Response of greenhouse cucumber to mineral fertilizers on a high phosphorus and potassium soil

The response of greenhouse cucumber (Cucumis sativus L. cv. Lolita) to nitrogen (N), phosphorus (P) and potassium (K) fertilizers on a soil high in available P and K was studied during 1986. The greenhouses were located in the Beqa Valley, central Lebanon, and their soil chemical properties before planting were: NO₃‐N = 52 ppm, P(NaHCO₃ ext.) = 100 ppm, K (ammonium acetate ext.) = 650 ppm, ECe = 1.6 dS/m, pH = 7.5. Nitrogen at 200 kg/ha, P at 85 kg/ha and K at 150 kg/ha were applied in the following combinations: N, N+K, N+P+K and an unfertilized control. The rates were split into four equal weekly applications starting on the fourth week after transplanting the seedlings to the greenhouse. The treatments were applied through the drip irrigation system of the greenhouses. Fruit yield over the two months of harvest was highest in plants receiving N alone, which yielded 57 ton/ha. Yields of the plots receiving N+K, N+P+K and the control were 55.0, 54.0 and 39.5 ton/ha, respectively. Yield during the first month of harvest was comparable in all fertilized treatments and was substantially higher than the control.     

Effects of nitrogen and phosphorus on yields and tissue analyses of chili peppers

Abstract

Nitrogen applications affected plant growth characteristics, color, nutrient content of leaves and yield of chili peppers as shown by results in this two‐year study. Moderate rates of N (100–150 kg/ha) tended to produce a more desirable type of plant and highest yields. Phosphorus treatments did not affect yields under these conditions.

Analysis of stem‐petiole samples for nitrate appeared to be a good indicator of the N status of the plant. A heavy fruit set in August accompanied with NO₃‐N values below 8,000 to 10,000 ppm resulted in harvest time N deficiencies and lower yields.     

Interaction of salinity,nitrogen, and phosphorus fertilization on wheat

This study determined whether the application of nitrogen (N) and phosphorus (P) could ameliorate salt‐induced reduction in wheat production. Saline irrigation water (0.5, 4.0, 8.2, and 12.5 dS/m) and N and P fertilizers (150 kg N/ha and 37.5 kg P₂O₅/ha) were applied to wheat (Triticum aestivum L. ‘Saka 92') grown on a calcareous soil in a greenhouse experiment. Plants received equal amounts of each fertilizer, but the time and frequency of application differed. All salinity levels reduced straw and grain yields, leaf soluble proteins, nitrate (NO₃) content, actual and potential nitrate reductase activity (NRA), and grain protein content. The delay in pollen meiotic cell division increased with salinity. Under saline conditions, applying N and P fertilizers at the end of the grain filling stage improved yield and metabolic performance of the plants compared to other fertilizer treatments.     

Effect of N supply on apparent recovery of fertilizer N as crop N and Nmin in soil during and after cultivation of winter cereals

Field trials were conducted over two years to investigate the effect of increasing N supply on apparent fertilizer N recovery by winter cereal crops (4 × wheat and 2 × barley) and on non‐recovered N. Apparent fertilizer N recovery was calculated by comparing N in fertilized and unfertilized crops. Non‐recovered N is defined as N which was neither found in crops nor soil mineral N (N_min = NH₄‐N + NO₃‐N). At N supply levels according to common farming practice (N_cfp = 190 to 220 kg N/ha), 60— 93% of the fertilizer N was recovered in crops at harvest, while at high N supply levels of 265 to 273 kg N/ha 58—76% of fertilizer N was recovered. There were small differences in soil N_min in 0—200 cm between N_cfp and unfertilized plots, but substantial increases in N_min occurred at the highest N supply. Amounts of non‐recovered N differed substantially between sites (maximum value of 84 kg N/ha). Non‐recovered N increased with increasing N rate on only 3 out of the 6 sites, indicating that N immobilization was not necessarily dependent on N rate. The fate of non‐recovered N was studied for a further year by growing catch crops on the sites after cereal harvest. N re‐mineralization deduced from changes in catch crop N and in N_min indicated that non‐recovered N had been immobilized in the soil. At three sites, crop N uptake was found between milk‐ripe stage and harvest (19 to 60 kg N/ha) suggesting substantial uptake of N mineralized from soil. However, grain yields were lower with N rates below N_cfp, indicating that late net soil N mineralization could not compensate for reductions in N fertilizer rate in these trials.     

