秸秆腐解与养分释放特征对腐熟剂用量的响应

农业生产系统存在秸秆养分释放与作物生长需求匹配程度低等问题,拟通过腐熟剂用量调节还田小麦秸秆腐解及养分释放率,使之与作物生长需求相吻合,进而提升夏玉米产量。以人元腐熟剂为供试腐熟剂,小麦秸秆为供试秸秆,郑单958为供试玉米品种。采用完全随机区组试验设计,设置4种腐熟剂施用量:30 kg/hm^(2)(T1)、45 kg/hm^(2)(T2)、60 kg/hm^(2)(T3)、75 kg/hm^(2)(T4),以不施腐熟剂为对照(CK)。测定秸秆腐解率、养分释放率、夏玉米关键生育期的株高、茎粗、生物量和作物产量,通过回归分析探究秸秆养分阶段性释放如何调控夏玉米生长及籽粒产量形成。腐熟剂用量为45 kg/hm^(2)时,秸秆最终腐解率可达69.28%。腐熟剂用量对不同养分释放的调控效果不同,其中,氮和有机碳的释放率呈线性变化,磷和钾的释放率呈阶段性变化。腐熟剂施用对抽雄期(VT)各养分释放率均有显著的促进效应。三叶期(V3)较CK而言,T2和T4处理氮、磷释放率增幅分别达到203.67%、187.05%和17.72%、45.24%;抽雄期,T3处理秸秆钾、有机碳释放率较CK分别增加5.33%和22.42%;生理成熟期(R6),T2处理的氮、磷、钾释放率分别较CK增加了2.55%、17.87%、3.78%,T1处理的有机碳释放率较CK、T3处理分别增加3.64%和4.61%。此外,腐熟剂施用后,夏玉米株高和茎粗均显著增加。成熟期,T2处理单株生物量可达320.0 g,较CK增幅17.19%。最终,T2处理玉米产量显著提升,达11.6 t/hm^(2)。腐熟剂施用显著影响麦秆腐解率,施用45~60 kg/hm^(2)腐熟剂后夏玉米花前小麦秸秆的养分释放率显著提升,在夏玉米生长关键期提供更多养分,最终显著提升了夏玉米籽粒产量。

半干旱区沟垄集雨种植谷子的肥料效应及其增产贡献

研究沟垄集雨种植施肥水平对谷子生长的影响及其对产量的贡献,为完善集雨种植技术理论体系及半干旱区谷子的合理施肥提供科学依据。在宁南旱农区进行了2个年型的二因素大田试验,研究了沟垄半覆膜集雨(R)和传统裸地平作(T)2种种植模式下4个施肥水平(高量N 270 kg hm–2+P2O5 180 kg hm–2,H;中量N 180 kg hm–2+P2O5120kg hm–2,M;低量N 90 kg hm–2+P2O5 60 kg hm–2,L;不施肥对照,CK)对谷子株高、叶面积、光合指标、干物质积累量和水肥利用效率的影响,并分析了集雨模式下的增产贡献来源。结果表明:(1)集雨模式有效促进了边行谷子光合生理和生长,在各施肥水平下谷子株高、顶三叶叶面积、Pn(净光合速率)、Tr(蒸腾速率)和生物量较平作模式分别提高7.1%~23.5%、1.7%~22.7%、10.4%~20.3%、8.0%~55.9%和9.8%~30.0%;中行各指标较平作模式均下降不显著。(2)集雨种植模式显著提高了谷子的水肥利用效率,配施氮磷肥水分利用效率显著增加,在丰水年高肥处理显著高于中、低肥处理,欠水年中肥处理最高且显著高于高肥处理,与低肥处理差异不显著;肥料利用效率随着施肥量的增加而下降,在丰水年低肥处理的肥料利用率显著大于高肥和中肥处理,欠水年各施肥水平间差异显著。(3)施肥对谷子的增产贡献大于种植模式。施肥对产量的贡献率在丰水年随施肥量的增加而增加,高、中、低施肥处理间差异显著,达27.8%~49.3%,欠水年各施肥处理间差异不显著(19.2%~23.7%);种植模式贡献率在2年中各施肥处理间差异均不显著。综合考虑,集雨模式在丰水年施高肥、欠水年施中肥可实现谷子高产高效生产。

