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1.
Drought stress is an important factor limiting the yield potential of peanut. In order to determine the effect of different irrigation scenarios on peanut production, field experiments were conducted in 2011 and 2012 growing seasons using factorial design with three replicates. On the other hand, the crop simulation models can be useful to predict crop yields and to investigate the impact of drought stress on plant growth and development. In this study, the Cropping System Model–Crop Growth (CSM-CROPGRO)-Peanut model was employed for the simulation of seed yield, pod yield, biomass, soil water balance components and water productivity for peanut in Astaneh-Ashrafiyeh, Iran. Results showed that the model was able to reasonably simulate seed yield, pod yield and final biomass for different irrigation scenarios (RMSEn < 20%, R2 > 0.8 and d > 0.8). According to the results, irrigation depth and interval were important factors affecting yield and biomass. In general, model error increased as the amount of water applied decreased. The least amount of water applied (40 mm) resulted in yield reductions by 76%, 70% and 67% of the greatest amount of water applied (480 mm) for seed yield, pod yield and final biomass, respectively. For each irrigation interval, larger irrigation depth led to lower water productivity (WP) of irrigation (WPI), but higher WP based on evapotranspiration (WPET) and transpiration (WPT).The average amounts of WPI, WPET, WPT based on seed yield were 1.2, 0.63 and 1.01 kg m?3, respectively.  相似文献   

2.
Agriculture is the major consumer of water and it is possible to decrease water consumption in this sector by proper irrigation scheduling. Irrigation scheduling is based on crop water requirements. Saffron is an important crop in Iran. The main purpose of this study was to determine the potential evapotranspiration and crop coefficient for saffron using single and dual crop coefficients, in Badjgah region, College of Agriculture, Shiraz University, Shiraz, Iran. Three water-balance lysimeters were used for this experiment in a two-year study. Total saffron potential evapotranspiration values were 523 and 640 mm in the first and second growing seasons, respectively. The maximum evapotranspiration rates for saffron were 4.5 and 6.1 mm d?1 in the first and second growing seasons, respectively. Based on the results of this study, different saffron growing stages for evapotranspiration were 30, 40, 70 and 60 days. Crop coefficient (K c) values for the initial, mid- and late-season growth stages were 0.41–0.45, 0.93–1.05 and 0.29–0.31 in both years, respectively. Basal crop coefficient (K cb) values for the initial, mid- and late-season growth stages were 0.15–0.16, 0.41–0.65 and 0.15–0.17 in both years, respectively.  相似文献   

3.
Dualex and SPAD are devices developed for the purpose of testing crop nitrogen (N) status. These instruments were used in a wheat experiment in order to compare their respective performance in assessing leaf nitrogen (N) concentration, response to N topdressing application, soil nitrate (NO3)-N levels and in predicting grain yield. The experiment included different N rates in 2005 and 2006 in the Montérégie region of Quebec, Canada. Dualex readings correlated negatively with SPAD readings, leaf N concentration, soil NO3-N content and wheat grain yield. SPAD alone and the ratio of SPAD to Dualex measurements (Chl/Phen) were linearly related to N application rate but no effect of N application rate was found for individual Dualex parameters. However, both SPAD and Dualex readings were affected by year effects. The Dualex was also capable of indirect evaluation of in-season soil NO3-N accumulation and the prediction of wheat yield, but more so as Chl/Phen.  相似文献   

4.
To determine the effects of irrigation water salinity and leaching fraction on crop evapotranspiration (ETc), grain yield, straw yield, shoot sodium (Na), and chloride (Cl) concentrations of spring wheat (Triticum aestivum L.) cultivar ‘Onfarom 9,’ a pot experiment was conducted using saline soil with electrical conductivity of soil paste extract (ECe) of 13.2 dS m?1. A factorial experiment with a completely randomized design replicated seven times was used with three levels of saline irrigation water (4, 9, and 12 dS m?1) and four leaching levels (0, 17, 29, and 37%) included as the factors. The results showed that ETc significantly decreased as a result of an increase in irrigation water salinity (ECi) and decrease in leaching level. Crop evapotranspiration deficit and decreasing irrigation and drainage water effectively resulted in grain and straw yield reduction. Increase in ECi increased accumulation of Cl and Na in crop shoot, but application of leaching decreased this accumulation.  相似文献   

