Evolution of soil and water conservation in rain-fed areas of China

Rain-fed (dryland) farming is an ancient agricultural production system in China. It occurs widely across almost the whole country, especially in the Northwest and North China. The semi-arid Loess Plateau is the most important region of rain-fed farming in China, but unfortunately, soil erosion on the Loess Plateau area is the highest in China, and indeed amongst the highest in the world. This highlights the necessity for developing practices that can reduce soil and water erosion, improve soil water use efficiency, improve crop productivity, and reduce rural poverty in the region. Many techniques of soil and water conservation are being used in rain-fed areas of China, including such systems as mulch, ridge and furrow systems. The Appendix describes a unique system of soil and water conservation, called Shatian.Modern research on conservation tillage (No Till), although essential for reducing erosion, increasing crop productivity, and ameliorating poverty, is just beginning in China. Modern conservation tillage research started in the1990s' with support from Australia and other countries. The procedures, however, were modified to be in accord with local conditions and prevailing farmer experiences. With 10 years of experimentation, results show that the most successful conservation practice on the Western Loess Plateau is no till with stubble retention. This technique helps to conserve soil water, increases soil organic carbon, improves soil structure and water infiltration, reduces soil and water erosion, and improves crop productivity and sustainability of rain-fed farming systems. However, its adoption rate remains low due to barriers such as traditional attitude, insufficient rural extension, and so forth.     

钾硅肥配施对胡麻茎秆碳水化合物及抗倒性的影响

为明确钾硅肥施用对胡麻茎秆碳水化合物主要成分含量及抗倒伏特性的影响,探讨钾硅肥运筹调控胡麻茎秆抗倒伏能力的机制,选用裂区试验设计进行了研究,以两个品种为主处理,三个K2O钾肥用量(K0:不施钾;K1:52.5 kg/hm2;K2:105 kg/hm2)为副处理,两个SiO2硅肥用量(Si0:不施硅;Si1:90 kg/...     

秸秆覆盖及播种方式对马铃薯耗水特性和产量的影响

为明确西北旱作雨养农业区不同秸秆带状覆盖种植模式下马铃薯耗水规律、水分利用效率及产量的变化规律,以地膜覆盖和露地种植(CK)为对照,设置4种秸秆带状覆盖模式(①种植带和覆盖带各40 cm、单行播种,②种植带和覆盖带各40cm、双行播种,③种植带和覆盖带各50cm、单行播种,④种植带和覆盖带各50 cm、双行播种),研究不同秸秆带状覆盖模式对旱地马铃薯耗水特性和产量的影响。结果表明:秸秆带状覆盖处理与CK相比,马铃薯薯块产量和水分利用效率平均分别显著提高34.0%、21.5%,分别平均较地膜覆盖显著降低31.3%、25.0%;其中40 cm覆盖种植结构产量和水分利用效率较50 cm覆盖种植结构分别明显提高4.5%和6.8%,双行播种较单行播种增产4.4%,二者水分利用效率无明显差异。秸秆带状覆盖条件下,播种—现蕾阶段的耗水量、耗水强度及耗水模系数平均较CK显著降低14.5%、15.2%、15.4%,平均较地膜覆盖显著增加20.9%、19.0%、31.5%;与CK相比,现蕾—块茎膨大阶段耗水量、耗水强度及耗水模系数无显著性差异,相比于地膜覆盖,则分别平均显著减少20.7%、22.2%、13.9%;块茎膨大—成熟阶段分别平均较CK显著提高51.7%、52.4%、50.0%。同时,相比于CK,单薯重、商品薯率分别显著提高17.3%、31.8%,单株结薯数和小薯率降低7.5%、17.6%。可见,秸秆带状覆盖栽培可通过降低现蕾前的耗水和增加块茎膨大后的耗水,一定程度上缓解马铃薯植株后期对水分的需求,延长块茎膨大后植株光合作用,提高有机物的积累量,从而提高薯块产量和水分利用效率。而秸秆带状覆盖中,单行种植以种植带∶覆盖带=40 cm︰40 cm最好,双行种植以种植带︰覆盖带=50 cm︰50 cm较适宜。     

