树木树冠阴影面积与种植间距的编程计算分析研究

主要是利用计算机编程软件Microsoft Visual C++6.0和现有的天文学公式以及对公式的分析计算处理,对决定树木所投射阴影大小起决定性因素的太阳方位角和太阳高度角进行编程化求解。然后根据所得出的实时数据和树木树冠模型化分析,最终计算得出不同的经纬度在某一时刻树木的投影面积,为果树等的合理种植间距分析提供依据。     

豫西地区行距配置对夏玉米产量及其构成因素的影响

为明确豫西地区夏玉米最优行距,以郑单958为试验材料,设置2个密度(82 500株/hm2和97 500株/hm2)和5个行距(宽+窄)配置[60 cm+60 cm(CK)、70 cm+50 cm、80 cm+40 cm、90 cm+30 cm、100 cm+20 cm,宽窄行种植],研究行距配置对高产条件下玉米产量及其构成因素的影响.结果表明,2个密度条件下均以80 cm+40 cm(宽+窄)行距配置产量最高.随密度增加,对照茎粗降低0.1％,单株叶面积减小2.1％,单株干物质量减小16.3％,空秆率增加1.8个百分点,80 cm+40 cm处理空秆率最小.宽窄行处理随着宽行距的逐渐增加,穗位叶SPAD值呈先增加后减小的趋势.密度增加,稳位叶SPAD值减小.因此,在豫西地区夏玉米种植条件下,建议种植密度为82 500株/hm时,采用80 cm+40 cm处理的种植行距;密度为97 500株/hm2时,采用80 cm+40 cm处理或50 cm+70 cm处理的种植行距,以利于玉米高密度群体植株的生长和最终产量的提高.     

Maize (Zea mays L.) Grain Yield Response to Methods of Nitrogen Fertilization

ABSTRACT

In the developing world, fertilizer application is commonly achieved by broadcasting nutrients to the soil surface without incorporation. A commonly used nitrogen (N) source is urea and if not incorporated, can sustain N losses via ammonia volatilization and lower crop yields. This study evaluated the effect of planting, N rate and application methods on maize (Zea mays L.) grain yield. An experiment with a randomized complete block design (nine treatments and three replications) was established in 2013 and 2018 in Oklahoma. The planting methods included; farmer practice (FP), Oklahoma State University hand planter (OSU-HP), and John Deere (JD) mechanical planter. Side-dress N application methods included; dribble surface band (DSB), broadcast (BR), and OSU-HP. Nitrogen was applied at the rate of 30 and 60 kg ha^?1 as urea and UAN at V8 growth stage. On average, planting and applying N at 60 kg ha^?1 using OSU-HP resulted in the highest yield (11.4 Mg ha^?1). This exceeded check plot yield (5.59 Mg ha^?1) by 104%. Nitrogen application improved grain yield by over 57% when compared to the 0-N check (8.77 Mg ha^?1). Mid-season N placement below the soil surface using OSU-HP makes it a suitable alternative to improve grain yield.     

Comparative performance of three small seed tuber sizes and standard size seed tubers planted at similar stem densities

Summary Small seed tubers of 1–5 g, 5–10 g and 10–20 g were planted at the same sprout densities as standard size seed tubers of 40–60 g in order to give similar stem densities. Early ground cover by foliage, total yield, and yield of tubers >45 mm were consistently greater in plots planted with larger seed tubers. The effect of seed tuber size on yield and tuber number per stem varied between years but 1–5 g seed tubers always gave lower yields per stem than larger seed tubers. Reducing the spacing between rows from 90 cm to 60 cm and maintaining the same sprout density was more effective in increasing yields from small seed tubers than increasing sprout density from 20 to 40 sprouts per m² by reducing plant spacing within the row.     

Effects of Ratio of Row Spacing to lntrarow Spacing on Yield and Nitrogen Accumulation and Utilization of Early and Late Rice

Objective] The aim was to provide a theoretical basis for the rational configuration of ratio of row spacing to intrarow spacing (RS/lS) of double-cropping rice. [Methods] With early rice ‘Ganxin 203’ ...     