5.
ABSTRACT

Field experiments were conducted for 2 years in sandy loam soil, to study the direct effect of organic manures i.e. sewage sludge (SS), vermicompost (VC) and sesbania (SB) and chemical fertilizers on rice (Oryza sativa) and their residual effect on wheat (Triticum aestivum) grown in sequence in winter (Rabi) and summer (Kharif) season during 2015–2016 to 2016–2017 at Varanasi, Uttar Pradesh. Residual effect of organic sources of nutrients as SS, VC and SB were monitored up to fourth crop (II wheat) in sequence applied in conjunction with 75% recommended dose of fertilize (RDF). Among the nutrient sources, the maximum grain yield in I rice (4.89 t ha?1), II rice (4.95 t ha?1), was recorded in treatment T3 (100% RDF with S, Zn, B) whereas in I wheat (4.68 t ha?1) and II wheat (4.59 t ha?1), it was recorded in T4 (customized fertilizer). The maximum straw yield during all four crops was recorded in T3 (100% RDF with S, Zn, B) in rice and T4 (customized fertilizer) in wheat crop, which showed 25, 32, 23 and 28% increase over 100% RDF (T2). Application of 100% RDF along with S, Zn, B and customized fertilizer increased the total uptake of N, P, K, S and B and also in net returns and B:C ratio followed by organic treatments.  相似文献   

6.
ABSTRACT

Field experiments for six seasons (2008–2013) for present time slice (PTS; 2008–2013) and simulation studies for mid-century (MC; 2021–2050) were carried out to assess different planting dates, varieties and irrigation schedules in addressing the impact of climate change on grain yield and water use efficiency (WUE) in bread wheat (Triticum aestivum L.). During field experimentation, WUE (averaged over other treatment) was unaffected by planting date; however, it was 6% higher in late variety (V1) than early variety (V2). Simulation study suggested that in MC, increase in maximum and minimum temperatures compared to PTS would reduce wheat yield by 17–27%. In MC, WUE would be reduced by 14.8% due to shortening of crop duration (1–11 days). The reduction in WUE could be ascribed to relatively more reduction in yield (22%) than evapotranspiration (ET) (4%). The WUE in MC3 (2041–2050) was relatively more than MC1 (2021–2030) and MC2 (2031–2040) due to more yield and less ET. Delaying planting date of wheat crop by 15–30 days in this region emerged as the best adaptation measure to tackle climate change impact for sustaining yield and having higher WUE in MC.  相似文献   

7.
为精确测定、准确模拟阿克苏地区滴灌枣树腾发过程,基于大型称重式蒸渗仪测定枣树全生育期逐时及逐日腾发强度（ET）,利用水量平衡方程、PM公式及经典统计原理,分析不同时间尺度下叶面积指数（LAI）、气象因素[温度（I）、风速（V）、净辐射（Rn）]、表层土壤含水率（W）与枣树腾发强度的相关关系并建立预测模型。结果表明：枣树日内腾发强度呈单峰型变化趋势,夜间变化幅度较小且腾发贡献率低。枣树全生育期逐日腾发强度变化呈先增大后减小的趋势,花期的腾发强度最大,为4.42 mm·d-1;全生育期腾发总量为640.83 mm,其中花期和果实生长发育期耗水量占比较大,分别为38.61%和32.72%。在小时和日时间尺度上,影响腾发强度的主要因素不完全相同,且影响程度有所差异。综合考虑各影响因素,以萌芽期、花期、果实发育期为基础,分别建立以小时、日尺度下估算腾发强度的经验模型ET1（h）=0.153+0.004T+0.012V+0.176Rn+0.002W+0.067LAI、ET2（d）=-3.325+0.081T+0.163Rn+0.069W+2.089LAI,拟合度R2均在0.7以上,以果实发育期与成熟期数据对模型进行检验,纳什效率系数分别达0.63、0.80。经偏相关检验,冠层净辐射（Rn）对两种尺度的腾发强度均影响最显著,因此以枣树全生育期数据量为基础,仅建立冠层净辐射（Rn）与腾发强度的回归模型ET1（h）=-0.063 3Rn2+0.361 2Rn—0.003 7、ET2（d）=-0.018 3Rn2+0.684 7Rn–1.642 1,R2分别为0.704 7与0.743 6,可满足缺少数据支撑情况下的腾发过程估算。这些模型明确了阿克苏地区滴灌枣树腾发机制及影响程度,可为水分管理精准化提供计算基础。  相似文献   

