水氮耦合供应对日光温室番茄产量和品质的影响

以番茄为试材,采用2水平灌水量(W1:4541.0 m3/hm2、W2:2270.6 m3/hm2)×3水平氮肥追施量(N1:747.4 kg/hm2、N2:373.7 kg/hm2、N3:0 kg/hm2),研究了不同水分和氮素供应水平对日光温室越冬栽培番茄产量和品质的影响。结果表明,氮肥追施量较多(N1)时可显著提高番茄产量,减少灌水量并未导致产量的显著下降。高量施氮或不施氮,番茄果实Vc含量均相应下降。高量施氮可显著提高果实中游离氨基酸及可溶性蛋白质含量。增加施氮量和灌水量可显著提高果实中有机酸含量,但对可溶性糖含量无显著影响。加大氮肥追施量和减少灌水量可显著增加果实中硝酸盐含量。采用灰关联理论对不同水分和氮素供应条件综合评价,结果以灌水量2270.6 m3/hm2和施氮量373.7 kg/hm2为最佳处理组合。     

Optimum Soil Acidity Indices for Dry Bean Production on an Oxisol in No‐Tillage System

Abstract

Soil acidity is one of the major yield constraints to crop production in various parts of the world. Quantifying optimum soil acidity indices is an important strategy for achieving maximum economic crop yields on acid soils. Five field experiments were conducted for three consecutive years using dry bean as a test crop on an Oxisol. The lime rates used were 0, 12, and 24 Mg ha^?1 for creating a wide range of soil acidity indices in a no‐tillage cropping system. Grain yield of dry bean was significantly increased by improving soil pH, base saturation, calcium (Ca), magnesium (Mg), and potassium (K) saturation and reducing aluminum (Al) saturation. These soil acidity indices were higher in the 0‐ to 10‐cm soil layer than the 10‐ to 20‐cm soil layer for maximum grain yield. Across two soil depths, optimum values for maximum bean yield were pH 6.5, base saturation 67%, Ca saturation 48%, and Mg saturation 19%. Bean yield linearly increased with increasing K saturation in the range of 1.5 to 3% across two soil depths. There was a significant linear decrease in grain yield with increasing Al saturation in the range of 0 to 8% across two soil depths. Optimal values of soil indices for maximum bean yield can be used as a reference for liming and improving yield of bean crop on Oxisols in a no‐tillage cropping system. Yield components, such as pod number, grain per pod, and 100‐grain weight were significantly improved with liming, and bean yield was significantly associated with these yield components.     

调控滴灌对棉花的生长和产量的影响研究

基于棉花种植中普遍存在中期旺长问题,通过在棉花生育期进行生态调控滴灌,从生长和产量方面分析得出:调控滴灌下棉花叶面积增长在全生育期均低于常规滴灌,在铃期出现叶片生长减慢的趋势;调控滴灌下棉花株高增长在蕾期末期和初花期开始低于常规滴灌处理,在前期差别不大;调控滴灌下棉花产量受灌溉量的影响较大,RADI?Ⅱ较常规滴灌节水9%,同时增产1%,RADI?Ⅲ与CDI灌水量相同,同时增产4.6%。调控滴灌利于控制棉花种植中的旺长问题,并在节水的同时保持棉花的产量不降低。     

极端天气对水稻生长和产量的影响

目前的水稻生产模式中,极端气候、病虫危害、栽培措施不当严重影响水稻优质、高产和稳产。综述干旱、高温等极端天气气候环境对水稻生长和产量的影响,并提出相应的对策,可为今后水稻的生产和科研提供依据。     

The potential use of heterosis in Beta vulgaris L. II. Yield performance of pure lines and their hybrids

Summary The yield performance is described of pure lines obtained from doubled monoploids and their corresponding polycross and pair-cross hybrids. The total dry matter yields of fifteen pure lines averaged 60–90% of the yields of the progenitor and control varieties. Seven of the resultant polycross hybrids gave dry matter yields similar to or higher than the progenitor varieties, whilst the remaining hybrids were less productive than their parental lines. In pair-cross hybrids significant reciprocal differences were found in some cases. This was attributed to differences in self-fertility and the degree of self-fertilization in reciprocal crosses. Based on the frequency of offspring with white or coloured roots, self-fertilization frequencies ranging from 14% to 92% were found. It is estimated that in the event of complete cross-fertilization, the yields of certain pair-cross hybrids would have exceeded those of the control varieties by 9–29%.     