果树栽植机光电定株距装置的设计与试验

针对果树栽植过程中株距难以控制的问题,考虑到现有的果树栽植机定株距存在结构复杂、制造成本高及受土壤滑移率影响较大等问题,设计了一种光电定株距装置,可以避免土壤滑移率对株距的影响,保证栽植果树株距的一致性,且可实现株距连续可调,满足不同果树栽植时对株距选择的要求。针对试验中出现的部分株距较设计值有所偏差的问题,分析了原因并提出了优化方案。试验结果表明:果树栽植机光电定株距装置栽植合格率92.5%,平均栽植深度合格率为92.9%,在1.7m栽植株距下,株距变异系数为5.9%,满足现代标准果园机械化生产要求。     

A dual-spectral camera system for paddy rice seedling row detection

A new method is presented for detecting rows of rice seedlings to facilitate the navigation of rice transplanters. Generally, an independent NIR or RGB camera is used as a vision sensor for agricultural vehicles; however, strong reflections on the water surface make row detection more difficult in flooded paddy fields compared to dry fields. To solve this problem, we developed a dual-spectral camera system that consists of a pair of low-cost monochrome cameras with optical filters. Different wavelength images of the same location can be taken simultaneously in real-time. An experiment conducted under cloudy conditions showed that this system could reduce water surface noise and clearly detect seedling rows.     

行距配置对大穗型品种兰考矮早八旗叶氮代谢酶活性、籽粒产量及蛋白质含量的影响

在大田高产栽培条件下。研究了行距配置对大穗型冬小麦品种兰考矮早八花后旗叶硝酸还原酶活性、谷氨酰胺合成酶活性、籽粒产量、蛋白质含量及单位面积蛋白质产量的影响。结果表明,15cm行距处理下,旗叶在灌浆中后期具有较高的氮代谢酶活性。籽粒产量随行距减小而增加,而籽粒蛋白质含量却减小,籽粒蛋白质产量与籽粒产量表现相同趋势。因此,适当缩小种植行距,降低了籽粒蛋白质含量,但有利于提高籽粒产量和单位面积蛋白质产量。     

不同初植密度的桉树人工林经济效益分析

通过分析1993年设立于广西东门林场的桉树人工林5种造林密度(1)2 222株·hm-2、(2)1 667株·hm-2、(3)1 250株·hm-2、(4)883株·hm-2和(5)667株·hm-212年的生长数据,计算了连年生长量、平均生长量、材种出材量、净现值和内部收益率.结果显示,6.3 a前5种密度蓄积生长量的差距达到极显著水平,8.3 a以后差异就不再显著;密度2 222株·hm-2、1 667株·hm-2和1 250株·hm-2的数量成熟均为6 a,密度883株·hm-2为6.5 a,密度667株·hm-2为7 a;造林密度越大,纸浆材的出材比例越高,而大、中径材出材比例越小,造林密度小,锯材和旋切材的出材比例更高;密度2 222株·hm-2、1 667株·hm-2、1 250株·hm-2、883株·hm-2和667株·hm-2的轮伐期分别为6 a、7 a、7 a、7 a和8 a,这时的净现值分别是17 661、18 457、22 257、24 755和24 007元·hm-2,内部收益率分别为56%、50%、55%、58%和51%;密度883株·hm-2有最高的净现值和内部收益率,是5种密度中最好的造林密度,其他从大到小的顺序是密度667株·hm-2、1 250株·hm-2、1 667株·hm-2和2 222株·hm-2.     

Fruit production and quality improvement in aonla （Emblica Officinalis Gaertn.） through canopy management

In order to maintain the health and vigour and to sustain the productivity, a pruning experiment was conducted on four year old ＂Balwant＂ cultivar of aonla grown in laterite soil, planted at a spacing of 5m×5m. To find out the best pruning method, six levels of pruning was performed i.e., （1） Light judicious pruning, （2） Detopping of primary branches at 8 feet from ground level ＋ removal of all secondary branches, （3） Detopping of primary branches at 8 feet from the ground level ＋ removal of all secondary branches at 2 feet from the base of primary branches, （4） Detopping of primary branches at 8 feet from the ground level ＋ removal of all secondary branches at 1 feet from the base of primary branches, （5） Light judicious pruning ＋ Detopping of plant canopy of at 8 feet from the ground level, （6） No pruning （control）. Results of three consecutive years of investigation revealed that light judicious pruning of thin, overlapping, criss-crossed, dead, unproductive and looping branches gave highest fruit yield in all the three years and resulted 64.4 percent yield increment over control when average of three years was considered. Severe pruning of primary and secondary branches caused drastic reduction of yield for two consecutive years after pruning. Judicious pruning helped to produce better sizeable and quality fruits.