge Tillage Alleviate the High Temperature Stress in Spring Maize in the North China Plain

High temperature stress（HTS） on spring maize（Zea mays L.） during the filling stage is the key factor that limits the yield increase in the North China Plain（NCP）.Subsoiling（SS） and ridge tillage（R） were introduced to enhance the ability of spring maize to resist HTS during the filling stage.The field experiments were conducted during the 2011 and 2012 maize growing seasons at Wuqiao County,Hebei Province,China.Compared with rotary tillage（RT）,the net photosynthetic rate,stomatal conductance,transpiration rate,and chlorophyll relative content（SPAD） of maize leaves was increased by 40.0,42.6,12.8,and 29.7% under SS,and increased by 20.4,20.0,5.4,and 14.2% under R,repectively.However,the treatments reduce the intercellular CO 2 concentration under HTS.The SS and R treatments increased the relative water content（RWC） by 11.9 and 6.2%,and the water use efficiency（WUE） by 24.3 and 14.3%,respectively,compared with RT.The SS treatment increased the root length density and soil moisture in the 0-80 cm soil profile,whereas the R treatment increased the root length density and soil moisture in the 0-40 cm soil profile compared with the RT treatment.Compared with 2011,the number of days with temperatures 33°C was more 2 d and the mean day temperature was higher 0.9°C than that in 2012,whereas the plant yield decreased by 2.5,8.5 and 10.9%,the net photosynthetic rate reduced by 7.5,10.5 and 18.0%,the RWC reduced by 3.9,5.6 and 6.2%,and the WUE at leaf level reduced by 1.8,5.2 and 13.1% in the SS,R and RT treatments,respectively.Both the root length density and the soil moisture also decreased at different levels.The yield,photosynthetic rate,plant water status,root length density,and soil moisture under the SS and R treatments declined less than that under the RT treatment.The results indicated that SS and R can enhance the HTS resistance of spring maize during the filling stage,and led to higher yield by directly improving soil moisture and root growth and indirectly improving plant water status,photosynthesis and grain filling.The study can provide a theoretical basis for improving yield of maize by adjusting soil tillage in the NCP.

Basic Soil Productivity of Spring Maize in Black Soil Under Long-Term Fertilization Based on DSSAT Model

Increasing basic farmland soil productivity has significance in reducing fertilizer application and maintaining high yield of crops. In this study, we defined that the basic soil productivity （BSP） is the production capacity of a farmland soil with its own physical and chemical properties for a specific crop season under local environment and field management. Based on 22-yr （1990-2011） long-term experimental data on black soil （Typic hapludoll） in Gongzhuling, Jilin Province, Northeast China, the decision support system for an agro-technology transfer （DSSAT）-CERES-Maize model was applied to simulate the yield by BSP of spring maize （Zea mays L.） to examine the effects of long-term fertilization on changes of BSP and explore the mechanisms of BSP increasing. Five treatments were examined： （1） no-fertilization control （control）; （2） chemical nitrogen, phosphorus, and potassium （NPK）; （3） NPK plus farmyard manure （NPKM）; （4） 1.5 time of NPKM （1.5NPKM） and （5） NPK plus straw （NPKS）. Results showed that after 22-yr fertilization, the yield by BSP of spring maize significantly increased 78.0, 101.2, and 69.4% under the NPKM, 1.5NPKM and NPKS, respectively, compared to the initial value （in 1992）, but not significant under NPK （26.9% increase） and the control （8.9% decrease）. The contribution percentage of BSP showed a significant rising trend （P〈0.05） under 1.5NPKM. The average contribution percentage of BSP among fertilizations ranged from 74.4 to 84.7%, and ranked as 1.5NPKM〉NPKM〉NPK〉NPKS, indicating that organic manure combined with chemical fertilizers （I.5NPKM and NPKM） could more effectively increase BSP compared with the inorganic fertilizer application alone （NPK） in the black soil. This study showed that soil organic matter （SOM） was the key factor among various fertility factors that could affect BSP in the black soil, and total N, total P and/or available P also played important role in BSP increasing. Compared with the chemical fertilization, a balanced chemical plus manure or straw fertilization （NPKM or NPKS） not only increased the concentrations of soil nutrient, but also improved the soil physical properties, and structure and diversity of soil microbial population, resulting in an iincrease of BSP. We recommend that a balanced chemical plus manure or straw fertilization （NPKM or NPKS） should be the fertilization practices to enhance spring maize yield and improve BSP in the black soil of Northeast China.

