近自然生态条件下千年桐竞争关系的研究

以近自然生态条件下千年桐直播造林林分为研究对象,研究其种内种间竞争关系。结果表明：直播造林林分中千年桐胸径＜8 cm时,千年桐种内竞争较弱,胸径在8～13 cm时,其竞争指数增长特别快,种内竞争非常大;当胸径＞13 cm时,种内竞争指数逐渐减少;其种间竞争中与杉木的竞争最为强烈。千年桐种内竞争与距离的关系表现为当其距离＜1.0 m时,其竞争指数最高,种内竞争最为激烈;距离在2.0～3.5 m时,种内竞争指数较为稳定;当其距离超过3.5 m后,千年桐种内竞争指数逐渐变小,竞争强度逐渐减弱。     

农村互联网发展对中国玉米全要素生产率的影响

采用DEA-mamlquist指数测算2004—2019年中国17个玉米主产省(区)的全要素生产率,运用联立方程组模型实证检验农村互联网发展对玉米全要素生产率的影响及其作用机理,并分区域探讨其差异性。结果显示:2004—2019年中国玉米全要素生产率年均增长0.2%,主要依靠技术进步的单轨模式驱动。农村互联网的发展显著(P<0.01)提升玉米全要素生产率,主要依靠技术进步和技术效率的协同作用驱动。分区域来看,农村互联网发展对玉米全要素生产率均具有显著(P<0.01)的促进作用,其影响程度由高到低依次为北方春播玉米区>黄淮海平原夏播玉米区>西北灌溉玉米区>西南山地玉米区。建议进一步提高农村互联网的配套设施建设,发挥互联网“连接经济”的优势,应用多元化互联网技术,促进不同生态类型区玉米生产效率的提升。     

200CS伴能在直播水稻上施用效果试验研究

Perennial live paddy planting rice on the basis of conventional fertilization, by basal + can, tillering, closed herbicide + company + can, can (20% less nitrogen) basal + partner, 100% of nitrogen in the whole stages base + can with different processing, performance from the growth of rice, rice tillering, leaf chlorophyll value, yield and increasing costs, unit yield inceement, VCR, etc, with increasing can improve rice leaf chlorophyll content, promote rice tillers, makes the rice growth, significantly increase rice yield and output value, according to labor saving, has demonstrated and value.     

玉米单交种豫玉27号高产栽培措施研究

采用单因素随机区组设计对豫玉27号（原名洛单94-1）进行密度试验，结果表明：该品种对密度具有广适性，适宜种植密切为45000-75000株/hm^2。采用N、P、K三因素旋转组合设计，通过计算机模拟寻优，建立了豫玉27号的产量-施肥量数学模型；分析了N(x1)、P(x2)、K(x3)的主效应及交互效应与产量的关系，它们对产量的影响大小依次为N、P、K。筛选出玉米产量大于等于108000kg/hm^2的最优方案为：N393.15-399.15kg/hm^2、P2O5171.90-175.05kg/hm^2、K2O167.25-174.60kg/hm^2，其比例为：2.3：1：1。     

热带种质在北方早熟春玉米改良中的利用

选用甸骨11A及其导入不同的热带种质及不同的比例和热带种质占25%比例姊妹系共9份材料,以早大黄、红玉米为测验种,采用二因素试验设计,测定了甸骨11A热导系杂交组合的产量和对照优势、农艺性状及自交系农艺性状。结果表明:同一自交系在不同的测验种间表现不同。若用“甸骨11A×早大黄”模式则采用Evt5导入甸骨11A选系效果较好;若用“甸骨11A×红玉米”模式,则用Suwan1导入甸骨11A选系杂交种产量高。Suwan1导入甸骨11A的比例以12.5%～50.0%为宜,其中25%的导入比例综合效果较理想。在Suwan1导入甸骨11A占25%的3个姊妹系间,其杂交种产量和农艺性状及自交系本身的主要性状均有较大差异,表明在导入遗传基础较广泛的热带种质的选系中,保持一定数量的姊妹系是有益的。     

基于APSIM模型的不同施肥处理下春玉米产量模拟及气候敏感性分析

以平凉市泾川县大田试验为基础,利用农业生产系统模拟模型,探究不同类型施肥处理对春玉米产量的影响以及气候变化对春玉米产量影响的敏感性差异,分析APSIM模型对模拟该地区春玉米产量的适应性。结果表明,APSIM模型对该区域春玉米产量的模拟效果较好,决定系数(R²)介于0.934～0.975,归一化均方根误差(NRMSE)介于6.073%～9.758%,模型一致性指标(D)介于0.952～0.987。模型敏感分析显示,年平均温度是模拟不同施肥处理下春玉米产量的敏感参数,其变化程度对模拟结果影响较大,不同施肥处理(CK、N、NP)下的敏感指数分别为0.533 2、0.558 7和0.568 2。     

