Variation of mineral nutrient contents of modern and heirloom cultivars of cabbage in different regimes of soil fertility

An improvement in the mineral nutrient contents of fruits and vegetables is needed to offset reported declines in concentrations of these elements in fruits and vegetables. The declines have been associated with the high productivity of modern cultivars and to depleted soil fertility. This research addressed differences in mineral nutrient concentrations between modern F1 hybrids and heirloom cultivars of cabbage (Brassica oleraceae var. capitata L.)and among fertilization practices with conventional chemical or organic fertilizers and compost. Crop production was greater with the chemical or organic fertilizers than with the compost. Mineral nutrient composition did not vary between modern or heirloom cultivars or among fertilization regimes but varied among cultivars, suggesting that cultivar selection could lead to production of nutrient-rich cabbage. Neither mass of heads nor days to maturation of crops affected nutrient composition.     

Economic viability of Phaseolus vulgaris (BRS Estilo) production in irrigated system in a function of application of leaf boron

Foliar fertilization may be a viable strategy to boron supply in irrigated cropping systems with common beans (Phaseolus vulgaris), since it prevent B leaching. The aim of this work was to evaluate the economic viability and physiological parameters of the common beans production in irrigated cropping systems using sources and increasing foliar boron doses. A field experiment was carried out using an experimental block design in a factorial scheme 2?×?5?×?3, with two sources of B (boric acid and borax) and five doses: 0 (control), 2, 4, 6 e 8?kg?ha^?1, with three repetitions. Foliar B applications were performed at 40 days after seeds germination, in pre-flowering stage. Physiological process (transpiration, stomatal conductance, CO₂ internal concentration, net photosynthesis, and relative chlorophyll index), B level in leaves and grain yield were measured. These data were used to determine the economic viability of B fertilization in common beans. Both boric acid and borax increased B levels in common beans leaves. Borax affected some physiological process reducing stomatal conductance and increasing net photosynthesis. Using borax, the highest net photosynthesis was observed at a rate of 4?kg?ha^?1, while the boric acid increased net photosynthesis linearly after increasing B doses application. An enhance of 311?kg?ha^?1 in the grain yield was observed using borax related to the control (without B application); however, grain yield decreased linearly after application of increasing B doses, as boric acid. Comparing the economic viability of sources and doses of B, the highest profitability is obtained using borax at a rate of 4?kg?ha^?1, which promoting a differential profit of US$534.44 per hectare compared to common beans cropping without B.     

Optimum N and P rates for greenhouse production of vegetative coleus using constant liquid feed

Many new coleus (C. hybridus cv.) cultivars are vegetatively propagated and require different fertilization practices from seed propagated cultivars. Two experiments were conducted to evaluate growth responses of Henna, Indian Summer, Mint Mocha, New Orleans Red, Red Head, and Trusty Rusty to 0, 70, 140, 280 and 420 mg·L^?1 nitrogen (N), and Henna, Mint Mocha, Red Head, and Trusty Rusty to 0, 6.2, 12.4, 24.8, or 49.6 mg·L^?1 phosphorus (P) to determine optimum constant liquid feed rates to produce marketable size plants from rooted cuttings. Positive growth responses in terms of biomass were found with increasing N rates but not P rates. For medium-sized cultivars such as Henna, Indian Summer, and New Orleans Red, quadratic responses were found in aboveground biomass, and N at 280 mg·L^?1 resulted in similar plant size and dry weight as those fertilized at 140 and 420 mg·L^?1 N. For large-sized cultivars such as Mint Mocha, Red Head and Trusty Rusty, plant dry weight responded linearly within the N range tested and were greatest at 420 mg·L^?1. However, plant visual quality was negatively affected by N rates at 280 and 420 mg·L^?1 in that, leaf color became less intense at these high N rates. Plants fertilized at 70 mg·L^?1 were smaller than those fertilized at 140 mg·L^?1, however, they received similar visual quality ratings because of more intense leaf color. Therefore, N at 70 to 140 mg·L^?1 can be used to grow most vegetative coleus for similar marketable quality. Mint Mocha and Henna were the only cultivars responded to P treatments that, 12.4 mg·L^?1 P rate resulted in greater biomass than the no-P control. All other cultivars had no response to supplemental P except a linear response in tissue P%. Therefore, supplemental P is not required during the 8 week production period when there is an initial P charge in the substrate. We found that substrate pH decreases with higher P rates, therefore supplemental P fertilizer can be used for adjusting pH. Both N and P rates found optimum in this study are lower than current industry practices (N at 150 to 250 mg·L^?1 and P at 24 mg·L^?1) and can significantly lower production cost and potential leaching of excessive nutrient into waterway. Nutrient treatments in further study on postharvest performance of vegetative coleus will be selected based on this study.     