8.
A pot experiment was conducted to investigate the effects of different water levels on water-use efficiency, yield and growth parameters of leek (Allium porrum L.) and was carried out in the practical research field of Ondokuz May?s University in Turkey. Different irrigation water levels were based on the weight changes of each pot and included 5 irrigation treatments [25% (I25), 50% (I50), 75% (I75), 100% (I100) and 118% (I118) times of consumed water]. Decreases in irrigation water resulted in decreases in plant height, stem diameter, leaf and stem fresh weights, leaf and stem dry weights and leaf area, but did not significantly affect leaf number or chlorophyll content. A yield-response factor of 1.26 was obtained, implying that the leek crop was sensitive to water stress caused by deficit irrigation. Comprehensive analysis of yield, water use efficiency, and evapotranspiration, the I75 treatment can be suggested for leek production in water-scarce regions.  相似文献   

9.
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10.
Nitrogen (N) and potassium (K) fertilization play a key role in forage crops and can significantly increase yields of ‘Marandu’ palisadegrass [Brachiaria brizantha (Hochst. exA. Rich.) Stapf.], one of the most important forage crops in Brazil. This study aimed to identify the concentrations of total N and K, nitrate (NO3?), and ammonium (NH4+), chlorophyll meter readings (SPAD), and nitrate reductase activity (At-RNA) required to maximize yield. Plants were grown in quartz substrate and treated with nutrient solutions that ranged from 2 to 33 mmol L?1 for N and 0.5 to 11 mmol L?1 for K. Dry matter production and At-RNA increased with increasing N and K supplies. SPAD readings correlated strongly with N leaf concentration and dry matter production and can be used to assess the N status of this species. The supply of N and K in the fertilization promoted high yield and adequate N and K concentration for plant metabolism.  相似文献   

11.
本文基于作物系数法并结合植被遥感信息(MODIS/NDVI),提出一种能反映作物空间分布和土壤供水差异信息的作物蒸散量估算模型。利用该模型得到2000—2013年华北平原冬小麦的蒸散量,模拟结果与遥感蒸散产品吻合度较高(R2=0.952,RMSE=1.3×107 m3),并分析了冬小麦蒸散量和灌溉耗水量的时空变化。结果表明:1华北平原冬小麦蒸散量呈南高北低的格局。基于250 m空间分辨率上来看,山东省、河南省的黄河灌区以及太行山前平原的冬小麦蒸散量可达400 mm以上,中部平原区冬小麦蒸散量350 mm,滨海一带蒸散量200 mm。2冬小麦灌溉耗水量与其蒸散量格局相一致。在太行山前平原、河南省和山东省的引黄灌区,灌溉耗水量可达250 mm以上;河北平原北部由于冬小麦种植比例较低,灌溉耗水量100 mm。3近14年河北平原北部冬小麦播种面积下降明显,区域灌溉耗水量减少,地下水位下降趋势得到明显缓解。本文提出的作物蒸散量估算模型能够较好地用于确定较大区域作物蒸散耗水量,并可应用于区域作物灌溉量的评估与管理中。  相似文献   

