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1.
The model ORYZA2000 simulates the growth and development of rice under conditions of potential production and water and nitrogen (N) limitations. Crop simulation models could provide an alternative, less time-consuming, and inexpensive means of determining the optimum crop N and irrigation requirements under varied irrigation and nitrogen conditions. Water productivity (WP) is a concept of partial productivity and denotes the amount or value of product over volume or value of water used. For the evaluated ORYZA2000 model in Iran, a study was carried out in a randomized complete block design between 2005 and 2007, with three replications at the Rice Research Institute of Iran, Rasht. Irrigation management (three regimes) was the main plot and N application (four levels) was the subplot. In this study, simulation modeling was used to quantify water productivity and water balance components of water and nitrogen interactions in rice. Evaluation simulated and measured total aboveground biomass and yield, by adjusted coefficient of correlation, T test of means, and absolute and normalized root mean square errors (RMSE). Results showed that with normalized root mean square errors (RMSEn) of 5–28%, ORYZA2000 satisfactorily simulated crop biomass and yield that strongly varied among irrigation and nitrogen fertilizer conditions. Yield was simulated with an RMSE of 237–443 kg ha?1 and a normalized RMSE of 5–11%. Results showed that the significant (28–56%) share of evaporation into evapotranspiration, using the actual yield (measured) and simulated water balance (ORYZA2000), the calculated average WPET was significantly lower than the average WPT: 37%. The average WPI, WPI+R, WPET, WPT, and WPETQ were 1.4, 1.07, 1.07, 1.57, and 0.82 kg m?3. Results also showed that irrigation with 8-day intervals and 60 kg N ha?1, nitrogen level was the optimum irrigation regime and nitrogen level.  相似文献   

2.
The objective of this study was to adapt and test the ability of the AquaCrop model under different nitrogen and irrigation management conditions in northern Iran. A three-year field experiment was conducted at the experimental farm of the Iranian Rice Research Institute in Rasht, Iran, from 2005 to 2007. Irrigation treatments comprised continuous submergence, irrigation at 5-day intervals, and irrigation at 8-day intervals. Nitrogen (N) application levels were 0, 45, 60, and 75 kg N ha?1. The goodness of fit between observed and simulated canopy cover, total and panicle biomass, grain yield, and final biomass was assessed by means of the coefficient of determination (R2) and the absolute and normalized root mean square errors (RMSEn). Results of the statistical test of the model for total and panicle biomass showed moderately high R2 (≥0.90) and moderate RMSEn (6–36%) values, confirming that the model simulated the total and panicle biomass accurately. The model was simulated for CC with RMSEn and R2 of 28 and 0.82, respectively. The agreement between predicted and observed rice grain yield and final biomass were with R2 of 0.81 and 0.82 and RMSEn of 13 and 10% respectively.  相似文献   

3.
Effect of potassium (K) fertilization (0, 20, 40, 60, 80 and 100 kg K ha?1) on yield, nitrogen (N) and K nutrition of Boro (dry season) rice and apparent soil K balance was studied. Experiment was conducted at Bangladesh Rice Research Institute (BRRI) regional station farm, Habiganj, Bangladesh during 2007–2008 to 2009–2010 in a wetland rice ecosystem under haor area. Cropping pattern was Boro–Fallow–Fallow. A popular rice variety BRRI dhan29 was tested in a randomized complete block design with three replications. Results indicated that BRRI dhan29 maintained an average grain yield of 5.19 t ha?1 year?1 without K fertilization. Potassium fertilization significantly increased the grain yield to 6.86 t ha?1 year?1. Quadratic equations best explained the progressive increase of rice yield with increasing K rates. Optimum dose of K in 3 years ranged from 78 to 93 kg ha?1. Internal N use efficiency of rice decreased with increasing K rates. However, K use efficiency was inconsistent. Apparent K balance study revealed that application of 100 kg K ha?1 was not able to maintain a positive K balance in soil under wetland ecosystem with Boro–Fallow–Fallow cropping system. However, K fertilization decreased the negativity of K balance in soil.  相似文献   

