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1.
半干旱区沟垄集雨对玉米光合特性及产量的影响   总被引：7，自引：0，他引：7  
在中国西北黄土高原半干旱区, 沟垄集雨种植(RFPRH)系统被逐步推行, 以改善农田水分状况, 提高作物水分利用效率(WUE), 达到高产稳产的目的。为了探索该种植方式的适宜降雨量, 在人工模拟不同降雨量下, 以传统平作为对照, 研究了沟垄集雨种植对夏玉米土壤水分含量、功能叶片的光合参数、荧光参数和叶绿素相对含量(SPAD)以及籽粒产量的影响。结果表明, 在230 mm和340 mm降雨量下, 集雨处理的净光合速率(Pn)、气孔导度(Gs)、最大荧光(Fm)、可变荧光(Fv)、PS II最大光化学量子产量(Fv/Fm)、PS II的潜在活性(Fv/Fo)和光化学猝灭系数(qP)均较对照显著增加; 叶绿素相对含量(SPAD)分别提高17.7%和13.9%, 叶片瞬时水分利用效率提高26.9%和10.1%, 籽粒产量增加75.4%和36.7%。在440 mm降雨量条件下, 集雨处理的Fm、Fv/Fm、Fv/Fo、qP和SPAD值在拔节期显著增加, Gs在抽雄期显著增加, Pn在抽雄期和孕穗期显著下降, 水分利用效率在全生育期比对照平均低13.2%, 其他各生育时期光合生理特性及籽粒产量与对照相比差异不明显。说明沟垄集雨种植在偏旱的年份, 可显著提高玉米光合效率和叶片水分利用效率, 其全生育期适宜雨量上限可能是440 mm。  相似文献   

2.
Ridge and furrow rainfall concentration (RC) system has gradually been popularized to increase water availability to crops for improving and stabilizing agricultural production in the semiarid area of northwest China. The system is comprised of two elements: the plastic-covered ridge serves as rainfall harvesting zones and the furrow serves as planting zones. To make this system more perfect for alleviating drought stress in semiarid region, it is necessary to test optimum planting systems. A field experiment was conducted from 2007 to 2010 to evaluate the effects of RC planting on soil moisture, wheat yield and water use efficiency (WUE) under different ridge widths. Four planting systems were designed (RC40: 40 cm ridge with 60 cm furrow width, RC60: 60 cm ridge with 60 cm furrow width, RC80: 80 cm ridge with 60 cm furrow width, and CF: conventional flat without ridging). The results showed that RC planting can significantly increase soil moisture in 0–200 cm during the growing seasons of winter wheat. The rainfall-harvesting effect increased with ridge width increasing. Winter wheat yield and WUE was significantly higher under RC60 than under CF by 405.1 kg ha−1 and 2.39 kg mm−1 ha−1, respectively, on average across the three experimental years (P < 0.05). The above findings indicate that RC60 can benefit winter wheat cropping for higher yield through improving soil moisture. It could be concluded that the RC planting system with 60 cm ridge and furrow width will offer a sound opportunity for sustainable farming in semiarid dryland agricultural area.  相似文献   

3.
A field study was conducted to determine the effect of a combination of the plastic‐covered ridge and furrow rainwater harvesting (PRFRH) with different mulching materials, namely, 0.08‐mm‐thick plastic film (T1), 10‐cm‐thick corn straw (T2), 8 % biodegradable film (T3), liquid film (T4), bare furrow (T5) and conventional flat (CF), on corn production, soil water storage and water use efficiency (WUE) in the subhumid areas prone to drought of China (SAPDC). The T1–T5 plots at 0–100 cm depth had higher (P < 0.05) soil water storage than CF, while at 100–200 cm soil layer there was no difference (P > 0.05) among treatments. The T1–T4 plots produced 209–1 107 kg ha?1 more grain yields than the T5 plots. Meanwhile, almost all treatments had WUE over 2 kg m?3. The order of WUE increase among different mulch treatments was as follows: T3 > T1 > T2 > T4. In the case of environmental and economic feasibility, a combination of the PRFRH system with biodegradable film and straw mulches would be an option with high potential to increase crop sustainability in dry land farming systems and can be adopted in many areas without irrigation capability.  相似文献   