不同施肥量对旱作沟垄集雨种植农田土壤水分及玉米产量的影响

【目的】沟垄集雨种植是西北旱作农田广泛运用的高效节水栽培模式。研究不同施肥处理对旱作沟垄集雨种植农田土壤水分及玉米产量的影响,为优化施肥配置,进一步提升其增产效能提供科学依据。【方法】以玉米为供试作物,在宁夏回族自治区固原市进行了连续5年的田间定位施肥试验。试验玉米栽培采用集雨沟垄栽培技术,设置4个施肥水平处理:无肥对照(CK),低肥(N 150 kg/hm^(2)、P2O575 kg/hm^(2)),中肥(N 300 kg/hm^(2)、P2O5150 kg/hm^(2)),高肥(N 450 kg/hm^(2),P2O5225 kg/hm^(2))。在玉米生长关键期,取0—200 cm深土壤不同层次的土壤样品,测定了土壤含水量、农田耗水量、水分利用效率,调查了玉米产量。【结果】无论缺水年、平水年还是丰水年,随施肥量的增加,农田耗水量、玉米干物质累积量均呈提高趋势,高、中、低水平施肥处理的农田耗水量较CK分别平均提高了8.8%、7.7%和5.3%,玉米干物质累积量分别显著(P<0.05)提高了38.3%、35.8%和31.2%。在各年份,各处理土壤含水量从四叶期到抽雄吐丝期均随施肥量的增加呈降低的趋势,而在收获期,各施肥处理土壤含水量均显著(P<0.05)低于CK,高、中、低水平施肥处理分别平均降低24.7%、24.2%和17.7%。综合来看,中肥处理5年平均籽粒产量最高(11.4 t/hm^(2)),产量变异系数最小(12.9%)。在丰水年,低肥处理玉米产量及籽粒水分利用效率均高于高肥和中肥处理,而在平水年和干旱年,中肥处理可获得较高的籽粒产量和水分利用效率。【结论】在半干旱地区,施肥量对沟垄集雨种植模式春玉米产量及水分利用效率的影响受制于降雨量。在丰水年,较低的施肥量(N 150 kg/hm^(2)、P2O575 kg/hm^(2))即可获得理想产量和水分利用效率,而在平水年和干旱年,中量施肥水平(N 300 kg/hm^(2)、P2O5150 kg/hm^(2))获得的产量和水分利用效率最高。高施肥量(N 450 kg/hm^(2)、P2O5225 kg/hm^(2))会造成土壤水分的大量消耗。

关中西部灌区限量节水灌溉对冬小麦水分利用效率和产量的影响

为探索在半湿润灌区基于沟垄集雨种植模式的小麦高产节水栽培技术途径,于2015年10月-2017年6月在西北农林科技大学农学院试验基地,以西农979为材料,研究了不同种植模式结合小麦主要生育期限量灌水对作物水分利用效率和小麦产量的影响。结果显示,在传统平作常量畦灌(F150)的基础上,减少50%的灌水量,F75小麦产量两年分别下降18.86%、10.07%;集雨种植+灌水75 mm处理(R75)与F150处理相比,小麦产量略有小幅降低,但尚未达显著(P<0.05)水平,且R75与R150处理亦无显著(P<0.05)差异。此外,R75较F150处理灌水利用效率显著(P<0.05)提高,两年增幅分别为95.51%、104.2%,作物水分利用效率分别提高了31.23%、13.1%。结果表明,集雨种植可高效利用降水及灌溉水,满足小麦生长发育及产量提升;基于集雨种植模式,通过在小麦关键生育期限量灌水,较传统平作常量畦灌(F150)产量无明显降低情况下,实现节水40%~70%。

