Empirical analysis and prediction of nitrate loading and crop yield for corn-soybean rotations

Nitrate nitrogen losses through subsurface drainage and crop yield are determined by multiple climatic and management variables. The combined and interactive effects of these variables, however, are poorly understood. Our objective is to predict crop yield, nitrate concentration, drainage volume, and nitrate loss in subsurface drainage from a corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) rotation as a function of rainfall amount, soybean yield for the year before the corn-soybean sequence being evaluated, N source, N rate, and timing of N application in northeastern Iowa, U.S.A. Ten years of data (1994-2003) from a long-term study near Nashua, Iowa were used to develop multivariate polynomial regression equations describing these variables. The regression equations described over 87, 85, 94, 76, and 95% of variation in soybean yield, corn yield, subsurface drainage, nitrate concentration, and nitrate loss in subsurface drainage, respectively. A two-year rotation under average soil, average climatic conditions, and 125 kg N/ha application was predicted to loose 29, 37, 36, and 30 kg N/ha in subsurface drainage for early-spring swine manure, fall-applied swine manure, early-spring UAN fertilizer, and late-spring split UAN fertilizer (urea ammonium nitrate), respectively. Predicted corn yields were 10.0 and 9.7 Mg/ha for the swine manure and UAN sources applied at 125 kg N/ha. Timing of application (i.e., fall or spring) did not significantly affect corn yield. These results confirm other research suggesting that manure application can result in less nitrate leaching than UAN (e.g., 29 vs. 36 kg N/ha), and that spring application reduces nitrate leaching compared to fall application (e.g., 29 vs. 37 kg N/ha). The regression equations improve our understanding of nitrate leaching; offer a simple method to quantify potential N losses from Midwestern corn-soybean rotations under the climate, soil, and management conditions of the Nashua field experiment; and are a step toward development of easy to use N management tools.     

Short-term effects of organo-mineral enriched biochar fertiliser on ginger yield and nutrient cycling

Purpose

Biochar has agronomic potential but currently is too expensive for widespread adoption. New methodologies are emerging to reduce the cost such as enriching biochar with nutrients that match crops and soil requirements. However, the effects of biochar-based fertilisers on plant yield and soil nutrient availability have not been widely examined. This study investigated the effects of a novel organo-mineral biochar fertiliser in comparison to organic and commercial biochar fertiliser on ginger (Zingiber officinale Canton).

Materials and methods

There were four treatments: (1) commercial organic fertiliser (5 t ha^?1), as the control; (2) commercial biochar-based fertiliser (5 t ha^?1); (3) organo-mineral biochar fertiliser at low rate (3 t ha^?1); and (4) organo-mineral biochar fertiliser at high rate (7.5 t ha^?1). A replicated pot trial was established with black dermosol soil and ten replicate pots for each treatment. Ginger was planted and grown for 30 weeks. Plant growth, biomass, foliar nutrients and water extractable soil nutrients including phosphorus (P), potassium (K) and calcium (Ca) were examined.

Results and discussion

High rate organo-mineral biochar fertiliser increased soil P and K availability at week 30 (harvest) after planting, compared to all other treatments and low rate organo-mineral biochar fertiliser performed similarly to the organic control for P and K. High rate organo-mineral biochar fertiliser increased total foliar nutrient content at week 30 in P, K and Ca compared to commercial biochar fertiliser. High rate organo-mineral biochar fertiliser improved the commercial value of ginger (+?36%) due to a shift in the proportion of higher grade rhizomes. Low rate organo-mineral biochar fertiliser plants displayed similar yield, total dry and aboveground biomass to commercial organic fertiliser. Commercial biochar fertiliser had significantly lower biomass measures compared with other treatments as the rate applied had lower nutrient concentrations.

Conclusions

Our results show organo-mineral biochar fertilisers could be substituted for commercial organic fertilisers at low rates to maintain similar yield or applied at high rates to increase commercial value where economically feasible.