4.
A long-term experiment was conducted at the Central Research Institute for Dryland Agriculture for 13 years to evaluate the effect of low tillage cum cheaper conjunctive nutrient management practices in terms of productivity, soil fertility, and nitrogen chemical pools of soil under sorghum–mung bean system in Alfisol soils. The results of the study clearly revealed that sorghum and mung bean grain yield as influenced by low tillage and conjunctive nutrient management practices varied from 764 to 1792 and 603 to 1008 kg ha?1 with an average yield of 1458 and 805 kg ha?1 over a period of 13 years, respectively. Of the tillage practices, conventional tillage (CT) maintained 11.0% higher yields (1534 kg ha?1) over the minimum tillage (MT) (1382 kg ha?1) practice. Among the conjunctive nutrient management treatments, the application of 2 t Gliricidia loppings + 20 kg nitrogen (N) through urea to sorghum crop recorded significantly highest grain yield of 1712 kg ha?1 followed by application of 4 t compost + 20 kg N through urea (1650 kg ha?1) as well as 40 kg N through urea alone (1594 kg ha?1). Similar to sorghum, in case of mung bean also, CT exhibited a significant influence on mung bean grain yields (888 kg ha?1) which was 6.7% higher compared to MT (832 kg ha?1). Among all the conjunctive nutrient management treatments, 2 t compost + 10 kg N through urea and 2 t compost + 1 t Gliricidia loppings performed significantly well and recorded similar mung bean grain yields of 960 kg ha?1 followed by 1 t Gliricidia loppings + 10 kg N through urea (930 kg ha?1). The soil nitrogen chemical fractions (SNCFs) were also found to be significantly influenced by tillage and conjunctive nutrient management treatments. Further, a significant correlation of SNCF with total soil nitrogen was observed. In the correlation study, it was also observed that N fraction dynamically played an important role in enhancing the availability pool of N in soil and significantly influenced the yield of sorghum grain and mung bean.  相似文献   

5.
Nitrogen and sulfur play an important role in maize production. The aim of this study was to evaluate the effect of nitrogen (N) and sulfur (S) levels applied in various ratios on maize hybrid Babar yield at Peshawar in 2011 and 2013. Four N levels (120, 160, 200 and 240 kg N ha?1) and four S levels (20, 25, 30 and 35 kg S ha?1) were applied in three splits: a, at sowing; b, V8 stage; c, VT stage in ratios of 10:50:40, 20:50:30 and 30:50:20. Grains ear?1, thousand grain weight, grain yield ha?1 and soil pH were significantly affected by years (Y), N, S and their ratios, while no effect of N, S and their ratios was noted on ears plant?1. Maximum grains ear?1 (390), thousand grain weight (230.1 g) and grain yield (4119 kg ha?1) were recorded in 2013. N increased grains ear?1 (438), thousand grain weight (252 g) and grain yield (5001 kg ha?1) up to 200 kg N ha?1. Each increment of S increased grains ear?1 and other parameters up to 35 kg S ha?1, producing maximum grains ear?1 (430), thousand grain weight (245 g) and grain yield (4752 kg ha?1), while soil pH decreased from 8.06 to 7.95 with the application of 35 kg S ha?1. In the case of N and S ratios, more grains ear?1 (432), heavier thousand grains (246.7 g) and higher grain yield (4806 kg ha?1) were observed at 30:50:20 where 30% of N and S were applied at sowing, 50% at V8 and 20% at VT stage. It is concluded that 200 kg N ha?1 and 35 kg S ha?1 applied in the ratio of 30% at sowing, 50% at V8 and 20% at VT stage is recommended for obtaining a higher yield of maize hybrid Babar.  相似文献   