不同生物质炭输入水平下旱作农田温室气体排放研究

在陇中黄土高原干旱半干旱区,采用小区定位试验,对不同生物质炭输入水平下春小麦农田土壤温室气体(CO_2、N_2O和CH_4)的排放通量进行全生育期连续观测,并分析其影响因子。结果表明:6个生物质炭输入水平处理下[0 t·hm~(-2)(CK)、10 t·hm~(-2)、20 t·hm~(-2)、30 t·hm~(-2)、40 t·hm~(-2)、50 t·hm~(-2)],旱作农田土壤在春小麦全生育期内均表现为CH_4弱源、N_2O源和CO_2源。全生育期各处理CH_4平均排放通量依次为:0.005 7 mg·m~(-2)·h~(-1)、0.0047 mg·m~(-2)·h~(-1)、0.003 6 mg·m~(-2)·h~(-1)、0.003 3 mg·m~(-2)·h~(-1)、0.002 7 mg·m~(-2)·h~(-1)和0.000 4 mg·m~(-2)·h~(-1),N_2O平均排放通量依次为:0.230 5 mg·m~(-2)·h~(-1)、0.144 1 mg·m~(-2)·h~(-1)、0.135 3 mg·m~(-2)·h~(-1)、0.098 9 mg·m~(-2)·h~(-1)、0.125 0 mg·m~(-2)·h~(-1)和0.151 3mg·m~(-2)·h~(-1),CO_2平均排放通量依次为:0.449 2μmol·m~(-2)·s~(-1)、0.447 0μmol·m~(-2)·s~(-1)、0.430 3μmol·m~(-2)·s~(-1)、0.391 4μmol·m~(-2)·s~(-1)、0.408 0μmol·m~(-2)·s~(-1)和0.416 4μmol·m~(-2)·s~(-1)。土壤CH_4排放通量随生物质炭输入量的增加而减小;当生物质炭输入量小于30 t·hm~(-2)时,土壤N_2O、CO_2排放通量随其输入量增加而显著减小,但当其输入量超过30 t·hm~(-2)时,N_2O、CO_2排放通量则呈显著增大趋势。各处理在5~15 cm土层平均土壤温度差异显著(P0.05),在5~10 cm土层平均土壤含水量差异显著(P0.05),土壤温度及含水量受生物质炭影响明显;且CK处理不同土层的土壤温度及含水量波动最大,生物质炭输入可在一定程度上降低不同土层土壤的水热变化幅度;N_2O、CO_2排放通量与10~15 cm土层土壤温度呈显著性负相关,与20~25 cm土壤温度呈显著性正相关;CH_4平均排放通量与5~10 cm土层土壤温度呈显著性负相关,与其含水量呈显著性正相关;N_2O平均排放通量与15~20 cm土层土壤温度呈显著性正相关;CH_4、N_2O、CO_2平均排放通量与0~5 cm土层土壤水分呈显著性负相关。生物质炭的输入能够减小温室气体的排放,且会因其输入量的不同而异,因此适量应用生物质炭有利于旱作农田生育期内增汇减排。     

Trichoderma harzianum T-E5 significantly affects cucumber root exudates and fungal community in the cucumber rhizosphere

The Fusarium wilt in cucumbers, caused by the pathogenic fungus Fusarium oxysporum f. sp. cucumerinum, is a serious and destructive disease worldwide. An effort was made to explore the role of Trichoderma harzianum T-E5 in reducing the incidence of Fusarium wilt. Three treatments (Control, T1, and T2) were established in the greenhouse experiment. The effects of T-E5 on the composition of root exudates and fungal community in the cucumber rhizosphere were measured. Compared with the control, the application of a bio-organic fertilizer (BIO) enriched with T-E5 was found to decrease the incidence of Fusarium wilt notably and promote the growth of cucumber plants. Based on real-time PCR, the population of F. oxysporum in the control without T-E5 increased from 10³ to 10⁴ ITS copies g⁻¹ soil, whereas the population decreased from 10³ to 10² ITS copies g⁻¹ soil in the T1 and T2 treatment groups when T-E5 was included. Significant difference in fungal community was also found among the treatment groups. HPLC analysis showed that the detected levels of phenolic compounds in control were significantly higher than the levels in the samples subjected to T1 and T2 treatments. The root exudates from the control group significantly increased the numbers of germinating spores of the pathogen compared with those from the samples treated with T1 and T2. In conclusion, the modification of root exudates and the fungal community by the application of BIO might account for the effective suppression of Fusarium wilt disease in cucumbers.     

不同施肥方式对马铃薯农田土壤有机碳组分和碳库管理指数的影响

针对马铃薯生产实践中长期单施化肥或化肥过量施用等不合理施肥措施导致土壤碳库活性变差和土壤生物活性降低等问题。通过田间定位试验,分析不同施肥方式:不施肥（CK）、单施化肥（NPK）、单施有机肥（M）、有机无机肥配施（NPKM）对旱作马铃薯农田土壤有机碳组分和碳库管理指数的影响。结果显示,连续施肥5年后添加有机肥的M、NPKM处理较CK和NPK处理显著提高了土壤闭蓄态颗粒有机碳（OPOC）和土壤颗粒态有机碳（POC）含量,降低了土壤矿质结合态有机碳（MOC）含量。与CK和NPK处理相比,M、NPKM处理闭蓄态颗粒有机碳（OPOC）含量分别提高了32.52%、30.39%和27.09%、24.78%;土壤颗粒态有机碳（POC）含量分别提高了31.52%、29.65%和25.18%、23.15%。添加有机肥的M和NPKM处理显著提高了颗粒态有机碳（POC）的比例,降低了MOC的比例,与CK和NPK相比,M、MNPK处理中POC的比例分别增加了27.72%、25.23%和10.61%、7.54%,MOC的比例分别降低39.42%、33.16%和14.97%、9.81%。添加有机肥显著提高了土壤总有机碳（TOC）、微生物量碳（MBC）、易氧化有机碳（ROC）的含量,与CK处理相比,M和NPKM处理的TOC分别增加了15.28%和13.64%,MBC增加了21.82%和19.17%,ROC的含量分别增加了32.45%和31.35%;施用有机肥和有机无机配施均显著提高碳库管理指数（CPMI）较单施化肥分别提高28.8%和35.65%。综上所述,施用有机肥处理（M处理和MNPK处理）显著地提高了马铃薯农田土壤闭蓄态颗粒有机碳（OPOC）、颗粒态有机碳（POC）和总有机碳（TOC）及微生物量碳（MBC）、易氧化有机碳（ROC）含量,提高了土壤碳库管理指数;即马铃薯栽培施用有机肥有利于土壤活性有机碳的积累、能够改变土壤有机碳组分分布特征。     