     

Effect of nitrogen fertiliser on temporal and spatial variation of mineral nitrogen and microbial biomass in a silvopastoral system

This paper describes a field study to assess the effect of increasing the frequency of split applications of N fertiliser on the pattern of plant uptake, soil N availability, and microbial biomass C and N. Measurements were taken during the growing season in different positions relative to young trees (Prunus avium L.) in an upland silvopastoral system in its first year after establishment. At fertiliser rates of 72 and 144 kg ha^-1 N applied as NH₄NO₃, increasing the number of split applications increased N uptake by the pasture. Mineral forms of soil N measured 2 weeks after application indicated that residual NH _inf4 ^sup+ -N and total mineral N were also greater in this treatment on certain dates. Soil NO _inf3 ^sup- -N was positively correlated with the soil moisture content, and nitrification reached a maximum in early May and declined rapidly thereafter except within the herbicide-treated areas around the trees where soil moisture had been conserved. Results of the study suggest that high NO _inf3 ^sup- -N in herbicide-treated areas was probably caused by mineralisation of grass residues and low uptake by the tree rather than by preferential urine excretion by sheep sheltering beside the trees. Mean microbial biomass C and N values of 894 and 213 kg ha^-1, respectively, were obtained. Microbial C was slightly increased by the higher frequency of split applications at 144 kg ha^-1 N and was probably related to the greater herbage production with this treatment. Microbial N was not significantly affected by the N treatments. Both microbial biomass C and N increased during the growing season, resulting in the net immobilisation of at least 45 kg ha^-1 N which was later released during the autumn.     

Effects of nitrogen fertiliser and pesticide management on floodwater ecology in a wetland ricefield

We investigated the effects of N fertiliser and pesticide applications on the population dynamics of benthic molluscs in a tropical wetland rice field. Populations were monitored for two consecutive dry seasons in selected treatments during a study on the effects of agricultural practices on the floodwater ecology of tropical rice fields. The most abundant species recorded in the ricefields were the snailsMelanoides tuberculata andMelanoides granifera. Population densities and biomass values in planted plots ranged between 0 and 1530 individuals m^-2 and 0 and 1060 kg ha^-1, respectively. Snails were more abundant in unplanted than planted plots (1991: 170–2040 versus 0–1040 individuals m^-2, respectively). Populations in planted plots declined as the crop season progressed. Snail populations were significantly reduced by the broadcast application of mineral N fertiliser at 110 kg N ha^-1. There was little evidence that snails were affected by carbofuran or butachlor applications.     

Sap analysis for diagnosis of nitrate accumulation in cereal forages

Abstract

Development of a quantitative, preharvest quiektest for NO₃ levels in cereal forages would improve crop management options to avoid NO₃ toxicity in livestock. Our objective was to determine if concentrations of NO₃ in sap expressed from oat (Avenasativa) and barley (Hordeum vulgare) are correlated with those in dry tissue of simultaneously harvested hay, and to test the reliability of the Cardy portable NO₃ meter for sap analysis in these species. In 1993, whole plant samples were gathered from plots fertilized with variable nitrogen (N) rates at four environments in Montana, and were analyzed for NO₃ concentration in lower‐internode sap and in whole plant dry matter. In 1994 and 1995, the study was repeated at two environments. The sampling technique included three subsamples from each plot for sap analysis, followed immediately by harvest of the entire plot for hay, and further subsampling for dry matter NO₃ analysis after drying. Linear correlations between dry matter and sap NO₃ concentrations were found across species at each environment in 1993 with r values of 0.64 to 0.81. No relationship was established for oat at one environment. Locations differed in the coefficient of correlation, indicating environmental influences on the relationship and/ or variability due to sampling technique. In 1994 and 1995, each species fit a separate linear correlation across site‐years with r values of 0.89 (oat) and 0.87 (barley). The consistency across site‐years (1994–1995) indicates that the variability in preliminary results was overcome with sampling technique. We propose a quantitative quiektest for NO₃ levels in cereal forages using conditional predictions of dry matter NO₃ based on observed values of sap NO₃. Since sap NO₃ readings with the Cardy portable nitrate meter were well correlated (r=0.93) with Accumet ISE readings across critical ranges, quiektest procedures are practical.     