The causes and impacts for heat stress in spring maize during grain filling in the North China Plain--A review

High-temperature stress （HTS） at the grain-filling stage in spring maize （Zea mays L.） is the main obstacle to increasing productivity in the North China Plain （NCP）. To solve this problem, the physiological mechanisms of HTS, and its causes and impacts, must be understood. The HTS threshold of the duration and rate in grain filling, photosynthetic characteristics （e.g., the thermal stability of thylakoid membrane, chlorophyll and electron transfer, photosynthetic carbon assimilation）, water status （e.g., leaf water potential, turgor and leaf relative water content） and signal transduction in maize are reviewed. The HTS threshold for spring maize is highly desirable to be appraised to prevent damages by unfavorable temperatures during grain filling in this region. HTS has negative impacts on maize photosynthesis by damaging the stability of the thylakoid membrane structure and degrading chlorophyll, which reduces light energy absorption, transfer and photosynthetic carbon assimilation. In addition, photosynthesis can be deleteriously affected due to inhibited root growth under HTS in which plants decrease their water-absorbing capacity, leaf water potential, turgor, leaf relative water content, and stomatal conductance. Inhibited photosynthesis decrease the supply of photosynthates to the grain, leading to falling of kernel weight and even grain yield. However, maize does not respond passively to HTS. The plant transduces the abscisic acid （ABA） signal to express heat shock proteins （HSPs）, which are molecular chaperones that participate in protein refolding and degradation caused by HTS. HSPs stabilize target protein configurations and indirectly improve thylakoid membrane structure stability, light energy absorption and passing, electron transport, and fixed carbon assimilation, leading to improved photosynthesis. ABA also induces stomatal closure to maintain a good water status for photosynthesis. Based on understanding of such mechanisms, strategies for alleviating HTS at the grain-filling stage in spring maize are summarized. Eight strategies have the potential to improve the ability of spring maize to avoid or tolerate HTS in this study, e.g., adjusting sowing date to avoid HTS, breeding heat-tolerance varieties, and tillage methods, optimizing irrigation, heat acclimation, regulating chemicals, nutritional management, and planting geometric design to tolerate HTS. Based on the single technology breakthrough, a com- prehensive integrated technical system is needed to improve heat tolerance and increase the spring maize yield in the NCP.

A preliminary study of the effects of plastic film-mulched raised beds on soil temperature and crop performance of early-sown short-season spring maize(Zea mays L.) in the North China Plain

To identify a strategy for earlier sowing and harvesting of spring maize(Zea mays L.) in an alternative maize–maize double cropping system, a 2-year field experiment was performed at Quzhou experimental station of China Agricultural University in 2014 and 2015. A short-season cultivar, Demeiya number 1(KX7349), was used in the experiment. Soil temperature to 5 cm depth in the early crop growth stage, crop growth, crop yield, and water use of different treatments(plastic film-mulched raised bed(RF) and flat field without plastic film mulching(CK) in 2014; RF, plastic film-mulched flat field(FF), and CK in 2015)were measured or calculated and compared. Soil temperature in the film-mulched treatments was consistently higher than that in CK(1.6–3.5 °C in average) during the early growth stage. Crops in plastic film-mulched treatments used 214 fewer growing-degree days(GDDs) in 2014 and 262 fewer GDDs in 2015. In 2014, the RF treatment yielded 32.7%higher biomass than CK, although its 9.4% higher grain yield was not statistically significant. Also, RF used 17.9% less water and showed 33.1% higher water use efficiency(WUE) than CK. In 2015, RF and FF showed 56.2% and 49.5% higher yield, 15.0% and 4.5%lower water use(ET), and 63.4% and 75.7% higher WUE, respectively, than CK. RF markedly increased soil temperature in the early crop season, accelerated crop growth, reduced ET,and greatly increased crop yield and WUE. Compared with FF, RF had no obvious effect on crop growth rate, although soil temperature during the period between sowing and stem elongation was slightly increased. However, RF resulted in lower ET and higher WUE than FF. Effects of RF on soil water dynamics as well as its cost-effectiveness remain topics for further study.