A petiole sap nitrate test for broccoli

Nitrogen (N) status of vegetable crops is often monitored by analysis of dried plant tissues. However, dry tissue analysis often causes a significant delay between sampling and analysis. This study was conducted to examine the accuracy of a portable nitrate meter for determining petiole sap nitrate (NO₃) contents, and the relationship between NO₃‐N concentration in fresh petiole sap and in dried petiole tissue of broccoli grown in southern Arizona during the 1993–94 and 1994–95 winter growing seasons. Experiments were factorial combinations of three irrigation rates and four N rates, both ranging from deficient to excessive. Petioles were sampled throughout each season, and split for sap and dry tissue analysis. A linear correlation was obtained between the two measurements in both seasons, with no consistent effect due to irrigation treatment or crop maturity. The regression coefficients did not differ among seasons. Therefore, a combined regression equation: Y=343+0.047X (r² = 0.799) was derived, in which Y=NO₃‐N (mg/L) in fresh petiole sap, and X=NO₃‐N (mg/kg) in dried petioles. These results suggest that the sap test can be a valuable and rapid technique to predict N needs of broccoli. Differences between the two methods are likely due to interferences in fresh petiole sap and slight differences in pools of extracted NO₃.     

Leaf nitrate partitioning and growth response in pumpkin as influenced by nitrogen rate

Abstract

Pumpkin species Cucurbita moschata ‘Dickenson Field’ and C. pepo ‘Connecticut Field’ were grown in the greenhouse in a Plain‐field sand at 8 rates of N applied as Ca(NO₃)_2. Petiole NO₃ concentrations in recently mature and mature leaves were highly responsive to N rate. Wien plants were stressed for N, translocation of petiole NO₃ was primarily to the corresponding blade. The levels as well as the range of NO₃ concentration in the leaf blade were lower than those in the petiole. The NO₃ content in the leaf blade was slower to react to N stress than that in the petiole. Variability in NO₃ concentration among leaf parts was lowest in the petiole and highest in the blade. For each leaf part, variability in NO₃ concentration decreased with leaf age. Critical NO₃‐N concentrations in C. moschata were estimated at 18950 and 3500 ppm in mature petioles and 14700 and 3050 ppm in recently mature petioles at early vegetative and full flower growth stages, respectively.     

Method of nitrogen application for muskmelons 1

Muskmelons (Cucumis melo L.) were transplanted through clear plastic mulch on May 22, 1981, with 45, 90, 135, or 180 kg N/ha applied either preplant broadcast incorporated or injected through the trickle system. Seventy percent of the N rate was injected by flowering (June 23) and the remaining 30% from June 23 to July 27, just prior to first harvest. Muskmelon petiole NO₃‐N concentration increased linearly with increasing N rates on all sampling dates for both application treatments. Trickle injected N resulted in a significantly higher plant N0₃‐N petiole concentration on June 22. Later in the season, July 13 and August 3, there were no petiole NO₃‐N concentration differences between the application methods. Marketable early and total yields were not affected by the N rate or application method; but the broadcast method, as compared with trickle injection, increased total fruit per plant by 12%. Soluble: solids and fruit size were not affected by the Nirate on application method; but the broadcast method, as compared with trickle injection, increased total fruit per plant by 12%. Soluble solids and fruit size were not affected by the N rate or application method.     

Response of fall greenhouse COS lettuce to clear mulch and nitrogen fertilizer

Application of clear plastic mulch with or without N fertilizer did not significantly increase (P > 0.05) yield of cos lettuce (Lactuca sativa L. cv. Paris Island), grown in Fall in a greenhouse in the Mediterranean mountains. Yield ranged from 31 to 38 kg/50 heads. Leaf NO₃‐N and total P levels were higher in mulched than unmulched plants, and in fertilized than in unfertilized plants, and always above the sufficiency level in all treatments. Soil levels of NO₃‐N were higher under mulched than unmulched plots, and under fertilized than unfertilized plots, which had more than 50 ppm NO₃‐N at harvest. This indicates ample supply of N and thus explains the lack of response to added N. It may be concluded that in mild climates and on soils with adequate N, lettuce will not respond to the use of clear mulch and N fertilizer.     

