宽垄沟播种植模式对夏玉米生长发育及水分利用率的影响

探讨水地条件下种植模式对夏玉米产量及水分利用的影响,为夏玉米节水种植高产稳产栽培提供依据。以玉米品种"登海685"为试验材料,研究宽垄沟播和等行距平播模式下不同种植密度(6.00,6.75,7.50万株/hm~2)对夏玉米生长发育、产量、养分吸收及水分利用率的影响。结果表明:沟播种植模式较平播增加玉米植株株高,使茎粗和单株干物质重降低。沟播模式的穗性状比平播处理较优,单穗重增加,且受种植密度影响较小,表现出明显的边行优势。沟播模式的玉米叶片叶绿素相对含量始终高于平播处理,生育期延长,为后期籽粒形成提供了物质保障。在种植密度为7.50万株/hm~2时,沟播模式夏玉米产量最高。沟播模式下夏玉米灌水量较平播减少52.9%,灌水时间减少50.1%,日均蒸发量减少,且水分含量高于平播处理,使灌溉水利用效率提高139.5%,水分利用效率平均提高16.7%。可见,宽垄沟播是夏玉米增产增效的一种节水种植模式,明显提高玉米水分利用效率。     

株行距配置连作对黄土旱塬覆膜春玉米土壤水分和产量的影响

探讨株行距配置调整后密度对旱地覆膜春玉米连作稳产和水分利用的影响,为旱地雨养区春玉米高产稳产栽培提供依据。试验于2014—2017年在黄土旱塬区甘肃省镇原县(35°30′N,107°39′E)进行,以紧凑型耐密高产春玉米品种"先玉335"为试验材料,设55,75 cm 2种等行距垄沟覆盖种植方式,6.0,7.5,9.0,10.5万株/hm~2 4个种植密度水平,采用裂区设计,连作定位观测。使用烘干法测定不同处理春玉米生育期0—200 cm土层土壤水分,研究黄土旱塬连作春玉米籽粒产量和土壤剖面水分变化。结果表明,在试验设计行距下,在干旱年份55,75 cm行距0—200 cm土层土壤剖面水分均有低湿区形成,2种行距40—200 cm土层最低含水率均出现在160 cm土层剖面,55 cm行距土壤含水量为8.9%,75 cm行距土壤含水量为8.7%,受降水及植株生育耗水的影响,20—120 cm土层土壤水分变化较为剧烈。不论降水年型如何,2种行距下0—200 cm土壤深层水分均未产生土壤干层,75 cm行距低湿区较55 cm行距随年份变化有不同程度扩大,但2种行距下7.5～10.5万株/hm~2相同密度耗水量没有显著差异。4年平均产量75 cm行距相同密度均高于55 cm行距,9.0万株/hm~2及以下种植密度处理稳产性较好,密度由低到高产量分别增加2.2%,5.8%,4.1%和3.0%,平均水分利用效率分别提升1.1%,5.9%,0.3%和-1.5%,不同行距相同密度产量和水分利用效率没有显著差异。研究表明,在黄土旱塬区55,75 cm行距配置7.5万株/hm~2种植密度连作具有稳定产量,并且不会导致土壤深层水分亏缺至产生土壤干层,是较为理想的连作稳产株行距配置种植模式。     

Relationships between Doses and Application Methods of Phosphorus and Corn Nutrition Status and Grain Yield

The broadcast application of phosphate fertilizers may be more effective than localized application methods for the growth of corn in medium textured oxisol, which have lower phosphorus (P) adsorption capacity. This study aimed to evaluate three phosphate fertilizer application methods at five different doses onto corn grown in oxisol, over two seasons. The experiment was conducted on corn crops in Passos city, Minas Gerais state, Brazil. Stripes with split plots were used to investigate the different application methods where each plot represented double furrow, single furrow, or broadcast application. Within the sub plots, the five doses (0.0, 50, 100, 200, and 400 kg ha^?1) of phosphorus pentoxide (P₂O₅) as granulated monoammonium phosphate (MAP) were applied. Four replications were used. The doses were reapplied in the second cultivation year only for the localized treatments (single and double furrow). The nitrogen in the MAP was held constant among treatments. The corn grain yield in both years was dependent upon both dose and application method, primarily for the single furrow and broadcast methods. In the first year, the broadcast application method of P fertilizer at a estimated dose of 319 kg ha^?1 of P₂O₅ provided a greater accumulated yield over two seasons. Broadcast application is therefore a viable method for growing corn with a reduced spacing distribution on medium textured oxisol.     

