高产夏玉米施肥模型的初步研究

本试验应用二次回归通用旋转设计试验方法,研究了氮磷钾肥与夏玉米产量的关系,建立了数学模型,得出了各因素与产量的主次关系和双因素交互的产量效应。根据模型求极值找到了最高产量的施肥方案。利用微机模拟仿真试验,得到了指定产量水平的最优施肥方案。     

北方杂交粳稻产量性状分析

以辽宁省的13个杂交粳稻品种为试材,研究了产量性状与产量的相关性。结果表明:产量性状中,穗粒数是影响产量的主导因素,千粒重是影响产量的重要因素。穗长和二次枝梗数对产量影响大,株高对产量也有一定影响。     

水稻产量性状QTL的克隆研究及育种应用进展

提高稻谷产量是作物育种的主要目标之一。随着水稻全基因组测序的完成,近年来水稻产量性状QTL的克隆取得了快速的发展。本文简要介绍了水稻产量及其构成因子QTL克隆进展,分析了产量性状QTL的一些基本特点,并简述了产量性状QTL在育种中的应用情况。     

作物次生产量特性及其利用对策探讨

为了提高相关研究和生产管理的效率,本文探讨了非传统作物产量性状的特性及其利用研究对策,同时提出了作物原生产量（即一次形成,一造一次只收获的作物产量）和次生产量（即反复形成, 多次收获的作物产量）的概念, 并以橡胶树干胶产量为例,阐述了次生产量具有可反复合理收获胁迫（由收获引起的某种伤害）形成的产量特性;并探讨了采用收获胁迫诱导次生产量性状表现,以改进橡胶树产量评价方法或获取橡胶生产最佳经济效益等在相关研究和生产管理方面的对策。     

福优晚3的产量构成与栽培技术

通过调查福优晚3百亩示范片不同产量水平的产量构成因素,并进行了产量构成因素间的相关和通径分析,明确了决定福优晚3产量的首要因素是穗粒数,在此基础上提出了福优晚3高产栽培技术规程。     

西藏裸大麦品种产量及产量构成因素演变规律研究

对西藏 6 0年代以来审定通过的 15个品种进行品种比较试验 ,研究近 4 0年来裸大麦品种更换过程中产量和产量构成因素的表现和稳定性变化。结果表明 ,4 0年来 ,西藏裸大麦品种的平均产量提高了 5 0 84 % ,产量的提高是在保持一定的穗数和穗粒数的基础上增加了千粒重实现的。结合产量构成因素的演变 ,提出了今后西藏裸大麦产量育种的发展目标     

不同栽培措施对青贮玉米产量和营养品质的影响

采用随机区组设计和“3414”最优回归设计,研究青贮玉米不同种植密度、收获期和施肥水平对产量和营养品质的影响。结果表明：不同种植密度、收获期和施肥水平均极显著影响青贮玉米的产量和营养品质。其中,氮肥对青贮玉米的鲜、干生物产量的提高及青贮玉米营养品质、饲用价值的提高贡献最大,其次是磷肥,钾肥的影响较小。建立了氮、磷、钾肥和青贮玉米鲜、干生物产量,蛋白质产量,中、酸性洗涤纤维产量,脂肪产量的回归数学模型。得出了青贮玉米新饲玉14号在海南中等肥力土壤上的适宜种植密度为7.50～9.00万株/hm2;最佳收获期是籽粒乳熟中期; 预测出了获得青贮玉米最大鲜、干生物产量,蛋白质产量,中、酸性洗涤纤维产量,脂肪产量时所需氮、磷、钾肥的施用量。     

运用马尔科夫模型对我国食糖产量的预测

采用定量方法对我国食糖年度产量进行分析研究。根据历史食糖产量数据,运用马尔科夫模型对未来一年食糖的产量进行了预测,对长期的市场产量进行趋势分析。     

遇旱灌水和施肥对大豆产量及农艺性状的影响

于2008～2009年研究了遇旱灌水和不同施肥方式对大豆农艺性状和产量的影响.结果表明:遇旱灌水能显著提高大豆叶面积指数、生物产量、单株荚数、单株粒重和产量的不同施肥方式对大豆叶面积指数、生物产量、单株荚数、单株粒重和产量的影响表现为优化施肥>常规施肥>不施肥,并且灌溉条件下,不同施肥方式产量和产量相关性状差异更显著,表明灌溉在保证水份供应的同时,促进了肥料的吸收,起到了以水调肥的作用.     