Impacts of Fertilization Alternatives and Crop Straw Incorporation on N_2O Emissions from a Spring Maize Field in Northeastern China

Spring maize is one of the most popular crops planted in northeastem China. The cropping systems involving spring maize have been maintaining high production through intensive management practices. However, the high rates of nitrogen （N） fertilizers application could have introduced a great amount of nitrous oxide （N2O） into the atmosphere. It is crucial for sustaining the maize production systems to reduce N2O emissions meanwhile maintaining the optimum yields by adopting alternative farming management practices. The goal of this study was to evaluate effects of alternative fertilization and crop residue management practices on N2O emission as well as crop yield for a typical maize field in northeastern China. Field experiments were conducted during the 2010-2011 maize growing seasons （from early May to late September） in Liaoning Province, northeastern China. N2O fluxes were measured at the field plots with six different treatments including no N fertilizer use （CK）, farmers＇ conventional N fertilizer application rate （FP）, reduced N fertilizer rate （OPT）, reduced N fertilizer rate combined with crop straw amendment （OPTS）, slow-release N fertilizer （CRF）, and reduced N fertilizer rate combined with nitrification inhibitor （OPT＋DCD）. The static chamber method combined with gas chromatography technique was employed to conduct the measurements of N2O fluxes. The field data showed that N2O emissions varied across the treatments. During the maize growing season in 2010, the total N2O emissions under the treatments of CK, FP, OPT, OPTS, and CRF were 0.63, 1.11, 1.03, 1.26, and 0.98 kg N ha-1, respectively. The seasonal cumulative N2O emissions were 0.54, 1.07, 0.96, 1.12, and 0.84 kg N ha1, respectively, under CK, FP, OPT, OPTS, and OPT＋DCD in 2011. In comparison with FP, CRF or OPT＋DCD reduced the N2O emissions by 12 or 21%, respectively, while the crop yields remained unchanged. The results indicate that the reduction of N-fertilizer application rate in combination with the slow-release fertilizer type or nitrification inhibitor could effectively mitigate N2O emissions from the tested field. The incorporation of crop residue didn＇t show positive effect on mitigating N2O emissions from the tested cropping system. The field study can provide useful information for the on-going debate on alternative N fertilization strategies and crop straw management in China. However, further studies would be needed to explore the long-term impacts of the alternative management practices on a wide range of environmental services.

Estimates of N_2O Emissions and Mitigation Potential from a Spring Maize Field Based on DNDC Model

Agricultural production plays an important role in affecting atmospheric nitrous oxide （N20） concentrations. Field measurements were conducted in Dalian City, Liaoning Province in Northeast China from two consecutive years （2009 and 2010） to estimate NzO emissions from a spring maize field, a main cropping system across the Chinese agricultural regions. The observed flux data in conjunction with the local climate, soil and management information were utilized to test a process-based model, DeNitrification-DeComposition （DNDC）, for its applicability for the cropping system. The validated DNDC was then used for exploring strategies to reduce N20 emissions from the target field. The results showed that the major N20 pulse emissions occurred with duration of about 3-5 d after fertilizer application in both years 2009 and 2010, which on average accounted for about 60% of the total N20 emissions each year. Rainfall and fertilizer application were the major factors influencing the N20 emissions from spring maize field. The average N20 flUXeS from the CK （control plot, without fertilization） and FP （traditional chemical N fertilizer） treatments were 23.1 and 60.6 gg m-2 h-~ in 2009, respectively, and 21.5 and 64.3 gg m-2 h-~ in 2010, respectively. The emission factors （EFs） of the applied N fertilizer （270 kg N ha-1） as N20- N were 0.62% in 2009 and 0.77% in 2010, respectively. The comparison of modeled daily NzO emission fluxes against observations indicated that the DNDC model had a good performance even if without adjusting the internal parameters. The modeled results showed that management practices such as no-till, changing timing or rate of fertilizer application, increasing residue incorporation, and other technically applicable measures could effectively reduce N20 emissions from the tested fields. Our study indicated that avoiding application of N fertilizers at heavy rainfall events or splitting the fertilizer into more applications would be the most feasible approaches to reduce N20 emissions from spring maize production in Northeast China.