4.
The Rolling Pampa is the most productive region of the Argentine Humid Pampa comprising around 10 Mha. Wheat (Triticum aestivum L.), corn (Zea mays L.), and soya bean [Glycine max (L.) Merr.] are the main grain crops produced. To develop sound cropping strategies, a better understanding of the impact of soil fertility and management on crops is needed. The objective of this study was to develop models for estimating the effects of growing season precipitation, soil fertility and management on wheat and corn yields. Data from 347 wheat and 323 corn field experiments and production fields over six growing seasons were used. Soil, management and weather characteristics were determined and yields were then evaluated. Data were analysed using linear and quadratic models and a quadratic polynomial surface model. Soil fertility, management and rainfall and interactions were analysed. Growing season precipitation correlated with wheat (R2 = 0.42) and corn (R2 = 0.25) yield. Maximum wheat yield was achieved with 350–400 mm rainfall and corn yield reached a plateau around 700 mm. Soil fertility accounted for 33 % of wheat yield variability and 5 % of corn yield variability. Management accounted for 48 and 9 % respectively. Whole polynomial models integrating rainfall, fertilizer N and P rates, soil N and P, previous crop and tillage system accounted for 67 % of wheat yield variability and 51 % of corn yield variability. Soil organic matter was not included in the models but an indirect effect on yield was detected as organic matter correlated with initial soil N levels for both crops. Soya bean as a previous crop had a positive effect on wheat and corn yields. Wheat was insensitive to tillage system but corn yield was higher under no till. N and P fertilization had a two- to three-fold greater impact on yield than soil nutrient levels. As this region is considered to be of high soil fertility and has a history of very low fertilizer consumption, adequate use of N and P fertilization will be essential to maintaining high wheat and corn yields.  相似文献   

5.
《Soil Technology》1992,5(3):249-256
The approach in this study of runoff and erosion control on steep slopes was to combine soil stabilizers with the planting of drought-resistant, perennial plants.The effect of 10 t ha−1 phosphogypsum (PG) + 70 kg ha−1 polysaccharide (PS), 10 t ha−1 PG and 20 kg ha−1 polyacrylamide (PAM), and 200 kg ha−1 PS on the erosion of steep slopes (30–60%) was studied in plots 2 m in width and of different lengths (12–20 m), at three of different sites in Israel (semiarid conditions), and under natural rainfall conditions. Likewise, observations on the establishment and development of nonirrigated, drought-resistant, perennial plants on steep slopes (40–60%), combined with 10 t ha−1 PG + 70 kg ha−1 PS, were conducted at two sites in Israel.PS + PG and PAM + PG treatments were very efficient in erosion control in a wide range of soil types, ESP, CaCO3 level, and weather conditions. These treatments reduced erosion six- to eleven-fold in comparison with the control. No significant difference was found between PS + PG and PAM + PG treatments. However, the application of PAM was problematic due to its very low dissulution rate and its high viscosity in water. Two-hundred kg PS without PG was found efficient only at one experimental site with calcic haploxeralf soil and 300 mm average annual rainfall.The combination of PS + PG, and drought-resistant, perennial plants was very sucessful. The plants developed very well without irrigation throughout the long, dry summer. Only one year later, the creeper plant canopy covered an area of 0.75–1.5 m, and the bushes were 0.8–1.2 m in height.  相似文献   

6.
This study analyses the role of variability induced by climate and soil properties (texture and total available soil water in the root zone, TAW) on the “corn deficit irrigation–water use efficiency” relation over a 25-year period, between 1981 and 2005, in three different sites located in the South of Italy. The analysis of water use efficiency was carried out by means of three indexes: crops water use efficiency (WUEET and WUET) and irrigation water use efficiency (IWUE). These indexes can be obtained by calculating the ratio between the yield and the seasonal values of evapotranspiration (ET), transpiration (T) and irrigation volume (I). After its validation, the STICS model was retained to simulate the variables required to determine these indexes.Climatic variability affected the three indexes in different ways during the 25-year period studied. The dispersion around the mean values of the water use efficiency is 17% on average for the WUE (ET or T) indexes, whereas it could reach 54% for the IWUE index. This last index is only poorly reliable due to the high variability of rainfall during the corn growing season in the Mediterranean region.For the same level of soil water deficit, TAW led to an improvement (the case of the site with a high TAW and loam–clay soil texture), a stabilisation (the case of the site with a high TAW and clay soil texture) or a decrease (the case of the site with a poor TAW and clay soil texture) in WUEET and WUET values. For the same conditions of soil water deficit and TAW, crops water use efficiency was higher in loam textured soil than in clay soil.The results derived by analyzing three indexes (WUEET, WUET and IWUE) converge to the same conclusions on the “corn deficit irrigation–water use efficiency” relation observed at the three different sites.The hypotheses which may explain the differences observed in the different sites studied in terms of water use efficiency are discussed, with the presentation of some suggestions devised for corn irrigation practices.  相似文献   