水稻航天诱变后代产量与品质的差异研究

综述了航天诱变对水稻产量及品质的影响,从基因突变、遗传背景等方面分析了水稻航天诱变后代产量及品质差异的原因,提出提高水稻航天诱变后代产量及品质的策略,并对水稻航天诱变后代产量与品质差异的综合研究进行了汇总,对水稻航天诱变后代产量与品质差异研究的相关方面提出了展望,为水稻航天诱变后代品种的选育与改良提供依据。     

THE EFFECT OF WEEDS, AND THEIR CONTROL BY MCPA SPRAYING, ON THE ESTABLISHMENT OF PERENNIAL RYEGRASS AND COCKSFOOT IN THE KENYA HIGHLANDS

The vigour of perennial ryegrass and cocksfoot after spraying with the sodium salt of MCPA during establishment was estimated from their yields in small-plot cutting experiments on weedy land. Where the weed yields of control plots was of the order of a ton of air-dry matter an acre (mostly Spergula arvensis L.), spraying at up to 1·2 1b. acid equivalent an acre caused twofold to threefold increases in grass yields. The optimum time to spray perennial ryegrass was at the three- to four-leaf stage or 26 days after sowing; for cocksfoot, which appeared more susceptible to the herbicide, spraying at the tillering stage, or about 40 days after sowing, was best. Increasing the seed rates of ryegrass produced transitory increases in yields while decreasing weed yields. Increasing phosphate or nitrogen caused decreases in weed yields. Although the former gave a large increase in weed yield in the first cut this was offset by a large decrease in the second cut. There was an indication that the level of nitrogenous manuring affected the toxicity of the herbicide to the grasses.     

Fantastic yields in the system of rice intensification: fact or fallacy?

The combination of natural resources, genes, weather and management systems largely determines maximum crop yields. Recently, one of those elements was portrayed as the key to releasing hitherto unrecognized, but significant, untapped growth potential in rice. That element, the system of rice intensification (SRI), is an unconventional management system developed in Madagascar, where it was reported to increase rice yields to ‘fantastic’ levels. To investigate the general potency of the SRI, we conducted experiments in three locations in China comparing yields in conventional and SRI management systems. In addition, we used a theoretical model to predict maximum yields and compared those with reported yields for various locations, including China and Madagascar. Our results imply that the SRI has no inherent advantage over the conventional system and that the original reports of extraordinary high yields are likely to be the consequence of error.     

Double cropping of potatoes in a semi-arid environment: the association of ground cover with tuber yields

Summary The association of ground cover and ground cover duration with fresh- and dry-weight potato tuber yields in a semi-arid Mediterranean climate, was investigated. Cultivars of different maturity classes were tested under the contrasting climatological conditions of the spring and autumn seasons. The correlation coefficients of ground cover (GC) and ground cover duration (GCD) with fresh- and dry-weight tuber yields were lower for the autumn than for the spring season. In both seasons, high yields were positively correlated with high GCD. However, variation in tuber yields was evident in cultivars with similar GCD, indicating the involvement of factors other than ground cover and light interception in tuber yield. This investigation was supported by a grant from the Ministry of Foreign Affairs, Technical Assistance Department, Netherlands.     

THE EFFECT OF A RYEGRASS COMPANION GRASS AND THE VARIETY OF RED CLOVER ON THE PRODUCTIVITY OF RED-CLOVER SWARDS

An experiment was conducted to measure the effects of differrat ryegrass companion grasses and red-clover varieties on the productivity of red-clover swards. Three silage harvests per year were taken over a 2-year period. The addition of a companion grass increased total herbage yields; S24 perennial ryegrass gave the highest herbage yield over the two years, followed by Reveille perennial ryegrass. Because of lack of persistence, Tetila Italian ryegrass yielded poorly the second year. A companion grass had little effect on red-clover yields in the mixed swards but improved percentage digestibility of the OM of the total herbage and lowered the CP percentage. Its presence also reduced the ingress of unsown species. The variety of red clover used had little effect on total herbage yields or red-clover yields in the first harvest year. In the second year, Hungaropoly and Tilo persisted better and so gave higher total herbage yields and red-clover yields than Dorset Marl or Essex. The fall in total herbage yields from the first to the second year was entirely due to a fall in red-clover yield since yields of the ‘non-red clover’ fraction of the total herbage increased. A red-clover/grass sward may have advantages over a pure red-clover sward nutritionally, for silage-making and for its effect in diluting the oestrogenic activity of a pure clover sward. A major reappraisal of the role and potential of red-clover swards in the UK is warranted because of their many valuable attributes, particularly their ability to give high herbage yields of high nutritive value without the addition of fertilizer N. The improved persistency of some of the tetraploid varieties of red clover enhances the value of the plant.     

