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。     

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。     

济麦22号生物学特性研究

对国审小麦品种济麦22号进行生物学栽培试验,采用顺序排列、2次重复试验设计.结果表明：①播期在越冬以前≥0℃积温为558.4～712.1℃,为最佳播种期;②各叶龄期的出叶速度是倒1～4叶需9.6d,冬前叶为5.6d,越冬期为34.7d;③10月1日前播种的在越冬期前出现分蘖高峰;④早播的穗分化时间早,穗分化的历期长,利于大穗形成;⑤从干物质积累看,10月1日之前播种均高于其他各期,平均为1 556.9kg/667m2;⑥灌浆速度以9月24日至10月8日播种的为高,千粒质量高.在本试验条件下,济麦22号在9月下旬—10月中旬播种,因苗管理,可获得理想产量.     

Characterization of Organic Acids Recovered from Rhizosphere of Corn Grown on Biosolids‐Treated Medium

Abstract

Organic acid production by plants and microorganisms was quantified in sand media amended with biosolids in the presence and absence of corn (Zea mays L.) in a sand‐culture hydroponic medium. Total quantities of organic acids were greatest in treatments containing both plants and biosolids, with lesser amounts in treatments with plants alone, biosolids‐treated media alone, and a nutrient solution–irrigated blank medium. Biosolids enhanced organic acid production in the rhizosphere and influenced the composition of organic acid mixtures. Only lactic, acetic, butyric, and oxalic acids were detected in media without plants. When the medium was planted, additional organic acids were recovered including tartaric, maleic, succinic, valeric, glutaric, pyruvic, and propionic. Lactic, acetic, and butyric acids were predominant in solutions recovered from the planted media and collectively accounted for 0.65 to 0.75 of the COO^? mole fraction. Oxalic, maleic, and tartaric acids were the second most abundant and varied from 0.05 to 0.1 of the mole fraction, followed by succinic, valeric, glutaric, propionic, and pyruvic acids, comprising ≤0.05 of the mole fraction. Plant growth stage had no effect on relative proportions of organic acids but did influence the total quantities of organic acids recovered. Biosolids sources did not have a significant effect on either the quantity or composition of organic acids in any media. The predominance of organic acids that are microbial fermentation products suggests that the carbon contained in root exudates and biosolid amendments was transformed into a mixture of various fermentation products that accumulated in the rhizosphere solution and sand medium as a result of microbial growth and activity.     

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.     

Influence of Nitrogen and Potassium Fertilization on Yield and Quality of Rosemary in Relation to Harvest Number

Rosemary is an important aromatic and spice plant. Its cultivation for production of its essential oil has gained importance in recent years. An experiment was conducted in a red sandy loam (Kandiustalf) soil to study the impact of cultivation of this multiharvest crop at different nitrogen (N) and potassium (K) application regimes on soil fertility and crop yield at the farm of the Central Institute of Medicinal and Aromatic Plants, Resource Center, Bangalore, during 2003–2005. The treatments consisted of all combinations of N levels (0, 150, and 300 kg per hectare per year) and K levels (0, 50, and 100 kg per hectare per year). Five harvests were taken at about 5‐month intervals. The results showed that initially the soil alone was able to meet the crop requirements for K, but with the progress of time, addition of K to the soil in the form of fertilizer became necessary for obtaining optimum yields. At the end of five harvests, exchangeable K in soil was significantly lower as application of K decreased from 100 to 50 and 0 kg per hectare per year. Soil fertility could be maintained and oil yields of rosemary from four harvests could be increased from 146.6 L to 344.7 L per hectare by application of 150 kg N and 100 kg K.     

Modeling of Interactive Effects of Rainfall,Evaporation, Soil Temperature,and Soil Fertility for Sustainable Productivity of Sorghum + Cowpea and Cotton + Black Gram Intercrops under Rotation Trials in a Rain-Fed Semi-arid Vertisol