2ZGK-6型可调宽窄行高速水稻插秧机设计与试验

针对我国水稻生产存在类型品种多、土壤水肥条件差异大,现有水稻插秧机作业行距固定,难以满足水稻生产对插秧行距的要求等问题,研究设计了2ZGK-6型可调宽窄行高速水稻插秧机,其插秧宽行距为300 mm,窄行距为200~300 mm,可以调节。该机器是在久保田SPU-68C型高速水稻插秧机基础上研制而成,根据插秧行距可调要求,确定了关键结构参数,并设计了正反向双螺旋行距调节机构、偏心轮锁紧装置和分体组合式秧箱等关键部件。样机田间试验结果表明:该机作业性能良好,伤秧率小于2.5%,漏插率小于3%,相对均匀度合格率大于96%,漂秧率小于2.5%,翻倒率小于2.5%,插秧深度合格率大于92%,均符合《水稻插秧机技术条件》(GB/T 20864-2007),满足实际生产要求,提高了水稻生产率和机械化水平。     

Optimum rate of nitrogen fertilization for drip-irrigated wheat under semi-arid conditions

Limited water availability in arid and semi-arid wheat production systems increases the need of applying efficient drip irrigation systems. However, there is little information available about the optimum level of nitrogen (N) fertilization for drip-irrigated wheat. A two-years field study in the semi-arid region of Upper Egypt was carried out in a randomized complete block design to investigate the response of drip-irrigated wheat to three levels of N fertilization (N₁₂₀ = 120, N₁₈₀ = 180, and N₂₄₀ = 240 kg ha^?1). N₂₄₀ increased the uptake of N, P, and K by 66.3, 48.6, and 43.5%, respectively, as compared to N₁₂₀. The application of N₂₄₀ increased the grain yield by 28.4 and 40.4% and water use efficiency by 27.6 and 41.8% the first and second season, respectively, as compared to N₁₂₀. Based on the obtained results, it is recommended to fertilize drip-irrigated wheat by 240 kg ha^?1.     

大垄宽窄行免耕种植对土壤水分和玉米产量的影响

为了解决东北玉米小垄原垄免耕播种机具易掉入垄沟的问题,发挥宽窄行优势,加强农机农艺结合,该文提出了大垄宽窄行错茬免耕播种的作业思路。于2007－2009年在辽宁省苏家屯区垄作保护性耕作建立试验区,研究了大垄宽窄行免耕种植对土壤体积质量、土壤含水率、作物生长及水分利用效率的影响。试验结果表明：大垄宽窄行免耕种植模式能够改善土壤结构,增加土壤蓄水保水能力,其中在出苗期提高土壤水分9.39%～11.03%;与均行小垄免耕种植模式相比,大垄宽窄行免耕种植模式改善了玉米群体结构,促进了个体发育,增加了叶面积指数和干物质积累,作物产量提高了6.70%～9.49%,土壤水分利用效率提高了4.96%～8.56%,是东北地区一种较为理想的保护性耕作模式。     

