Timing Of Nitrogen Fertilizer Application Research Articles

Increase in rice productivity in the Senegal River valley due to improved collective management of irrigation schemes

Village irrigation schemes cover about 25% of the irrigated area on the two banks of the Senegal River. We analyzed irrigation scheme and rice crop management practices during the 1998 wet season in this type of irrigation scheme in Mauritania. Average yield was 4.8 t ha-1; problems with irrigation rules resulted in great variability of irrigation frequency between fields, and sub-optimal timing of nitrogen fertilizer application resulted in yield losses. Based on this diagnosis, we suggested to farmers new irrigation rules and cropping calendars planned on the scale of the irrigation scheme. Planned cropping calendars were built using CalCul, a software that we designed on the basis of the irrigated rice development model RIDEV. These suggestions of improved collective management were implemented in the 1999 and 2000 wet seasons. Average yield reached 7.2 t ha-1 in 1999 and 8.2 t ha-1 in 2000, without any significant increase in production costs. This great increase in rice productivity was mainly due to better collective management obtained through planning cropping calendars. This result showed that technical innovation is not the only way to improve productivity. (Resume d'auteur)

Influence of nitrogen application rate and timing on grain protein composition and gluten strength in Swedish wheat cultivars

AbstractThe influence of nitrogen (N) fertilizer application rate (0 vs. 70 vs. 140 kg N ha–1) and timing (early = at sowing vs. late = at sowing and before heading) on the amount of protein groups, amount and size distribution of mono‐ and polymeric proteins, and gluten strength was investigated in one set of wheat cultivars (Triticum aestivum L.). Due to their genetic background, the cultivars had different protein concentrations and gluten strengths. Despite this, all of them reacted similarly on rate and timing of nitrogen application. The rate of nitrogen fertilizer increased the variation in protein concentration, gluten strength, and also the variation in most of the investigated protein components. Higher nitrogen fertilizer rate increased protein concentration, decreased gluten strength, and increased the total amount of glutenins and gliadins as well as the amounts of most mono‐ and polymeric proteins. Timing of fertilizer did not influence protein concentration. The gluten strength and the relations of proteins were changed by the timing of fertilizer. Early nitrogen feritilizer applications led to higher gluten strength and a higher percentage of total unextractable polymeric protein in the total polymeric protein and large unextractable polymeric protein in the total large polymeric protein, compared to late nitrogen fertilizer applications.

Crop uptake of 15N labelled fertilizer in spring wheat affected by application time

Time of nitrogen fertilizer application on crop recovery was studied in a field experiment at Foulumgaard, Denmark, in 2001. A solution of 15N-ammonium-15N-nitrate was applied in bands parallel to a single row of spring wheat grown in frames of 30 cm×40 cm. The labelled fertilizer was applied on 16 dates with intervals of 4–5 days from tillering to the start of grain-filling. Crop 15N recovery increased by 0.47%-point day−1 when the time of fertilizer application was postponed from tillering until the second node stage (GS32). On the other hand, a decrease in crop 15N recovery of –0.19%-point day−1 was recorded from GS47 to maturity (GS85–87). The effect of the 16 application times on 15N recovery was described by two straight lines having intersection at the time of full expanded flag leaf and ear emergence halfway (GS55). It was concluded that leaf area expansion is important for crop N demand and 15N recovery.

Influence of Rate, Timing, and Method of Nitrogen Fertilizer Application on Uptake and Use of Fertilizer Nitrogen, Growth, and Yield of June-bearing Strawberry