Differences of yield and nitrogen use efficiency under different applications of slow release fertilizer in spring maize

Excessive or insufficient application of fertilizer has raised broader concerns regarding soil and environmental degradation.One-time application of slow release fertilizer (SF) has been widely used to reduce yield gap with potential maize yield and improve nitrogen use efficiency (NUE).A 2-year field experiment (2018–2019) was conducted to evaluate the effects of SF rates from 0 to 405 kg N ha^(–1) (named F0,SF225,SF270,SF315,SF360,and SF405) and 405 kg N ha^(–1) of common fertilizer(CF405) on the grain yield,biomass and N accumulation,enzymatic activities related with carbon–nitrogen metabolism,NUE and economic analysis.Results indicated that the highest grain yields,NUEs and economic returns were achieved at SF360in both varieties.The enzymatic activities related with carbon–nitrogen metabolism,pre-and post-silking accumulation of biomass and N increased with increasing SF rate,and they were the highest at SF360 and SF405.The grain yield at SF360had no significant difference with that at SF405.However,the N partial factor productivity,N agronomic efficiency and N recovery efficiency at SF360 were 9.8,6.6 and 8.9% higher than that at SF405.The results also indicated that the average grain yields,NUE and economic benefit at SF405 were 5.2,12.3 and 18.1% higher than that at CF405.In conclusion,decreasing N rate from 405 kg ha^(–1)(CF) to 360 kg ha^(–1)(SF) could effectively reduce the yield gap between realized and potential maize yields.The N decreased by 11.1%,but the yield,NUE and economic benefit increased by 3.2,22.2 and 17.5%,which created a simple,efficient and business-friendly system for spring maize production in Jiangsu Province,China.

Water Requirements and Irrigation Scheduling of Spring Maize Using GIS and CropWat Model in Beijing-Tianjin-Hebei Region

Due to the over use of available water resources, it has become very important to define appropriate strategies for planning and management of irrigated farmland. In this paper, Beijing-Tianjin-Hebei (Jing-Jin-Ji) region was chosen as the case study area for its special political and economic status and its severe water problem. To achieve effective planning, the information about crop water requirements, irrigation withdrawals, soil types and climatic conditions were obtained in the study area. In the meantime, a GIS method was adopted, which extends the capabilities of the crop models to a regional level. The main objectives of the study are: 1) to estimate the spatial distribution of the evapotranspiration of spring maize; 2) to estimate climatic water deficit; 3) to estimate the yield reduction of spring maize under different rainfed and irrigated conditions. Based on the water deficit analysis, recommended supplemental irrigation schedule was developed using CropWat model. Compared to the rainfed control, the two or three times of supplemental water irrigated to spring maize at the right time reduced the loss of yield, under different scenarios.

The Effect of Organo-Mineral Fertilizer Applications on the Yield of Winter Wheat, Spring Barley, Forage Maize and Grass Cut for Silage

Biosolids were applied with urea to produce a granulated organo-mineral fertiliser (OMF) for application by farm fertiliser equipment to a range of agricultural crops. The recommended rates of nitrogen, phosphate and potash were calculated for the test crops using “The Fertiliser Manual”, which assesses the nutrient requirement based on previous cropping, rainfall and soil index. The OMF produced similar crop yields compared to ammonium nitrate fertiliser when applied as a top-dressing to winter wheat, forage maize and grass cut for silage in the cropping years 2010 to 2014. In 2012 the grain yield of spring barley top-dressed with OMF was significantly lower than the conventional fertiliser treatment, due to dry conditions following application. For this reason it is recommended that OMF is incorporated into the seedbed for spring sown crops and The Safe Sludge Matrix guidelines followed. The experimental work presented shows that OMF can be used in sustainable crop production systems as a source of nitrogen and phosphorus for a range of agricultural crops.

Study on the Photosynthetic Characteristics in Spring Maize (Zea mays L.)of Different Quality Type

common maize synthetic rate（ Photosynthetic characteristics were probed by sweet maize, waxy maize, high starch maize and The results revealed that leaf area index （LAI）, chlorophyll a content, chlorophyll b content,photo-PR） showed single peak curve at the whole growth stage. The stages of peak were different according to different varieties. NEAUS4 had the lowest peak and while SIDAN 19 had the highest among all stages. Ratio of chlorophyll a to b was low at seedling stage, reached the peak atjointing stage and then declined. SIDAN 19 had the lower level at the last stages.

