Regression model to estimate flood impact on corn yield using MODIS NDVI and USDA cropland data layer

Flood events and their impact on crops are extremely significant scientific research issues; however, flood monitoring is an exceedingly complicated process. Flood damages on crops are directly related to yield change, which requires accurate assessment to quantify the damages. Various remote sensing products and indices have been used in the past for this purpose. This paper utilizes the moderate resolution imaging spectroradiometer （MODIS） weekly normalized difference vegetation index （NDVI） product to detect and further quantify flood damages on corn within the major corn producing states in the Midwest region of the US. County-level analyses were performed by taking weighted average of all pure corn pixels （〉90%） masked by the United States Department of Agriculture （USDA） Cropland Data Layer （CDL）. The NDVI-based time-series difference between flood years and normal year （median of years 2000-2014） was used to detect flood occur- rences. To further measure the impact of the flood on corn yield, regression analysis between change in NDVI and change in corn yield as independent and dependent variables respectively was performed for 30 different flooding events within growing seasons of the corn. With the R2 value of 0.85, the model indicates statistically significant linear relation between the NDVI and corn yield. Testing the predictability of the model with 10 new cases, the average relative error of the model was only 4.47%. Furthermore, small error （4.8%） of leave-one-out cross validation （LOOCV） along with smaller statistical error indicators （root mean square error （RMSE）, mean absolute error （MAE）, and mean bias error （MBE））, further validated the accuracy of the model. Utilizing the linear regression approach, change in NDVI during the growing season of corn appeared to be a good indicator to quantify the yield loss due to flood. Additionally, with the 250 m MODIS-based NDVI, these yield losses can be estimated up to field level.

Effects of Straw Returning with Different Tillage Patterns on Corn Yield and Nitrogen Utilization

To explore the effects of farming methods,straw returning and their interaction on corn yield and nitrogen utilization,the experiment was conducted for two consecutive years from 2016 to 2017 at the Xiangyang Experimental Base of Northeast Agricultural University in Heilongjiang Province of China.The method of combining farming with straw returning was used and six treatments as rotary tillage(R)+no straw returning(K),rotary tillage(R)+straw returning(S),tillage(T)+no straw returning(K),tillage(T)+straw returning(S),tillage(T)+subsoiling(D)+no straw returning(K)and tillage(T)+subsoiling(D)+straw returning(S)were set to study the effects of different tillage methods and straw returning on corn yield and nitrogen accumulation and utilization.The corn yield,nitrogen accumulation,nitrogen transport,grain weight and dry matter accumulation of tillage(T)+subsoiling(D)and tillage(T)were significantly higher than those of rotary tillage(R)treatment.Meanwhile,the corn yield,nitrogen accumulation and dry matter accumulation of TD treatment were significantly higher than those of T treatment;the corn yield,dry matter accumulation,kernel weight,nitrogen dry matter production efficiency and nitrogen grain production efficiency of S treatment were significantly higher than those of K treatment.Among the treatments,the yield,nitrogen accumulation and utilization efficiency of TDS,TS and TDK were the highest.The yield,nitrogen accumulation and nitrogen transport of TDS were significantly higher than those of TS.In 2016,TDS production increased by 7.30%and 8.20%compared with TS;and TDS nitrogen accumulation increased by 6.78%and 9.50%compared with TS,while the yield and nitrogen grain production efficiency were significantly higher than those of TDK.Therefore,under the conditions of this experiment,on the basis of straw returning,tillage+subsoiling was the suitable farming method.

Corn Yield Forecasting in Northeast China Using Remotely Sensed Spectral Indices and Crop Phenology Metrics

