甘肃中部半干旱灌区马铃薯平衡施肥效应研究

以克新1号为指示品种,研究了甘肃中部半干旱灌区黄麻土马铃薯平衡施肥的效应。综合分析研究结果表明,在甘肃中部半干旱灌区马铃薯平衡施肥的OPT中,磷量不足,氮量基本适宜,钾量偏高。     

旱作棉田渗水地膜覆盖的生态及产量效应研究

采用地膜创新产品——渗水地膜,以普通地膜及露地为对照,对渗水地膜覆盖棉田后土壤水分、温度、通透性等生态因子的变化及其对棉花生理性状及产量的影响进行了初步探讨。结果表明:(1)渗水地膜覆盖除具有普通地膜的增温、保水、提墒以及改善土壤理化性状等作用外,更具有普通地膜所不具有的从膜面垂直入渗降水的作用,使全生育期土壤含水量具较高水平,水分供应充足,同时,由于渗水地膜的微通气作用,使土壤容重降低,孔隙度提高,气相比例增加,土壤通透性增强,土壤温度较为稳定。(2)渗水地膜覆盖进一步改善了棉田土壤水分、温度及通透性等生态环境,为棉花生长发育和产量形成提供了良好的生活条件。从多项生理指标的变化看出,棉花植株抗逆性增强。渗水地膜进一步提高了棉花覆盖栽培的增产潜力。(3)在北部特早熟棉区降水较多的年景下,渗水地膜覆盖棉花产量比露地增产22.3%,比普通地膜增产12.1%,增产效果显著。渗水地膜比普通地膜增产主要在于铃重的增加,普通地膜比露地的增产主要得益于衣分的提高,渗水地膜比露地的增产是得益于铃重及衣分的共同作用。渗水地膜与普通地膜相比并未增加投资。(4)在同等条件下,渗水地膜总耗水量比露地降低10.1%,比普通地膜降低6.5%。水分利用率比露地提高36.7%,比普通地膜提高20.7%,此结果对北方半干旱地区旱作棉花提高降水利用率及新疆内陆棉区灌溉条件下的棉田节水均有重要参考价值。     

半干旱区玉米密度对产量及商品品质的影响

在吉林省西部半干旱区开展半干旱区玉米密度对产量及商品品质的影响研究。结果表明,半干旱区耐密型玉米品种郑单958、先玉335适宜播种密度在65000～75000株/hm²,稀植大穗型玉米品种吉单257、吉单137适宜播种密度在60000～65000株/hm²;郑单958、先玉335、吉单257、吉单137百粒重与密度呈负相关;4个品种的容重与密度关系呈二次抛物线,郑单958在50000株/hm²、先玉335、吉单257在57500株/hm²、吉单137在50000株/hm²时容重最高,商品等级最好;4个品种随播种密度增加,穗位叶叶绿素SPAD值降低。     

Improvement of FAO-56 method for olive orchards through sequential assimilation of thermal infrared-based estimates of ET

The aim of this study is to use the FAO-56-based single crop coefficient approach to estimate actual evapotranspiration (AET) of an olive (Olea europaea L.) orchard in the Mediterranean semi arid region of Tensift-basin (central Morocco) during two consecutive growing seasons (2003 and 2004). The results showed that using crop coefficients K_c suggested by FAO-56 method yielded an AET overestimation by about 18% when compared against eddy covariance measurements. Therefore, the determination of appropriate K_c values is required to accurately estimate crop water requirement of olive orchards in such water scarce area.In this study, after applying the K_c values derived over olive orchard in Spain by Pastor and Orgaz [Pastor, M., Orgaz, F., 1994. Riego deficitario del olivar: los programas de recorte de riego en olivar. Agricultura 746, 768-776 (in Spanish)], a better agreement was observed between measured and simulated AET. The root mean square error (RMSE) was reduced by about 28%, from 0.80 to 0.61 mm/day for 2003 and from 0.93 to 0.69 mm/day for 2004. The used K_c values of olives at three crop growth stages (initial, mid-season and maturity) were 0.65, 0.45, and 0.65, respectively, the mid-season stage value being considerably lower than that suggested by the FAO-56.Despite these improvements in the performance of AET simulations, some discrepancies between measured and simulated AET remained, especially when water stress occurred. These discrepancies were ascribed to the estimation of the stress coefficient K_c To overcome this problem, we assimilated into FAO-56 single source model estimates of AET derived from a simple energy balance model along with thermal infrared observations. The latter were collected with the ASTER sensor in 2003 and from ground-based measurements in 2004. The results showed a clear improvement for FAO-56 performances after assimilation: for 2003 and 2004, the RMSE values between observations and simulations, respectively, dropped down from 0.61 to 0.52 and from 0.69 to 0.46 (corresponding to relative reductions of 15 and 40%, respectively).     