No relationship between leaf size and yield in medium leaf size white clover varieties under rotational sheep grazing and cutting

Nine medium leaf size varieties of white clover ( Trifolium repens L.) were grown in field plots with perennial ryegrass ( Lolium perenne L.) variety Fennema, and yield measurements were taken under both cutting and rotational sheep grazing. The sampling and management protocols in the cut plots mirrored those for the National List testing of white clover varieties in the UK. Dry-matter yields of the white clover and perennial ryegrass components of the mixture were recorded for six cuts in each of three harvest years. White clover yields were highest under cutting, perennial ryegrass yields under grazing. Significant differences were seen between the yields of white clover varieties, and significant interactions between white clover yields and management type were also observed. This interaction effect was not seen with respect to perennial ryegrass yields. No correlation was observed between leaf size and white clover dry-matter yield under either management type. The results suggest that leaf size, on the scale of variation represented within a leaf size category, is not a good predictor of yield under rotational sheep grazing or cutting. The significance of these results for varietal evaluation and for ascertaining the underlying bases for yield differences is discussed.     

我国亚热带地区甘蔗产量的模型模拟

应用基于甘蔗生长机理的APSIM-Sugarcane动态模拟模型对南宁一块试验蔗地的甘蔗产量进行动态模拟和验证。结果表明,蔗茎和蔗糖的模拟产量与实测产量分别相差440g/m2和330g/m2,地上部干物重模拟值与实测值的线性回归方程斜率为1.1,决定系数为0.94,说明模型对甘蔗产量的模拟具有较高的准确性。回归模型表明,降水量、太阳辐射和气温的累积量也可精确反映甘蔗产量的动态变化。APSIM-Sugarcane模型的应用可为我国甘蔗产业的精准化管理提供科学依据。     

WILD WHITE CLOVER SEED PRODUCTION

A survey, covering some 140 fields, totalling 1540 acres, in Kent was conducted in 1961 on the effect of different methods of management on yields of perennial ryegrass and white clover seed. The main results were: (a) the majority of seed growers harvested seed from short-term leys and only a limited acreage of permanent pasture was used for producing seed. Yields of both ryegrass and clover seed were considerably higher on the younger leys; (b) the highest seed yields in 1961 were obtained from fields where sheep grazing was stopped on 24 May. However, a large number of growers continued sheep grazing well after this date: (c) mechanical defoliation, especially when used to supplement sheep grazing, proved an effective method for producing high yields of clover seed; (d) honey bees are important in increasing seed yields, particularly on recently sown leys; (e) combine harvesting from the swath was the most common method of harvesting and no instance of the use of tripods was reported. Seed yields from baling methods were generally low, but direct combining produced a high average yield of clover seed. From these results it was concluded that there was much scope for raising the general level of clover seed yields, especially by giving greater attention to details of management.     

牧草兼用型花生新品系在闽南地区的适应性试验

在闽南地区对5份辐射牧草兼用型花生新品系进行3 a的适应性试验。结果表明：TJ和泉N两个品系花生秧干草产量分别比泉花7号增产12.00％和12.77％；花生产量分别比泉花7号（对照）增产13.04％和12.59％，且均达显著水平，丰产性、稳定性、适应性好，主要经济性状优良，适宜福建闽南地区推广种植。     

The spatial patterns in long-term temporal trends of three major crops’ yields in Japan

Long-term trend of crop yields has been widely studied in global scales to find which crops and which geographic regions offer the best hope of meeting food demands, and which regions needed the most improvements. In this study, a mathematical method was applied to analyze spatial patterns in long-term temporal trends of three major crops’ yields in Japan archipelago. The changes in annual yields of rice, wheat, and soybean over a period of about 60 years in all 47 prefectures of Japan was analyzed by using the data of agricultural records. For all the three crops, the nationwide yields previously improved, but currently were stagnating in Japan. The result suggests that the annual yields were not improving in 53, 85, and 89% of those prefectures in Japan for rice, wheat, and soybean, respectively. The spatial patterns in temporal trends show that the percentage of number of yield-not-improving prefecture was higher in low latitude regions than high latitude regions. These results highlight the increasingly difficult challenge of meeting the growing demands and stagnating supplies in daily staple foods not only for agricultural scientists but also for Japanese society.     

The influence of reduced temperatures after emergence on the subsequent growth and development of the potato

Summary The performance of potato platato plants raised under glass and transplanted to the field after emergence was compared with that of field-raised plants. The transfer from the warmer environment of the glasshouse to the cooler environment of the field resulted in immediate initiation of tubers. The period between initiation and the commencement of rapid bulking was, however, prolonged so that some of the advantage was lost. Nevertheless, this technique enabled yields, in the range of 2–6 tons per acre to be achieved some 4–5 days carlier; the tubers were also more uniform in size. Foliar applications of urea after tuber initiation hastened and extended the phase of rapid bulking, leading to carlier marketable yields and to higher yields at maturity. Urea applied before tuber initiation delayed its commencement. Plants which were transplanted after raising under glass always matured more quickly and gave lower final yields than field-raised plants. The physiological bases of the respones found are discussed. Some plants were exposed to frosts. Recovery from frost damage was rapid; the rate of tuber bulking was slower but yields at maturity were slightly higher than those of plants protected from forst.