Fertilizer nitrogen (FN) recovery, and changes in nitrogen (N) and dry weight partitioning were studied over three fruiting seasons in June-bearing strawberry (Fragaria ×ananassa Duch. `Totem') grown in a matted row system. Fertilizer nitrogen treatments were initiated in 1999, the year after planting. The standard ammonium nitrate N application at renovation (55 kg·ha-1 of N) was compared to treatments where additional N was applied. Supplemental treatments included both ground-applied granular ammonium nitrate (28 kg·ha-1 of N) applied early in the season and foliar urea [5% (weight/volume); 16 kg·ha-1 of N] applied early in the season and after renovation. When labeled N was applied (eight of nine treatments) it was applied only once. The impact of no FN from the second through the third fruiting season was also evaluated. Fertilizer nitrogen treatment had no impact on total plant dry weight, total plant N, yield or fruit quality from the first through the third fruiting seasons. Net dry matter accumulation in the first fruiting season was 2 t·ha-1 not including the 4 t·ha-1 of dry matter removed when leaves were mowed during the renovation process. Seasonal plant dry weight and N accumulation decreased as the planting aged. Net nitrogen accumulation was estimated at 40 kg·ha-1 from spring growth to dormancy in the first fruiting season (including 30 kg·ha-1 in harvested fruit, but not including the 52 kg·ha-1 of N lost at renovation). Recovery of fertilizer N ranged from 42% to 63% for the broadcast granular applications and 15% to 52% for the foliar FN applications, depending on rate and timing. Fertilizer N from spring applications (granular or foliar) was predominantly partitioned to leaves and reproductive tissues. A large portion of the spring applied FN was lost when plants were mowed at renovation. Maximum fertilizer use efficiency was 42% for a granular 55 kg·ha-1 application at renovation, but declined to 42% just before plant growth the following spring, likely a result of FN loss in leaves that senesced. In June, ≈30% of the N in strawberry plants was derived from FN that was applied at renovation the previous season, depending on year. This stored FN was reallocated to reproductive tissues (22% to 35%) and leaves (43% to 53%), depending on year. Applying fertilizer after renovation increased the amount of remobilized N to new growth the following spring. The following June, 15% of plant nitrogen was derived from fertilizer applied at renovation 2 years prior.

The impact of defoliation frequency and nitrogen fertilizer application in spring on summer survival of perennial ryegrass under grazing in subtropical Australia

Abstract This field study investigated the effect of timing of nitrogen (N) fertilizer application in spring on the survival of grazed perennial ryegrass (Lolium perenne cv. Dobson and Yatsyn) over summer in a subtropical environment. There were five N fertilizer treatments: no applied N, 46 kg N ha−1 on 22 October or 22 November or 22 December, or on 22 October and again on 22 December. Water‐soluble carbohydrate (WSC) concentration of perennial ryegrass plants entering the summer was altered by varying defoliation frequency, with defoliation interval based on the number of leaves per tiller. Frequent defoliation was set at a regrowth level of one leaf per tiller and less frequent defoliation at a regrowth level of three leaves per tiller, over a total of two by three‐leaf per tiller regrowth periods. Application of N fertilizer was found to have no significant effect (P > 0·05) on survival of perennial ryegrass plants over summer. On the other hand, defoliation had a marked effect on perennial ryegrass persistence, with frequent defoliation decreasing ryegrass plant density (51 vs. 88 plants m−2; P < 0·001) and increasing the density of tropical weed grasses (99 vs. 73 plants m−2; P < 0·001) by autumn. Frequently defoliated plants had a lower stubble WSC content on a per plant basis than less frequently defoliated plants in spring (103 vs. 201 mg per plant; P < 0·001) and summer (59 vs. 101 mg per plant; P < 0·001). The lower WSC content was associated with a smaller root system in spring (1·50 vs. 2·14 g per plant; P < 0·001) and autumn (1·79 vs. 2·66 g per plant; P < 0·01), and this was reflected in 0·29 more plants being pulled from the soil by livestock between November 1996 and April 1997. Rhizoctonia fungus was associated with roots of pulled plants, but not with roots of seemingly healthy plants, indicating that this fungus may have a role in a weakened root system, which was more prone to sod pulling. Nitrogen applied in October and November resulted in a reduced WSC concentration, although the effect was restricted to 1 month after N application. The present study indicates that survival of perennial ryegrass plants over the summer in a subtropical region is prejudiced by frequent defoliation, which is associated with a lower WSC concentration and a shallower root system. Under grazing, sod pulling is a reflection of this weaker root system and contributes to plant mortality.

