Puddling, irrigation, and transplanting-time effects on productivity of rice–wheat system on a sandy loam soil of Punjab, India

Rice–wheat productivity in irrigated tract of the Indo-Gangetic plains is constrained by water and energy limitations. In order to minimize unproductive soil water evaporation and percolation loss at a field scale, management practices include soil puddling, water-economizing irrigation schedule, and matching growth cycle with periods of low evaporative demand. This 3-year field study examines combined effects of these options on rice–wheat productivity and water-use efficiency (WUE) and energy-use efficiency (EUE) on a sandy loam soil in an irrigated semi-arid sub-tropical environment. Treatments included combinations of three puddling intensities, viz., one (P₁), two (P₂), and four (P₄) runs of a tine cultivator in ponded water after a common pre-puddling tillage; with two irrigation regimes, viz., continuous submergence (I₁) throughout the growing season, and intermittent submergence (I₂) with continuous submergence for 2 weeks after transplanting followed by 2-day interval between successive irrigations, and two transplanting dates, viz., first fortnight of June (D₁) and end June (D₂) to impose variation in seasonal evaporative demand. Residual effect of puddling in rice on succeeding wheat was also evaluated during the 3 years.

Intensive puddling and water-economizing schedule caused a significant reduction in seasonal percolation loss primarily due to puddling-induced changes in soil bulk density and hydraulic behavior. Increasing puddling intensity from P₁ to P₂ enhanced mean rice yield by 0.2–0.3 Mg ha⁻¹, but additional puddling did not improve yield significantly. Mean grain yield increase with I₁ over I₂ ranged between 0.3 and 0.6 Mg ha⁻¹. Interaction effect between puddling and irrigation indicate that yield benefit with I₁ over I₂ was greatest in P₁ regime (0.6 Mg ha⁻¹), and the effect decreased with increase in puddling intensity. Delayed transplanting caused a decline of 0.3–0.5 Mg ha⁻¹ in rice yield. Although maximum yield was realized with combination of P₂ or P₄ regime with I₁ regime, but water-use efficiency was greater with I₂ compared to I₁ regime by 1.1 kg ha⁻¹ mm⁻¹ in 2000 and by 0.3 kg ha⁻¹ mm⁻¹ in 2001. It indicates that yield gain with additional irrigation were not commensurate with additional water input. Energy analysis also showed that energy-use efficiency was 6.8, 7.2, and 6.6 kg kWh⁻¹ for P₁, P₂, and P₄ regimes suggesting that yield gain with P₄ did not match energy input for additional puddling. Further, there was a greater risk of yield reduction of succeeding wheat with P₄ (by 0.2–0.3 Mg ha⁻¹) compared to P₁ or P₂ regime.     

栽插密度对水稻产量及品质的影响

试验结果表明,适宜的栽插密度有利于产量和稻米品质的提高。栽插密度主要通过水稻的群体结构来影响产量,对其品质的影响,以垩白米粒率、垩白度、直链淀粉含量、整精米率及蛋白质含量等影响较大,在试验范围内(7.5￣25.5万丛/hm2),栽插密度与垩白米粒率、垩白度、直链淀粉含量呈显著线性负相关;与整精米率呈倒二次曲线分布关系;与蛋白质含量接近线性正相关。从优质高产兼顾的角度考虑,在浙江地区的生态条件下,单季杂交籼稻的栽插密度以16.5￣21.0万丛/hm2为宜。     

新型高密度灌木幼苗移栽机仿真与试验研究

针对裸根灌木幼苗具有根系软、乱,股头多等特点,已有的链夹式移栽机不能满足小行距高密度移栽要求的问题,提出了一种可用于株距小于200mm、行距小于160mm,10行同时推进的新型灌木幼苗移栽机械。对高密度灌木幼苗的移栽工艺研究后,设计了移栽机栽植机构、放苗机构、起垄机构、旋耕机构及悬挂系统,并进行传动系统仿真,仿真表明,移栽机的传动系统达到移栽过程中设计要求。设计了一种的新型开沟器,且根据开沟器的实际受力特点,运用离散元技术和有限元分析技术对其进行仿真,仿真实验表明：开沟器的强度满足强度要求。对新型移栽机的物理样机进行现场移栽试验,试验结果表明,该移栽机能高效的解决根系软、乱,股头多的裸根灌木幼苗的移栽问题,并且平行排布,除草方便,适合小行距高密度移栽。 幼苗的植入深度（移栽深度）达7-12厘米,直立度达800-900, 移栽苗成活率达90%以上。     