钾肥和硅肥对油用亚麻茎秆抗倒伏特性的影响

为了优化油用亚麻抗倒伏的肥料运筹措施,以‘陇亚11号’和‘定亚23号’为试验材料,通过裂区设计,研究了钾肥（不施钾、52.5 kg K₂O/hm²和105 kg K₂O /hm² 3个水平）和硅肥（不施硅和90 kg SiO₂/hm² 2个水平）用量对油用亚麻茎秆形态学、力学抗倒伏特性及产量的影响。结果表明：‘陇亚11号’的株高、重心高度及茎粗、壁厚、抗折力均显著大于‘定亚23号’,茎秆形态学及力学抗倒伏特性的综合影响下,‘陇亚11号’较‘定亚23号’倒伏率提高21.24%而产量降低9.43%。钾肥显著改善了抗倒的茎秆表观形态学特性,施钾后茎粗、壁厚、茎秆抗折力、抗倒伏指数提高而株高和重心高度降低,千粒重和籽粒产量分别提高7.35%和9.34%。硅肥对茎秆形态学、力学特性及籽粒产量均无主效应,但硅肥与钾肥的互作使茎粗显著增加。抗倒伏指数与茎粗、壁厚呈显著正相关,与株高、重心高度呈显著负相关。品种间的茎秆抗倒伏特性差异较大,施用钾肥显著改善了抗倒的茎秆表观形态学特性,优化了茎秆机械性能,增强了油用亚麻的抗倒伏能力;供钾量较低时,硅肥与钾肥对茎粗的互作正效应明显。     

生物有机肥对马铃薯根际土壤生物活性 及根系活力的影响

针对大量化肥长期施用对马铃薯田土壤造成的生物活性降低等问题,利用根际益生菌（PGPR）制成生物有机肥,通过盆栽试验,研究了不施肥（对照,CK）以及分别施化肥（CF）、普通有机肥（OF）和5种生物有机肥（BOF1,BOF2,BOF3,BOF4和BOF5）对马铃薯根际土壤生物活性和根系活力的影响。结果表明,在马铃薯的成熟期,5种生物有机肥处理的可培养细菌数量平均比CF及OF高52%和37%,微生物量碳比CF和OF处理平均增加了30%,其中以BOF3效果最明显,比其它生物有机肥处理的可培养细菌数量和微生物量碳增加达3%～7%和2%～7%;且土壤脲酶、蔗糖酶和磷酸酶活性显著提高(P<0.05),相比CF和OF,5种生物有机肥处理土壤酶活性的增幅为11%～114%;根系活力分别增加了265%和224%,块茎产量分别增加了16%和21%,根系活力和块茎产量的提高也以BOF3效果最明显,其根系活力比BOF5高出166%,其块茎产量比其它生物有机肥处理的增幅为5%～9%。说明生物有机肥有助于提高土壤的生物活性,改善马铃薯的根际环境,进而提高了马铃薯的根系活力,增加了马铃薯的块茎产量。     

可降解地膜覆盖和有机无机氮肥配施对胡麻干物质和产量的影响

通过田间定位试验,研究了不覆膜、普通地膜和0.008、0.010、0.012 mm厚度的可降解地膜以及不施氮、单施化学氮肥(120 kg·hm~(-2))、化学氮肥与有机氮肥配施(120 kg·hm~(-2),2/3化学氮肥,1/3有机氮肥)对胡麻干物质积累、籽粒灌浆以及经济产量的影响。结果表明,可降解地膜和普通地膜覆盖胡麻生育期的差异较小(≤2 d),0.012 mm可降解地膜对生育进程的影响最接近普通地膜。普通地膜对干物质积累的促进作用较可降解膜提高了12.88%～160.22%;0.012 mm可降解地膜对胡麻生长的促进作用更接近于普通地膜,其干物质量较普通膜的降幅(11.41%～27.92%)低于其余2种降解膜(16.55%～61.57%);0.012 mm的可降解膜与普通地膜灌浆速率无显著差异。有机无机氮肥配施较单施化肥对胡麻生长的促进作用显著,营养生长阶段中后期的干物质积累量增加了11.69%～16.44%,但对灌浆速率的提升作用较单施化肥小。3种可降解地膜具有与普通地膜同等的增产作用,覆膜后平均增产19.18%;施氮提高了籽粒产量,有机无机氮肥配施和单施化肥间无显著差异。覆膜和施肥仅对干物质积累具有显著的交互作用。试区胡麻生产上可用0.012 mm的可降解地膜代替普通地膜。