Maize kernel weight responses to sowing dateassociated variation in weather conditions

Variation in weather conditions during grain filling has substantial effects on maize kernel weight(KW). The objective of this work was to characterize variation in KW with sowing date-associated weather conditions and examine the relationship between KW, grain filling parameters, and weather factors. Maize was sown on eight sowing dates(SD) at 15–20-day intervals from mid-March to mid-July during 2012 and 2013 in the North China Plain. With sowing date delay, KW increased initially and later declined, and the greatest KW was obtained at SD6 in both years. The increased KW at SD6 was attributed mainly to kernel growth rate(Gmean), and effective grain-filling period(P). Variations in temperature and radiation were the primary factors that influenced KW and grain-filling parameters. When the effective cumulative temperature(AT) and radiation(Ra)during grain filling were 950 °C and 1005.4 MJ m-2, respectively, P and KW were greatest. High temperatures(daily maximum temperature [Tmax] > 30.2 °C) during grain filling under early sowing conditions, or low temperatures(daily minimum temperature [Tmin] < 20.7 °C) under late sowing conditions combined with high diurnal temperature range(Tmax-min> 7.1 °C) decreased kernel growth rate and ultimately final KW. When sowing was performed from May 25 through June 27, higher KW and yield of maize were obtained. We conclude that variations in environmental conditions(temperature and radiation) during grain filling markedly affect growth rate and duration of grain filling and eventually affect kernel weight and yield of maize.

Effect of Rice Sowing Date on Occurrence of Small Brown Planthopper and Epidemics of Planthopper-Transmitted Rice Stripe Viral Disease

To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper （SBPH） Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted rice stripe viral （RSV） disease, four sowing dates of rice were evaluated in 2006 and 2007. The results showed that the peak density of SBPH and RSV incidence in the nursery and in the transplanted field decreased with the delay of sowing date in single crop of japonica rice in north Zhejiang Province of China. The relationship between seedling RSV incidence at the end of the nursery trial with sowing date was well described by Weibull equation. The area under the curve of population dynamics （AUCPD or planthopper-day accumulation） or the peak density of the planthopper in the nursery could be summarized by a logistic equation. RSV incidence in the transplanted fields could be characterized quantitatively by a multivariate regression equation, including the variables of sowing date, peak density of the vector, and RSV incidence at the end of the nursery trial. That the descriptive model excluded the AUCPD in transplanted field implies that this variable is not necessary in forecasting disease epidemics in the field. The 2-year experiments sufficiently indicated that suitable sowing of rice could be used as one of the effective measures to control the vector population and therefore the planthopper-transmitted RSV on a larger scale. The optimal sowing date for the single-cropped transplanted japonica rice is recommended from late May to early June in north Zhejiang, China.

A Dynamic Knowledge Model for Design of Suitable Sowing Date and Sowing Rate in Winter Wheat

Based on research concerning dynamic relationships of winter wheat growth to environments and production conditions, a winter wheat model for selecting suitable sowing date, population density and sowing rate under different varieties, spatial and temporal environments was developed. Case studies on sowing date with the data sets of five different eco-sites, three climatic years and soil fertility levels, and on population density and sowing rate with the data sets of two different variety types, three different soil types, soil fertility levels, sowing dates and grain yield levels indicate a good model performance for decision-making.

Adaptation of potato production to climate change by optimizing sowing date in the Loess Plateau of central Gansu, China

Potato grows in most part of China, it achieves higher yield and better quality in Gansu Province than in others. With global warming, its growth duration has been prolonged and sowing date become earlier than before. Therefore, to regulate its sowing date and growing period is of great significance for better harvest. In this study, experiments were conducted with six sowing-date treatments of potato in Dingxi, which is in the Loess Plateau of central Gansu Province in Northwest China in 2010. The growth period, morphological index and change in yield and their relationships with temperature, precipitation, and other climatic factors were investigated for each treatment. Results show that the crop with different sowing dates experienced different climate conditions, leading to distinct growth duration, plant height, and leaf area index. The growth duration was shortened due to a delay in sowing date. For each 15-day delay in sowing, the growth duration was reduced by 12 days on average. A significant linear relationship was found between numbers of days either from seeding to emergence or from flowering to harvest and mean temperature over the corresponding period. Dry matter accumulation, tuber fresh weight, and final yield were all decreased because of insufficient cumulative temperature over the shorter growing periods. Marked differences in tuber yield were discovered among the six treatments of sowing date, the potato planted on May 27 giving the highest yield. The potato planted either earlier or later would produce invariably lower yield than the treatment of May 27. Late May therefore can be taken as the optimum sowing time of potato in this region because the crop can fully utilize thermal resource. We conclude that to postpone sowing time is a good practice for potato production to adapt to climate warming in the Loess Plateau of central Gansu, China.