Long-term effects of the different combinations of nutrient-management treatments were studied on crop yields of sorghum + cowpea in rotation with cotton + black gram. The effects of rainfall, soil temperature, and evaporation on the status of soil fertility and productivity of crops were also modeled and evaluated using a multivariate regression technique. The study was conducted on a permanent experimental site of rain-fed semi-arid Vertisol at the All-India Coordinated Research Project on Dryland Agriculture, Kovilpatti Centre, India, during 1995 to 2007 using 13 combinations of nutrient-management treatments. Application of 20 kg nitrogen (N) (urea) + 20 kg N [farmyard manure (FYM)] + 20 kg phosphorus (P) ha^?1 gave the greatest mean grain yield (2146 kg ha^?1) of sorghum and the fourth greatest mean yield (76 kg ha^?1) of cowpea under sorghum + cowpea system. The same treatment maintained the greatest mean yield of cotton (546 kg ha^?1) and black gram (236 kg ha^?1) under a cotton + cowpea system. When soil fertility was monitored, this treatment maintained the greatest mean soil organic carbon (4.4 g kg^?1), available soil P (10.9 kg ha^?1), and available soil potassium (K) (411 kg ha^?1), and the second greatest level of mean available soil N (135 kg ha^?1) after the 13-year study. The treatments differed significantly from each other in influencing soil organic carbon (C); available soil N, P, and K; and yield of crops attained under sorghum + cowpea and cotton + black gram rotations. Soil temperature at different soil depths at 07:20 h and rainfall had a significant influence on the status of soil organic C. Based on the prediction models developed between long-term yield and soil fertility variables, 20 kg N (urea) + 20 kg N (FYM) + 20 kg P ha^?1 could be prescribed for sorghum + cowpea, and 20 kg N (urea) + 20 kg N (FYM) could be prescribed for cotton + black gram. These combinations of treatments would provide a sustainable yield in the range of 1681 to 2146 kg ha^?1 of sorghum, 74 to 76 kg ha^?1 of cowpea, 486 to 546 kg ha^?1 of cotton, and 180 to 236 kg ha^?1 of black gram over the years. Beside assuring greater yields, these soil and nutrient management options would also help in maintaining maximum soil organic C of 3.8 to 4.4 g kg^?1 soil, available N of 126 to 135 kg ha^?1, available soil P of 8.9 to 10.9 kg ha^?1, and available soil K of 392 to 411 kg ha^?1 over the years. These prediction models for crop yields and fertility status can help us to understand the quantitative relationships between crop yields and nutrients status in soil. Because black gram is unsustainable, as an alternative, sorghum + cowpea could be rotated with cotton for attaining maximum productivity, assuring sustainability, and maintaining soil fertility on rain-fed semi-arid Vertisol soils.     

Retention of applied p by volcanic ash soils ‐ influence on available p and soluble al

Abstract

Most fertilizer (and lime) recommendations are based on: i) a level of available nutrient (or pH) sufficient for at least near‐maximum crop yields and ii) an average rate of buildup of the available nutrient (or pH) per unit of fertilizer (or lime) added.

Soils differ widely in the rate of buildup of available nutrient per unit of added fertilizer. Soil type (or association) is generally not available for individual soil samples submitted for testing. Even if it were, research information is generally inadequate to adjust the recommendations with any great degree of accuracy on this basis alone. Thus it seems imperative that new tests and/or equilibrations for individual soil samples be developed to provide the information needed. Recent results by us and others seems to offer hope of success in such efforts.

Lime and fertilizer costs are a substantial portion of the total production costs in modern farming. Thus, it is important that the rates recommended be the best possible for the individual soil, crop, and farming situation. The question of how good our current recommendations are is examined, as is that of how they might be improved with some possible refinements. In order to be brief, use is made of charts, most of which have appeared in previous papers.     

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.     

不同施肥措施对沿淮区麦-玉周年产量及氮素利用的影响

沿淮砂姜黑土区,设置5种施肥措施(常规施肥、推荐施肥、推荐施肥+秸秆粉碎全量还田,推荐施肥+控失肥,推荐施肥+粉煤灰),探讨其对麦-玉轮作周年产量及氮素吸收与利用的影响。结果表明,麦-玉轮作周年产量以推荐施肥+秸秆粉碎全量还田处理最高(12921kg/hm2),推荐施肥+粉煤灰处理次之(12365kg/hm2),较常规施肥处理分别增产12.5%、7.7%。冬小麦季:籽粒产量、氮素累积量(NAA)、氮肥利用率(NUE)、氮素吸收效率(NUPE)均以推荐施肥+粉煤灰处理较高,分别为6134 kg/hm2、180.0 kg/hm2、42.1%、0.80 kg/kg;夏玉米季:籽粒产量、NAA、NUE、NUPE则以推荐施肥+秸秆粉碎全量还田处理较高,分别为6971 kg/hm2、176.5 kg/hm2、38.3%、0.65 kg/kg。本试验条件下,推荐施肥+粉煤灰处理对提高沿淮砂姜黑土区麦-玉轮作周年产量、麦-玉氮肥利用率及氮素吸收效率较好,而长期而言,推荐施肥+秸秆粉碎全量还田处理更适。