栽培方式对玉米根系生长及水分利用效率的影响

为进一步明确我国西北地区全膜双垄沟播玉米栽培技术的增产机理,为干旱半干旱地区玉米高产栽培提供理论与技术支持,2008—2009年采用田间试验方法,研究了7种不同栽培方式对陇东地区旱地玉米根系时空分布、产量及水分利用效率的影响。结果表明:不同栽培方式下玉米根系长度和根干重均随生育期的推进逐渐增加,且随土层的加深呈逐渐下降趋势。其中,全膜双垄沟播等行距种植模式0~150 cm土层玉米根系长度显著大于半膜双垄沟播、常规地膜覆盖和露地种植模式(P<0.05);120~150 cm土层根长百分比表现为全膜双垄沟播撮苗种植模式最大,全膜双垄沟播等行距种植模式次之,露地种植模式最小;根干重主要集中在0~30 cm土层,且垄沟>垄中,全膜双垄沟播>常规覆膜>半膜双垄沟播,等行距种植>撮苗种植;与半膜双垄沟播、常规地膜覆盖和露地种植模式相比,全膜双垄沟播等行距种植玉米籽粒产量分别提高17.72%、22.01%和47.00%,水分利用效率分别提高6.41%、18.54%和43.57%,是陇东地区旱作玉米的最佳栽培方式。     

Okra Crop Response Under Subsurface Drip and Conventional Furrow Irrigation with Varying N Fertilization

ABSTRACT

There is a growing concern about excessive use of nitrogen (N) and water in agricultural system with unscientific management in Indian and developing countries of the world. Field experiments were conducted on the lateritic sandy loam soils of Kharagpur, West Bengal, India, during spring–summer (February-June) seasons for three years (2015–2017) to evaluate okra crop response under subsurface drip and conventional furrow irrigation with varying amount of nitrogen treatments. Irrigation treatments had three levels of soil water depletion from field capacity (i.e., 20%, 35%, and 50%) under subsurface drip system. There was no soil water depletion under conventional furrow irrigation system. There were four levels of nitrogen fertilizer treatments (i.e., 0, 80, 100, and 120 kg ha^?1). This was supplied using urea as a nitrogenous fertilizer. The yield response of okra crop under subsurface drip was found to be 56.4% higher than that of the furrow irrigation treatment. Best yield response and maximum water use efficiency and nitrogen use efficiency were recorded under 20% soil water depletion with 100 kg ha^?1 of nitrogen fertigation. Among the various soil moisture depletions, subsurface drip at 20% soil water depletion treatment responded least quantity of water lost through deep drainage and nitrogen loss beyond the root zone as compared to other irrigation treatments. The water loss through subsurface drainage was observed as 33.11 mm lesser under subsurface drip as compared to that of the furrow irrigation, and this may due to low-volume and frequent irrigation water application with subsurface drip. Hence, irrigation through subsurface drip should be used for improving water and nitrogen fertilizer use efficiency of okra crop cultivation.     

行距及密度影响玉米密植潜力的干物质累积和产量构成机制

空间布局是决定玉米密植潜力的重要因子,但有关行距配置对不同密度玉米产量及其构成因素的调控研究比较薄弱,使得生产实践中缺乏通过行距配置优化挖掘玉米密植潜力的理论依据。2017-2018年,在带宽相同条件下,研究了7∶3(L1:宽行56 cm∶窄行24 cm)、6∶4(L2:宽行48 cm∶窄行32 cm)、5∶5(L3:行距配置均为40 cm)3种行距配置对5种密度(D1:82 500株·hm~(-2)、D2:90 000株·hm~(-2)、D3:97 500株·hm~(-2)、D4:105 000株·hm~(-2)、D5:112 500株·hm~(-2))玉米产量及其构成因素的影响。行距配置、密度及二者的互作效应显著影响玉米籽粒产量, L1行距配置较L3增产5.2%～10.5%,增幅显著; D2、D3密度处理分别较D1密度处理增产6.1%～12.0%、6.5%～15.0%(P0.05), L1D3、L2D3产量较L3D1提高了8.3%～34.2%、4.8%～27.5%(P0.05), L1D3的增产效果最好,说明宽窄行种植增强了玉米植株的耐密性,提高了玉米群体的密植潜力。宽窄行结合密植有利于提高玉米的生物产量,其中L1行距配置较L3提高3.0%～6.6%(P0.05),D3密度较D1密度高3.4%～8.0%(P0.05), L1D3较L3D1处理提高5.2%～15.0%(P0.05)。宽窄行种植提高玉米密植潜力的原因是:1)提高了玉米生长后期(大喇叭口期至灌浆期)的干物质累积速率,该时期玉米的干物质累积速率L1行距配置较L3提高32.9%～42.0%, D3密度较D1密度高9.2%～23.9%, L1D3处理较L3D1处理高29.1%～34.3%,增幅均显著; 2)提高了光合产物向穗部的转移, 2017年度玉米收获指数D3密度较D1密度高6.4%, L1D3处理较L3D1处理高16.2%,2018年无显著差异;3)提高了玉米的成穗数和穗粒数,D3密度的成穗数较D1密度高16.0%～20.2%,L1D3较L3D1成穗数高16.9%～25.9%,L1行距配置较L2、L3穗粒数分别高3.0%～4.4%、3.9%～7.0%,提高幅度均显著。56 cm∶24 cm宽窄行结合密度97 500株·hm~(-2)是绿洲灌区获得高产,密植潜力充分发挥的理想种植模式。     

