The effect of agricultural fertilizer on growth rate of benthic diatoms

The aim of this work was to consider a non-conventional medium for benthic diatoms culture, formulated with liquid agricultural fertilizers and with the ‘f/2’ medium used as control. Three strains of benthic marine diatoms (Nitzschia laevis, Nitzschia thermalis var. minor and Navicula incerta) were grown with these two media, in batch cultures in 18-l plastic containers. There were no significant differences in mean cell concentration and growth rate between three diatoms raised with agricultural fertilizers compared to the standard ‘f/2’ medium. The cost for non-conventional culture media is less than 1/8 the cost of the ‘f/2’ medium.     

Integrated Nitrogen Fertilization for Intensive and Sustainable Agriculture

Summary

Increased efficiency of land use and resource-use are critical for agriculture to feed the ever increasing population and yet remain sustainable for the future generations. Mineral fertilizers, particularly, nitrogen (N) fertilizer has played a very important role in meeting the increased food demand and in saving millions of hectares of marginal and wildlife reserves from coming under cultivation. Apart from higher yields per unit land, N application also results in higher protein content. Improper use of N fertilizers due to high application rates, incorrect source and method of application, and poor timing of application have led to air and water pollution and economic losses. Integrated and balanced N fertilization results in a win-win situation with intensive and sustainable agriculture that feed the world without harming the environment. Since multitude of management, soil, crop, and weather-related factors control soil and plant N dynamics, N management recommendations based on field trials alone are too costly and time-consuming. Dynamic N management recommendations that are both site— and season-specific combine field trials with decision support systems (DSS) that simulate crop growth and N transformations as a function of above-mentioned factors. Innovative N fertilizer products and N efficient plant types will further improve N use efficiency.     

Effectiveness of Vivianite to Prevent Lime-Induced Iron Deficiency in Lemon Trees Grown on Highly Calcareous Soil

The short-term effectiveness of three application rates of vivianite [(Fe₃(PO₄)₂·8H₂O)] in preventing lime-induced iron (Fe) chlorosis in Eureka lemon (Citrus lemon L.) cuttings grafted on sour orange (Citrus aurantium L.) was investigated and compared with the commonly applied iron ethylenediaminedi(o-hydroxyphenylacetic) acid (FeEDDHA). Treatments were suspension of vivianite injected into the soil at three rates (0.5, 1.0, and 2.0 g kg^?1 soil), 417 mg FeEDDHA per plant, and untreated plants. Chlorophyll concentration index (CCI) of the youngest fully expanded leaves was estimated. Growth vigor and leaf Fe concentration were also measured. Vivianite, particularly at the greatest two rates, resulted in significantly greater growth vigor and leaf Fe concentration and exhibited greater CCI values compared to untreated plants similar to FeEDDHA. However, if excessive growth vigor is not favorable, the 0.5 g vivianite kg^?1 soil is recommended for farmers. Vivianite is a potential environmentally safe alternative to the expensive FeEDDHA to prevent Fe chlorosis in lemon.     

Evaluation of Mineral and Bacterial Fertilization Influence on the Number of Microorganisms from the Nitrogen Cycle in Soil under Maize

In 2006, the influence of different rates of applied mineral fertilizers and their combinations with bacterial inoculants [nitrogen (N)–fixing Klebsiella planticola and Enterobacter spp.] on the number of microorganisms from the N cycle in a Cambisol and the yield of maize was evaluated in this study. The results obtained implied that high rates of mineral fertilizers brought about an increase in the number of fungi and a decrease in the number of Azotobacter spp., oligonitrophiles, ammonifiers, and nitrifiers in soil. Combined application of microbial inoculants and low rates of mineral fertilizers resulted in the greatest increase in the number of Azotobacter spp., oligonitrophiles, and ammonifiers in soil. The greatest number of soil nitrifiers, as well as the grain yield of maize studied, were determined in the variants where combinations of the microbial inoculants and low and high rates of mineral fertilizers were applied.     

Towards Improving the Vegetative and Qualitative Traits of Sunflower Using Amending Soil (Zeolite and Manure Farmyard) under Water Deficit Stress

ABSTRACT

The effect of different sources of nitrogen fertilizers (organic fertilizers and urea) and zeolite under different irrigation regime on the qualitative traits of sunflower seeds was investigated by a trial, in 2014 and 2015 in Iran with split factorial on a randomized complete block design with three replications. Main plots consisted of irrigation regimes (irrigation after unloading 40%, 60% and 80% of available soil water (ASW)). The sub-plots consisted of factorial combinations of three nitrogen fertilizer treatments (100% organic, integrated treatment and 100% chemical treatment) and three levels of zeolite (10, 5 and 0 ton ha^?1). Farmyard manure and urea were the organic and chemical sources of nitrogen, respectively; integrated treatment included 50% organic +50% chemical nitrogen. The percentage of nitrogen required by urea was set in a way that 100% of the required nitrogen could be provided by urea. The maximum diameter and stems height as well as the performance of the oil and protein by application of zeolite were measured in terms of the lack of stress in the first and second year, respectively. In sum, it can be concluded that the severe water stress can reduce the percentage of unsaturated fatty acids. In the first year, oleic acid and linoleic acid were decreased by 22% and 7%, respectively; while in the second year, they were reduced by 27% and 6.8%. Stearic acid also declined in the first and second years by 50% and 52%, respectively. However, an increase was observed for palmitic acid of sunflower. In both years, the application of organic fertilizer increased linoleic acid and oleic and improved the quality of sunflower seed oil. Under favorable irrigation conditions, organic fertilizers could be advantageous; while organic fertilizers and zeolite can be helpful under drought stress conditions.     