12.
A field study was conducted over two years on maize at Islam Abad Research Station at 34°7′42′′N and 46°27′23′′E and elevation of 1348 m a.s.l in Kermanshah Province, western Iran in order to compare the effects of different irrigation methods and treatments on irrigation water use efficiency, crop yield, yield response factor, pan and seasonal crop coefficients, and other maize parameters. The experiment was a complete randomized block design with three replicates. During the study, irrigation water was applied at 40, 60, 80 and 100% of the maize seasonal water requirement for different surface drip tape (SDT) treatments, and 100% only for conventional furrow irrigation treatments with and without soil and water monitoring. The results showed that by using the above-mentioned different drip tape and surface treatments with soil and water monitoring, maize seasonal irrigation water use savings of 81, 71, 61, 52 and 36% were achieved compared with local conventional furrow irrigation without any soil, water and root monitoring, respectively. The yield response factor (K y), seasonal crop (K c) and pan coefficient (K p) for maize were 0.80, 0.76 and 0.97, respectively.  相似文献   

13.
A 2-year field experiment (2013 and 2014) was conducted in calcareous soil (CaCO3 19.2%), on soybean grown under three irrigation regimes 100%, 85% and 70% of crop evapotranspiration combined with three potassium (K2O) levels (90, 120 and 150 kg ha?1). The objective was to investigate the complementary properties of potassium fertilizer in improving soybean physiological response under water deficit. Plant water status (relative water content RWC, chlorophyll fluorescence Fv/F0 and Fv/Fm), had been significantly affected by irrigation or/and potassium application. Potassium improved growth characteristics (i.e. shoot length, number, leaf area and dry weight of leaves) as well as physiochemical attributes (total soluble sugars, free proline and contents of N, P, K, Ca and Na). Yield and yield water use efficiency (Y-WUE) were significantly affected by irrigation and potassium treatments. Results indicated that potassium application of 150 and 120 kg ha?1 significantly increased seed yield by 29.6% and 13.89%, respectively, compared with 90 kg ha?1 as average for two seasons. It was concluded that application of higher levels of potassium fertilizer in arid environment improves plant water status as well as growth and yield of soybean under water stress.  相似文献   

14.
In the present study, the effect of buried straw (two levels; MS; buried straw layer and MN; no straw layer), nitrogen fertilizer (two levels: FH, 120 kg ha?1 and FL, 80 kg ha?1), and deficit drip irrigation with irrigation frequency of 2 days (two irrigation regimes: I50; 50% and I30; 30% of evapotranspiration) was investigated on a greenhouse-grown leafy cabbage for two consecutive seasons. The results indicated that in both the seasons, T5 (MNFHI50) gave higher yield when compared to all other treatments but it also utilized more water and fertilizer. On the other hand, with a 5–10% decrease in yield comparing to T5 (MNFHI50), T2 (MBSFLI50) and T4 (MSFLI30) saved 33% of fertilizer. T4 (MBSFLI30) also gave the highest water and fertilizer use efficiencies when compared to all other treatments. However, it was clearly noted that T4 (MSFLI30) treatment could save water and nitrogen without a significant decrease in fresh yield of Chinese cabbage. Hence, T4 (MsFLI30) is the recommended strategy to manage water and nitrogen fertilizer for getting optimal leafy cabbage plant growth and yield.  相似文献   

15.
Cereal cropping productivity in the Indo‐Gangetic Plain (IGP) of India is declining, which may be overcome by diversification, alternate crop establishment methods and mulching. This study was conducted to determine whether no‐till flat (NTF), permanent raised beds (PRB) and nontraditional ex situ mulching would improve crop and water productivity, economic profitability and soil biological properties in an irrigated maize (Zea mays)–wheat (Triticum aestivum) system (MWS). NTF systems produced 10% higher economic net returns compared with PRBs. Non‐traditional mulching (Sesbania, Jatropha and Brassica) increased yields by >10% and net returns by >12% compared with no‐mulch. The water saving in PRBs compared with NTF systems was 79, 94 and 173 mm/ha in maize, wheat and MWS, respectively. PRBs saved 29.2% of irrigation water and improved the MWS irrigation water productivity (WPI) by 24.5% over NTF. On average, mulching saved 23.8 mm/ha irrigation water over no‐mulch and improved WPI by 12.0%. PRBs with ex situ mulching produced wheat and maize equivalent system yields lower than NTF but improved WPI and soil biological properties. Jatropha and Sesbania mulching improved yield, water saving, WPI and system profitability. In limited irrigation and no crop residue availability conditions, Sesbania, Jatropha and Brassica vegetation material have potential applications for ex situ mulching under PRBs for water saving and NTF for productivity.  相似文献   