Effects of tillage, organic resources and nitrogen fertiliser on soil carbon dynamics and crop nitrogen uptake in semi-arid West Africa

Tillage, organic resources and fertiliser effects on soil carbon (C) dynamics were investigated in 2000 and 2001 in Burkina Faso (West Africa). A split plot design with four replications was laid-out on a loamy-sand Ferric Lixisol with till and no-till as main treatments and fertiliser types as sub-treatments. Soil was fractionated physically into coarse (0.250–2 mm), medium (0.053–0.250 mm) and fine fractions (< 0.053 mm). Particulate organic carbon (POC) accounted for 47–53% of total soil organic carbon (SOC) concentration and particulate organic nitrogen (PON) for 30–37% of total soil nitrogen concentration. The POC decreased from 53% of total SOC in 2000 to 47% of total SOC in 2001. Tillage increased the contribution of POC to SOC. No-till led to the lowest loss in SOC in the fine fraction compared to tilled plots. Well-decomposed compost and single urea application in tilled as well as in no-till plots induced loss in POC. Crop N uptake was enhanced in tilled plots and may be up to 226 kg N ha⁻¹ against a maximum of 146 kg N ha⁻¹ in no-till plots. Combining crop residues and urea enhanced incorporation of new organic matter in the coarse fraction and the reduction of soil carbon mineralisation from the fine fraction. The PON and crop N uptake are strongly correlated in both till and no-till plots. Mineral-associated N is more correlated to N uptake by crop in tilled than in no-till plots. Combining recalcitrant organic resources and nitrogen fertiliser is the best option for sustaining crop production and reducing soil carbon decline in the more stabilised soil fraction in the semi-arid West Africa.     

油菜因产定氮及猪厩肥中氮素利用折算率研究

在浙江中部发育于第四纪红土母质上的红壤性水稻土上设置田间试验 .提出当地油菜定氮公式 :N需 =0 0 7( y -1 1x) /E肥 .式中 ,y—足肥丰产下产量 ;x—无氮情况下产量 ;y和x之间可用y =67 2 2 58+1 2 1 98x表达 ;0 0 7是生产 1kg油菜籽 (含秸秆 )的需N量 (kg) ;E肥 为化肥利用率 ,它与x之间可用E肥 =4 9 2 3 6-0 2 3 53x表达 .此外明确在化肥和猪厩肥一起施用中 ,猪厩肥中N素利用折算率约为化肥N的一半左右 .     

Effects of nitrogen fertigation frequency on yield and nitrogen retention in drip-irrigated cotton

Fertigation techniques have been widely used in drip-irrigated cotton. The timing of nitrogen (N) fertilizer injections then becomes a management question producers need guidance on. This study investigated the effect of nitrogen (N) fertigation frequency on drip-irrigated cotton. Experiments were conducted in the Southeastern Anatolia Region of Turkey in 2011 and 2012. A split-plot experimental design was applied. The main plots contained two different lateral spaces: A, one drip-line (lateral) per row; and B, one lateral for every two rows. Sub-plots were designed with different frequencies of fertigation as follows: a, the application of fixed amount of N at each irrigation cycle (5 days); b, the application of fixed amount of N every two irrigation cycles (10 days); and c, the application of one-fifth of the total N between the first irrigation and first flowering, two-fifths between the first flowering and formation of the first boll, and one-fifth between the formation of the first boll and last irrigation cycle. One-fifth of the total N was applied to the soil at sowing in all treatment regimens. The maximum cotton yield (4120 kg ha^?1) and highest total N content (2.57–2.94%) in the leaves were obtained with one lateral for every two rows and the application of fixed amount of N every two irrigation cycles (10 days). One-fifth of the total N might be applied to the soil at sowing, and the remaining N should be applied in equal doses (an average of 7 fertigations) every two irrigation cycles (10 days) by fertigation. However, further research fertigation methods for cotton, including the amount of N that needs to be applied and the use of different injection systems, is required.     

Diagnosis of the nitrogen status of wheat at tillering and prognosis for maximal grain yield

Abstract

From a field experiment in which wheat was supplied with nitrogen fertilizer at 0, 20, 40, 60, 80, 100, 150, 200, or 400 kg ha^‐1N, a correlation existed between nitrate concentration in wheat stems at tillering and subsequent grain yield. At early tillering, NO₃‐N concentrations around 8,000 μg g^‐1 were indicative of sufficient nitrogen in the crop‐soil system for maximum grain yield.