Sustainable productivity and profitability of diversified rice-based cropping systems in an irrigated ecosystem

An experiment was conducted at ICAR Research Complex for Eastern Region, Research Farm, Sabajpura, Patna (longitude 85°13′N and 1atitude 25°37′E), Bihar, India for four consecutive years 2004–05 to 2007–08 to develop a diversified cropping system for an irrigated ecosystem in Bihar by introducing pulse/oilseed/vegetables as a second or third crop in 10 rice-based cropping systems. Four crop cycles have been completed for all the cropping systems. During all years of the experiment there were significant variations among the cropping systems. Maximum paddy yield equivalent was recorded in rice–tomato–bottle gourd (40.44 t ha^?1) followed by rice–potato–onion (28.47 t ha^?1), rice–coriander–lady's fingers (26.79 t ha^?1), rice–carrot–cowpea (24.59 t ha^?1) and rice–mustard–tomato (24.44 t ha^?1). A higher value for the diversification index (DI) represents a higher level of crop diversification. It is evident from the results, that DI varies from 0.299 on a medium-sized farm to 0.903 on a small farm, with an average DI value of 0.643 among all farm categories. A survey revealed that the average DI value for small-scale farmers was highest (0.741) compared with the medium- (0.591) and large-scale (0.626) categories, and the differences were negligible. This seems reinforce the view that the smaller the farm, the higher the level of crop diversification.     

缓释复混肥料对玉米产量和土壤硝态氮淋失累积效应的影响

在大田条件下,研究了4种缓释复混肥料对玉米产量和土壤硝态氮淋洗累积的影响。结果表明,缓释复混肥料较普通化肥的常规施肥方式增产10%左右,土壤剖面硝态氮累积量降低20%~70%,从而降低了地下水硝态氮污染的生态风险。与施用常规化肥的传统施肥方式比较,缓释复混肥料可作为基肥一次性使用,故其具有省工省时和环境友好的特点。     

Impact of Locally Derived Organic Materials and Method of Addition on Maize Yields and Nitrogen Use Efficiencies in Major and Minor Seasons of Tropical South Asia

Maize is the most important highland cereal grown in the tropics, generally cultivated under rainfed smallholder conditions in Asia. Field experiments were carried out in Sri Lanka with the objective of determining the impact of three types of organic matter applied as mulch or incorporated on the yields and nitrogen uptake by maize cultivated under rainfed conditions in the South Asian major and minor seasons. The organic matter used was leaves of Gliricidia sepium, Tithonia diversifolia, or rice straw, with the full compliment of recommended mineral fertilizers. Organic matter, especially the two green manures, enhanced yields and nitrogen (N) uptake of maize, and the impact was more prominent in the minor dry season where the yields were lower. Incorporation of organic matter had a greater positive impact in the dry season in terms of N utilization efficiency and seed yields. The beneficial impact of organic matter with low carbon (C):N ratios in enhancing N nutrition and seed yields of rainfed maize in major and more importantly in the minor seasons is presented.     

Soil tests to inventory the initially available levels and to assess the fates of added P and K as bases for improved fertilizer recommendations

Abstract

Preliminary studies indicate that “quicktest”; methodology can be used to measure the individual tendencies of soils to fix (or not to fix) added P and K into plant‐unavailable forms. It appears that the fraction of added P recovered after two hours in Bray 1 or of K in 1N NH₄OAc extracts can be used for adjusting fertilizer recommendations to maximize yields. It is suggested that the reciprocals of the recovery fractions be used as multiples of the differences between sufficiency and existing levels of available P and K to obtain amounts of fertilizer P and K to apply. This method offers promise for both improving fertilizer recommendations and identifying soils of unique fixation tendencies where choice of fertilizer materials or application methodology may be most suitable. The possibility of using the new extracting solution of Mehlich to assess‐ the fate of both applied P and K in one extractant looks promising.     

应用高稳系数法分析棉花新品种高产稳产性

应用高稳系数法分析了１９９６～１９９７年江苏省早熟抗病棉花品种区域各参试品种的高产稳产性,并与常用的统计分析方法计算的几种稳定性参数进行了比较和分析。结果表明,高稳系数法是分析棉花新品种（系）高产稳产性的准确、简便的方法。