Using Insurance to Enhance Nitrogen Fertilizer Application Timing to Reduce Nitrogen Losses

AbstractNitrogen applied before planting is more vulnerable to loss to the environment than nitrogen applied during the growing season, but the growing season application can increase the risk of lower yields caused by adverse weather that prohibits farmers to complete N application. An expected utility framework is used to illustrate the potential economic benefit of insurance for a farmer to reduce this risk cost. An expected-value variance analysis is used to illustrate the potential benefit of insurance to Iowa corn growers who apply N fertilizer only during the growing season.

Improving the productivity and profitability of irrigated rice production in Mauritania

Yield, input use, productivity and profitability of irrigated rice in Mauritania were analyzed during the 1997 wet season (July–December) in the Senegal river delta and middle valley, in collaboration with 42 large farmers and extension staff. Objectives were to determine agronomic constraints to rice cropping and to evaluate alternative crop management strategies aimed at overcoming these constraints. Grain yields ranged from 0.9 to 8.5 t ha −1 and averaged 4.4 t ha −1. Based on crop simulations, average yield potential in farmers' fields was estimated at 8.6 t ha −1, indicating considerable scope for increased yields. Our survey identified the following main agronomic constraints: (i) mismatches between timing of nitrogen (N) fertilizer applications and critical N demanding growth stages of the rice plant; (ii) non-use of phosphorus (P) fertilizer on P deficient soils; (iii) largely neglected or inefficient weed management and (iv) late harvesting, often due to non-availability of combine harvesters. Based on these results we tested improved nutrient and weed management practices with farmers during the 1998 wet season. Improved nutrient management (i.e. T1: application of 20 kg P ha −1 and 150 kg N ha −1 in three splits at start tillering, panicle initiation and booting) increased yields by 0.9 t ha −1. Improved weed management (i.e. T2: application of 6.0 L propanil ha −1 and 2.0 L 2,4- d-amine ha −1 at 2–3 leaf stage of weeds) also raised yields by 0.9 t ha −1 as compared to farmers' practice (TP). The combined effect of T1 and T2 (i.e. T3) was additive: improving both nutrient and weed management raised yields by 1.8 t ha −1 over average farmers’ yields of 3.9 t ha −1, i.e. an increase of almost 50%. The improved crop management practices were highly profitable: compared to farmers’ practice, net benefits increased by 40% for T1 and T2 and by about 85% for T3, with minimal additive investments. Inputs used for T3 are relatively easily available in Mauritania. We concluded that increased farmer awareness of the profitability of improved nutrient and weed management may have a tremendous impact on the competitiveness of rice production in Mauritania

Simulation of Water and Nitrogen Balances of Irrigated and Fertilized Corn-Crop Soil

Soil water and nitrogen dynamics under a corn-crop field in Northern Greece were simulated during the 1996 growing period and the subsequent noncropped period. The soil water and nitrogen simulations were evaluated using a one-dimensional model based on the Galerkin finite-element method. The simulations describe dynamic environmental conditions, irrigation schedule, and inorganic N applications. They were carried on two plots of the field that differed in the amount and timing of nitrogen fertilizer applications. Inadequate irrigation water was applied, resulting in low availability of water in the root zone. The qualitative and quan- titative procedures for model evaluation showed that there was good agreement between the simulated and the measured values of water content and inorganic species of N at different soil depths and the cumulative N uptake by plants. The average error was 0.006 cm 3 /cm 3 for water content and ranged from 21.06 to 0.052 mg/g soil for NH4-N and from 20.107 to 2.753 mg/g soil for NO3-N. Different procedures for getting the characteristic curves result in differing water contents and nitrogen concentrations in the soil.

Rate and timing of nitrogen fertilizer applications on wheat grown under dryland and supplementary irrigation

Field experiments were carried out at the University of Sydney Farm, to examine nitrogen fertilizer application strategies for increasing N uptake and productivity of wheat (Triticum aestivum L.) grown on a red-brown earth (Natrixeralf) in Australia, under dryland and supplementary irrigation. Increasing N rate increased shoot dry matter and N uptake consistently but grain yield response was greatly dependent on soil moisture or rainfall in the post-heading period. Water availability at this time determined kernel weight and hence grain yield, even when sufficient grain number had been established. Split application of N increased N uptake most, when the second dose was applied at tillering. On the other hand, delayed applications to the time of heading or anthesis resulted in a relatively lower uptake of N even with supplementary irrigation. The effect of a single pre-sowing application was similar to that applied at sowing or early tillering. We conclude that a split application of N is important for increasing N uptake when the second dose is applied during tillering rather than at heading or anthesis.