Averaging the results of this experiment with those from another seven field experiments, it was concluded that at tillering, the prognostic levels of NO₃‐N concentration in stems were: below 4000 μg g^‐1 deficient, between 4000 and 6000 μg g^‐1 intermediate, between 6000 and 10000 μg g^‐1 sufficient and above 10000 excessive for maximum grain yield. These values are applicable in a wide range of water supply conditions and to a number of cereal genotypes.     

A logistic equation for yield response of forage grass to nitrogen

Abstract

A logistic equation was used to relate dry matter yield to applied nitrogen for Pensacola bahiagrass. Data from Georgia with 5 N rates and for 5 years were used. Procedures were outlined for evaluation of the 3 parameters. The 2nd order Newton‐Raphson method was used to optimize parameters. The error matrix provided estimates of the standard error for each parameter, which were used for sensitivity analysis. Probability contours were constructed for the nonlinear parameters at 75% and 95% confidence levels. Finally, it was shown by analysis of variance that each parameter had a common value for all 5 years of data. Additional work is underway to relate model parameters to water availability and harvest interval.     

氮素施用比例对双季超级稻产量和氮素吸收、利用的影响

以超级早、晚稻品种淦鑫203和淦鑫688为材料,研究了氮素基蘖肥:穗肥的施用比例对产量及氮肥利用率的影响.结果表明,在早稻180 kg/hm2和晚稻232.5 kg/hm2的施氮水平下,早稻在N(8∶2)和N(7∶3)、晚稻在N(6∶4)时的生物产量、稻谷产量、总吸氮量、氮肥利用率最高.     

Effects of overall herbicide management and nitrogen fertiliser on the mineral composition of apple and pear fruits grown on various soils

Abstract

Cox's orange Pippin apple fruit samples obtained over five years from trials in five commercial orchards on different soil types where management systems were changed from herbicide strips in grassed alleys to overall herbicide were analysed for N, P, K, Mg, Ca and, in the early years, Na. At four of the sites an additional amount of N fertiliser was applied to half of the trees. When the treatments became established they usually lowered P concentrations and these effects of overall herbicide management and additional N were additive. The years in which the maximum effects occurred and the magnitude of the effects varied with site. Calcium concentrations were lowered at only two sites in some years mainly because overall herbicide management increased mean fruit mass. Treatment effects on other constituents varied but, at one site, overall herbicide and extra N fertiliser consistently increased N concentrations.

Conference and Doyenne du Comice pear fruits from a sixth site differed in composition with Conference having higher N and P concentrations but less Ca for a given mean fruit mass. Overall herbicide treatment lowered P and Ca concentrations in the Conference pears.     

Effect of nitrogen application on growth and yield of pumpkin

Evaluation of any crop response to different nitrogen amounts is important for determining the amount that can be considered as optimum from economical and environmental point of view. This study was conducted to (1) evaluate the growth and yield of pumpkin (Cucurbita pepo L.) under different nitrogen rates and (2) determine the nitrogen use efficiency (NUE) of pumpkin in two growing seasons (2013 and 2014). In both growing seasons, nitrogen fertilizer (at three rates including 50, 150, and 250 kg ha^?1) was band-dressed on the planted side of each furrow, coinciding with 4–6 leaves stage and flowering. Crop performance over 2 years was evaluated by measuring shoot dry matter, crop growth rate (CGR), leaf area index (LAI), leaf area duration (LAD), intercepted PAR (PAR_i), radiation use efficiency (RUE), shoot nitrogen uptake, water use efficiency (WUE), NUE, and fruit and seed yield. The results showed that in both growing seasons, the highest growth and yield of pumpkin were obtained by applying 250 kg N ha^?1 (using urea fertilizer containing 46% nitrogen). Increased nitrogen rate from 50 to 250 kg ha^?1 resulted in 87.3%, 27.0%, 62.1%, 87.5%, and 84.5% increase in shoot dry weight, RUE, WUE, fruit yield, and seed yield of pumpkin, respectively, across both growing seasons. However, higher application nitrogen rate decreased the NUE of pumpkin, i.e., the NUE decreased by 62.5% when the nitrogen rate increased from 50 to 250 kg ha^?1. The effect of nitrogen applied in 2014 growing season on growth and yield of pumpkin was higher than that in 2013 growing season, which might be due to more suitable weather condition. In conclusion, the nitrogen rate of 250 kg ha^?1 produced the highest amount of fruit and seed yield in pumpkin.     