Effects of Water-Collecting and -Retaining Techniques on Photosynthetic Rates, Yield, and Water Use Efficiency of Millet Grown in a Semiarid Region

Field experiments were conducted in 2003 and 2004 to study the effects of plastic ridges and furrow film mulching （plastic film on sowing, as well as plastic film on flat soil and hole sowing） and chemicals （a drought resistant agent and a water- retaining agent） on growth, photosynthetic rate, yield, and water use efficiency （WUE） of spring millet （Setaria italica L.）. The experimental results showed that water-collecting and -retaining techniques can effectively increase soil moisture content, the leaf photosynthetic rate and crop growth. Due to increased soil moisture under the plastic-covered ridge and furrow water-collecting in July and August, dry matter and plant height had a increase at the booting stage （late growth advantage）. However, the plastic-covered flat soil and hole sowing reduced soil evaporation during early growth, the increase of dry matter and plant height appeared at the seedling stage （early growth advantage）. Plastic-covered ridge and furrow sowing supplemented with chemical reagents had significant positive effects on water collection and soil moisture retention. Improvement of soil moisture resulted into the increase of the photosynthetic rate, dry matter accumulation yield and WUE. The water-collecting and -retaining techniques can improve WUE and enhance crop yield. Correlation analysis demonstrated that the photosynthetic rate under the water-collecting and -retaining techniques was significantly associated with the soil moisture, but had no significant relationship with leaf chlorophyll content. Plastic- covered ridge and furrow sowing supplemented with chemical reagents increased the yield and WUE by 114% and 8.16 kg ha-1 mm-1, respectively, compared with the control; while without the chemical reagents the yield and WUE were 95% and 7.42 kg ha-1 mm-1 higher, respectively, than those of the control.

Characteristics of Endogenous Hormone Variations in the Roots of Alfalfa (Medicago sativa L.) Cultivars of Different Fall Dormancies During Spring Regrowth Stage

Regrowth traits of alfalfa （Medicago sativa L.） in spring are closely related to its fall dormancy before winter. In order to determine the relationship between fall dormancy （FD） grade and hormone variation pattern and provide academic references for the variety improvement and production of alfalfa, the variations of gibberellins （GA3）, indole-3-acetic acid （IAA）, and abscisic acid （ABA） in alfalfa roots during regrowth period in spring were examined by high performance liquid chromatography （HPLC）. The study involved seven alfalfa cultivars that belonged to four fall dormant grades, i.e., 2, 4, 6, and 8. The results showed that the differences in spring regrowth among the alfalfa cultivars were partially associated with their root hormone levels. The alfalfa cultivars that belonged to the same dormancy grades presented similar variation trends in endogenous hormone content in their roots during the spring regrowth stage. At the early regrowth stage, cultivars with a higher dormant grade had a higher GA3 concent and a lower ABA content in their roots than the cultivars with a lower dormant grade; and IAA content in roots of non- and semi-fall dormancy cultivars was higher than that of fall dormancy cultivars. During the whole period of spring regrowth, the root ABA content of fall dormancy alfalfa cultivar is significantly higher than those of semi- and non-fall dormancy cultivars. GA3 contents in the roots of all cultivars under study showed a double-peak dynamic curve; root IAA contents of the studied cultivars presented a downward trend. But the trend did not significantly differed among the different fall dormant cultivars. The higher GA3 content and lower ABA content in root of non-fall dormancy alfalfa lead to its earlier regrowth. Regrowth time and rate of alfalfa can be regulated by exogenous GA3 or ABA at the early regrowth stage to meet producing requirement.