The Effect of Moderate Salinity on Nitrate Leaching from Bermudagrass Turf: A Lysimeter Study

A column lysimeter study was conducted under greenhouse conditions to determine the impact of moderately saline irrigation water on NO₃ leaching from turfgrass. Bermudagrass (Cynodon dactylon L. ‘NuMex Sahara’) was fertilized at three N levels (25, 50 and 75 kg NH₄NO₃-N ha^?1 month^?1) and irrigated with saline water (0, 3.0 and 6.0 dS m^?1) in a factorial arrangement. Leachate was analyzed for salinity and NO₃, and clippings were collected and analyzed for total N. Nitrate leaching was not affected by either N level or salinity. Nitrate concentrations in the leachate were low, averaging approximately 0.3 mg N L^?1; less than 1% of the applied N leached. Longer-term N allocation to leaf growth accounted for up to 98% of applied N, whereas short-term allocation, determined using ¹⁵N, ranged from 46–67%. Salinity had no affect on clipping yield, the biomass of root and verdure, or root distribution. These data indicate the potential for moderately saline irrigation water to be used on bermudagrass turf without increasing NO₃ contamination of groundwater, as long as leaching is adequate to prevent rootzone salinity reaching damaging levels.     

Phosphorus nutrition of white rose potato in relation to growth and minerals of leaf and root tissues

Abstract

White Rose potato plants (Solanum tuberosum, L.) were grown outdoors, without tuber formation, in a modified Hoagland's nutrient solution with 9 treatments of KH₂PO₄ ranging from 0 to 4.0 mmoles per liter. Deficiency symptoms ranged from very severe to none at harvest after 27 days of growth. Growth of the potato plants increased with increased P supply and was associated with an increased P content of the plant tissues. The critical H₂PO₄‐P concentration at a 10% reduction of top growth, based on a second leaf analysis, was about 1,000 ppm for the petiole and terminal bladelet and about 1,200 ppm for the lateral bladelet, dry weight basis.

Phosphorus nutrition had only a slight effect on the K, Na, Mg and NO₃‐N concentrations of the root tissues but Ca increased as phosphate increased which suggests a calcium phosphate precipitation. Phosphorus stress lowered the K, Na, Ca, Mg and NO₃‐N concentrations of the petiole tissues of the recently matured leaf which suggests that P increases salt accumulation. Phosphorus nutrition had only a slight effect on the concentrations of K, Na, Mg and Ca of the blade tissues of the recently matured leaf but NO₃‐N increased greatly with P supply.     

Estimating nitrogen requirements for irrigated malting barley

Abstract

The production of marketable malting barley requires careful N management to meet the quality standards set by the malting industry. Nine field trials were conducted over an eight‐year period at four locations to develop N fertilization guidelines for irrigated malting barley. Residual soil NO₃‐N (0 to 60 cm) ranged from 15 to 103 kg N/ha. Nitrogen fertilizer was applied preplant as either urea or NH₄NO₃ at rates ranging from 0 to 269 kg N/ha. Maximum yields were obtained when the sum of residual plus applied N (available N) was above 110 kg N/ha. However, the percentage of plump kernels generally fell below acceptable levels (85%) when available N exceeded 135 kg N/ha. Grain protein exceeded acceptable levels (12%) when available N was above 210 kg N/ha. Stem NO₃‐N sufficiency levels were determined from high‐yielding barley with acceptable quality parameters. At the three‐leaf stage, the barley stem NO₃‐N sufficiency level was approximately 6,000 μg/g and decreased to about 1,000 μg/g at the eight‐leaf stage.     

INTERACTIVE EFFECTS OF SALINITY AND N ON PEPPER (CAPSICUM ANNUUM L.) YIELD,WATER USE EFFICIENCY AND ROOT ZONE AND DRAINAGE SALINITY

The aim of this study was to determine the salt tolerance of pepper (Capsicum annuum L.) under greenhouse conditions and to examine the interactive effects of salinity and nitrogen (N) fertilizer levels on yield. The present study shows the effects of optimal and suboptimal N fertilizer levels (270 kg ha^?1 and 135 kg ha^?1) in combination with five different irrigation waters of varying electrical conductivity (EC) (EC_iw = 0.25, 1.0, 1.5, 2.0, 4.0, and 6.0 dS m^?1) and three replicates per treatment. At optimal N level, yield decreased when the irrigation water salinity was above EC_iw 2 dS m^?1. At the suboptimal N level, a significant decrease in yield occurred only above EC_iw 4 dS m^?1. At high salinity levels the salinity stress was dominant with respect to yield and response was similar for both N levels. Based on the results it can also be concluded that under saline conditions (higher than threshold salinity for a given crop) there is a lesser need for N fertilization relative to the optimal levels established in the absence of other significant stresses.     