The effect of preplant nitrogen and soil temperature on yield and nitrogen accumulation of alfalfa 1

Abstract

Recommendations for the use of preplant N in alfalfa establishment are controversial. Growth chamber experiments were conducted to examine the effect of preplant N and soil temperature on yield and N accumulation of alfalfa (Medicago sativa L.). Alfalfa was grown in river sand at three day/night soil temperatures (18/12°C, 24/16°C, and 27/21°C), and at five levels of preplant N (0, 10, 20, 40, 80 kg ha^?1). At 18/12°C, 40 kg ha^?1 preplant N resulted in a 69% increase in shoot dry matter yield. Dry matter and N accumulation rates were greatest at 40 and 80 kg ha^?1. Preplant N effects on dry matter and N accumulation at 18/12°C were expressed primarily between the early bud and early flowering stages. Assessment of soil temperature and soil N availability is necessary to determine the potential for a yield response of alfalfa to preplant N.     

Yield and chemical composition of five common grassland species in response to nitrogen fertiliser application and phenological growth stage

Abstract

The interaction of grassland management factors such as plant species, rate of nitrogen (N) fertiliser application and stage of maturity at harvest, will determine the optimal balance of herbage yield, nutritive quality and ensilability for ruminant nutrition and/or industrial applications. This study investigated the effects of N fertiliser input and harvest date on the yield and chemical composition of five common grass species, and made comparisons with red clover. Perennial ryegrass (PRG), Italian ryegrass (IRG), tall fescue, cocksfoot, timothy and red clover were grown under two inorganic N fertiliser inputs (0 kg N ha^?1 and 125 kg N ha^?1; except red clover) and harvested at five dates (fortnightly from 12 May to 7 July) in the primary growth. Regression analysis of these data allowed comparison of the yield and chemical composition of each grass species at common growth stages, without the confounding effects of variation in maturity between grass species at common harvest dates. Of the grass species investigated, timothy was most productive in terms of dry matter (DM) yield and thus has the potential to provide a cheaper feed per unit DM. However, the most digestible grass species was PRG, with timothy being the lowest, and this could impact on both animal and bioenergy production potential. The most suitable grass species for ensiling was IRG (particularly when grown without fertiliser N) due to its higher water soluble carbohydrate (WSC) concentration and lower buffering capacity (BC) compared to all other grass species. In comparison to the grasses receiving inorganic N fertiliser, red clover had a numerically lower DM yield, but a higher mean DM digestibility and crude protein concentration. The lower WSC concentration and higher BC of the red clover may result in a greater preservation challenge during ensiling.     

Optimal rate and schedule of nitrogen fertilizer application for enhanced yield and nitrogen use efficiency in dry-seeded rice in north-western India

Dry direct-seeded aerobic rice (DSR) is an emerging attractive alternative to traditional puddled transplanted rice (PTR) production system for reducing labour and irrigation water requirements in the Indo-Gangetic plains (IGP) of India. The fertilizer N requirement of DSR grown with alternate wetting and drying water management may differ from that of PTR grown under continuous flooding due to differences in N dynamics in the soil/water system and crop growth patterns. Limited studies have been conducted on optimizing N management and application schedule for enhanced N use efficiency in DSR. Therefore, field experiments were conducted over 3 years in NW India to evaluate the effects of N rate and timing of its application on crop performance and N use efficiency. Interaction effects of four N rates (0, 120, 150, and 180 kg ha^?1) as urea and four schedules of N application on yield and N use efficiency were evaluated in DSR. The N schedules included N application in three equal split doses (0, 35 and 63, and 14, 35 and 63 days after sowing, DAS) and four equal split doses (0, 28, 49 and 70; 14, 28, 49 and 70 DAS). There was no significant interaction between N rate and schedules on grain yield. Significant response to fertilizer N was observed at 120 kg N ha^?1 and economic optimum dose for three equal split doses and skipping N at sowing was 130 kg N ha^?1. Highest mean grain yield of 6.60 t ha^?1 was obtained when N was applied in three equal split doses at 14, 35 and 63 DAS which was about 8.5% higher compared with N applied in four equal split doses at 14, 28, 49 and 70 DAS. Under the best N application schedule, agronomic N use efficiency (26 kg grain kg^?1), recovery efficiency (49%) and physiological efficiency (53 kg kg^?1) were comparable to the values reported in Asia for PTR. Results from our study will help to achieve high yields and N use efficiency in DSR to replace resource intensive PTR.     