6.
Experiments were conducted to test the superiority of treatment combinations of nitrogen (N; 0, 50, 100, 150, 200 kg ha?1), phosphorus (0, 30, 60, 90 kg ha?1) and potassium (0, 30, 60 kg ha?1) for finger millet during 2005–2007. Application of 200-90-60 kg ha?1 gave maximum yield of 1666, 1426 and 1640 kg ha?1 in 3 years, respectively. The yield regression model through soil and fertilizer nutrients gave predictability of 0.98, 0.97 and 0.98, with sustainability yield index (SYI) of 50.4, 49.4 and 52.5 in 2005, 2006 and 2007, respectively. Optimum nitrogen, phosphorus and potassium (NPK) doses for attaining yields of 800 and 1200 kg ha?1 were derived at soil nitrogen, phosphorus and potassium of 75–400, 10–70 and 150–750 kg ha?1. Fertilizer nitrogen, phosphorus and potassium ranged from 30–128, 3–19, 13–25 kg ha?1 and 105–203, 4–32, 27–39 kg ha?1 for attaining 800 and 1200 kg ha?1 yield, respectively. The doses could be adopted for attaining sustainable yields under semiarid Alfisols.  相似文献   

7.
ABSTRACT

Soil fertility and water use are two important aspects that influence rice productivity. This study was conducted to evaluate the performance of in-situ (sesbania and rice bean) and ex-situ (subabul) green manuring along with zinc fertilization on water productivity and soil fertility in rice under rice–wheat cropping system at Indian Agricultural Research Institute, New Delhi, India. Sesbania incorporation recorded higher total water productivity (2.20 and 3.24 kg ha?1 mm?1), available soil nutrients, organic carbon, alkaline phosphatase activity, microbial biomass carbon and increased soil dehydrogenase activity by 39.6 and 26.8% over subabul and rice bean respectively. Among interaction of green manures and zinc fertilization, subabul × foliar application of chelated zinc-ethylenediaminetetraacetic acid at 20, 40, 60 and 80 days after transplanting recorded highest total water productivity (2.56 and 3.79 kg ha?1 mm?1). Foliar application of chelated Zn-EDTA at 20, 40, 60 and 80 days after transplanting recorded significantly higher water productivity than other Zn treatments, however it was statistically similar with foliar application of zinc at active tillering + flowering + grain filling. Sesbania × 5 kg Zn ha?1 through chelated Zn-EDTA, recorded highest available nitrogen, phosphorus, potassium, zinc, manganese, copper and iron than other green manure and Zn fertilization interactions, although it was statistically similar with rice bean × 5 kg Zn ha?1 through chelated Zn-EDTA as soil application. Sesbania × foliar application of 5 kg Zn ha?1 through chelated Zn-EDTA as soil application recorded highest soil enzymatic activities and microbial biomass carbon.  相似文献   

8.
On-farm research was conducted to investigate the effects of nitrogen (N) and compost (C) on yield and yield components of spring maize (Zea mays L.) under conventional and deep tillage system (T) at the research farm of the University of Agriculture, Peshawar, Pakistan, during spring 2013. The experiment was laid out in a randomized complete block design with split-plot arrangement, using three replications. Three compost levels (0, 1, and 2 t ha?1) and two tillage systems (conventional and deep tillage) were allotted to the main plot, whereas N levels (60, 90, 120, and 150 kg N ha?1) were allotted to subplots in the form of urea. Nitrogen and compost levels had significantly affected all the parameters. Plots treated with 150 kg N ha?1 increased ear length (31 cm), grains ear?1 (413), thousand-grain weight (240.2 g), grain yield (3097 kg ha?1), straw yield (9294 kg ha?1), harvest index (24.7 percent), and shelling percentage (81.7 percent). Compost applied at 2 t ha?1 increased ear length (32 cm), grains ear?1 (430), thousand-grain weight (242.3 g), grain yield (2974 kg ha?1), straw yield (8984 kg ha?1), harvest index (24.6 percent), and shelling percentage (83.2 percent). Tillage system had significant effect on all parameters except ear length and harvest index. Deep tillage system produced more grains ear?1 (365), thousand-grain weight (233.3 g), grain yield (2630 kg ha?1), straw yield (8549 kg ha?1), and shelling percentage (79.6 percent). It was concluded from the results that application of 120 kg N ha?1 + 2 C t ha?1 under a deep tillage system could improve spring maize yield and yield-contributing traits under semi-arid conditions.  相似文献   