16.
This work examines the long-term effects of deficit-irrigation (DI) practices in almond crop (Prunus dulcis Mill.) in agronomical and physiological terms. The trial was conducted during four-year monitoring period (2014–2017), in an experimental orchard (SW Spain), subjected to three irrigation regimes; i) a full-irrigation treatment (FI), which received 100% of crop evapotranspiration (ETC); ii) a regulated-deficit irrigation (RDI50), which received 50% of ETC during the kernel-filling period; and iii) a low-frequency deficit irrigation (LFDI), that was subjected to continuous periods of irrigation-restriction defined in terms of threshold values of leaf-water potential (Ψleaf) during the kernel-filling period. During the water stress period, there were monitored Ψleaf, stomatal conductance (gs) and canopy temperature (TC). Significant improvements in terms of water-use efficiency were found, as no differences in terms of yield between FI and LFDI were found, leading to the conclusion that significant water savings (between 27 and 40%) can be achieved without compromising the yield. Moreover, threshold values of Ψleaf and thermal indicators were defined which will allow establishing future irrigation scheduling without compromising almond yield, especially when DI strategies are being applied.  相似文献   

17.
Maize （Zea mays L.）, a staple crop grown from June to September during the rainy season on the North China Plain, is usually inter-planted in winter wheat （Triticum aestivum L.） fields about one week before harvesting of the winter wheat. In order to improve irrigation efficiency in this region of serious water shortage, field studies in 1999 and 2001, two dry seasons with less than average seasonal rainfall, were conducted with up to five irrigation applications to determine evapotranspiration, calculate the crop coefficient, and optimize the irrigation schedule with maize under mulch, as well as to establish the effects of irrigation timing and the number of applications on grain yield and water use efficiency （WUE） of maize. Results showed that with grain production at about 8 000 kg ha^-1 the total evapotranspiration and WUE of irrigated maize under mulch were about 380-400 mm and 2.0-2.2 kg m^-3, respectively. Also in 2001 WUE of maize with mulch for the treatment with three irrigations was 11.8% better than that without mulch. In the 1999 and 2001 seasons, maize yield significantly improved （P = 0.05） with four irrigation applications, however, further increases were not significant. At the same time there were no significant differences for WUE with two to four irrigation applications. In the 2001 season mulch lead to a decrease of 50 mm in the total soil evaporation, and the maize crop coefficient under mulch varied between 0.3-1.3 with a seasonal average of 1.0.  相似文献   

18.
Swine lagoon sludge is commonly applied to soil as a source of nitrogen (N) for crop production but the fate of applied N not recovered from the soil by the receiver crop has received little attention. The objectives of this study were to (1) assess the yield and N accumulation responses of corn (Zea mays L.) and wheat (Triticum aestivum) to different levels of N applied as swine lagoon sludge, (2) quantify recovery of residual N accumulation by the second and third crops after sludge application, and (3) evaluate the effect of different sludge N rates on nitrate (NO3-N) concentrations in the soil. Sludge N trials were conducted with wheat on two swine farms and with corn on one swine farm in the coastal plain of North Carolina. Agronomic optimum N rates for wheat grown at two locations was 360 kg total sludge N ha?1 and the optimum N rate for corn at one location was 327 kg total sludge N ha?1. Residual N recovered by subsequent wheat and corn crops following the corn crop that received lagoon sludge was 3 and 12 kg N ha?1, respectively, on a whole-plant basis and 2 and 10 kg N ha?1, respectively, on a grain basis at the agronomic optimum N rate for corn (327 kg sludge N ha?1). From the 327 kg ha?1 of sludge N applied to corn, 249 kg N ha?1 were not recovered after harvest of three crops for grain. Accumulation in recalcitrant soil organic N pools, ammonia (NH3) volatilization during sludge application, return of N in stover/straw to the soil, and leaching of NO3 from the root zone probably account for much of the nonutilized N. At the agronomic sludge N rate for corn (327 kg N ha?1), downward movement of NO3-N through the soil was similar to that for the 168 kg N ha?1 urea ammonium nitrate (UAN) treatment. Thus, potential N pollution of groundwater by land application of lagoon sludge would not exceed that caused by UAN application.  相似文献   