适宜机械收获株行距对黄土旱塬春玉米产量及水分利用效率的影响

通过黄土旱塬适宜机械化收获的不同株行距种植模式,研究不同株行距对春玉米产量和水分利用效率的影响,为该春玉米生产力提升提供理论依据。以紧凑型高产先玉335为供试品种,设置适宜机械化收获的55cm和75cm两种行距,通过株距调整设置6.0万株/hm~2,7.5万株/hm~2,9.0万株/hm~2,10.5万株/hm~2共4种栽培密度,于2014年和2015年连续2年定位试验,研究株行距对春玉米生长发育及水分利用效率的影响。结果表明:与55cm行距相比,75cm行距在干旱条件下能够有效延缓叶片衰老,成熟期依然具有较高的SPAD值、叶面积和叶面积指数,持绿性良好,为光合产物提高给予了支撑。不同株行距种植模式WUE表现不同,吐丝期WUEF基本随密度增加而增大,2种行距下2014年和2015年均是9.0万株/hm~2,10.5万株/hm~2密度处理WUEF较高;收获期2014年55cm行距9.0万株/hm~2,10.5万株/hm~2密度处理WUEH较高,75cm行距7.5万株/hm~2,10.5万株/hm~2密度处理WUEH较高,2015年2种行距下均为6.0万株/hm~2,10.5万株/hm~2密度处理WUEH较高。产量水分利用效率WUEY,55cm行距变化无规律,75cm行距随密度增加而增大。55cm行距和75cm行距均可以作为黄土旱塬区春玉米机械化收获种植行距,综合土壤水分变化、叶面积指数、SPAD值、收获指数、产量及水分利用效率等,75cm行距7.5万株/hm~2种植密度可以作为紧凑型春玉米试验区域内最佳株行距设置。     

Effect of nitrogen application on growth and yield of pumpkin

Evaluation of any crop response to different nitrogen amounts is important for determining the amount that can be considered as optimum from economical and environmental point of view. This study was conducted to (1) evaluate the growth and yield of pumpkin (Cucurbita pepo L.) under different nitrogen rates and (2) determine the nitrogen use efficiency (NUE) of pumpkin in two growing seasons (2013 and 2014). In both growing seasons, nitrogen fertilizer (at three rates including 50, 150, and 250 kg ha^?1) was band-dressed on the planted side of each furrow, coinciding with 4–6 leaves stage and flowering. Crop performance over 2 years was evaluated by measuring shoot dry matter, crop growth rate (CGR), leaf area index (LAI), leaf area duration (LAD), intercepted PAR (PAR_i), radiation use efficiency (RUE), shoot nitrogen uptake, water use efficiency (WUE), NUE, and fruit and seed yield. The results showed that in both growing seasons, the highest growth and yield of pumpkin were obtained by applying 250 kg N ha^?1 (using urea fertilizer containing 46% nitrogen). Increased nitrogen rate from 50 to 250 kg ha^?1 resulted in 87.3%, 27.0%, 62.1%, 87.5%, and 84.5% increase in shoot dry weight, RUE, WUE, fruit yield, and seed yield of pumpkin, respectively, across both growing seasons. However, higher application nitrogen rate decreased the NUE of pumpkin, i.e., the NUE decreased by 62.5% when the nitrogen rate increased from 50 to 250 kg ha^?1. The effect of nitrogen applied in 2014 growing season on growth and yield of pumpkin was higher than that in 2013 growing season, which might be due to more suitable weather condition. In conclusion, the nitrogen rate of 250 kg ha^?1 produced the highest amount of fruit and seed yield in pumpkin.     