Manure management practices applied to a seven‐course rotation on a sandy soil: effects on nitrate leaching

This experiment tested whether it was possible to incorporate broiler litter (BL) or cattle farmyard manure (FYM) into a 7‐yr arable rotation on a sandy soil without causing an increase in nitrate‐nitrogen (NO₃‐N) leaching. Four manure treatments (with adjusted fertilizer inputs), varying in frequency and timing of application, were imposed on the rotation and compared with a control that received inorganic fertilizer according to recommended rates. Over seven winters, the annual average NO₃‐N leached from the inorganic fertilizer treatment (control) was 39 kg/ha in 183 mm drainage. Total manure N loadings over the period of the experiment ranged between 557 and 1719 kg/ha (80–246 kg/ha/yr) for the four treatments. Three of the four manure treatments significantly increased NO₃‐N leaching over the rotation (P < 0.001). Annual applications of FYM (1719 kg/ha manure N or 246 kg/ha/yr) increased NO₃‐N leaching by 39%. We hypothesize that this was due to increased mineralization of the organic N accumulating from repeated FYM applications. BL applied each year (1526 kg/ha manure N or 218 kg N/ha/yr) increased NO₃‐N leaching by 52% above the control; BL applied 5 of 7 yr (972 kg/ha manure N or 139 kg N/ha/yr on average) and including inadvisable autumn applications increased leaching by 50%. BL applied in late winter or early spring every 2–3 yr (557 kg/ha manure N or 80 kg N/ha/yr on average) resulted in NO₃‐N leaching similar to the control. This suggests that to avoid additional NO₃‐N leaching from manure use in an arable rotation, manure should not be applied every year and autumn applications should be avoided; there are real challenges where manure is used on an annual basis.     

Influence of surfactants on potassium uptake and yield response of cotton to foliar potassium nitrate

Foliar potassium (K) applications are intended to supplement soil K uptake, and thereby, increase cotton (Gossypium hirsutum L.) yields. Considerable research has been conducted to evaluate yield response to foliar K, but research evaluating surfactant effects on foliar uptake has been limited. Research was initiated in West Tennessee in 1991 to evaluate effects of foliar applied potassium nitrate (KNO₃) with and without surfactants on leaf and petiole K concentrations and on lint yield. Field research was conducted on three sites over a four year period using upland cotton ‘DPL 50’. Treatments included a check (no foliar treatment), 4.1 kg K/ha in water, 4.1 kg K/ha with Penetrator Plus, 4.1 kg K/ha with X‐77, 2.0 kg K/ha with Penetrator Plus, and 2.0 kg K/ha with X‐77. Surfactants were added to KNO₃ solutions at 1.25% v/v for Penetrator Plus and 0.5% v/v for X‐77. Kinetic was substituted for X‐77 after 1991 and was applied at 0.12% v/v. Cotton leaves and petioles were collected one, three, and seven days after each foliar application for K concentration determinations. Applying 4.1 kg K/ha (high‐K rate) as KNO₃ in water increased four‐year average leaf K but not petiole K concentrations in tissue collected 24 h after treatment relative to the check. Applying the high‐K rate with a surfactant increased the four‐year average concentration of leaves and petioles collected one, three, and seven days after application relative to the check or to the high‐K rate applied with water. Increases in both leaf and petiole K concentrations varied with year, with significant increases in two of the four years of the study. Yearly K concentrations of the day‐one and day‐three petioles were higher after applying the high‐K rate with Penetrator Plus relative to the check. Petiole K was not increased by applying low‐K rates with surfactants or the high‐K rate in water. First harvest lint yields were generally unaffected by foliar treatments. Second harvest and total yields were increased by applying the high‐K rate with Penetrator Plus relative to the other treatments. Yield responses may have been due in part to the nitrate anion (NO₃‐) being applied with the K+ cation, but higher K concentrations generally accompanied higher yields. These results suggest that surfactants may enhance K uptake and yield, but that more research is needed to determine why responses vary from year to year.     