9.
Proper doses of nitrogenous fertilizer are most important for rice production system because a large part of the nitrogen may be lost if it is not applied judiciously. A study was conducted covering five blocks of Balasore and two blocks of Bhadrak districts. Soil samples were collected randomly, and field visit was conducted during peak vegetative stage of rice. Two approaches have been used in this study for estimating the site-specific nitrogen (N) requirement in the study area. In one approach, geostatisical analysis and kriging was used to develop the soil test–based N recommendation map by which a minimum of 72 kg N ha?1 and maximum of 94 kg N ha?1 were recommended. In a second approach, remote sensing was used and N recommendation map was developed using the moderate-resolution imaging spectroradiometer (MODIS) leaf area index (LAI) and normalized difference vegetation index (NDVI) satellite data, and a minimum requirement of 60 kg N ha?1 and maximum of 120 kg N ha?1 was estimated through this approach.  相似文献   

10.
Excessive nitrogen (N) fertilizer application is common in the central Zhejiang Province area, China. A three-year (2009–11) experiment was conducted to determine the optimum N application rate for this area by studying the effects of various N rates on rice (Oryza sativa L.) yield, N-use efficiency (NUE), and quality of paddy field water. Results showed that no significant yield differences were observed under N rates from 180 to 315 kg ha?1. The NUE could be improved by reducing N application rates without significantly decreasing yield. Due to high ammonia (NH4+-N) and nitrate (NO3—N) concentrations, 5–7 days after N application was a critical stage for reducing N pollution. The N rate for the greatest yield was 176 kg ha?1, accounting for 65 percent of the conventional N rate (270 kg ha?1). The N-rate reduction in this area may be necessary for maintaining high yield, improving NUE, and reducing environmental pollution.  相似文献   

11.
Soil-test crop-response experiments on rice were conducted in the Bastar Plateau Agroclimatic Zone of Chhattisgarh during 2009–2011 to assess yield, soil, plant, and fertilizer nitrogen (N), phosphorus (P), and potassium (K) nutrient relationships and calibrate optimum fertilizer doses for attaining yield targets. Soil fertility status was poor to medium for N (194–283 kg ha?1) and P (7.53–19.66 kg ha?1), and medium to good for K (226–320 kg ha?1). Based on nutrient requirements (NR, kg q?1) and contributions from soil (CS, %), fertilizer (CF, %), and farmyard manure (CFYM, %), optimum fertilizer doses were derived. The fertilizer doses were validated for attaining yield targets of 5000 and 6000 kg ha?1 in farmer’s fields. Rice yield within 10% deviation was attained, which indicated that soil-test-based fertilizer dose was superior. This approach could be adopted for regions with similar soil and agroclimatic conditions in other parts of the world to increase rice yields.  相似文献   

12.
This study investigates the effect of rice nitrogen (N) management on the dynamics of plant nitrogen accumulation (PNA) during internodal elongation (IE) in relation to grain yield. Four field experiments were conducted in two soils with six preflood N treatments. The PNA was monitored for 3 weeks, starting at the beginning of IE (BIE). The PNA explained 54–72% of yield variability. The effect of midseason N application on yield varied with fields, indicating a need for assessing midseason N requirement for each field. One week after BIE was a better time to assess the N requirement of rice crop. The greatest grain yields in Cocodrie and Wells cultivars corresponded to PNA of 10.9 and 11.1 g m?2 at BIE. A midseason application of 50 kg N ha?1 as urea at 7–10 days after BIE increased the rice yield in the Glossaqualfs field when the PNA at BIE was less than 8.3 g m?2.  相似文献   