Influence of staggered sown Spring sunflower (Helianthus Annuus L.) at varying intra–row spacing and applied–N on pre– and post–anthesis N dynamics and dry matter partitioning in Indo–Gangetic Plains Region

In current study, dry–matter accumulation (DMA), pre– and post–anthesis nitrogen (N) accumulation, N translocation (NT) and dry–matter partitioning by sunflower seeds was investigated under three sowing dates (January 20, February 10 & March 2), two intra–row spacings (30 & 24 cm) and four nitrogen doses (0, 45, 60 & 75 kg ha^–1) in two alluvial soils. Early sowing resulted in higher DMA and NT; leading to higher nitrogen use efficiency (NUE) that could be associated with higher pre–anthesis N accumulation. The closer intra–row spacing resulted in higher DMA by all plant parts except seed. Each graded N dose improved DMA, but improvement in dry–matter partitioning to seed was significant up to 60 and 75 kg N ha^–1 during 2014 and 2015, respectively owing to higher NT under respective treatments. NUE was highest at 60 kg N ha^–1 during both years.     

两种生态条件下氮素调控对不同栽培方式水稻干物质积累和产量的影响

以Ⅱ优498水稻为试材,在温江和汉源两种生态条件下,研究了不同施氮量及氮肥运筹方式对宽窄行、三角形、扩行减株稀植和抛秧栽培等4种栽培方式水稻干物质积累、产量及构成因素的影响。结果表明,各栽培方式在两地最佳施氮量均为N 180 kg/hm2。在此施氮量下,宽窄行和三角形栽培氮肥运筹措施以基肥:蘖肥:穗肥比例为6:3:1最佳,扩行减株稀植栽培方式以5:2:3最佳,抛秧栽培温江点和汉源点分别为4:1:5和5:2:3最佳。不同栽培方式在温江点均可通过适宜的氮肥调控,提高群体颖花量和生物产量而获得高产;汉源点三角形栽培通过适宜的氮肥调控措不仅生物产量极显著提高,还维持了较高的收获指数（HI）,增产潜力显著高于其他栽培方式。此外,宽窄行栽培较扩行减株稀植栽培具有一定的边际效应,生态条件和氮肥调控措施的改变对其物质积累和产量的影响与后期群体大小和温光条件有关;抛秧栽培抽穗前干物质生产优势明显,在不同生态条件下采取适宜的氮肥后移措施来提高其抽穗后的干物质积累是其高产的关键。     

Water use efficiency of rice (Oryza sativa L.) under intermittent ponding and different intensity of puddling

Abstract

To increase the water use efficiency (WUE) of rice, two sets of experiments were carried out from 1997 – 1999. Experiment one: Irrigation period of rice was divided into three stages: early (S₁, 10 – 35 days after transplanting, [DAT]); middle (S₂, 36 – 60 DAT) and late (S₃, 61 – 85 DAT). Intermittent ponding (IP) was imposed at single, two stages or the entire growing period. Continuous ponding (CP) in all three stages was taken as control. Though the highest grain yield (6.71 mg ha^?1) was obtained under control, this regime was responsible for the lowest WUE. In contrast, IP in all stages was responsible for maximum WUE with minimum yield level. Imposition of IP in S₁ resulted in higher (0.529 kg m^?3) WUE along with insignificant reduction in yield over control. Experiment two: Three puddling practices were: (i) High intensity puddling (HIP); (ii) Moderate intensity puddling (MIP); and (iii) Low intensity puddling (LIP). On average, HIP resulted in the lowest value (6.5 mm d^?1) of percolation rate. Both grain yield (6.93 mg ha^?1) and WUE (0.597 kg m^?3) attained highest value under HIP. A decrease in puddling intensity under MIP and LIP lowered the yield by 2.97 and 17.75% respectively. In the case of WUE, the reduction was 16.27 and 54.66%.     