糯玉米杂交种产量及主要农艺性状相关分析

试验选用自育的20个糯玉米杂交种为供试材料,采用随机区组设计。通过对鲜穗采收期和成熟期产量、穗长、穗粗、穗行数、行粒数、株高、穗位高等性状进行相关和通径分析。结果表明,在鲜穗采收期,穗长、双穗率、百粒重、出籽率等性状均与鲜穗产量呈正相关,作用最大的因素是穗长(r=0.600 0**)。通径分析显示各性状对鲜穗产量作用大小顺序为双穗率>穗长>百粒重>出籽率>穗位高>行粒数>穗粗>株高。在完熟期,行粒数(r=0.504 2*)、穗粗(r=0.495 9*)与干子粒产量呈正相关,达显著水平,进一步通径分析表明,各性状对干子粒产量作用排序为行粒数>穗位高>穗粗>穗长>秃尖长。     

Spatial variability in the growth of direct-seeded rainfed lowland rice (Oryza sativa L.) in northeast Thailand

Large within-field variation in rice growth often causes production loss in broadcast-seeded (BC) rainfed lowland rice. The spatial variability of direct-seeded rainfed lowland rice was evaluated in 2004, 2005, and 2007 in on-station experiments at Ubon Ratchathani, northeast Thailand, in relation to soil water content and weed infestation, by adopting semivariogram and block kriging, including comparisons among BC with harrowing (BCH; no weeding), BC with no harrowing (BCNH; no weeding), and row-seeded (RS; interrow weeding once) fields. BCH and BCNH were also compared in 11 farmers’ fields in 2006 and 2007, to assess the effect of harrowing on rice growth and weed infestation. During most of the rice growing periods, flooded and non-flooded portions existed simultaneously in the fields, with different proportions among years and among seeding methods in the on-station experiment. BCH and BCNH rice had large within-field variation in seedling density, heading date, shoot dry matter, grain yield, harvest index, panicle density, and filled spikelet per panicle, as well as in weed infestation, measured by a quick visual estimation. Many of the measured variables (except mean soil water content in RS in 2007, seedling density in BCH in 2005 and 2007, shoot dry matter in BCH and BCNH in 2007, and panicle density in BCH in 2007) were spatially dependent (i.e., data from nearby locations were most similar) by geostatistical analysis. Analysis of correlations using the 420 data sets of BCH plots in 2005 and BCH, BCNH, and RS plots in 2007 revealed a positive correlation between soil water content and grain yield and negative correlations between weed infestation and soil water content and grain yield. Compared with BCH, in 2007 BCNH had much lower grain yield because of lower soil water content after establishment and more weed infestation. BCH had higher grain yield than BCNH in weedy fields in the farmers’ fields experiment. RS with interrow weeding resulted in a smaller coefficient of variation, smaller sill value, and higher grain yield than BCH, due to less weed infestation and a higher proportion of flooded water. These results indicated that reducing the spatial variability in rice growth requires careful field preparation, such as harrowing to level the soil surface and to reduce the uneven distribution of standing water and the variability in soil water content, combined with effective crop and weed management (i.e., harrowing and row-seeding). This is the first study that examined spatial variability in the growth of direct-seeded rice as a function of soil water content and weed infestation in a rainfed lowland environment.     

株行配置对春玉米根冠空间分布及产量的影响

以先玉335为试验材料,设置7.50万株/hm2和9.75万株/hm2两个种植密度,60 cm+60 cm等行距和40 cm+80 cm宽窄行两个行距配置,比较株行配置对春玉米冠层、根系结构与功能及产量的影响。结果表明,随种植密度增加,果穗、茎鞘干重百分比垂直分布明显上移,叶片干重百分比在垂直分布变化较小,行距配置对果穗、茎鞘干重百分比在垂直分布上影响较小。相对于等行距种植,宽窄行种植叶片干重百分比有下移趋势,群体不同叶位叶面积指数也表现为同一密度下,宽窄行种植群体上层LAI较小,穗位叶高效叶层LAI较大;随密度增加,根重有纵向下移的趋势,根系TTC还原强度在不同土层深度都显著降低。同一密度下,宽窄行种植根重的垂直分布出现下移趋势,根系TTC还原强度略高于等行距种植。高密度条件下,宽窄行种植降低了玉米果穗秃尖长,显著增加果穗穗粒数,因而显著提高产量,增产2.73%~10.86%,说明在宁夏扬黄灌区较高种植密度下,采用宽窄行种植能优化不同叶层结构,适当增加深层土壤根系所占比例及活力,有利于获得高产。