Early crop yield forecasting is important for food safety as well as large-scale food related planning. The phenology-adjusted spectral indices derived from Moderate Resolution Imaging Spectroradiometer （MODIS） data were used to develop liner regression models with the county-level corn yield data in Northeast China. We also compared the different spectral indices in predicting yield. The results showed that, using Enhanced Vegetation Index （EVI）, Normalized Difference Water Index （NDWI） and Land Surface Water Index （LSWI）, the best time to predict corn yields was 55-60 days after green-up date. LSWI showed the strongest correlation （R2=0.568）, followed by EVI （R2=0.497） and NDWI （R2=0.495）. The peak correlation between Wide Dynamic Range Vegetation Index （WDRVI） and yield was detected 85 days after green-up date （RZ=0.506）. The correlation was generally low for Normalized Difference Vegetation Index （NDVI） （R2=0.385） and no obvious peak correlation existed for NDVI. The coefficients of determination of the different spectral indices varied from year to year, which were greater in 2001 and 2004 than in other years. Leave-one-year-out approach was used to test the performance of the model. Normalized root mean square error （NRMSE） ranged from 7.3 to 16.9% for different spectral indices. Overall, our results showed that crop phenology-tuned spectral indices were feasible and helpful for regional corn yield forecasting.

Resistance Analysis of 25 Corn Varieties to Stalk Rot and Evaluation of Yield Loss

Due to the meteorological factors, Henan Province had a large-scale outbreak of corn stalk rot in 2014, and the incidence status of 25 varieties was investigated. According to the relevant resistance identification standards, Xundan.509 was classified as resistance variety; Yudan606, Jinsai38 and Xundan3136 were classified as moderate resistance ones, while the other 21 varieties were highly susceptible varieties. Using the yield loss rate of 5% as the critical value of disease tolerance standard, XundanS09, Yudan606, Jinsai38, Xundan3136, Huaiyu5288, QiaoyuS, XY046, Zhengyu10, Lile66, WeikeT02 and Xundan29 were classified into tolerance varieties of corn stalk rot. The concept between disease resistance and disease tolerance was distinguished. The diseased plant rate was used as the classification basis of disease resistance and the yield loss rate was used as the evaluation standard of disease tolerance. The relationship between both was showed by a Venn diagram.

Study on the Theory and Technology of High Yield Culture of Compact Corn

Using the split plot and multi-quadric regressive orthogonal cross-course rotary combination design, corn variety Denghai 6’s yield and yield components, important colony quality and physiological index, microclimate index in field and technical planting for high yield were studied. Cultivation for high yield showed that Denghai 6 had the great potential of increase yield. The average yield of two years was

Studies on the Relationship Between Grain-yield and Climatic Ecological Factors in Summer Corn Under Super-high-yielding Cultivation Conditions

Cultivation experiments on super-high-yield (^12000kg/ha) of summer corn (Zea mays L.) were conducted in Laizhou, Shangdong Province, from 1986 to 1997, and in Wenxian, Henan Province, from 1996 to 1997. The results showed that requirements of accumulated temperature and hours of sunshine for super-high-yield of summer corn could be met in normal years in the areas of the Huanghuaihai Plain. Amount of precipitation influenced the yield most strongly in indirect way among all the meteorological factors, and the relationship between them displayed significant negative correlation (r= - 0.5418). The regression equation between yield and amount of precipitation at seedling stage and grain filling stage both reached significant level, and the partial regression coefficients were - 4.8735 and - 13.7415, respectively. Further research revealed that the key climatic-ecological factors influencing yield were as fellows: the average temperature in the third and the ninth Xun (note: a Xun indicates ten days and the accounting of Xun was from the corresponding sowing date), the hours of sunshine in the sixth and the eighth Xun, the amount of precipitation in the sixth, the seventh and the second Xun. Results obtained by analyzing yield components of summer corn showed that grain numbers per ear (GN/E) made greater contribution to super-high-yield than kernel weight (KW) and the numbers of ears did. The key factors influencing GN/E were the amount of precipitation in the sixth and the eighth Xun and the hours of sunshine in the sixth Xun, with the correlation coefficients of -0.6074, 0.5793 and 0.5854, respectively.