Nutrient uptake and use efficiency of onion seed yield as influenced by nitrogen and phosphorus fertilization

Abstract

The experiment was conducted at Kulumsa, South East Ethiopia, using four levels of nitrogen (N) (0, 50,100 and 150?kg N ha^?1) and four levels of phosphorus (P) (0, 35, 70 and 105?kg P₂O₅ ha^?1) fertilizers arranged in 4?×?4 factorial arrangements in randomized complete block design with three replications. The available P was increased after harvest due to the application of N and P fertilizer at the rates of 100 or 150?kg N ha^?1 and 70 or 105?kg P₂O₅ ha^?1. More specifically, nutrients concentration and nutrient uptake were significantly (p?<?.01) varied among treatment combinations and nutrient use efficiency was declined by increasing N and P after optimum rates. The higher physiological efficiency of N (53.47?kg kg^?1) and P (580.41?kg kg^?1) and the highest apparent recovery of N (19.62%) and P (2.47%) was recorded from application of 50?kg N ha^?1 and P at 70?kg P₂O₅ ha^?1 and the highest agronomic efficiency of N (10.78?kg kg^?1) and P (15.25?kg kg^?1) was recorded from N at the rate of 50?kg N ha^?1 and P at 35?kg P₂O₅ ha^?1, respectively. The combination of N at 100?kg N ha^?1 and P at 70?kg P₂O₅ ha^?1 was promising combination that generated highest net benefit 488,878.5 ETB (Ethiopian birr) ha^?1 with the highest marginal rate of return (36638%) and gave the highest seed yield (1858.82?kg ha^?1) with yield increment of about 57.72% over the control.     

Sustainable production of pigeon pea and sarpagandha (Rauvolfia serpentina) by intercropping

Sarpagandha (Rauvolfia serpentinaBenth. Ex Kurz.), a natural source of the alkaloid reserpine, is generally found growing under partial shade of deciduous forests in the tropics and subtropics. To promote its commercial cultivation under subtropical environment of the north Indian plains, a field trial was conducted during 2006–2009 to optimize the plant populations (row ratios) of pigeon pea and sarpagandha for higher productivity, land utilization efficiency and economic return in an intercropping system. Intercropping of two rows of sarpagandha with pigeon pea sown at a row distance of 90 cm proved highly beneficial in terms of total production (5.15 t ha^?1 grain and 10.27 t ha^?1 straw + stalk of pigeon pea and an additional dry root yield of 2.56 t ha^?1 of sarpagandha) from a unit area and time. The highest land equivalent ratio, LER (2.21), area time equivalent ratio, ATER (1.76), monetary equivalent ratio, MER (2.0), land-use efficiency, LUE (198%) and net return (Rs. 273,810 ha^?1) were obtained for the combination of pigeon pea and sarpagandha in 1:2 row ratio. Integration of two rows of sarpagandha as an intercrop with pigeon pea sown at 90 cm row distance is recommended for sustainable crop production.     

Efficacy of starter N fertilizer and rhizobia inoculant in dry pea (Pisum sativum Linn.) production in a semi-arid temperate environment

ABSTRACT

Uncertainties exist about the importance of rhizobia inoculant and starter nitrogen (N) application in dry pea (Pisum sativum L.) production. Three field experiments were conducted to evaluate how rhizobia inoculant and starter N fertilizer affect pea seed yield and protein concentration in a semi-arid environment in central Montana. Commercial rhizobia inoculant was mixed with seed prior to planting at the manufacturer’s recommended rate. Starter N fertilizers were applied into the same furrow as seed at 0, 22, 44 and 88 kg ha^?1 as urea, slow-release polymer-coated N fertilizer (ESN), and a combination of both. The application of rhizobia inoculant had no or a very small beneficial effect on pea yield in lands with a previous history of peas. In a land without pea history, application of rhizobia increased pea seed yield by 16%. The positive effect of starter N was only pronounced when initial soil N was low (≤ 10 kg ha^?1 nitrate-nitrogen), which increased net return by up to US$ 42 ha^?1. In this condition, application of slow-release N outperformed urea. However, application of starter N (especially with urea) had a negative effect on pea establishment, vigor and seed yield when soil initial N was high (≥ 44 kg ha^?1 NO₃-N). The results indicate that the rate, placement and form of the starter N must be optimized to benefit pea yield and protein without detrimental effects on germination and nodulation. Moreover, application of starter N must be guided by the soil nitrate content.     