Grain yield and nitrogen use efficiency of various modern rice cultivars grown at different nitrogen levels

Field trials were conducted to study the responses of grain yield and nitrogen (N) use efficiency at five input rates (N₀, N_82.5, N₁₆₅, N_247.5, and N₃₃₀ kg ha^?1) in a set of nine of the most representative rice cultivars. Grain yields of rice across the nine cultivars were increased significantly by N level. All the cultivars contained a significant linear plus plateau or quadratic relationship between N levels and grain yields.The minimum yields (means of 2 years) at N₀, N_82.5, N₁₆₅, N_247.5, and N₃₃₀ level all occurred in No. 2 cultivar. Compared with the grain yield of No. 2 at different N levels, those of the maximum cultivars increased by 37.1 (No. 8), 39.1 (No. 7), 48.4 (No.3), 43.3 (No. 4), and 43.9% (No. 3), respectively. In 2011, the highest average apparent nitrogen recovery efficiency (ANRE) in grain of the 4 N levels occurred in No. 3 cultivar (45.9%), followed by No. 4, No. 6, and No. 1, and the highest average agronomic efficiency (AE) in grain of the 4 N levels occurred in No. 9 cultivar [29.0 kg (kg N)^?1], followed by No. 3, No. 1, and No. 4. For the second-season planting, the highest average ANRE occurred in No. 4 cultivar (28.4%), followed by No. 3, No. 5, and No. 6, and the highest average AE occurred in No. 5 cultivar [18.1 kg (kg N)^?1], followed by No. 4, No. 3, and No. 7. Overall, No. 3 and No. 4 cultivars were the ideal ones that not only increased the grain yield but also improved the N use efficiency.     

Salinity and nitrogen fertilization affecting the macronutrient content and yield of sweet pepper plants

The effects of salinity due to sodium chloride (NaCl) and nitrogen (N) concentration in the nutrient solution were studied with sweet pepper plants. Four saline treatments combined with two N fertilization were used. Nitrate‐nitrogen (NO₃ ^‐‐N) presence in the nutrient solution produced an increase of sodium (Na) and potassium (K) contents in leaves as well as N. Salinity promoted a reduction of K, phosphorus (P) and Ca and increased the Na concentration in leaves. Calcium (Ca) concentrations were lower in the higher NO₃ ^‐‐N treatment although N level was reached adding calcium nitrate and salinity increased P, K, Na, Ca, and magnesium (Mg) contents in fruits. Yield was increased in the highest N treatment.     

Developing a dynamic yield and growth model for maize under various water and nitrogen regimes

Better irrigation and nitrogen (N) scheduling and more efficient management of crop production require modeling of plant growth and crop yield. Models become more applicable if they are simple and require less and accessible inputs. The objective of this study was to use simple equations of soil water budget, evapotranspiration (ET), leaf area index (LAI), yield, and harvest index (HI)–transpiration function to develop a model for the prediction of growth and yield of maize under various water and N rates. The model was calibrated based on given data under sprinkler irrigation and verified based on independent data under furrow irrigation. The comparison between predicted and measured values of different crop parameters did not show any significant difference and the model was able to estimate LAI, ET, soil water content, HI, dry matter, and grain yield properly. Furthermore, an equation was presented to predict daily dry matter accumulation by a logistic curve for different water and N applications. It was concluded that the presented simple model was able to predict crop yield quite well and hence could be used for farm irrigation and N scheduling and management of both. Furthermore, the relationship between LAI and ET may be different in various environmental conditions that should be considered in using the model.