13.
The environmental and economic consequences of nitrogen (N) lost in rice-based systems in Vietnam is important but has not been extensively studied. The objective of this study was to quantify the amount of N lost in major cropping systems in the Red River Delta. An experiment was conducted in the Red River Delta of Vietnam, on five different crops including rose, daisy, cabbage, chili, and a rice–rice–maize rotation during 2004 and 2005. Core soil samples were taken periodically in 20-cm increments to a depth of 1 m and analyzed for nitrate–nitrogen and ammonium–nitrogen. The results indicate appreciable leaching losses on N in high-rainfall and irrigation conditions, especially when fertilizer application was not well synchronized with crop N demand. Highest annual leaching losses of N were recorded in flowers with 185–190 mm of percolation and 173–193 kg N ha?1, followed by vegetable (cabbage and chili) with 120–122 mm of percolation and 112–115 kg N ha?1, while it was lowest in rice with about 50 kg N ha?1. We developed a simple N transport model that combined water and N movement through the soil profile. In most cases, the model accurately predicted the seasonal dynamics of N as well as N flow between soil layers and the amounts of N lost from the soil profile. The simulated results of N leaching with soil “puddling” conditions illustrate the advantage of an impermeable or hardpan layer in increasing water and nutrient use efficiencies in these soils. These model results also showed that it is possible to accurately estimate N losses with only a few parameters and helped us identify the risks of N leaching.  相似文献   

14.
Wheat (Triticum aestivum L.) residues and nitrogen (N) management are the major problems in the southern part of Iran where irrigated wheat–cotton (Gossypium hirsutum L.)–wheat rotation is a common practice. A 2-year (2009–2011) field experiment was conducted as a split plot design with four replications at a cotton field (Darab), Fars Province, Iran, to determine the influence of different rates of wheat residue (0%, 25%, 50%, and 75%) incorporation and N rates (150, 200, 300, and 400 kg ha?1) on weed suppression, yield, and yield components of cotton. Results showed that a higher residue incorporation and a lower N rate improved weed suppression in both years. For treatments receiving 150 kg N ha?1 and 75% of wheat residues (2250 kg ha?1), weed biomass and density were significantly lower compared to treatments receiving 400 kg N ha?1. The highest cotton lint yield (about 2400–2700 kg ha?1) was obtained by 300 kg N ha?1 in the absence of residue application, in both years. Incorporation of 25% of wheat residue (750 kg ha?1) and application of 300 kg N ha?1 are recommended to guarantee an optimum level of cotton lint yield and weed suppression in a wheat–cotton–wheat rotation in this region.  相似文献   

15.
A 2-year field experiment was conducted to assess system productivity, nutrient use efficiency and apparent balances of phosphorus (P) and potassium (K) in diversified rice-based cropping systems at Gazipur, Bangladesh. Four cropping systems: wheat–fallow–rice, maize–fallow–rice, potato–fallow–rice and mustard–fallow–rice in main plots and four nutrient combinations: NPK, NK, NP and PK in sub-plots were arranged in a split-plot design with three replications. Receiving the NPK treatment, all the component crops gave the highest yield, and omission of N from fertilizer package gave the lowest yield. The maize–rice system removed the highest amount of N (217 kg ha?1), P (41 kg ha?1) and K (227 kg ha?1) followed by wheat–rice, potato–rice and the least in mustard–rice system. The wheat–rice and maize–rice system showed negative K balance of –35.5 and –60.4 kg ha?1 in NPK treatment, while potato–rice system showed a positive K balance of 31.0 kg ha–1 with NPK treatment. The N, P and K uptake and apparent recovery by the test crops may be used for site-specific nutrient management. The K rates for fertilizer recommendation in wheat and maize in Indo-Gangetic plain need to be revised to take account for the negative K balance in soil.  相似文献   

16.
Bambara groundnut has great potential as an alternative crop for improving food security in its production regions and beyond. A field experiment was conducted at the Field Research Centre of the Crops for the Future to obtain information on the nitrogen (N) fixation and N balance of Bambara groundnut landraces on tropical acidic soils of Malaysia. Treatments consisted of three Bambara groundnut landraces (Ex-Sokoto, Kaaro, and NN-1) laid out in a randomized complete block design replicated three times. Results obtained revealed that Ex-Sokoto landrace was greater in yield and N fixation, whereas N balance (-haulm) was greater in NN-1 landrace. The results revealed grain yield of 703–2256 kg ha?1 and N fixation from 32–81 kg ha?1 and suggest that Bambara groundnut could be integrated into a cereal-based cropping system. Ex-Sokoto landrace appeared to be the most promising for yield and N fixation under Malaysian acidic soil conditions.  相似文献   