Quantifying rainfall-runoff relationships on the Dera Calcic Fluvic Regosol ecotope in Ethiopia

Droughts, resulting in low crop yields, are common in the semi-arid areas of Ethiopia and adversely influence the well-being of many people. The objective of this study was to assess the benefit that in-field rainwater harvesting (IRWH) would have, compared to conventional tillage, on maize yields on a semi-arid ecotope at Dera situated on the eastern part of the Rift Valley. Rainfall-runoff measurements were made during 2003 and 2004 on 2 m × 2 m plots provided with a runoff measuring system and replicated three times for each treatment. There were two treatments: conventional tillage (CT) and no-till (NT), the latter with a flat surface that promotes runoff and therefore IRWH. Rainfall intensity was measured at 1 min intervals with an automatic tipping bucket instrument, and runoff was measured after each rain event. Measured runoff as a function of rainfall intensity and duration from half the rainfall-runoff events was used to determine the critical parameters of a appropriate runoff model. The calibrated model was found to be capable of predicting runoff in a satisfactory way.Rainfall-runoff measurements were made during the rain seasons in 2003 and 2004 during which there were 25 rain events with >9 mm of rain. There was no statistical difference between the runoff on the two treatments. The measured runoff (R) for the two rain seasons, expressed as a fraction of the rainfall during the measuring period (P), i.e. R/P, gave values of 0.46 and 0.39 for the NT and CT treatments, respectively.Results from 7 years of field experiments with IRWH at Glen in South Africa were used to estimate the yield benefit of NT for Dera compared to CT. The results were 696 and 494 kg ha⁻¹ for 2003 and 2004, respectively. Based on the estimated average long-term maize yield of 2000 kg ha⁻¹ at Dera, this was an estimated yield increase ranging from 25% to 35%.     

Perspective on oil flax yield and dry biomass with reduced nitrogen supply

Field experiment was arranged in a randomized complete block design to determine effects of nitrogen (N) application levels (J0: 150 ​kg/hm², J1: 120 ​kg/hm², J2: 90 ​kg/hm², J3: 60 ​kg/hm²) on regulating dry biomass accumulation, allocation and translocation, and grain yield of oil flax during 2018 cropping season. Significant promotion was observed in dry matter during accumulation stage of oil flax, when N rate was reduced by 40% (from 150 to 90 ​kg/hm²). Under J2 treatment, translocation of dry matter from vegetative organs to pod increased by 38.46% and 61.54% respectively, when compared with J1 and J0 treatment. Dry matter distribution proportion of pod at maturity increased 4.47%–7.61%, contribution rate of leaf to grain upgraded 5.09%–8.77%, and number of effective pods and grains per pod increased by 27.16%–45.38% and 6.49%–26.59% respectively compared to other treatments. As a result, seed yield of oil flax under J2 treatment was 2.23%–18.21% higher than those of other treatments. Our study recommended 90 ​kg/hm² as the best N fertilizer level to improve seed yield of oil flax.     