Comparison of Phosphorous Absorption, Quality and Yield Between High Oil Corn and Common Corn as Influenced by Phosphorous Application

A field trial was carried out to investigate phosphorous (P) absorption, grain quality and yield between high oil corn and common corn. The results indicated that high oil corn var.Tongyou 1 obtained lower highest P absorption rate (HAR) and later occurring date of HAR, in comparison with common corn var. Simi 25. The highest HAR and the earliest occurring date of HAR was obtained by the treatments of P45 and P75 in Tongyou 1 and Simi 25 separately; while the total amount of P accumulated by maize plant was achieved by P105 treatment in both varieties. P in grain relied mainly on root uptake at maturation that accounted for 85.7-96.8% and 79.3-84.3% for Tongyou 1 and Simi 25, respectively. Tongyou 1 contained more oil and protein contents, but less starch content with lower grain yield. P application at appropriate rate enhanced contents of protein and fatty acid, but the increment of starch content was neglectable. Acknowledgements This study was financed by the National Key Tech- nologies R & D Program (2004BA520A13), P.R.China.

Factors Impacting Corn (<i>Zea mays</i>L.) Establishment and the Role of Uniform Establishment on Yield

Information from actual farm fields can help corn producers understand the value and importance of establishing uniform crop emergence and within-row plant spacing. Thirty-eight fields planted with corn (Zea mays L.) by North Dakota producers were evaluated to determine the effects of uneven plant emergence timing and within-row plant space variability, as well as identifying contributing factors. Rows within a planter’s width with the most variability yielded 6% less than the least variable rows. Individual ear weights decreased as the number of days after normal emergence (date when 50% of plant stand emerged) increased. Ears next to within-row gaps (>30.5 cm) weighed 11% more than the normally spaced plants. Combined ears from both plants situated <5.1 cm apart weighed 36% more than from a single ear from normally spaced plants. Surface residue and planting speed impacted stand establishment variability more often than other factors measured. Producers should assess each field environment individually in order to identify best practices to achieve uniform stand establishment.

Analysis on High-yield Experience and Protective Measures of Wheat and Corn: A Case Study of Jieshou City in Anhui Province

This paper summarized the experience in high yield of wheat and corn in Jieshou City and made a further study on the supporting measures for the high yield of wheat and corn on this basis.

Effect of Sweet Corn Straw Returning to the Field on Soil Fertility, Yield and Benefit

It is an important way for realizing sustainable development of sweet corn production to stabilize and improve soil fertility of cultivated land in sweet corn production region.Through the test of sweet corn straw directly returning to the field after 6seasons for 3years,the results showed that continuous single application of chemical fertilizer is not conducive to the stability of soil fertility and yield improvement,and implementation of straw returning could receive fertility,improve soil acidic conditions,and enhance the yield of sweet corn.Compared with before the test,the single application of chemical fertilizer increased soil available phosphorus,while the contents of soil organic matter,available nitrogen and available potassium decreased by 1.08,1.18 and 2.47mg/kg respectively,and the soil pH decreased by 0.15.Under the same fertilizer conditions,organic matter contents of single and double-season straw returning increased by 0.71 and 1.29g/kg,available nitrogen increased by 17.15 and 28.27mg/kg,available phosphorus increased by 0.96 and 1.73mg/kg,available potassium increased by 2.41 and 5.92mg/kg,the soil pH increased by 0.16 and 0.2.Compared with the single application of chemical fertilizer,the average yields of single and double-season straw returning increased by 7.5%and 11.8%,and their average income increased by 87.3and 117.1yuan of per mu(667m^2)respectively.

Part Physical Characteristics Research of Three High-yield Corn Varieties

The physiological properties of new compact vertical-leaf type varieties, such as corn Zhengdan 958, Xundan 18, Jidan 7, etc. were analyzed in order to provid references for its large extension and new high-yield breeding. Results showed that reasons of high-yield included reasonable indices of leaf-area changing, long keeping of corn leaves and slow aging. Photosynthetic pigment, protein and soluble sugar in varietal leaves were high with the high peroxide enzyme activation, photosynthesis inherent ability and photosynthesis efficiency, but with low malondialdehyde. The volume of grain seed was big, with long forming or starch grouting time of cells and the weight of thousand-granules was high. It indicated that Zhengdan 958 was still the best corn variety for the extensive utilization. The seeds production should pay attention to keep the pure degree and the hallmark for giving full potential advantages on the yield of these species.