19.
Irrigation of high‐value vegetable crops on sandy soils with poor water‐retention capacities may result in fertilizer nitrogen (N) displacement below the effective root zone prior to complete crop uptake. As a result, fertilizer N‐uptake efficiency (FUE) of vegetable crops is often relatively low, thereby increasing the potential risk of groundwater contamination. The objective of this study was to determine how time of exposure of the root zone to the N fertilizer (which is referred to as “fertilizer residence time” or t R), as related to irrigation management, affects N uptake, FUE, growth, and yield of bell pepper (Capsicum annuum L.). Plants were grown in PVC columns with 45 kg of soil equipped with a drainage valve in the bottom of the column. Weekly irrigation with dissolved fertilizers (potassium nitrate; KNO3) was applied 1, 3, or 7 d before weekly removal of residual soil N by leaching. Weekly N uptake rates were calculated by comparing total N recovery between unplanted (reference) and planted columns. At 77 d after planting, increasing the t R from 1 to 3 or 7 d increased the weekly N uptake from 1.4 to 10.8 and/or 13.3 kg N ha?1, respectively. Total calculated plant N accumulations were 19, 72, and 106 kg N ha?1 for the 1‐, 3‐, and 7‐d t R treatments, with overall FUE values being 8, 31, and 45%, respectively. It is concluded that during initial growth crop, uptake capacity is limiting, and more frequent (daily) fertilizer injection into the irrigation water may be required to enhance FUE. It is proposed also that via sound or innovative irrigation management practices, fertilizer retention in the root zone can be enhanced, thereby improving crop growth, yield, and FUE while reducing production cost and potential environmental impacts.  相似文献   

20.
Excessive nitrogen (N) fertilizer with improper split-application in small-scale farming is widespread for reducing N use efficiency and polluting the environment. The objective of this study was to develop a strategy for providing winter wheat with twice-topdressing N by quickly measuring the soil and plant N status. During the period 2009–2011, a field experiment was conducted for winter wheat cultivar Zhongmai-175 in the North China Plain. The mineral N (Nmin) pool at a soil depth of 0–90 cm and topdressing N twice, as total N supply, was gradually increased from 0 to 420 kg N ha–1 to mimic the farmers´ practices. Measurements with the Soil Plant Analysis Development (SPAD) meter were taken on the uppermost fully expanded leaf, and the SPAD index was expressed relative to SPAD readings of sufficiently fertilized plants. Grain yield exhibited linear-plus-plateau responses to total N supply with a significant difference between years, the r2 ranged from 0.73 to 0.94. With a basal N application of 30 kg ha–1, the soil Nmin at 0–90 cm supplemented by twice-topdressing N (1:1 ratio) at Zadoks growth stage (ZGS) 22–23 in early spring and ZGS 47–52 was required at 150–165 kg N ha–1 to achieve a maximum grain yield of 3.9–5.3 t ha–1. The SPAD index exhibited a strong exponential response to N supply irrespective of plant growth stage and year (r2 = 0.95–0.97); the value of 0.94 was critical in denoting N deficiency from sufficiency status. The N topdressing at ZGS 47–52 could be precisely modified/estimated by the equation y = 161.7–218x5.16, where x is the SPAD index. Since SPAD readings varied significantly from year to year, our study suggests that it might be difficult to precisely manage field N for winter wheat.  相似文献   

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