Effect of Nitrogen Nutrition on Solute Accumulation and Ion Contents of Maize under Sodium Chloride Stress

Salinity is a major abiotic stress that limits the productivity of crops, particularly cereal crops, while decreasing nutrient availability, especially of nitrogen. An experiment was conducted to study the effects of salt stress [i.e., S₀, S₁, and S₂ (control, 1.09; 5; and 10 dS m^?1)] and four different nitrogen (N) levels [i.e., N₀, N₁, N₂, and N₃ (control, 175, 225, and 275 kg N ha^?1)] on two maize hybrids, Pioneer 32B33 (salt tolerant) and Dekalb 979 (salt sensitive). The experiment was conducted in a wire house. The experiment was laid out with three factors in a completely randomized design. The plant tissue was analyzed for solute and ion contents. With the increase in salt stress and N rate, solute (i.e., glycinebetaine), protein, total soluble sugar, and total free amino acids accumulated in both hybrids. Nitrate (NO₃) and nitrite (NO₂) reductase activity decreased sharply at 10 dS m^?1 compared to lower levels of salinity but it increased significantly with the addition of N. The uptake of potassium (K⁺), calcium (Ca²⁺), magnesium (Mg²⁺), N, and phosphorus (P) reduced significantly in shoots with increased salinity while the sodium (Na⁺) and chloride (Cl) contents were increased. It is concluded from the present study that at greater salinity level, hybrid Pioneer32B33 maintained statistically greater solute and ion contents excluding Na⁺ and Cl ions and significantly decreased enzyme activity. However, these parameters were increased by N rate.     

Effect of nitrogen and salinity levels in the nutrient solution on the DRIS diagnosis of greenhouse tomato

Abstract

Norms for the Diagnosis and Recommendation Integrated system (DRIS) developed for greenhouse tomato (Lycopersicon esculentum L.) were evaluated experimentally by varying the N concentration (115, 243, and 443 mg N L^‐1 ) or the salinity level (1.4, 2.5, and 3.7 dS m^‐1 ) of the nutrient solution. Foliar samples were taken at different intervals during the season for total N, P, K, Ca and Mg analysis. The nutrient imbalance index (NII) was calculated by summing up DRIS indexes irrespective of sign. A dry matter index (DM) was included in the modified DRIS (M‐DRIS) approach as a separator between excessive or deficient nutrients. Yield of marketable fruit that accumulated over a 8 week harvest period was quadratically related to N fertilization: 115, 243, and 443 mg N L^‐1 produced 2.9, 3.3, and 2.3 kg per plant respectively. Larger than critical NII values, 82 days after transplanting, were associated with excess of N, and Mg, and Ca deficiencies. Contrary to the DRIS and M‐DRIS approaches, the critical nutrient range approach (CNR) did not indicate any N excess. In the salinity experiment, marketable yield decreased linearly with salinity: 1.4, 2.5, and 3.7 dS m^‐1 produced 3.3, 2.9, and 2.3 kg per plant, respectively. Increasing salinity caused an increase in the NII at all sampling periods. However, Nil's were always smaller than the critical NII and were inconsistent with the low yields obtained. Thus, NII was considered a poor indicator of the salt effect.     

Layer and broiler poultry manure as nitrogen fertilizer sources for cabbage production

Abstract

Floor litter from one‐year‐old laying hens (LHM) and from eight‐week‐old broiler chickens (BCM) were incorporated in the soil of two fields and evaluated as nitrogen (N) sources for cabbage production on a non nutrient‐depleted soil. LHM had 3.4% moisture, 3.84% N and 3.41% phosphorus (P). BCM had 2.3% moisture, 4.46% N and 2.19% P. Field 1 recieved 2.4 t/ha BCM, 3.0 t/ha LHM, whereas Field 2 recieved 4.8 t/ha BCM and 6.1 t/ha LHM. Also, each field received ammonium sulfate [(NH₄)₂SO₄] at a N rate of 100 kg/ha and an unfertilized control treatment. The manure was applied one week before cabbage transplanting on 18 May 1992. Ammonium sulfate was applied in two equal split applications during the growing season. Leaf nitrate‐nitrogen (NO₃‐N) was higher at harvest in plants receiving the higher manure rate than in other treatments (P<0.05). Leaf phosphate (PO₄‐P) was higher in early season in plants receiving LHM at both Tates than in other treatments. Soil BD, EC, NO₃‐N, and P at harvest were not affected by the treatments (P>0.05). Soil pH was reduced by the LHM in comparison to other treatments (P<0.05). Yield was comparable among all treatments (P>0.05) . It may be concluded that low application rates of LHM and BCM are equally effective in supplying the N requirements of cabbage, with BCM recommended when only N is limiting, and LHM when P is limiting.     