7.
张玉娇  李军  郭正  岳志芳 《作物学报》2015,41(11):1726-1739
为探索不同肥力水平对渭北旱塬连作冬小麦田在长周期免耕/深松轮耕措施下土壤蓄水保墒和作物增产效应的影响,在模拟精度验证基础上,应用Win EPIC模型长周期定量模拟研究了1980–2009年渭北旱塬免耕/深松轮耕连作麦田5个不同施肥水平下(T1,N 75 kg hm–2+P2O5 60 kg hm–2;T2,N 120 kg hm–2+P2O5 90 kg hm–2;T3,N 150 kg hm–2+P2O5 120 kg hm–2;T4,N 180 kg hm–2+P2O5 150 kg hm–2;T5,N 255 kg hm–2+P2O5 90 kg hm–2)冬小麦产量和土壤水分效应。在30年模拟期间,各处理的冬小麦产量、年度耗水量和水分利用效率均呈波动下降趋势,下降幅度表现为T5T4T3T2T1。0~5 m土层土壤有效含水量呈季节性波动降低趋势,且随施肥水平的升高而降低,5个处理的麦田平均干燥化速率依次为每年13.5、17.1、17.4、20.1和23.9 mm。0~1.5 m土层土壤湿度随季节降水波动;各处理在不同深度形成稳定的土壤干层,其中T1在1.5~2.0 m,T2和T3在1.5~3.0 m,T4和T5在1.5~4.0 m。上述结果表明,随着肥力水平的增加,旱作冬小麦产量和耗水量也增加,土壤干层加厚。综合考虑认为,在渭北旱塬免耕/深松轮耕长期连作小麦田适宜的施肥量为纯氮150 kg hm–2+P2O5 120 kg hm–2。  相似文献   

8.
The study was conducted to determine the feasibility of canopy temperature based crop water stress index (CWSI) for scheduling irrigation of Indian mustard (Brassica juncea). Field crop experiments were conducted in Hamirpur, Himachal Pradesh (India) during three consecutive cropping seasons (2015, 2016 and 2017). The experimental field was divided into five plots with different levels of irrigation treatments based on depletion of total available soil water (TASW) in the crop root zone. The maximum soil moisture depletion (SMD) of TASW at 10%, 30% and 50%, full irrigated (non-stressed) and extremely dry (full stressed) conditions were maintained in respective plots. Relationships were developed between canopy-air temperature differential (TC-TA) and vapour pressure deficit (VPD) for non-stressed and fully stressed conditions to generate non-water-stressed baseline (NWSB) and maximum water-stressed baseline (MWSB) baselines for Indian mustard crop. The CWSI was computed for different SMD of TASW by using a proven empirical approach based on the baselines. The irrigation treatment corresponding to 30% SMD with a mean CWSI of 0.4 resulted in optimal yield and maximum water use efficiency. Results of the study suggest that established CWSI value can be used to detect stress and schedule irrigations for Indian mustard.  相似文献   

9.
为进一步研究冬小麦节水灌溉,明确其水分运筹规律,2014—2015年度和2015—2016年度,在冬小麦全生育期降雨量与常年相当的情况下,采取趁墒播种等技术措施,示范研究了"一水千斤"简化栽培模式。试验表明:石家庄地区近十年冬小麦全生育期平均降雨量为132.4 mm,仅占平均需水量三分之一左右;不考虑0~40 cm水分活跃层的情况,40 cm以下土层土壤含水量随土层的下降呈逐渐增加的趋势,冬小麦拔节前各土层的含水量均在萎蔫系数之上;"一水千斤"模式下全生育期冬小麦平均耗水量4404.0 m~3/hm~2,土壤平均耗水量1852.5 m~3/hm~2,全生育期耗水量与常规灌溉模式下接近;明确了冀中南地区实施"一水千斤"模式实现节水与高产相统一,冬小麦灌水量应在1200 m~3/hm~2以上,全生育总耗水量应达到4650 m~3/hm~2以上。  相似文献   