冷凉区黑土有机质和玉米产量双提升技术探索及经济效益分析

为明确有机肥还田+保护性耕作措施下黑龙江省西部土壤有机质和作物产量的双提升技术效果,2021年10月,在黑龙江省西部齐齐哈尔市梅里斯区开展试验,以玉米为供试作物,设置5个处理:有机肥+深松40 cm(YS40)、秸秆留茬+深松40 cm(WS40)、有机肥+旋耕20 cm(YS20)、秸秆留茬+旋耕20 cm(WS20)、有机肥表施+免耕(YB);一个对照:秸秆留茬+免耕(CK)。结果表明:施入有机肥的处理能够提升深土层土壤肥力,在20~40 cm土层中YS20处理与CK处理相比有机质和全氮依次提升11.56 g·kg^(-1)和0.57 g·kg^(-1);40~60 cm土层中YS40处理与CK处理相比有机质和全氮依次提升2.83 g·kg^(-1)和0.28 g·kg^(-1)。土壤结构方面,在0~20 cm土层中YB处理的容重较CK降低17.5%、含水量提升35.5%,40~60 cm土层中YS40处理的容重较CK处理降低5.3%、含水量提升38.4%。有机肥与保护性耕作处理提高了玉米不同生育时期叶面积指数、叶绿素含量和干物质积累量,进而提高了玉米产量,第二年的YS40、YS20、YB处理较CK处理分别增产14.5%、18.5%、11.4%。收益分析表明,与CK处理相比,2021年YB处理和2022年YS20处理收益增加最多,分别增加5770元·hm^(-2)和5223元·hm^(-2)。综上所述,黑龙江省西部薄层黑土实施有机肥还田+保护性耕作是提升土壤有机质、有机碳储量、全氮、全氮储量、玉米产量和经济效益的有效措施。

Effect of phenophase based irrigation schedules on growth, yield and quality of baby corn (Zea mays L.)

The field experiment was conduced at the Agronomy Field Unit, Main Research Station, University of Agricultural Sciences, Hebbal, Bangalore, India during 2002 and 2003 to study the effect of irrigation schedules on growth, yield and quality of baby corn. The soil of the experimental site was red sandy loam in texture with neutral reaction. The experiment was laid out in a randomized complete block design with three replications. There were seven treatments of irrigation schedules based on IW/CPE ratio of 0.6 and 1.0 during different phenophases of baby corn. The results of the experiment revealed that the baby corn dry matter was significantly higher (75.57 g.plant–1) with higher green fodder yield of 43.47 t.ha–1 due to irrigation scheduled at IW/CPE ratio of 1.0 followed by moisture stress at early stage (I3). Irrigations scheduled at IW/CPE ratio of 1.0 registered significantly higher baby corn yield of 6.60 t.ha–1 followed by the delayed irrigation at early stage of 10 - 25 DAS. Significantly higher crude protein, phosphorus, potassium and lower reducing sugars and ascorbic acid content of baby corn was recorded under IW/CPE ratio of 1.0. Delayed irrigation at 0.6 IW/CPE ratio through-out produced baby corn with higher taste and juiciness. The total crop water use ranged from 294.10 to 469.10 mm, respectively under continuously delayed irrigation at 0.6 IW/CPE ratio and frequent irrigation at IW/CPE ratio of 1.0 which also recorded higher water use efficiency.