Enhancing Nitrogen Fertilizer Application Timing by Insurance

ABSTRACT The advantage of using insurance to help a farmer adopt a best nitrogen management plan (BNMP) that reduces the impact of agricultural production on the environment is analytically and empirically demonstrated. Using an expected value analysis, it is shown that an insurance program can be structured so as to reduce a farmer's cost of bearing the adoption risk associated with changing production practices and, thus, to improve the farmer's certainty equivalent net return thereby promoting the adoption of a BNMP. Using the adoption of growing-season only N fertilizer application in Iowa as a case study, it is illustrated how insurance may be used to promote the adoption of this practice to reduce N fertilizer use. It is shown that it is possible for a farmer and an insurance company both to have an incentive to develop an insurance adoption program that will benefit both the farmer and the insurance company, increasing net social welfare and improving environmental quality in Iowa.

Level and Timing of Nitrogen Fertilizer Application to Early and Semi-early Potatoes (Solanum tuberosum L.) Grown with Irrigation on Light Soils in Norway

Trials were performed with early and semi-early potatoes to test the effects of nitrogen (N) fertilizer level (0-160 kg N ha-1) and timing (all at planting versus half then and half either soon after emergence or 3 weeks later). All seven trials with earlies were irrigated as required, whilst different irrigation regimes (moderate versus intensive) were compared in two trials with semi-earlies. No benefit was derived from splitting the N application. Haulm growth and N uptake increased in all cases almost linearly up to the highest N level, but tuber yield did not respond in the same way. The optimum N level was 80 kg N ha-1 for a yield of 15 Mg ha-1, rising to 120 kg N ha-1 for a yield of 40 Mg ha-1. Tuber quality was lowered by the use of excess N fertilizer, particularly in the case of earlies. The quantity of mineralised N present in the soil after harvest rose sharply with above optimum fertilizer use, and the amount of N present in crop residues also increased. The likely leaching after early potatoes was estimated to be up to 80 kg N ha-1. The proportion of fertilizer N which was not accounted for in either tuber yield, crop residues or mineral N in soil was 26% in earlies and 38% in semi-earlies.

Modelling of Soil Water Dynamics in an Irrigated Corn Field using Direct and Pedotransfer Functions for Hydraulic Properties

A simulation study of the soil waterdynamics in a corn field was carried out inan area of Northern Greece during the 1996growing period. The soil water dynamicswere evaluated using a one-dimensionalmodel based on the Galerkin finite elementmethod. The simulations were carried out ontwo plots in the field which differed as tothe amount and timing of nitrogenfertilizer application. The irrigationwater was applied to the field ininadequate quantities, which resulted inlow water availability. Two procedures forobtaining soil hydraulic properties weretested with regard to the application inthe simulations. The pedotransfer functionsdeveloped by Vereecken et al. (1989,1990) were used to determine the parametersof the soil hydraulic functions, which werethen used in the model to simulate the soilwater dynamics. The simulated results werecompared with available measurements ofwater content at different depths in thesoil during the growing period. Thequalitative and quantitative procedures formodel evaluation showed that there was goodagreement between the simulated and themeasured values of water content atdifferent depths of soil. Results show thatsimulations based on pedotransfer functionspredict the water content reasonably wellcompared to results with the directedestimated hydraulic functions.