10.
Soils were collected from an experimental site (initiated in 1991) at which leguminous crops were grown as natural soil cover in the interspaces of a 19‐year‐old coconut plantation. Atylosia scarabaeoides, Centrosema pubescens, Calopogonium mucunoides and Pueraria phaseoloides were grown in separate plots during the rainy season and ploughed into the soil towards the end of the monsoon (in December every year). Soil samples were collected from this site at the end of the 7th year and incubated in PVC columns at 35 ± 1°C and 0.01 MPa moisture content for 36 weeks. The soils were then leached at periodic intervals for up to 36 weeks and nitrogen (N) mineralization rates and kinetics were determined by the double exponential model. The N mineralization rates were highest during the first week and decreased with time in all soils. Soils amended (in situ ploughing) with cover crops leached 191 mg kg–1 more NO3– + NO2–‐N than the unamended control. The per cent organic N mineralized (total and net) and the cumulative inorganic N mineralized (NO3– + NO2–‐N) varied with the amount (biomass) and type of cover crop incorporated into the soil. In general, soils amended with cover crops had greater N mineralization potentials and rate constants than the unamended control. The kinetic parameters NoS and No(1 – S) and their respective rate constants h and k also varied with the amount and type of cover crops incorporated into the soil. The results further indicated that the lignin + polyphenol : N ratio of the cover crops is extremely important in predicting the rate of decomposition and N mineralization in soils.  相似文献   

11.
采用田间试验和观测方法研究了渭北旱塬东部旱作区的农田土壤水分特征和水分生产效率,结果表明,该区在麦田夏闲蓄水期(7—9月)降水量在212.7mm以下时,1～1.2m深处存在一相对干土层,使小麦生育后期对深层土壤水分利用产生一定影响,并使旱地农田水分生效率降低。研究还看出,旱地农田水分生产效率具有明显地随播前土壤储水量增加而提高的趋势,说明渭北旱塬使东部的土壤水库在旱农条件下作物供水调节中的不可代替作用。  相似文献   

12.
J. R. Baggett  D. Kean 《Euphytica》1984,33(2):587-590
Summary Internal anthocyanin pigmentation (IP), previously reported to be controlled by a single gene dominant to aa of normal green cabbage, was studied further to determine its relationship to A RC A RC of red cabbage. When IP line R52 was crossed with an early red cabbage line. F1 heads were pigmented throughout, but pigment intensity was intermediate. Subjective classification of F2 plants by pigmentation intensity and distribution scores gave a ratio of 1 intense red throughout (red cabbage):2 medium red throughout:1 medium to light red, restricted to the central portion of the head (IP). The genotypes A RC A RC: A RC A IP: A IP A IP. respectively, are proposed to explain these 3 phenotypic classes. F2 progenies contained no normal green plants, supporting the conclusion that A IP and A RC are alleles.Technical Paper 7052, Oregon Agricultural Experiment Station.  相似文献   

13.
Three different tillage practices, conventional (mouldboard ploughing at 22–25 cm plus one rotary hoeing at 5–6 cm, CT), minimum (one rotary hoeing at 12–15 cm, MT), and no‐tillage (direct drilling in soil covered by vetch residues, NT), combined with three fertilization treatments, inorganic (50 kg N ha?1 as ammonium sulphate), cattle manuring (30 t ha?1), and control (no‐fertilizer), were applied on a cotton crop (Gossypium hirsutum L. cv. Acala SJ‐2) grown on a clay loam soil in the field of the Agricultural University of Athens. Soil (gravimetric water content, bulk density, and penetration resistance in the top 40 cm) and plant parameters (root growth, leaf water potential, leaf area growth and seedcotton yield) were recorded throughout the cultivation period in all treatments. No‐tillage was associated with significantly higher values of soil water throughout the observation period caused by the vetch mulch. Bulk density and penetration resistance were initially higher in the no‐tilled plots, but they became significantly lower after 2–3 months from sowing. These beneficial effects on soil properties favoured root growth, expressed as root surface density, in the NT‐plots at the top soil layer. Similar, although less spectacular, effects were observed in the manured plots. Plant water status, expressed in terms of the water potential index, was significantly and consistently best in the NT‐ and worst in the CT‐plots throughout crop growth. In addition, NT favoured a better foliage growth and resulted in significantly higher yields than the other tillage practices. In general, NT, and in second instance, MT considerably improved plant water status, and hence foliage growth and yield in comparison with CT by maintaining higher levels of soil water and improving root growth. Manuring positively interacted with the reduced tillage practices for most soil and plant parameters.  相似文献   