热带作物秸秆覆盖对土壤质量及玉米产量和品质的影响

【目的】探究甘蔗叶、菠萝茎叶等热带作物秸秆作为农业覆盖材料对土壤质量及玉米生长的影响,为热带作物秸秆废弃物资源化利用提供参考依据。【方法】以玉米为种植对象,采用田间小区对比试验,设置甘蔗叶覆盖(SLM)、腐熟甘蔗叶覆盖(RSLM)、菠萝茎叶覆盖(PLM)和富贵竹茎叶覆盖(FLM)4个处理,以塑料地膜覆盖(CK1)和无覆盖(CK2)为对照,研究不同秸秆覆盖对土壤pH、有机质、全氮、有效磷和速效钾的影响,以及对玉米产量和品质的影响。【结果】热带作物秸秆覆盖,与无覆盖相比,可以有效提升土壤pH、有机质、全氮、有效磷和速效钾含量,对提升土壤质量具有积极作用。富贵竹茎叶覆盖效果最显著,与塑料地膜覆盖相比,土壤pH提高9.01%,有机质提高6.42%,全氮提高17.59%,速效钾提高477.79%,有效磷含量低于塑料地膜覆盖,但差异不显著;与无覆盖相比,土壤pH提高22.22%,有机质提高21.63%,全氮提高24.51%,有效磷提高2.74%,速效钾提高389.38%。腐熟甘蔗叶和富贵竹茎叶覆盖可以显著提升玉米产量,其他秸秆覆盖对玉米产量和品质的影响均不显著。【结论】热带作物秸秆覆盖可以提升土壤质量、促进玉米增产,富贵竹茎叶覆盖在改良土壤方面的效果显著,腐熟甘蔗叶覆盖对于玉米增产有较好的促进作用。

基于无人机多光谱遥感数据的植被指数玉米估产模型研究

玉米作为主要的粮食作物,其产量估产意义较为重大。传统的产量估算方法均以数据抽样调查为主,产量估算精度较低。随着新技术新方法的不断涌现,该文以无人机结合多光谱遥感技术,通过采集玉米的拔节期、吐丝期、乳熟期、蜡熟期4个关键生育期植被指数的变化,通过产量构建分析模型,并验证筛选合理的模型用于产量估算。经验证,在乳熟期,依据RVI、DVI、SAVI构建的产量模型精度较高。在蜡熟期,依据NDVI、RVI、DVI、SAVI构建的产量模型较高。通过以上研究,对于在玉米生长过程中,能够积极结合数据变化,便于高效开展农作物种植,估测作物产量具有重要的指导意义。

鲜食玉米收获机高净度清选智能测产装置研究

为改善国内小区鲜食玉米育种测产机械装备缺乏、小区鲜食玉米种子清选和测产过程完全依靠人工的现状,设计一种小区鲜食玉米种子高净度清选智能测产装置。该装置采用双层网筛、风力清选、智能测产流程完成高净度清选及测产作业,实现种子高净度清选和智能测产的作业要求。以上筛夹角、下筛夹角和螺旋分离装置入口风速为试验因素,以作业时千克籽粒含杂率为试验指标进行正交试验,建立因素与指标的响应面数学模型,并进行试验验证。结果表明:上筛夹角为14.0°,下筛夹角为4.0°,螺旋清选装置入口风速为27.0 m/s时为最佳作业组合,此参数组合下,鲜食玉米籽粒千克籽粒含杂率为1.2%,籽粒残留清理合格率为99.69%,测产平均误差为0.412%,籽粒含水率测量平均误差为3.57%,玉米种子千粒质量测量平均误差为0.276%。为小区鲜食玉米种子的高净度清选以及智能测产提供研究基础。

Carcass Traits, Meat Yield and Primal Meat Cuts from Arsi, Harar, Ogaden and F1 Jersey*Horro Crossbred Bulls Fed Corn Silage Based Similar Finishing Diet

This study was conducted with the objective to determine carcass traits, meat yield, and primal meat cuts of Arsi, Harar, Jersey*Horro crossbred, and Ogaden cattle breeds at Haramaya University, Ethiopia. A total of 12 bulls of four cattle breeds (3 Arsi, 3 Harar, 3 F1 Jersey*Horro crossbred and 3 Ogaden) with almost similar ages were randomly assigned to four treatments in a completely randomised design (CRD). Data on carcass traits, meat yield, and primal meat cuts were analyzed using the General Linear Model (GLM) of the Statistical Analysis Software (SAS) 9.4 version. The overall averages of live body weight, hot carcass weight, chilled carcass weight, dressing percentages based on hot carcass weight, and rib eye area of experimental cattle breeds were 215.58 kg, 102.93 kg, 99.56 kg, 47.61%, and 8.13 inch2, respectively. The hot carcass weight and chilled carcass weight of the Ogaden (136.57;133.30 kg, resp.) breed were higher (p < 0.01) compared to other experimental cattle breeds. Dressing percentages based on hot carcass weight were higher (p < 0.05) for the Ogaden (49.61%) and Arsi (49.82%) cattle breeds compared to Harar and Jersey*Horro crossbred (45.73%, 45.27%, resp.) cattle breeds. The average meat yield and proportion of meat yield of cattle breeds were 77.52 kg and 77.46%, respectively. With a linear regression coefficient of prediction (R2) ranging from 52.26% to 93.58%, primal meat cuts significantly (p dicted meat yield. In conclusion, the breed of cattle had a significant (p 0.05) influence on live body weight, hot and chilled carcass weight, dressing percentage, rib eye area, subcutaneous fat thickness, meat yield, and the weights of most primal meat cuts. The Ogaden cattle breed had a higher and better meat yield, carcass traits, and most primal meat cuts compared to other experimental cattle breeds. Furthermore, the inclusion of corn silage in the diet of fattening bulls improved the carcass and meat yield. Therefore, the performance of Ogaden cattle compared to other and previous studies suggests the possibility of using this breed for export purposes in addition to Borana and Harar cattle breeds in the future.