The effects of sowing date on cottonseed properties at different fruiting-branch positions

A two-year field experiment was conducted to illustrate the effects of sowing date on cottonseed properties at different fruiting-branch positions（FBPs）.Two cotton cultivars（Kemian 1 and Sumian 15）were sowed on 25 April,25 May,and10 June in 2010 and 2011,respectively.The boll maturation period increased with the delaying of sowing date.Normal sowing treatment（25 April）had higher seed weight,embryo weight,embryo oil content and protein content than late sowing treatments（25 May and 10 June）.The flowering date,seed weight,embryo weight,embryo oil and protein contents,and the dynamic changes of embryo oil and protein contents were altered by different FBPs.A significant interaction of sowing date×FBP was observed on embryo weight,embryo oil content,embryo protein content and the dynamic changes of embryo oil and protein contents,but was not observed on seed weight.Seed weight,embryo weight,embryo oil and protein content had significant positive correlations with the mean daily temperature（MDT）,mean daily maximum temperature（MDTmax）,mean daily minimum temperature（MDTmin）,and mean daily solar radiation（MDSR）,indicating that temperature and light resources were the main reasons for different sowing dates affecting the cottonseed properties at different FBPs.Moreover,the difference in MDT was the main difference in climatic factors among different sowing dates.

Effects of Sowing Dates on Yield,Agronomic Traits and Resistance of Millet in Yan'an

[ Objective ] This study aimed to investigate the appropriate sowing dates of different millet varieties and analyzed the yield, agronomic traits and resist- ance of millet. [ Method ] Split-plot design was employed with sowing date and millet variety assigned to the main plot and sub-plot, respectively, to investigate the effects of sowing dates on yield, agronomic traits and resistance of millet. [ Result] The results showed that early or late sowing would lead to yield reduction. Changsheng 07, Jingu 36 and Changnong 35 exhibited higher yield. Based on the yield, agronomic traits and resistance, the appropriate sowing date of Changsheng 07, Jingu 40 and Jingu 36 was May 13 ; the appropriate sowing date of Yangu 13 and Changnong 35 was May 20. [ Conclusion] The most appropriate sowing date of millet in Yan＇an was May 10 to May 20. Key words Millet; Sowing date; Yield; Agronomic traits ; Resistance

Effect of Sowing Date on Growth,Yield and Diseases and Pests Occurrence in Sunflower Helianthus annuus L.

Effect of sowing date on growth, yield and diseases and pests occurrence in sunflower Helianthus annus L. were compared and the relationship between sowing date and occurrence degree of diseases and pests or yield were analyzed in the paper, aiming to reduce the occurrence of diseases and pests in sunflower by adjusting sowing date. The results showed that sowing date was obviously correlated with occurrence of diseases and pests in sunflowers, and appropriate sowing date could effectively reduce the occurrence degree of diseases and pests, beneficial to high yield and good quality. In the main sunflower producing area in Changji Hui Autonomous Prefecture of Xinjiang, it is more appropriate to sow sunflower in early and mid May, resulting in lighter occurrence of diseases and pests, and better yield and quality.

Effect of Dates and Methods of Sowing with and without Hydropriming on Growth,Phenology and Yield of Sorghum under Semi Arid Conditions of Eritrea

A study was carried out at the research farm of Hamelmalo Agricultural College during summer 2015 to study the effect of dates and methods of sowing with and without hydro-priming on growth,development and yield of sorghum.The experiment consisted of 2 factors-three dates of sowing viz.D0(Sowing before the onset of first summer rain,June 30),D1(Sowing with the onset of first summer rains,July 7)and D2(Sowing after the onset of summer rains,July 14)and three methods of sowing viz.SP(Direct sowing with hydro seed priming),TR(Transplanting)and DS(Direct sowing without hydro seed priming).The experiment was conducted in split plot design with 4 replications by keeping dates of sowing in the main plots and methods of sowing in the sub plots.The data on growth parameters,crop phenology,yield components and yield were recorded.The data were analysed using GENSTAT software and inferences were drawn by using LSD at 5%level of significance.Sowing methods significantly affected leaf area and leaf area index but sowing dates and their interaction with sowing methods did not show significant difference.Stand count,plant height,phenological parameters,thousand grain weight,grain and biomass yield were significantly affected by the sowing dates and methods but no significant difference in their interaction on all the parameters except in stand count and phenological parameters.Sowing before the onset of first summer rains(D0)resulted in significantly highest grain yield.Among the sowing methods,transplanting resulted in significantly higher grain yield seconded by direct sowing with hydro seed priming.Transplanting is less profitable and practicable as it is more laborious and difficult to apply in larger areas.