耕作措施与施氮量对旱作玉米产量及土壤水氮利用效率的影响

于2018-2019年依托甘肃农业大学旱作综合试验站2012年建立的长期定位试验,研究4种耕作措施[翻耕(T1)、旋耕(T2)、深松耕(T3)与免耕(T4)]和2个施氮水平[基施纯氮200 kg·hm~(-2)(N2)、基施纯氮200 kg·hm~(-2)+拔节期纯氮100 kg·hm~(-2)(N3)]下土壤水分的时空动态、耗水量、产量及水氮资源利用效率。结果表明:在黄土高原半干旱区,200 kg·hm~(-2)施氮水平下,与翻耕和旋耕相比,深松耕与免耕能显著提高玉米花后土壤贮水量和含水量,同时,两个处理的水氮协同利用较好,其在降低耗水12.8%～20.6%的条件下,产量增加11.5%～16.2%,致使水分利用效率提高28.7%～31.9%,300 kg·hm~(-2)施氮水平未起到增产和提高水分利用效率的作用,反而降低氮肥偏生产力。因此,200 kg·hm~(-2)施氮水平和免耕或深松耕是该区全膜双垄沟播玉米稳产高产和高水分利用效率的施氮水平和耕作措施。     

陇中旱塬不同覆盖集雨种植方式对春玉米生长特性和产量的影响

以春玉米"金凯3号"为供试材料,2015年和2016年开展两年6个不同处理大田试验,设置平地全膜覆盖(WM)、平地半膜覆盖(HM)、隔沟覆膜垄播(MRM)、全膜双垄沟播(WRF)、垄沟秸秆覆盖(SM)和露地平播(CK)6个处理,测定春玉米不同生育阶段生长特性、收获后产量、水分利用效率(WUE)及经济效益等指标。结果表明,覆盖集雨种植方式均能显著促进春玉米生长和干物质积累,提高产量、水分利用效率和经济效益。较露地平作(CK),WRF和MRM处理玉米产量和WUE分别提高了4 561.34、4 126.31 kg/hm2和14.48、12.72 kg/(hm2·mm),以全膜双垄沟播种植方式增幅最显著。试验结果表明,WRF处理纯收益最高,达5 878.26元/hm2,WM处理次之,为4 599.18元/hm2,分别较CK处理增加5 113.3 1和3 834.23元/hm2,可显著提高投入产出比。全膜双垄沟播春玉米种植由于其良好耕作生产特性,是陇中旱塬春玉米高产、稳产的优势选择。     

Dry pea (Pisum sativum L.) yielding and weed infestation response,under different tillage conditions

Legume-crops are considered important components of conservation farming and also of the conventional system in recent years. However, a lack of studies reflect a priority need for primary research into food legumes and their impact on farming systems, which is currently at secondary level to cereals in terms of investigation. The present field study was undertaken to compare the effects of different tillage systems on yielding and weed infestation of pea. Tillage treatments employed included conservation (minimum-tillage and zero-tillage) and conventional system (conventional-tillage) under semi-arid conditions. The weather had a marked influence on yielding and weed diversity of pea crop over the study period. Tillage system had no effect on pea grain yield and the yield components of pea. We observed, with scarcer annual rainfall, lower values of grain yield, straw biomass, harvest index and yield components in minimum-tillage plots. This could be attributable to an increase of the weed community favoured by rooting conditions. Weed density and diversity indices (Shannon and Evenness) presented the highest values in minimum tillage system. Particularly, we observed that decreasing tillage favoured the increase of one annual grass weed (Lolium rigidum Gaudin). Our results highlight the research on weed species associated with low-input systems.     

半干旱区全膜双垄沟播对马铃薯耗水规律的影响

为探讨半干旱区全膜双垄沟播对马铃薯耗水规律的影响,连续2 a测定了马铃薯0~300 cm处土壤水分季节变化、垂直变化、年际变化、产量及耗水量。试验结果表明,全膜双垄沟播(PM)明显改善了马铃薯开花前0~300 cm土壤的水分条件,且与裸地(CK)处理相比,产量、水分利用效率(WUE)都存在显著差异,2012年和2013年PM的产量均显著高于CK,分别提高了20.64%和32.64%,水分利用效率分别提高了27.29%和47.37%,但处理间土壤耗水量无显著差异。因此,全膜双垄沟播是通过覆盖降低棵间蒸发来调控马铃薯的耗水过程,进而提高旱地马铃薯产量和水分利用效率。