The effect of changing patterns of fertilizer applications on the major mineral composition of herbage in relation to the requirements of cattle: a 50-year review

Abstract Annual surveys of fertilizer practice have been conducted since 1942. Since 1985, nitrogen application rates to grass have progressively declined and phosphorus application has been reduced since the mid 1970s. Increasing environmental issues and the present interest in organic farming and low input systems indicate that these trends will continue. Present overall fertilizer use for grazing on dairy farms is about 170 kg N, 10 kg P and 20 kg К per ha. Higher rates are used for intensive silage production, 200 kg N, 15 kg P and 50 kg К per ha. In contrast, recommended applications are 340 kg N, 18 kg P and 25 kg К per ha for grazing and 380 kg N, 40 kg P and 260 kg К per ha for intensive silage. Herbage yield is controlled by the amount and timing of nitrogen fertilizer applications. The major mineral content depends on herbage maturity within the growth cycle; both phosphorus and potassium contents fall with declining crude protein concentrations. Nitrogen fertilizer generally increases both magnesium and sodium concentration whilst potassium application decreases both. The overall effect of combined applications is to minimize changes. In the critical spring and autumn periods, herbage dry-matter intakes may be as important as magnesium content and availability when assessing the risk of hypomagnesaemia in the grazing cow. Fertilizers, including phosphorus, even in the long term, have little effect on the calcium and phosphorus contents of herbage. Nitrogen and phosphorus concentrations are significantly ocrrelated in grazed herbage, silage and hay. If environmental or economic policies were to result in a reduction in the crude protein content of grazed herbage from ca. 250 to ca. 200 g/kg dry matter, the phosphorus intake of a cow giving 30 kg milk per day would fall by 0·5 g/kg dry-matter intake. This, together with any desirable additional magnesium, should preferably be given as an oral mineral supplement rather than by attempting to modify the mineral content of herbage.

Effects of density of planting and time of nitrogen application on maize varieties in different ecological zones of West Africa

Field experiments were conducted in 1992 on soils which have been classified as Alfisols ranging from Paleustalf to Oxic Paleustalf which represent three different ecological zones of West Africa. This research was conducted to determine the effect of density of planting on yield and yield components at 53,333, 66,666, and 79,999 plants‐ha‐1 and time of nitrogen (N) fertilizer application [50% at planting and 50% at four weeks after planting (4WAP), entire N application at two weeks after planting (2WAP), and 50% at planting and 50% at anthesis]. The experiment was a factorial arrangement fitted to randomized complete block design and replicated three times. The maize (Zea mays L.) varieties used in this study gave increased yields at population density up to 53,333 plants‐ha‐1 in Ikenne and Mokwa, while a response of 79,999 plants‐ha‐1 was obtained at Kaduna. The results also showed that a split application of N at planting and 4 WAP appeared to be the best for Ikenne, while the entire application at 2WAP appeared to be the best in savanna ecologies. The results indicate increase yield with increasing latitude suggesting that the higher solar radiation in the savanna ecologies increase the photosynthetic capacity of the maize plants used in the study. Maize genotypes used in this study did not respond to density beyond 53,333 plants‐ha‐1 at Ikenne and Mokwa, though a response was obtained up to 79,999 plants‐ha‐1 at Kaduna. Thus, it can be concluded that density response is location dependent and that farmers should plant maize at highest optimum plant population density as determined by experimental results in each ecological zone of West Africa. The results also showed that a split application of N at planting and 4WAP appeared to be the best for Ikenne, while the entire N application at 2WAP appeared to be the best for the savanna ecologies.

Effect of Nitrogen Fertilizer Application at Different Stages on the Quality of Green Tea

Abstract Studies were carried out on the effect of the time of nitrogen fertilizer application to tea plants in spring on the quality constituents of new shoots using sand culture in a green house. Fertilizer was applied in spring each week at 300 ppm N starting from 35 d before the first plucking. The contents of total nitrogen, total amino acids, tannin, caffeine, and the composition of the amino acids and amides were determined. Nitrogen application, 5 to 3 weeks before the first plucking, did not affect the content of theanine (γ-glutamyl ethylamide), one of the major constituents of tea quality, and thereafter the content decreased. These results suggested that inorganic nitrogen fertilizer should be supplied until two weeks before the first plucking. 15N-nitrogen labeling experiment was also conducted to study the contribution of 15N-nitrogen in new shoots of tea and the content of theanine, and the results were discussed.