Delaying application time of slow-release fertilizer increases soil rhizosphere nitrogen content,root activity,and grain yield of spring maize

Application of slow-release fertilizer(SF)is a nutrient-management measure aimed at improving maize nutrient use and yield and saving labor cost.One-time application of SF at sowing usually results in nutrient deficiency during the post-silking stage,owing to the long growth period of spring maize.This study was conducted to investigate the effects on spring maize of SF application stage(zero,three-,and six-leaf stages,designated as SF0,SF3,and SF6,respectively)on grain yield,total soil rhizosphere nitrogen(N)content,and root activity,in comparison with the conventional fertilization mode(CF,application of compound fertilizer at sowing time,and topdressing urea at six-leaf and tasseling stages)at the same fertilization level as the control.Compared with no fertilization(F0)and CF,SF increased grain number and weight.The maize cultivars Suyu 30(SY30)and Jiangyu 877(JY877)produced the highest grain yield and net return under SF6 treatment over the three years.SF6 increased enzymatic activities including oxidoreductase,hydrolase,transferase,and lyase in rhizosphere soil at silking(R1)and milking stages(R3).SF6 increased the total N contents of rhizosphere soil by 7.1%at R1 and 9.2%R3 stages compared with SF0.The activities of antioxidant enzymes in roots were increased under SF6 treatments at R1and R3.The mean root activities of SF0,SF3,and SF6 increased by 7.1%,12.8%,and 20.5%compared with CF at R1 and by 8.8%,13.0%,and 23.5%at R3.Delaying the application time of SF could increase grain yield by increasing total N content of rhizosphere soil,delaying root senescence,and increasing root activity at the late reproductive stage.Applying SF at the six-leaf stage is recommended as an effective fertilization strategy for the sustainable production of spring maize in southern China.

Effect of Limited Single Irrigation on Yield of Winter Wheat and Spring Maize Relay Intercropping

一个场地实验在收割冬小麦(Triticum aestivum ) 和春天玉米(Zea mays ) 的季节评估有限单身者的效果的 2002/2003 期间被进行在接力赛在西北的中国的一个半干旱的区域杂种下面在收益和两庄稼的水使用上滴灌溉。A 控制了 35 公里单身者灌溉，早或迟了，在某个生长阶段被用于每庄稼。土壤水，叶面积，最后的谷物收益和产量构成因素象千谷物的重量那样，一些尖铁，肥沃的小穗状花小穗数，每尖铁谷物数，并且粒重每尖铁被测量，并且水使用效率和叶面积指数被计算为灌溉并且非灌溉的接力赛杂种处理和唯一的收割控制。结果在杂种的继电器显示出那收益，产量构成因素，水使用效率，和叶面积指数处理被有限单身者影响在小麦和玉米的各种各样的生长阶段期间滴灌溉。处理在小麦和标题的出发阶段和玉米的开花期舞台期间灌溉了的在杂种的继电器的全部的收益在所有处理之中是最高的，由在小麦的开花期阶段和玉米的 silking 舞台期间灌溉了那列在后面；那么是水使用效率。重要差别发生在大多数产量构成因素在之间灌溉并且非灌溉的杂种继电器的处理。在杂种继电器或完全收割的小麦和玉米的叶面积指数的动力学显示出单个山峰的模式的一种类型，而杂种的继电器，处理显示出双山峰的一种类型模式。适当地，有限单个灌溉和控制土壤水分含量水平能导致更高全部的产量，水使用效率，和叶面积指数，并且在接力赛杂种改进产量构成因素。这个惯例节省了为灌溉使用并且也增加了收益的水的数量。因此，小麦和标题的标题舞台和玉米的开花期舞台被建议是最佳在半干旱的区域的杂种继电器的小麦和玉米的有限单个灌溉时间。

Study on micro-water-collecting technique in dryland field of spring maize

This paper analyses the effect of water storage and soil moisture conservation by means of micro water collecting technique in the dryland field of spring maize. The results indicate that the rainfall infiltration depth is deeper by means of micro water collecting treatment than that of the control. In micro water collecting treatment, the amount of soil water storage within 0～200 cm of soil layers increases by 50.5 mm, 13.5～58.6 mm, and 24.5 mm respectively during seedling stage, the critical stage of water requirement and the ripening and harvesting stage compared with the control. The micro water collecting technique not only has the function of regulating and adjusting the amount and distribution of field evapotranspiration, but also can raise the water use efficiency, which results in an obvious effect of increasing crop yield, especially in the dry years.