Sap analysis for the prediction of stem yield and the need for extra nitrogen fertiliser for Kenaf

Abstract

Kenaf (Hibiscus cannabinus var. Guatemala 4) was grown at Ayr in north Queensland under eleven nitrogen (N) treatments, including seven treatments with all nitrogen applied at planting and four split treatments in which half the nitrogen was applied at planting and half applied 67 days after planting. At weekly intervals from 36 days after planting, petioles from the youngest mature blades were sampled to investigate the possibility of using petiole sap analysis as a fertiliser‐management tool.

The sap nitrate test showed promise in prognosing final stem dry‐matter yield. Relationships between final stem yield and sap NO₃‐N at various sampling times, leading up to canopy closure of treatments supplied with 240 kg N/ha or more, are presented. Estimated desirable NO₃‐N concentrations are also presented.

Sap nitrate levels declined rapidly from 36 days after planting. The rate of decline of petiole nitrate levels depended upon the rate of nitrogen applied at planting. Monitoring sap nitrate over the four‐week period before canopy closure is expected and using the levels established as desirable in this work as a guide, will help the kenaf grower to identify the need for extra nitrogen.     

Effects of biochar,urea and their co‐application on nitrogen mineralization in soil and growth of Chinese cabbage

Experiments were conducted to study the effect of soil applications of kunai grass (Imperata cylindrica) biochar (0 and 10 t/ha) and laboratory grade urea (0, 200 and 500 kg N/ha) and their co‐application on nitrogen (N) mineralization in an acid soil. The results of an incubation study showed that the biochar only treatment and co‐application with urea at 200 kg N/ha could impede transformation of urea to ammonium‐N (NH₄⁺‐N). Soil application of biochar together with urea at 500 kg N/ha produced the highest nitrate‐N (NO₃^?‐N) and mineral N concentrations in the soil over 90 days. Co‐application of urea N with biochar improved soil N mineralization parameters such as mineralization potential (N_A) and coefficient of mineralization rate (k) compared to biochar alone. In a parallel study performed under greenhouse conditions, Chinese cabbage (Brassica rapa L. ssp. chinensis L.) showed significantly greater (P < 0.05) marketable fresh weight, dry matter production and N uptake in soil receiving urea N at 500 kg/ha or co‐application of biochar with urea N compared to the control. Application of biochar only or urea only at 200 kg N/ha did not offer any short‐term agronomic advantages. The N use efficiency of the crop remained unaffected by the fertilizer regimes. Applications of biochar only at 10 t/ha did not offer benefits in this tropical acid soil unless co‐applied with sufficient urea N.     

Soil chemical properties after long‐term n fertilization of bromegrass: Nitrogen rate

Abstract

Nitrogen (N) fertilizers increase yield and quality of grass forage, and may also alter soil chemical properties. A field experiment was conducted in south‐central Alberta to determine the effect of long‐term application of ammonium nitrate to bromegrass on concentration and downward mobility of soluble NO₃‐N, extractable NH₄‐N, P, Ca, Mg, and K, and total C and N in a Thin Black Chernozemic loam soil. The fertilizer was applied annually in early spring for 16 years at 0 to 336 kg N/ha. There was little accumulation of NO₃‐N in the soil at N rates of 112 kg/ha or less. However, at rates higher than 112 kg N/ha there was accumulation of NO₃‐N in the 15–30 and 30–60 cm layers, but very little in the 90–120 cm depth. The NH₄‐N accumulated in the 0–5 cm layer when the fertilizer was applied at rates between 168 to 280 kg N/ha and in the 5–10 cm layer at N rates exceeding 280 kg/ha. There was a decline in extractable P in soil with N application up to 84 kg N/ha rate, while it increased with high N rates. The increasing amounts of applied N resulted in a decline in extractable soil Ca, Mg and K, and this decrease was more pronounced in the 0–5,5–10,10–15, and 15–30 cm layers for K, 0–5 and 5–10 cm layers for Ca, and 0–5, 5–10, and 10–15 cm layers for Mg. There was a build‐up of total C and N in the surface soil with increasing rate of applied N.