The environment,especially the minimum temperature,affects summer maize grain yield by regulating ear differentiation and grain development

Ear differentiation,grain development and their interaction with factors in the growing environment,such as temperature,solar radiation and precipitation,greatly influence grain number and grain weight,and ultimately affect summer maize production.In this study,field experiments involving different sowing dates were conducted over three years to evaluate the effects of temperature factors,average solar radiation and total precipitation on the growth process,ear differentiation,fertilization characteristics,grain filling and yield of summer maize varieties with different growth durations.Four hybrids were evaluated in Huang-Huai-Hai Plain(HHHP),China from 2018 to 2020 with five different sowing dates.The results showed that the grain yield formation of summer maize was strongly impacted by the environment from the silking(R1)to milking(R3)stage.Average minimum temperature(ATmin)was the key environmental factor that determined yield.Reductions in the length of the growing season(r=–0.556,P<0.01)and the total floret number on ear(R^(2)=0.200,P<0.001)were found when ATmin was elevated from the emerging(VE)to R1 stage.Both grain-filling rate(R^(2)=0.520,P<0.001)and the floret abortion rate on ear(R^(2)=0.437,P<0.001)showed quadratic relationships with ATmin from the R1 to physiological maturity(R6)stage,while the number of days after the R1 stage(r=–0.756,P<0.01)was negatively correlated with ATmin.An increase in ATmin was beneficial for the promotion of yield when it did not exceeded a certain level(above 23°C during the R1–R3 stage and 20–21°C during the R1-R6 stage).Enhanced solar radiation and precipitation during R1–R6 increased the grain-filling rate(R^(2)=0.562,P<0.001 and R^(2)=0.229,P<0.05,respectively).Compared with short-season hybrids,full-season hybrids showed much greater suitability for a critical environment.The coordinated regulation of ATmin,ear differentiation and grain development at the pre-and post-silking stages improved maize yield by increasing total floret number and grain-filling rate,and by reducing the floret abortion rate on ear.

Effects of Sowing Periods on Growth and Development,Yield and Quality of Maize in Cold Area

In order to determine the most suitable sowing periods for maize in the cold area of Harbin City,the field test method was adopted.From 2018 to 2019,the main maize variety Xianyu 696 which was planted in Harbin City,Heilongjiang Province,was used as the test material for the six-sowing-period treatment experiments.The sowing period settings were as the followings:April 20(T1),April 24(T2),April 27(T3),May 4(T4),May 11(T5)and May 18(T6).In the experiment,the effects of different sowing periods on the growth and development,yields and quality of maize were studied.The results showed that the maize through T1 treatment had the longest growth period,the lowest height and the highest ear height,and the highest grain protein content.The maize through T6 treatment had the highest height and ear height,as well as the highest starch and oil content.And the grain crude fat,soluble protein,soluble sugar and the moisture content increased and then decreased with the delay of the sowing period.The maize through T4 treatment had the highest content of soluble protein.However,other quality indicators and the number of rows,the length of the bald tip,the number of grains per spike and the weight of 100 grains first increased and then decreased with the delay of the sowing period.The dry matter accumulation through T4 treatment was significantly higher than the ones through five treatments,and the 100-kernel weight and other ear-grain traits were the highest,the maizes through T4 treatment increased the yield by 21.54%compared with that through T1 treatment.Thus,the most suitable sowing period for the maize in the cold area of Harbin City was from May 4 to May 11.It provided technical supports for guiding maize planting in the cold area of Harbin City.