Effect of soil water management and different sowing dates on maize yield and water use efficiency under drip irrigation system

A 2-year field experiment (2012–2013) was conducted to evaluate the yield and water use efficiency (WUE) response of maize (Zea mays L.) to different soil water managements at different sowing dates. The experiment included three sowing dates (22 June, 6 July and 21 July) and four irrigation regimes based on maximum allowable depletion (MAD) of the total available soil water (TAW). The irrigation treatments were marked by I₁ to I₃ as 40%, 60% and 80% MAD of TAW, respectively, and with no irrigation. The results showed that grain yield reduced when planting was delayed in both years, ranging from 6105 to 4577 kg ha^?1 in 2012 and from 7079 to 5380 kg ha^?1 in 2013. However, WUE increased when planting was delayed from 22 June until 21 July. Also the highest grain yield was observed in the first irrigation treatment (MAD = 40%) in both years, and the highest WUE was obtained in the second irrigation treatment (MAD = 60%) with 1.64 and 1.61 (kg m^?3) in 2012 and 2013, respectively. These findings suggest that delay in planting date and the use of MAD = 60% treatment in Mediterranean-type region such as Golestan, Iran, can be useful in saving water that is highly important in such regions.     

行距和行向对不同密度玉米群体田间小气候和产量的影响

"浚单20"是目前我国种植面积较大的紧凑性高产玉米品种。为充分发挥该品种在安徽种植区域的高产潜力, 开展了种植密度、行距和行向三者相配置的田间试验, 在60 000株·hm^-2和67 500株·hm^-2两种种植密度下, 研究了不同行距和行向对"浚单20"的田间小气候和玉米产量的影响。结果表明: 随着行距增大, 玉米群体内部的日均风速和日均光照强度逐渐增大, 累计积温和日均相对湿度则呈下降趋势。在同一种植密度和行距条件下, 东西行向种植比南北行向种植的玉米群体日均风速较大、日均光照强度较高、累计积温较低和日均相对湿度较小, 且产量高。同一种植行向, 不同种植密度和行距配置条件下, 玉米产量差异达显著水平(P<0.05)。其中种植密度为60 000株·hm^-2, 东西行向种植, 行距为50 cm时, 玉米群体结构较为合理, 所形成的田间小气候较有利于"浚单20"的生长发育, 籽粒产量达到10 582.5 kg·hm^-2。通过研究阐明了行距、行向和密度三者不同配置所形成的田间小气候与玉米产量形成的关系, 为提高"浚单20"在安徽省的种植水平提供指导。     

Nitrogen rate applied affects dry matter translocation and performance attributes of wheat under deficit irrigation

Crop production in arid/semi-arid regions is restricted by soil moisture and nitrogen (N) deficiencies. Consequently, sufficient levels of N and irrigation are important in improving the crop's productivity. Therefore, a 2-year field experiment was conducted to understand influences of watering techniques namely 300, 500 and 700 mm with contrasting N supply (0, 60, 120 and 180 kg ha^?1) on wheat cv. “landrace” productivity, dry matter translocation (DMT) and contribution of pre-anthesis assimilates to the grain (CPAAG, %). Experiments were conducted each year using a split-plot design with three replications at a private farm, North Hamedan Province, Iran. Accordingly, when 500/700 mm water was applied, CPAAG values were higher than those obtained after applying 300 mm water, i.e. 49.99 and 45.45 vs. 40.13%. The highest productivity in terms of grain yield, grain N concentration, nitrogen harvest index, special products analysis division and protein content was achieved in normal deficiencies of irrigation and N. This was further supported by a higher leaf area index, crop growth rate and N uptake of such treatment. Meanwhile, co-application of 120 kg N and 500 mm water significantly improved DMT, water and N use efficiency, and it was the optimal scheme for wheat production.