Improvement in winter wheat productivity through regulating PSⅡ photochemistry,photosynthesis and chlorophyll fluorescence under deficit irrigation conditions

Deficit irrigation is critical to global food production,particularly in arid and semi-arid regions with low precipitation.Given water shortage has threatened agricultural sustainability under the dry-land farming system in China,there is an urgent need to develop effective water-saving technologies.We carried out a field study under two cultivation techniques:(1) the ridge and furrow cultivation model(R);and(2) the conventional flat farming model(F),and three simulated precipitation levels(1,275 mm;2,200 mm;3,125 mm) with two deficit irrigation levels(150 and 75 mm).We demonstrated that under the ridge furrow(R) model,rainfall harvesting planting under 150 mm deficit irrigation combined with 200 mm simulated precipitation can considerably increase net photosynthesis rate(P_(n)),quantum yield of PSII(ΦPSⅡ),electron transport rate(ETR),performance index of photosynthetic PSII(F_(v)/F_(m)′),and transformation energy potential of PSII(F_(v)/F_(o)).In addition,during the jointing,anthesis and grain-filling stages,the grain and biomass yield in the R model are 18.9 and 11.1% higher than those in the flat cultivation model,respectively,primarily due to improved soil water contents.The winter wheat fluorescence parameters were significantly positively associated with the photosynthesis,biomass and wheat production.The result suggests that the R cultivation model with irrigation of 150 mm and simulated precipitation of 200 mm is an effective planting method for enhancing P_(n),biomass,wheat production,and chlorophyll fluorescence parameters in dry-land farming areas.

Application of Mulching Materials of Rainfall Harvesting System for Improving Soil Water and Corn Growth in Northwest of China

The ridge and furrow rainfall harvesting（RFRH） system is used for dryland crop production in northwest of China.To determine the effects of RFRH using different mulching materials on corn growth and water use efficiency（WUE）,a field experiment was conducted during 2008-2010 at the Heyang Dryland Experimental Station,China.Four treatments were used in the study.Furrows received uncovered mulching in all RFRH treatments whereas ridges were mulched with plastic film（PF）,biodegradable film（BF） or liquid film（LF）.A conventional flat field without mulching was used as the control（CK）.The results indicated that the average soil water storage at depths of 0-200 cm were 8.2 and 7.3%,respectively higher with PF and BF than with CK.However,LF improved soil water storage during the early growth stage of the crop.Compared with CK,the corn yields with PF and BF were increased by 20.4 and 19.4%,respectively,and WUE with each treatment increased by 23.3 and 21.7%,respectively.There were no significant differences in corn yield or WUE with the PF and BF treatments.The net income was the highest with PF,followed by BF,and the 3-yr average net incomes with these treatments were increased by 2 559 and 2 430 CNY ha-1,respectively,compared with CK.BF and PF had similar effects in enhancing the soil water content,crop yield and net income.Therefore,it can be concluded that biodegradable film may be a sustainable ecological alternative to plastic film for use in the RFRH system in northwest of China.

Retraction notice to“Improvement in winter wheat productivity through regulating PSⅡ photochemistry,photosynthesis and chlorophyll fluorescence under deficit irrigation conditions”

This article has been retracted:please see Elsevier Policy on Article Withdrawal(http://www.elsevier.com/locate/withdrawalpolicy).This article has been retracted at the request of the Editor and Authors.The article was submitted by the first author Shahzad ALI without permission from corresponding author,Dr.JIA Zhi-kuan.The editor and corresponding author requested to retract the article.Apologies are offered to the readers of the journal.