Combined Impact of Climate Change, Cultivar Shift, and Sowing Date on Spring Wheat Phenology in Northern China

Distinct climate changes since the end of the 1980s have led to clear responses in crop phenology in many parts of the world. This study investigated the trends in the dates of spring wheat phenology in relation to mean temperature for different growth stages. It also analyzed the impacts of climate change, cultivar shift, and sowing date adjustments on phenological events/phases of spring wheat in northern China （NC）. The results showed that significant changes have occurred in spring wheat phenology in NC due to climate warming in the past 30 years. Specifically, the dates of anthesis and maturity of spring wheat advanced on average by 1.8 and 1.7 day （10 yr）-1. Moreover, while the vegetative growth period （VGP） shortened at most stations, the reproductive growth period （RGP） prolonged slightly at half of the investigated stations. As a result, the whole growth period （WGP） of spring wheat shortened at most stations. The findings from the Agricultural Production Systems Simulator （APSIM）-Wheat model simulated results for six representative stations further suggested that temperature rise generally shortened the spring wheat growth period in NC. Although the warming trend shortened the lengths of VGP, RGP, and WGP, the shift of new cultivars with high accumulated temperature requirements, to some extent, mitigated and adapted to the ongoing climate change. Furthermore, shifts in sowing date exerted significant impacts on the phenology of spring wheat. Generally, an advanced sowing date was able to lower the rise in mean temperature during the different growth stages （i.e., VGP, RGP, and WGP） of spring wheat. As a result, the lengths of the growth stages should be prolonged. Both measures （cultivar shift and sowing date adjustments） could be vital adaptation strategies of spring wheat to a warming climate, with potentially beneficial effects in terms of productivity.

Impacts of climate warming and crop management on maize phenology in northern China

Climate warming has and will continue to exert a significantly impact on crop phenology in the past and coming decades.Combining observed data of phenology and a crop growth model provides a good approach for quantitating the effects of climate warming and crop management on crop phenology.The purpose of this study is to determine the impacts of temperature change, sowing date(SD) adjustment and cultivar shift on maize phenology in northern China during 1981–2010.Results indicated that climate warming caused anthesis date(AD) and maturity date(MD) of maize to advance by 0.2-5.5 and 0.6-11.1 d/10 a, respectively.Due to climate-driven changes in maize phenology, three growth periods of maize, i.e., vegetative growth period(VGP;from sowing to anthesis), reproductive growth period(RGP;from anthesis to maturity) and whole growth period(WGP;from sowing to maturity) shortened by 0.2-5.5, 0.4-5.6 and 0.6-11.1 d/10 a, respectively.With SD adjustment(i.e., SD advancement), AD and MD occurred early by 0.5-2.6 and 0.1-3.4 d/10 a, respectively.SD adjustment caused duration of VGP of maize to prolong.However, duration of RGP slightly shortened by 0.1-1.3 d/10 a.Furthermore, due to cultivar shift, MD of maize significantly delayed by 4.9-12.2 d/10 a.Durations of VGP, RGP and WGP of maize prolonged by 0.2-4.1, 1.6-8.4 and 4.3-11.8 d/10 a, respectively.In conclusion, our results indicated that cultivar shift, to some extent, could mitigate the negative impact of climate warming on maize phenology.

The Variation of β-glucan and Protein Content in Barley as Affected by Agronomic Practices

The influences of N application rate, timing, sowing date and seeding rate on β-glucan and protein content in barley grains were studied through the field experiments in Hangzhou, China during 1997 -2001. Protein content increased with N application rate and with N proportion applied at late stage. β-glucan content also responded significantly to N application rate and timing, but with different pattern with protein content. Of three N rate treatments, the medium N rate (135 kg ha-1) had the highest β-glucan content, being significantly higher than low N rate (90 kg ha-1) and no difference with high N rate (180 kg ha-1). A-mong three N timing treatments, two times of N top-dressing at both tillering and booting stage had significantly higher β-glucan content than once N top-dressing at tillering or booting stage. Sowing date has the dramatic effect on both β-glucan and protein content. Protein content decreased with the delayed sowing, and kernel weight showed opposite tendency. Either earlier or later sowing caused increased β-glucan content relative to sowing in early November, which is the normal date for barley sowing locally. Seeding rate had no significant influence on both β-glucan and protein content.