A technique for predicting urea release from coated urea in wetland soil

Abstract

A simple technique for measuring urea release from different coated urea fertilizer materials in simulated wetland soil has been developed and tested. The laboratory soil system used simulates physical, chemical, and microbiological environments of wetland soils under field conditions. Laboratory and field values for urea release are in good agreement.     

海藻寡糖(ADO)增效尿素对小麦的影响

我国以尿素为主的氮肥利用率较低,而增效氮肥可提高氮素利用率(NUE).利用海藻寡糖(ADO)制备ADO增效尿素,同时以普通尿素、Pasp增效尿素为对照组,进行小麦的大田试验.通过比较小麦单位面积产量、千粒质量、穗粒数、氮素利用率、穗长、粗蛋白及糖类含量等指标,探究ADO增效尿素对小麦的影响.结果表明,ADO增效尿素组小麦667 m2产量高达680.96 kg,分别比普通尿素、Pasp增效尿素组提高了6.87％,2.28％,且小麦千粒质量及穗粒数均显著提高.ADO增效尿素组小麦的氮素利用率为43.18％,分别比普通尿素、Pasp增效尿素组提高了82.12％,43.36％,此外ADO增效尿素也增加了小麦穗长且使麦穗更为满,但对小麦粗蛋白、糖类含量无明显影响.对ADO增效尿素的实际生产有一定的指导意义,有助于提高氮还给利用率,减少农业成本.     

有机无机肥配施对棉花养分吸收及氮素效率的影响

新疆棉花连作田间小区试验,研究有机无机肥不同方式配施对棉花干物质积累、养分吸收、产量及氮素利用效率的影响。结果表明,有机无机肥配施在棉花生长中后期可以显著提高干物质累积及养分吸收量,与单施化肥处理相比,不同有机无机肥配施可以保持或提高棉花产量,提高棉花单株铃数和单铃重;有机无机肥配施还可以提高棉花氮素效率,氮素回收率可达到28．2％～57．7％,偏生产率提高了17．1％～76．3％。有机无机肥配施不仅可以使棉花稳产、高产,而且提高了氮肥利用效率,该结论可为肥料的科学合理施用提供重要依据。     

Effect of Pseudomonas putida and inorganic fertilizer on growth and productivity of habanero pepper (Capsicum Chinense Jacq.) in greenhouse

The habanero pepper is widely used in a variety of commercial food products. The increase in the cultivation area of the habanero pepper has increased the use of agricultural inputs, mainly inorganic fertilizers, which have high economic costs and cause negative effects to the soil and water. In recent years, the use of beneficial soil microorganisms has been studied as an alternative to inorganic fertilizers. In the present study, the effect of three strains of Pseudomonas putida on the growth and productivity of King Pakal hybrid habanero pepper with limited inorganic fertilizer in a greenhouse. It was found that a reduction of inorganic fertilizer application of 25% with P. putida rhizobacteria strains increased or maintained growth and productivity of King Pakal hybrid habanero pepper. Before these rhizobacteria can be used in the field, results will first need to be confirmed under more natural conditions.     

Ammonia Volatilization from Soils Fertilized with Different Nitrogen Type and Application Method in Germination and Early Seedling Stages from the Radish Field

Ammonia volatilization(AV) from basal fertilizer with different nitrogen(N) types and application methods was investigated by the ventilation method in germination and early seedling stages during radish growth seasons in 2014. Four N fertilizer types, urea(U), ammonium bicarbonate(AB), ammonia sulfate(AS), and controlled urea formaldehyde(CUF) were applied through 5 cm depth placement(I) and 10 cm depth placement(II). The results showed that the N fertilizer type was the main factor that caused AV loss in germination and early seedling stages from the radish field. The highest and the lowest cumulative AV losses in germination and early seedling stages from the radish fields were 33.23 and 11.21 N kg/hm~2 for the treatments of AB+I and CUF+II, respectively, accounting for 60.40 and 26.40% of the N application for each treatment. The 10 cm deep placement of N reduced AV rates and lagged the AV process, and CUF significantly reduced ammonia volatilization. The data showed that the suitable N fertilizer type and application method for basal fertilizer were CUF and deep placement, respectively.Therefore, fertilizing with proper N fertilizer types and methods should be the efficient measures to mitigate AV losses from the radish field and will alleviate environment problems.