17.
Baby spinach is a relatively new crop of commercial significance in South Africa with considerable health attributes. Three parallel trials to investigate its response to nitrogen (N), phosphorus (P), and potassium (K) were conducted. N and P (0, 45, 75, 105, and 120 kg·ha?1) and K (0, 63, 85, 127, and 148 kg·ha?1) treatments were applied to baby spinach in a randomized block design with four replications. After the parallel trial, NPK combination trial was also done. The biomass yield, chlorophyll content, and leaf area index increased significantly with increase in N and P rates; K had no effect on the yield, chlorophyll content, stomatal conductance, and leaf area index. Yield and chlorophyll content peaked at 75 kg·ha?1 of N/P but growth was best optimized at the NPK combination of 45:45:60 kg·ha?1.  相似文献   

18.
Besides being an essential macronutrient for plant growth, potassium (K) also acts as a stress-relieving agent against various biotic and abiotic stresses, especially water stress. An experiment consisting of three lowland Thai rice varieties (Pathumthani 1, RD57, RD41), two cultivation methods [dry direct seeding (DDS), transplanting (TP)] and four K doses (0, 80, 120,160?kg ha?1) under alternate wetting and drying (AWD) water regime was conducted to investigate the impact of K and cultivation method on lowland rice varieties subjected to AWD. Pathumthani 1 had significantly higher grain yield at the 120?kg K ha?1 compared with all other K doses. RD57 and RD41 had maximum grain yield at the 80 and 120?kg K ha?1, respectively, which was significantly higher than the control; however, grain yield among different K doses was mostly similar for RD57 and RD41. K application at the rate of 120?kg ha?1 for Pathumthani 1 and 80?kg ha?1 for RD57 and RD41 could be a feasible option. The performance of DDS and TP was better at the 80 and 120?kg K ha?1, respectively. Application of K at the optimum dose with proper selection of variety and cultivation method could help in sustainable rice production.  相似文献   

19.
In an incubation experiment with flooded rice soil fertilized with different N amounts and sampled at different rice stages, the methane (CH4) and carbon dioxide (CO2) production in relation to soil labile carbon (C) pools under two temperature (35°C and 45°C) and moisture (aerobic and submerged) regimes were investigated. The field treatments imposed in the wet season included unfertilized control and 40, 80 and 120 kg ha?1 N fertilization. The production of CH4 was significantly higher (27%) under submerged compared to aerobic conditions, whereas CO2 production was significantly increased under aerobic by 21% compared to submerged conditions. The average labile C pools were significantly increased by 21% at the highest dose of N (120 kg ha?1) compared to control and was found highest at rice panicle initiation stage. But the grain yield had significantly responded only up to 80 kg ha?1 N, although soil labile C as well as gaseous C emission was noticed to be highest at 120 kg ha?1 N. Hence, 80 kg N ha?1 is a better option in the wet season at low land tropical flooded rice in eastern India for sustaining grain yield and minimizing potential emission of CO2 and CH4.  相似文献   

20.
The main objective of this investigation was to evaluate the response of red pepper grown in a subhumid climate to different irrigation and nitrogen levels. Open-field trials were conducted in the Marmara Region, Turkey. Plants were subjected to three water levels [full irrigation (FI) = 100% crop evapotranspiration (ETc) and two deficit irrigations (DIs)= 66 and 33% ETc restoration] and four levels of N (0, 80, 160, and 240 kg N ha?1) during the 2012, 2013, and 2014 growing seasons. A split-plot experimental design was used. The highest values of biomass and marketable yield (MY) were observed under FI. DI significantly increased the fruit soluble solids content. The biomass yield, MY, and fruit weight significantly improved with increasing nitrogen levels. The 240 kg N ha?1 treatment under FI provided the maximum net income. Increasing N supply under DI conditions enhanced the water-use efficiency based on both biomass yield and MY. These results indicate that with respect to the yield, the net income, and the water productivity of red pepper, the FI with a nitrogen supply of 160–240 kg ha?1 is recommended for drip irrigated and N-fertigated red pepper under subhumid climate conditions.  相似文献   

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