14.
Perennial grasses provide forage and environmental benefits in the agricultural systems of southern Australia, but persistent cultivars are lacking for the lower rainfall inland margins (<600 mm average annual rainfall). Potential new cultivars of cocksfoot (Dactylis glomerata L.), tall fescue (Festuca arundinacea Schreb. = syn. Lolium arundinaceum (Schreb.) Darbysh.) and phalaris (Phalaris aquatica L.) have been developed in response to this need. These and older cultivars were evaluated for persistence at five sites in south‐eastern Australia from 2009 to 2013. A wide range in rainfall was experienced, but survival was principally reduced by a severe spring–summer–autumn drought in the final year in which all species began to decline in persistence once the spring 2012 to autumn 2013 cumulative climatic moisture deficit became higher than about 700 mm and declined very severely at deficits over 1000 mm. The highly summer‐dormant cocksfoot ssp. hispanica control cultivar Kasbah showed outstanding survival of this event in the cropping zone of southern New South Wales, but not at the drier of two sites with acidic soils in central Victorian where all cocksfoot cultivars showed similar survival. Potential new summer‐active tall fescue cultivars survived well at the higher rainfall Victorian site and under high rainfall in northern NSW. All tall fescue cultivars experienced high mortality during a period of high moisture stress in the spring of the establishment year in southern NSW, but the Mediterranean cultivar Grasslands Flecha MaxP gradually recovered. Differences among phalaris cultivars were not large with new cultivars of North African origin being marginally more persistent at the drier site in southern NSW. Comparisons with results from the Mediterranean Basin are discussed. Although there was no clear evidence of differences in persistence between the new and old cultivars, some of the new cultivars were considered to show potential for commercial release.  相似文献   

15.
花生复合系统是促进低丘红壤区农业水分资源综合利用的重要耕作方式,其在不同时段水分动态、水分平衡和利用过程差异值得进一步探索。土壤表层采用15 bar的先进负压计监测,结合定位法于2001—2003年监测收集了花生生长季花生复合系统、花生单作田间土壤水分、地表径流、降雨资料,分析了花生复合系统对土壤水分动态、降雨影响和水分平衡各要素的影响。分析表明,土壤10 cm与 60 cm水分单作花生地与复合系统在雨季无明显差异,但受降雨过程影响。旱季单作花生10 cm水势降到最低值-344.0 kPa,复合系统水势最低值为-50.6 kPa,60 cm单作花生地水势数值也低于复合系统花生地,旱季复合系统能减少土壤表层的蒸发。3年土壤水分周期动态可分为3个阶段,即水分盈余期、水分消耗期、水分稳定期。花生复合系统旱季表现出较强的耗水作用,2001年7月贮水量减少108.8 mm,2002年8月贮水量减少111.7 mm,2003年7月贮水量减少105.5 mm。花生复合系统平均渗漏量低于花生单作62.2 mm,平均贮水量变化低于花生单作41.8 mm。桔树与花生作物在旱季水分利用方面没有明显的竞争作用,花生复合系统系统的表土水分保持作用和生态效应明显。  相似文献   

16.
To determine the effects of ethephon [(2‐chloroethyl) phosphonic acid] on yield and yield components of rainfed barley in arid (150 mm rainfall) and semiarid (346 mm) regions, the present study was conducted during the growing seasons of 1999–2001. Ethephon was applied at the tillering, stem elongation and flowering stages. Acomparison of the effect of ethephon on rainfed and irrigated barley performed at the semiarid location in the following season confirmed the results. Ethephon decreased grain yield when sprayed at tillering and stem elongation compared with the later flowering stage for both the arid and semiarid locations. All arid‐location barley plants had lower grain yields than the semiarid‐location plants. There was a reduction in spikes m?2 in the tillering and stem elongation stage sprayings compared to the control for both locations. In the semiarid and arid locations no difference in earliness (50 % heading) was observed between spraying times but ethephon always delayed heading. All arid‐location plants were earlier than semiarid‐location plants. However, when ethephon was used with supplementary irrigation it was found to increase grain yield, spikes m?2 and earliness.  相似文献   