Nitrogen Fertilizer Rate and Timing Effect on Bread Wheat Protein in Eastern Canada

AbstractNitrogen management for production of bread quality wheat (Triticum aestivum L.) in eastern Canada has received little research attention. An experiment was conducted for 2 years at each of two sites in Québec to study the effect of level and timing of nitrogen (N) fertilizer application on grain protein concentration, protein content per seed, non‐protein seed dry matter, grain protein yield and nitrogen harvest index (portion of plant N in the grain) of four hard red spring wheat cultivars known to have potential as bread wheats in eastern Canada. The soil types were Bearbroock clay (fine, mixed, non‐acid, frigid, Humaquept) and Ste‐Rosalie clay (typic, non‐acid, frigid, Humaquept). The experiment was a 4 × 4 × 2 factorial. Four cultivars were used: Columbus, Katepwa, Max and Hege 155–85. In both years 0, 60, 120 and 180 kg Nha−1 were applied either all at seeding or 60 % at seeding and 40 % at heading. Grain protein concentration and grain protein yield increased consistently with increasing N fertilizer and with split N application. Nitrogen harvest index was not increased by increasing applications of N fertilizer. Protein content per seed was more critical in determining grain protein concentration than non‐protein seed dry matter content. The western Canadian cultivars Columbus and Katepwa generally had greater grain protein concentration than the European cultivars Max and Hege 155–85, With reasonable N fertility the grain protein concentration of spring wheats grown in eastern Canada are sufficient for bread production.

Application of a Maize Crop Simulation Model in the Central Region of Malawi

SUMMARYA computer crop simulation model of the growth and development of maize was validated using data sets obtained from field experiments run at various sites in the mid-altitude maize zone of central Malawi between 1989 and 1992. The model was used to provide information concerning management options such as the timing and quantity of nitrogen fertilizer applications and to quantify the weather-related risks of maize production in the region. It was linked to a Geographic Information System to provide information at a regional level that could ultimately be of value to policy makers and research and extension personnel.

A note on nitrogen fertilizer application timing

This paper is concerned with a farmer's decision on the timing of nitrogen fertilizer application. An analytical model is developed to determine the necessary conditions for the optimal timing of the application of nitrogen fertilizer. The empirical results explain various observed application timings of nitrogen fertilizer being used in cotton production in Mississippi and provide an estimate of the cost to a farmer when he or she must comply with a restriction on the timing of the application of nitrogen fertilizer.

Assessing a farmer's decision concerning the application timing of nitrogen fertilizer

This paper is concerned with a farmer's decision on the timing of nitrogen fertilizer application. Analytical models are developed to determine the necessary conditions for the optimal timing of the application of nitrogen fertilizer. The models, coupled with an estimated cotton yield function, are used to assess a farmer's decision on the optimal application timing of nitrogen fertilizer in cotton production. The empirical results explain various observed application timings of nitrogen fertilizer being used in cotton production in Mississippi, USA, and provide an estimate of the cost to a farmer when he or she must comply with a restriction on the timing of the application of nitrogen fertilizer.

Effect of rate and timing of nitrogen fertilizer application on the proportion of ear, the digestibility of straw constituent and the quality of whole crop barley at different stages of maturity

In each of two successive years, spring barley ( Hordeum vulgare L.) was fertilized with 90, 130 and 170 kg nitrogen (N) ha −1. For the higher application rates, N was either given entirely in the seedbed (i.e. single application), or the application was split, with most being given at sowing and 40 kg N ha −1 added when the crop reached the initial ear emergence stage of development (i.e. split application). Assessments were made of the proportion of ear and the quality of the whole crop and its straw fraction with advancing maturity. Raising the quantity of fertilizer N led to greater lignification and a reduction in the in vitro digestibility of organic matter (IVOMD) in the straw fraction. Responses were comparable at all stages of maturity, but differed between the two experiments, probably because of interactions with climatic factors. Compared with the single application, the split application approach reduced lignification and improved IVOMD. The proportion of ear in the barley crop was slightly reduced by higher N applications. In contrast, split applications had a small, positive, though non-significant, effect on this parameter. Increased lignification as well as a reduced proportion of ear may combine to depress the IVOMD of the whole crop barley in response to heavier N fertilization. By delaying the application of part of the N until the initial ear emergence stage the effects were partly alleviated.