Effect of future climate change on the water footprint of major crops in southern Tajikistan

Danghara,a major food production area in southern Tajikistan,is currently suffering from the impact of rapid climate change and intensive human activities.Assessing the future impact of climate change on crop water requirements(CWRs)for the current growing period and defining the optimal sowing date to reduce future crop water demand are essential for local/regional water and food planning.Therefore,this study attempted to analyze possible future climate change effects on the water requirements of major crops using the statistical downscaling method in the Danghara District to simulate the future temperature and precipitation for two future periods(2021-2050 and 2051-2080),under three representative concentration pathways(RCP2.6,RCP4.5,and RCP8.5)according to the CanESM2 global climate model.The water footprint(WFP)of major crops was calculated as a measure of their CWRs.The increased projection of precipitation and temperature probably caused an increase in the main crop’s WFP for the current growing period,which was mainly due to the green water(GW)component in the long term and a decrease in the blue water(BW)component during the second future period,except for cotton,where all components were predicted to remain stable.Under three scenarios for the two future potato and winter wheat decreased from 5.7%to 4.8%and 3.4%to 2.2%,respectively.Although the WFP of cotton demonstrated a stable increase,according to the optimal sowing date,adecrease in irrigation demand or Bw was expected.The results of our study might be useful fordeveloping a new strategy related to irrigation systems and could help to find a balance betweenwater and food for environmental water demands and human use.

The effect of time and type of stress moderators on yield and yield components of cotton on conventional and double‑cropping systems under saline conditions

Background:Today,stress moderators are employed to mitigate crop loss due to the adverse effects of environmental stress.The current research aimed to investigate the impacts of time and stress moderator types on agro-physiological responses of cotton on conventional and double-cropping systems during 2017 and 2018 under saline conditions.A split-plot factorial experiment was carried out in a randomized complete block design with three replications.Cultivation system[conventional(recommended planting date)and double-cropping systems(sowing after harvest of wheat)]were considered as the main plots,and stress moderator type at four levels[water control,2 mmol·L^(-1) Salicylic acid(SA),100 mmol·L^(-1) Glycine betaine(GB),and 100μmol·L^(-1) sodium nitroprusside(SNP)]and application time(flowering and flowering+bolling stages)were regarded as subplots.Results:Plant height,reproductive branch number,the number of bolls,10-boll weight,1000-seed weight,biological yield,seed cotton yield,lint yield,chlorophyll a,chlorophyll b,carotenoids,total chlorophyll,sodium,potassium,and proline content were less in double-cropping system comparing with conventional system.Spraying with the stress moderators alleviated soil salinity effects on yield,yield components,and biochemical traits of cotton.SNP spraying led to maximum plant height,branch number,the number of bolls per plant,10-boll weight and seed cotton yield.SA spraying yielded the highest 1000-seed weight,biological yield,lint percentage and lint yield.The highest chlorophyll a,chlorophyll b,carotenoids,and total chlorophyll content resulted from SNP spraying.Yield,yield components,and biochemical traits did not respond to the stress moderator types in double-cropping system.However,the highest chlorophyll a,carotenoids,proline content,the number of bolls per plant,and seed cotton yield resulted from SNP spraying in conventional system.No statistically significant differences were observed between spraying with SNP and SA in most studied traits.Conclusions:The results suggest that the optimum cotton planting time and SNP spraying could be recommended for producing the most suitable yield under saline conditions.Highlights:External application of stress modulators increases salinity stress tolerance.Spraying with sodium nitroprusside has more moderating effect.Agro-physiological response of cotton to moderators is stronger in early sowing.Maximum seed cotton yield was achieved at early sowing and spraying sodium nitroprusside.Delayed cultivation reduces cotton yield.

赣豆6号高产栽培技术研究

研究了不同播期、密度和氮肥追施量对赣豆6号产量及农艺性状的影响。结果表明,密度、播期、密度和氮肥互作效应对赣豆6号产量影响极显著,在施入等量的钙镁磷肥(375kg/hm2)和钾肥(100kg/hm2)前提下,赣豆6号在7月20日播种,密度为22.5万株/hm2,追施氮肥量为250kg/hm2的情况下产量最高,经济效益最好。

面向黄土高原耕地高效利用的两季种植模式可行性分析

Cropping systems worldwide have been affected by the current trend in global warming and the optimization of cropping systems is an important area of research in the transition of agricultural land. The Loess Plateau is a typical ecologically fragile region with the most serious soil erosion in China. We carried out a field experiment in Yan’an city on the Loess Plateau to explore the effect of sowing date on crop growth and yield. We then analyzed the feasibility of a double-cropping system by considering climatic adaptability, ecological suitability and economic viability. Our results showed that different sowing dates resulted in significant differences in crop growth and that appropriate early sowing can result in higher crop yields for early maturing varieties. We showed that double-cropping systems of sweet maize(Zea mays)–forage rape and feed maize–forage rape are feasible on the Loess Plateau. We discuss the implications for the efficient use of farmland, which is important in guiding agricultural supply-side reform and the development of modern agricultural management.