Effect of Transplantation in Different Seedling Age on Growth and Yield of Spring Maize in Shanxi Early Mature Area

In order to explore a new mulch-free maize planting mode and the best seedling age for maize transplantation in Shanxi early mature area,a field experiment was carried out using completely randomized block design. Taking mulch based direct sowing as the control group,effects of transplantation in different seedling age on maize growing process,plant height,yield and composition factors of maize were analyzed.Results indicate that growing process of maize seedlings transplanted in different seedling age is slightly slower than the control group. Transplantation has the effect of reducing plant height. Although the yield of transplanted maize in different seedling age is lower than the control group. Besides,with the growth of seedling age of transplantation,the gap is widening. However,it is expected to realize mulch-free maize planting by transplantation in Shanxi early mature area. The yield of maize transplanted in two-leaf seedling age is not significantly different from the control group,and the yield is only 9% lower than the mulch-based direct sowing( CK). In conclusion,two-leaf period is the best seedling transplantation age for maize in Shanxi early mature area in this experiment condition.

Influence of Transplantation in Different Stage on Growth and Yield of Spring Maize in Shanxi Early Mature Area

In order to explore a new mulch-free maize planting mode and the best seedling age for maize transplantation in Shanxi early mature area,a field experiment was carried out using completely randomized block design.Taking mulch-based direct sowing as the control group,effects of transplantation in different stage on maize growing process,plant height,three-ear leaf area in mature period,and yield and composition factors of maize were studied.Results indicate that growing process of maize seedlings transplanted in every stage is slightly slower than the control group.Transplantation has effect of reducing plant height and three-ear leaf area in mature period.There was no significant difference between the yield of maize transplanted on May 1st and the control group,and the yield declined only by 7% compared with mulch-based direct sowing(CK).Damages to maize seedlings by the local late frost must be noticed when maize is planted by the method of mulch-free transplantation in early mature area.Transplanting the seedlings earlier after the late frost is deemed as an appropriate period in this area.

Utilization of Agricultural Climatic Resources under the Spring Maize-Spring Potato Intercropping Pattern in Pengzhou City

According to the meteorological requirements of maize and potato,using the data of meteorological observations and soil moisture of Pengzhou City,the agricultural climatic resources of spring maize and spring potato planting and the advantages of agricultural climatic resources of their intercropping were analyzed. The suitable sowing dates for spring maize and spring potato are late March to early April,early February to early March,respectively. During the growth period,the heat resources are abundant,the soil moisture is sufficient,the precipitation and overall distribution are suitable,and the sunshine is still sufficient,which can meet the needs of each growth period. The overall configuration of agricultural meteorological resources is coordinated,which is suitable for the planting of the two. Spring maize-spring potato intercropping can make the most of land,time and space,improve light and heat utilization,reduce pests and diseases,and increase output per unit area,thereby maximizing economic benefits.

基于CERES-Maize模型的华北平原玉米生产潜力的估算与分析

在对DSSAT4.0中CERES-Maize模型进行参数校正和验证的基础上,进一步利用华北地区具有代表性的10个气象站30年(1976～2005年)的气象资料以及华北地区典型的土壤数据展开模拟。结果表明,在一年一季的生产条件下,华北平原各地区玉米多年平均光温生产潜力为13.53～22.56t/hm2;各地区玉米产量在4月下旬至6月中旬的播期范围内均呈随播期的延迟而增加的趋势,对这一趋势和各气象指标进行相关分析表明,在华北北部主要驱动因子是灌浆期平均日辐射量,而华北中南部主要驱动因子是灌浆期的温度。华北平原自北向南,优化播期呈逐渐推迟的趋势:北部怀来地区5月上旬播种较为适宜,北京、乐亭和天津地区以5月下旬至6月初播种产量最高;中南部以6月中上旬播种(夏播)较适宜。