17.
Drought during the pre‐flowering stage can increase yield of peanut. There is limited information on genotypic variation for tolerance to and recovery from pre‐flowering drought (PFD) and more importantly the physiological traits underlying genotypic variation. The objectives of this study were to determine the effects of moisture stress during the pre‐flowering phase on pod yield and to understand some of the physiological responses underlying genotypic variation in response to and recovery from PFD. A glasshouse and field experiments were conducted at Khon Kaen University, Thailand. The glasshouse experiment was a randomized complete block design consisting of two watering regimes, i.e. fully‐irrigated control and 1/3 available soil water from emergence to 40 days after emergence followed by adequate water supply, and 12 peanut genotypes. The field experiment was a split‐plot design with two watering regimes as main‐plots, and 12 peanut genotypes as sub‐plots. Measurements of N2 fixation, leaf area (LA) were made in both experiments. In addition, root growth was measured in the glasshouse experiment. Imposition of PFD followed by recovery resulted in an average increase in yield of 24 % (range from 10 % to 57 %) and 12 % (range from 2 % to 51 %) in the field and glasshouse experiments, respectively. Significant genotypic variation for N2 fixation, LA and root growth was also observed after recovery. The study revealed that recovery growth following release of PFD had a stronger influence on final yield than tolerance to water deficits during the PFD. A combination of N2 fixation, LA and root growth accounted for a major portion of the genotypic variation in yield (r = 0.68–0.93) suggesting that these traits could be used as selection criteria for identifying genotypes with rapid recovery from PFD. A combined analysis of glasshouse and field experiments showed that LA and N2 fixation during the recovery had low genotype × environment interaction indicating potential for using these traits for selecting genotypes in peanut improvement programs.  相似文献   

18.
《Soil Technology》1994,7(3):209-220
The effects of selected soil management practices (conventional tillage, tied ridges and crop residue mulching) on soil moisture conservation in a semi-arid area of Kenya were studied during the short rains period, 1988, and long rains period, 1989. Three treatments, mulching, tied ridges and conventional tillage with three replications of each practice under a completely randomized block design, were used in the study. Nine experimental plots, each 4 m × 10 m were set up on a slope of 2%. During the study period, soil moisture was monitored on a weekly basis using the neutron probe at predetermined depths to a maximum depth of 120 cm. Calibration of the neutron probe was done for the soil at two depth ranges: 0–90 cm and 90–120 cm. The need to calibrate the probe for the 90–120 cm depth arose due to the presence of iron concretions within this depth range. The results obtained from this study showed that overall, crop residue mulching did result in more moisture down the profile throughout the two seasons within 2 years than the other two tillage practices. The tied ridged plots had the lowest amount of soil moisture in the soil profile during the two seasons. Thus the application of surface crop residue mulch seems to be the best soil management practice for increased soil moisture conservation and improved crop performance in rainfall marginal areas of Kenya.  相似文献   

19.
Sustainable farming practices can be beneficial or detrimental to crop production in the short-term, which will strongly determine their appeal to farmers. We evaluated the effects of several sustainable practices on soil properties, plant nutrition and ecophysiology and crop yield in a semiarid agroecosystem. A three-year randomised experiment was conducted in a rainfed almond grove where the initial soil management was reduced tillage. Two alternative treatments were evaluated: reduced tillage plus green manure and no-tillage. The following soil and plant parameters were measured once per year: soil organic carbon, total nitrogen and Polsen; foliar N, P, δ13C and δ15N and crop yield. We found that soil bulk density increased significantly with no-tillage. Leaf δ15N was positively associated with soil fertility, foliar nutrient concentrations and crop yield across treatments. Leaf δ13C, Nfoliar and crop yield were strongly positively associated across treatments in every year of the study. Reduced tillage treatments displayed higher leaf δ15N, δ13C, Nfoliar and crop yield than the no-tillage treatment, indicating a sharp decrease in the leaf nitrogen status and intrinsic water use efficiency of almond trees during the transition from reduced tillage to no-tillage. In semiarid agroecosystems where soils are prone to compaction, some tillage is required to maintain optimal crop production in rainfed almonds.  相似文献   

20.
秸秆覆盖对农田土壤水分及玉米生长的影响   总被引：8，自引：0，他引：8  
秸秆覆盖的土壤剖面含水量与裸地显著不同,与前者相比,裸地土壤水分无明显的层次性变化,受降水及蒸发等因子影响明显。由于覆盖状况和土壤物理性质不同,土壤水分变化幅度也有明显差异,秸秆覆盖土壤水分含量较高,玉米拔节期0~40cm土层达到18%。苗期根长小并主要分布在0~30cm土层,孕穗期和灌浆期根长大大增加,主要分布在0~60cm和0~90cm土层。秸秆覆盖可以显著地增加土壤水分利用率和蓄水量,促进玉米根系生长,提高玉米单产32.1%。  相似文献   

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