蚯蚓粪基质对机插秧秧苗素质的影响

[目的]研究蚯蚓粪基质对机插秧秧苗素质的影响,为寻找适宜培育健壮机插秧的基质配方及机插秧的有效推广提供技术支持。[方法]设5个处理:处理1,蚯蚓粪∶营养土=1∶0;处理2,蚯蚓粪∶营养土=2∶1;处理3,蚯蚓粪∶营养土=1∶1;处理4,蚯蚓粪∶营养土=1∶2;处理5,蚯蚓粪∶营养土=0∶1,测定指标包括出苗期、根长、根数、白根数、叶长、苗高、根鲜重、根干重、茎粗。[结果]利用蚯蚓粪∶营养土=1∶1的配比最适宜机插秧秧苗素质的形成,秧苗的发根数量、根长、白根数、根鲜重和干物质积累均呈最佳状态。[结论]采用蚯蚓粪与营养土有机结合,是培育优质机插秧的重要途径,其最适宜的配比为1∶1。     

基于MATLAB的移栽机械臂运动学分析与仿真

为了实现对四自由度移栽机械臂的精确控制,采用D-H法建立机械臂的连杆坐标系和运动学方程,实现了机械臂运动学正解。根据移栽机械臂的特点及参数,用解析法求得移栽机械臂的运动学逆解。运用MATLAB中的Robotics Tool-box工具箱对移栽机械臂进行运动学仿真,验证了所求得的正解和逆解。     

南方芦笋组培苗移栽技术研究

以芦笋新品种“津宁”的生根组培苗为试验材料,通过移栽基质、基质消毒措施、生根培养类型及移栽时期对芦笋组培苗移栽成活率影响的研究。结果表明：在南方,冬、春两季采用二步生根法培养的生根组培苗,选用椰糠作为移栽基质、200g/m3根病治杀菌剂进行消毒处理,移栽成活率可达95.20%~99.25%。     

不同插秧密度和施肥量对水稻新品种丹粳17号产量及其产量性状的影响

[目的]探求丹粳17号合理的密度和施肥量。[方法]设计4种插秧密度3种施肥量,采用随机区组设计进行田间试验,对不同密度、不同施肥量对产量及其性状的效应进行分析。[结果]密度对产量、穴成穗数和穗粒数具有显著影响,随着密度的增加穴成穗数增加,穗粒数减少,但产量不一定增加,产量受穗数和穗粒数的共同作用。施肥量则主要影响结实率,从而影响产量。随着施肥量的增加,结实率降低,产量降低。密度和施肥在产量、成穗率、株高、结实率和穴成穗数上表现出较明显的互作效应。[结论]实际生产中可以针对特定的密度采用相适应的施肥量。     

不同移栽深度对烤烟翠碧一号生长及抗逆性的影响

[目的]为寻找福建三明烟区生态条件下特色烤烟品种翠碧一号采用湿润育苗技术所育烟苗较为适宜的移栽深度.[方法]探讨翠碧一号湿润育苗烟苗浅栽、适度深栽和过度深栽对烤烟生长及抗逆性的影响.[结果]适度深栽有助于烟株早生快发,烟株根系发达,株型合理,田间整齐度较高,烟株生长较为老健,抗逆性有所提高,有助于提高烟叶的产量和产值,但对均价、上等烟比例及烟叶内在化学成分影响不明显.[结论]福建三明烟区生态条件下烤烟翠碧一号采用湿润育苗技术所育烟苗较为适宜的移栽深度约15 cm.     

不同组培方式对花生子叶离体组培获得再生苗影响的研究

花生栽培种在长期的种植过程中,往往由于多种因素的影响,造成种性退化,产量下降,品质变劣,抗病(逆)性降低,为了保持花生品种的固有特性,利用植物的组织培养技术,以花生种仁中的子叶作为外植体,采用MS培养基,附加不同种类和浓度的激素,进行愈伤组织的诱导培养,获得再生组培苗,再用不同的基质种植组培苗,搬到室外炼苗,约15d后移栽至大田。试验结果以混合NAA和2,4-D的培养基诱导率最高,达81%,基质以蛭石∶腐土=1∶1的幼苗成活率最高,达91%,幼苗室外移栽的最佳时期是3月份;大田定植期为4月上旬。     

移栽期对烤烟叶片组织结构的影响

采用石蜡切片的方法对烤烟龙江911的叶片解剖结构进行了研究,旨在通过比较不同移栽期 烤烟叶片厚度、栅栏组织厚度、海绵组织厚度等指标探索烤烟移栽期和成熟度的关系。研究结果表 明:移栽期对于叶片解剖结构的影响很大。3个移栽期相比,5月1日移栽的烤烟中部叶片厚度、栅栏 组织、海绵组织、细胞空隙度最大,各部位叶片差异达极显著水平;5月10日和5月20目的烤烟下 部叶最厚,叶片厚度随叶位的上升而变薄,各部位之间差异不显著。