2种强化措施辅助紫茉莉修复镉污染土壤研究

[目的]通过2种强化措施,提高紫茉莉的修复效率。[方法]以紫茉莉为材料,实验室模拟受cd污染土壤,进行90d盆栽试验。同时采用2种辅助强化手段（螯合及施肥）,探讨重金属污染土壤的生物修复可行性。[结果]当螯合剂EDTA的浓度为2．0mmol/kg时,紫茉莉对Cd的最大转移系数为3．64,比对照增加了97．83％;施加氮肥可以促进紫菜莉对Cd的吸收,使Cd的总吸收量比对照增加了73．65％。[结论]螯合及施肥2种强化措施提高了紫茉莉的修复能力。     

牛卵母细胞体外受精和培养技术

本文综述了牛卵母细胞体外受精和体外成熟技术的研究进展,包括精子的体外获能、卵母细胞成熟培养和体外受精、体外受精早期胚胎的培养等,并且对影响该技术的主要原因进行了分析。     

苏丹草-黑麦草轮作制中施肥对饲草产量与土壤酶的影响

 【目的】为苏丹草-黑麦草这一新型种植制度的科学施肥、土壤肥力的改善提供依据。【方法】采用4年苏丹草(Sorghum sudanense)与黑麦草(Lolium L.)轮作定位试验研究氮、磷、钾肥对饲草产量、土壤蔗糖酶、脲酶和磷酸酶的影响。【结果】氮、磷、钾肥配施(NPK处理)明显增加苏丹草、黑麦草鲜草产量,4个年度的饲草总产量在各个处理中均最高,分别比NP(氮、磷肥配施)处理增产17.9%、17.3%、21.7%、23.2%,分别比NK(氮、钾肥配施)处理增产26.9%、20.2%、23.3%、25.9%,分别比PK(磷、钾肥配施)处理增产312..9%、339.8%、231.7%、223.1%,且效果显著。苏丹草-黑麦草轮作制中,NPK处理的土壤蔗糖酶、脲酶高于CK、PK处理,部分达到显著水平,与NP、NK处理相当;土壤磷酸酶以碱性磷酸酶为主,苏丹草、黑麦草试验期NP、NK、NPK处理的碱性磷酸酶均显著低于CK、PK处理。【结论】苏丹草-黑麦草轮作制中,氮、磷、钾肥配施能够明显提高饲草产量,影响土壤蔗糖酶、脲酶、磷酸酶活性,从而改善土壤肥力。     

Influence of long-term nitrogen fertilization on micronutrient density in grain of winter wheat (Triticum aestivum L.)

A long-term (1999–2007) field experiment was conducted to investigate the effects of three nitrogen (N) fertilization rates (0, 130, and 300 kg N/ha) on micronutrient density in wheat grain and its milling fractions. At maturity, grains were harvested and fractionated into flour, shorts, and bran for micronutrient and N analysis. N fertilization increased iron (Fe), zinc (Zn), and copper (Cu) density in wheat grain compared to the control. Increase of N application rate from 130 to 300 kg N/ha, however, did not further increase the three micronutrient densities in grain. Micronutrient concentrations were usually highest in the bran and lowest in the flour. High N application increased Zn and Cu densities in all three milling fractions and increased Fe concentration in shorts and bran but not in flour. N application did not affect the manganese (Mn) concentration in grain. N fertilization changed the proportions of Fe and Cu in flour and bran but did not affect the distribution of Zn. Because N fertilization increased micronutrient accumulation in wheat grain, proper management of N fertilization has the potential to enhance the nutritional quality of this important food.     

种植密度和施肥水平对油菜茎叶可溶性糖和游离氨基酸及籽粒产量的影响

以湘杂油763为材料,测定不同施肥量(以N、P<,2>O<,5>、K<,2>O、B计,处理A:240、120、210、1.2kg/hm<'2>;处理B:180、90、157.5、0.9kg/hm<'2>;处理C:120、60、105、0.6kg/hm<'2>;处理D:60、30、52.5、0.3kg/hm<'2>;E:...     

樱梅嫩枝扦插育苗技术

总结了樱梅嫩枝扦插育苗技术,包括圃地选择、设施建设、插条采集与处理、扦插、肥水运筹、温湿度与通风管理、病虫害防治、扦插苗炼苗与越冬等内容,以期对樱梅的栽培提供技术参考。     

罗布泊“湖心”位置的探讨

罗布泊是我国干旱地区著名的湖泊,地处古代沟通东西文化的通道—丝绸之路的要冲,在我国古代史上享有盛名,是一个充满自然和文化之谜的神秘地区。通过对罗布泊地区高程测量数据的分析,确定其湖心的具体位置。罗布泊＂大耳朵＂纹理目前被认为是罗布泊湖水退缩留下的印迹,从沉积学角度考虑,罗布泊的湖心应处在耳心处。2006年DGPS实测结果表明罗布泊最低点处于＂大耳朵＂的耳心处（90.500°E、40.131°N）。研究罗布泊的＂湖心＂位置确定对科考、科研、旅游和文化等有较高的价值。