不同灌水处理对春玉米土壤水分、耗水特征及产量的影响

【目的】探究不同灌水定额对春玉米全生育期耗水特征及产量的影响,优化克拉玛依地区春玉米节水灌溉制度,以提高当地水分利用效率。【方法】于2021年5—9月在克拉玛依农业综合开发区开展春玉米田间试验,设置6个灌水处理W1(225 m^(3)/hm^(2))、W2(300 m^(3)/hm^(2))、W3(375 m^(3)/hm^(2))、W4(450 m^(3)/hm^(2))、W5(525 m^(3)/hm^(2))、W6(600 m^(3)/hm^(2)),探究不同灌水定额对春玉米耗水特征及产量的影响。【结果】①各生育期不同灌水处理0~100 cm土层土壤含水率随土层深度增加呈“增-减-增”的变化趋势。W5处理在喇叭口期、抽雄散粉期、乳熟期、完熟期较W1、W2、W3、W4、W6处理0~100 cm土层土壤贮水量平均增加了2.35%~9.11%、0.21%~4.37%、0.39%~1.79%、0.60%~4.48%。②完熟期W5处理百粒质量显著高于W1处理和W2处理,但与W3、W4、W6处理无显著性差异。W5处理穗粒数较其他处理显著提高10.49%~36.01%,穗长较其他处理显著提高8.31%~27.12%。③综合评判模型计算得出W5处理(525 m3/hm^(2))综合评价指数最高。【结论】因此,全生育期灌水10次,灌水定额为525 m3/hm^(2)是克拉玛依地区最优灌水处理。

极端高温天气条件下不同鲜食玉米品种的种植表现

为科学选择适宜鲜食玉米/鲜食大豆带状复合种植的耐密、抗病、抗倒的鲜食玉米品种,为玉米大豆带状复合种植技术示范推广提供品种支撑,开展了11个鲜食玉米品种与鲜食大豆的带状复合种植试验。结果表明:在2022年夏季极端高温且持续时间较长的气候条件下,鲜食玉米/鲜食大豆带状复合种植模式下不同鲜食玉米品种在双穗率、空秆率等植株性状及千粒鲜重、出籽率、结实率等产量性状上差异明显,其中晶白甜糯、虞珑糯1612、苏玉糯5号、苏科糯1801、苏科糯1901这5个品种结实率较高,表现出较强的耐高温能力;苏甜糯818、斯达糯41、扬甜糯104结实率较低,表现出较低的耐高温能力。复种区各玉米品种鲜穗产量在7332~11440 kg/hm^(2)之间,除苏科糯1801、晶白甜糯较对照苏玉糯5号(CK)略增产外,其他各品种均较对照苏玉糯5号(CK)减产,减产幅度在1.53%~34.58%之间,以苏甜糯818、苏科糯1501减产最严重。清种区各玉米品种鲜穗产量在7638.89~14828.70 kg/hm^(2)之间,除苏科糯1801较对照苏玉糯5号(CK)略增产1.42%外,其他各品种均较对照苏玉糯5号(CK)减产,减产幅度在0.95%~47.75%之间,以苏科糯1501减产最严重。