施用生物炭对中国农田土壤有机碳含量的影响--基于Meta分析

探明不同生产条件下施加生物炭对中国农田土壤有机碳含量的影响,以期为科学施用生物炭和提高农田土壤碳库储量提供理论参考。研究基于已公开发表的施加生物炭对于我国农田土壤有机碳含量影响的相关文献,以不施加生物炭为对照组,施加生物炭为试验组,使用Meta分析方法定量整合分析了不同自然条件、土壤性质、农田管理措施等因素下生物炭施用对农田土壤有机碳含量的影响。研究表明,施加生物炭显著提高了农田土壤有机碳含量(P <0.05),平均提高33.98%;当年均温在10~15℃时,土壤有机碳含量增幅最大,可显著提高48.05%(P <0.05),且不同年均温之间有极显著差异(P <0.01),年均降雨量对生物炭提高土壤有机碳的效应也有显著影响(P <0.05);在壤土上施加生物炭对土壤有机碳的提升效果较其他质地土壤极显著提高26.66%(P <0.01);随着施用生物炭pH的提高,其对土壤有机碳的增加效应越大,当生物炭pH> 10时平均可显著提高49.20%(P <0.05);在生物炭施用下,轮作相比于连作,极显著提高了土壤有机碳含量,提高率为28.42%(P <0.01);生物炭配施氮肥对土壤有机碳含量的提高主要取决于生物炭施用量而不是氮肥施用量。此外,试验农田土壤pH、耕地类型、生物炭制备来源和C/N比等因素均对生物炭施用下土壤有机碳含量有不同程度影响。在年均温10~15℃的壤土地区,采用轮作种植方式,施加pH> 10的生物炭对农田土壤的固碳效果最佳。

Effect of Rotational Tillage on Soil Aggregates, Organic Carbon and Nitrogen in the Loess Plateau Area of China

In rain-fed semi-arid agroecosystems, continuous conventional tillage can cause serious problems in soil quality and crop production, whereas rotational tillage (no-tillage and subsoiling) could decrease soil bulk density, and increase soil aggregates and organic carbon in the 0-40 cm soil layer. A 3-year field study was conducted to determine the effect of tillage practices on soil organic carbon (SOC), total nitrogen (TN), water-stable aggregate size distribution and aggregate C and N sequestration from 0 to 40 cm soil in semi-arid areas of southern Ningxia. Three tillage treatments were tested: no-tillage in year 1, subsoiling in year 2, and no-tillage in year 3 (NT-ST-NT); subsoiling in year 1, no-tillage in year 2, and subsoiling in year 3 (ST-NT-ST); and conventional tillage over years 1-3 (CT). Mean values of soil bulk density in 0-40 cm under NT-ST-NT and ST-NT-ST were significantly decreased by 3.3% and 6.5%, respectively, compared with CT, while soil total porosity was greatly improved. Rotational tillage increased SOC, TN, and water-stable aggregates in the 0-40 cm soil, with the greatest effect under ST-NT-ST. In 0-20 and 20-40 cm soils, the tillage effect was confined to the 2-0.25 mm size fraction of soil aggregates, and rotational tillage treatments obtained significantly higher SOC and TN contents than conventional tillage. No significant differences were detected in SOC and TN contents in the >2 mm and <0.25 mm aggregates among all treatments. In conclusion, rotational tillage practices could significantly increase SOC and TN levels, due to a fundamental change in soil structure, and maintain agroecosystem sustainability in the Loess Plateau area of China.

半干旱区不同秋覆盖方式对农田土壤水温效应及玉米水分利用效率的影响

2013~2015年在黄土高原半干旱区以传统平作不覆盖为对照(CK)、地膜全覆盖(PA)、可降解膜全覆盖(BA)、玉米秸秆全覆盖(sA)和沟垄集雨半膜覆盖(RH)4种覆盖方式,研究不同秋季覆盖方式的土壤水分保蓄效果及对春玉米生长的影响。结果表明,在冬春休闲期,PA、BA、SA、RH处理均能有效提高播种前土壤水分,SA和RH处理在整个生育期土壤蓄水量显著高于CK,PA和BA处理仅在生育前期有较高的土壤水分;PA、BA和RH处理均有增温效果。不同处理中,PA处理产量最高,2年平均较CK提高58.17%,RH与BA处理分别较CK提高34.16%和27.05%,SA处理低于CK;水分利用效率与产量规律一致,PA、BA和RH处理分别较CK提高36.89%、14.34%和29.51%。