Response of Cotton to Irrigation Methods and Nitrogen Fertilization: Yield Components,Water‐Use Efficiency,Nitrogen Uptake,and Recovery

Efficient crop use of nitrogen (N) fertilizer is critical from economic and environmental viewpoints, especially under irrigated conditions. Cotton yield parameters, fiber quality, water‐ and N‐use efficiency responses to N, and irrigation methods in northern Syria were evaluated. Field trials were conducted for two growing seasons on a Chromoxerertic Rhodoxeralf. Treatments consisted of drip fertigation, furrow irrigation, and five different rates of N fertilizer (50, 100, 150, 200, and 250 kg N /ha). Cotton was irrigated when soil moisture in the specified active root depth was 80% of the field capacity as indicated by the neutron probe.

Seed cotton yield was higher than the national average (3,928 kg/ha) by at least 12% as compared to all treatments. Lint properties were not negatively affected by the irrigation method or N rates. Water savings under drip fertigation ranged between 25 and 50% of irrigation water relative to furrow irrigation. Crop water‐use efficiencies of the drip‐fertigated treatments were in most cases 100% higher than those of the corresponding furrow‐irrigated treatments. The highest water demand was during the fruit‐setting growth stage. It was also concluded that under drip fertigation, 100–150 N kg/ha was adequate and comparable with the highest N rates tested under furrow irrigation regarding lint yield, N uptake, and recovery. Based on cotton seed yield and weight of stems, the overall amount of N removed from the field for the drip‐fertigated treatments ranged between 101 and 118kg and 116 and 188 N/ha for 2001 and 2002, respectively. The N removal ranged between 94 and 113 and 111 and 144 kg N/ha for the furrow‐irrigated treatments for 2001 and 2002, respectively.     

干旱对不同地力水平、不同品种小麦生育性状及产量的影响

在相同的水分条件下 ,对不同地力水平、不同品种小麦的生育性状及产量进行比较。研究结果表明 ,小麦品种 9350 31在高肥力条件下表现突出 ,鲁麦 2 1适应性广 ,在中、低肥力地块上表现最佳     

花椰菜新品种—丰花60

‘丰花６０’为秋中早熟花椰菜一代杂种，成熟期约６０ｄ，花球组织致密，雪白细嫩，平均单球重０．５７－０．９０ｋｇ，产量３００００ｋｇ／ｈｍ＾２，比对照品种白峰增产２６．９％－４８．３％，生长势强，抗病性好。     

科学养狐 走出困境

本文详细介绍了新源良种狐繁育场引进国内外科研成果，改良提高国产蓝狐质量，加大科技投入，保持和发挥优良种狐的遗传潜力和抓好基础建设，提高饲养管理的科技含量的成功经验。     

吉林省肉牛品种选择与开发利用初探

结合我省肉牛生产发展的实际，从未来牛肉消费市场需求和进一步开发的可能，就肉牛品种的选择、建立肉牛杂交配套系和配套系的品种组合等方面进行了探讨。     

柚矮化病的品种感病性调查

以特征性症状春梢叶片扭曲畸形和枝条茎陷点为诊断依据，调查结果表明，５５个柚类品种中有２２个发病，占调查品种数的４０％；２８个沙田柚砧穗组合中有２２个发病，占调查砧穗组合数的７８．５％。以沙田柚实生苗和酸柚实生苗作指示植物，对温州蜜柑上的类似矮化病的叶片扭曲症状进行鉴定的结果，指示植物上表现出与接种沙田柚矮化病病原的指示植物相似的春梢叶片扭曲及茎陷点症状。     

浅谈早稻生产的几个问题

要夺取早稻生产的持续增产,扩大早稻种植面积,选择适宜品种,选准栽培方式,培育健壮秧苗,建立高产群体是五项关键措施。     

兰旗榆——一个在干旱草原区很有发展潜力的造林树种

兰旗榆为白榆的一个地理生态变种,在锡盟浑善达克沙地及其南缘的镶黄旗、正镶白旗、正兰旗等地区生长表现突出。该树种较之其它的白榆品种具有抗旱、抗寒、抗风沙,物候期早,所需积温低以及生长迅速等优良特性,对我区北部干旱草原气候生态条件适应能力强,在草原造林中有着其它树种不可替代的地位和作用,建议大力推广。     

福建省桐棉松区域栽培试验

初步试验表明：桐棉松能够适应福建省地理生境且具抗逆性，生长迅速；同当地马尾松生长相比，树高生长差异达极显著水平，地径生长差异达显著水平；在海拔800m以下，海拔因子对树高生长有一定影响，但未达显著水平。     

黑龙江省大豆品种数据库建模

从种子推广人员、育种工作者、农户等多种人员需求的角度,对黑龙江省育成大豆品种信息进行了分析,将大豆品种信息归纳为品种来源、产量表现、特征特性、栽培要点、审定情况等内容,按照软件工程学和数据库原理,建立了大豆品种数据库模型,绘制了实体关系图。依据此图可以在Microsoft SQL或其他数据库软件下建立物理的数据库,建立良好的查询,为农业生产等应用提供服务。