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1.
Drip irrigation in dry-seeded rice (DSR) is a new water-saving cultivation technology; however, very little is known of its productivity and water-saving capacities. The study was conducted for 2 years (2013 and 2014) in a split-plot design in three replicates with treatment combinations of four irrigation regimes [drip irrigation at 1.5, 2.25, and 3.0× pan evaporation (Epan) and flood irrigation at 3.0× Epan] and three nitrogen (N) levels (120, 150, and 180 kg ha?1). Drip irrigation in DSR resulted in higher grain yield (7.34–8.01 t ha?1) than flood irrigation (6.63–7.60 t ha?1) , with water savings of more than 40 %. Water-use efficiency with drip irrigation was higher (0.81–0.88 kg m?3) than flood irrigation (0.42–0.52 kg m?3) , being highest with drip irrigation at 1.5× Epan. Root density at soil depths of 15–30 cm was also higher in drip (0.86–1.05 mg cm?3) as compared to the flood (0.76–0.80 kg m?3)-irrigated crop. This study implicated that under water-scarce scenario, drip-irrigated DSR is a profitable, and water- and energy-saving technology. This study also suggested that policy focus in future must be tilted towards the promotion of solar-operated drip irrigation in those regions, where DSR is being promoted in the face of water and energy crisis.  相似文献   

2.
To study the radiation utilization efficiency, latent heat flux, and simulate growth of rice during post-flood period in eastern coast of India, on-farm trial was conducted with three water regimes in main plots (W 1 = continuous flooding of 5 cm, W 2 = irrigation after 2 days of water disappearance, and W 3 = irrigation after 5 days of water disappearance) and five nitrogen levels in subplots (N 1 = 0 kg N ha?1, N 2 = 60 kg N ha?1, N 3 = 90 kg N ha?1, N 4 = 120 kg N ha?1, and N 5 = 150 kg N ha?1) on a rice cultivar, ‘Lalat’. Average maximum radiation utilization efficiency (RUE) in terms of above ground dry biomass of 2.09 (±0.05), 2.10 (±0.02), and 1.9 (±0.08) g MJ?1 were computed under W 1, W 2, and W 3, respectively. Nitrogen increased the RUE significantly, mean RUE values were computed as 1.60 (±0.07), 1.78 (±0.02), 2.060 (±0.08), 2.30 (±0.07), and 2.34 (±0.08) g MJ?1 when the crop was grown with 0, 60, 90, 120, and 150 kg ha?1 nitrogen, respectively. Midday average latent heat flux (on clear days) varied from 7.4 to 14.9 and 8 to 13.6 MJ m?2 day?1 under W 2 and W 3 treatments, respectively, at different growth stages of the crop in different seasons. The DSSAT 4.5 model was used to simulate phenology, growth, and yield which predicted fairly well under higher dose of nitrogen (90 kg and above), but the model performance was found to be poor under low-nitrogen dose.  相似文献   

3.
The system of rice intensification (SRI) reportedly enhances yield with less water requirement. This claim was investigated to determine the effects of alternative cultivation methods and water regimes on crop growth and physiological performance. Treatment combinations compared SRI with the conventional transplanting system (CTS) using standard practices, evaluating both along a continuum from continuous flooding to water applications at 1, 3, 5, or 7 days after disappearance of ponded water (DAD), subjecting plants to differing degrees of water stress while reducing total water expenditure. SRI methods gave significant changes in plants’ phenotype in terms of root growth and tillering, with improved xylem exudation and photosynthetic rates during the grain-filling stage compared to CTS. This resulted in significant increases in panicle length, more grains and more filled grains panicle?1, greater 1,000-grain weight, and higher grain yield under SRI management. Overall, averaged across the five water regimes evaluated, SRI practice produced 49 % higher grain yield with 14 % less water than under CTS; under SRI, water productivity increased by 73 %, from 3.3 to 5.7 kg ha-mm?1. The highest CTS grain yield and water productivity were with the 1-DAD treatment (4.35 t ha?1 and 3.73 kg ha-mm?1); SRI grain yield and water productivity were the greatest at 3-DAD (6.35 t ha?1 and 6.47 kg ha-mm?1).  相似文献   

4.
Soil and water pollution caused by organic waste is a concern for livestock-breeding areas. Nitrogen balance in a paddy-field water-purifying system in which cattle feces were applied was studied for 4 years to assess the suitability of the system for a subtropical area, Japan. Three successive harvestings using ratoon of forage rice following one rice transplanting were conducted with chemical fertilizer and high and low rates of cattle-feces application. Nitrogen load was 81.3–495.0 kg N ha?1 year?1, while nitrogen uptake was highly dependent on the yield of the first harvesting. Annual variation of forage rice yields was large, ranging from 15.5 to 26.8 Mg ha?1 owing to fluctuation in the yield at second and later harvestings. On average, nitrogen was lost by leaching at a rate of 2.3–3.4 kg N ha?1 year?1. The nitrogen content in soil at a depth of 0–5 cm increased up to 12.2 kg N ha?1 over the 4-year period compared with that before the field experiment. However, continuous application of cattle feces could slightly increase the nitrogen content in soil at a depth greater than 35 cm. Our results showed the ability of flooded forage rice to remove nitrogen at up to 320.1 kg ha?1 year?1 for a field to which cattle feces were applied. Further investigation is needed to produce a high and stable yield at second harvesting each year, to prevent the accumulation of soil nitrogen, and to assess gaseous nitrogen loss.  相似文献   

5.
Methane (CH4) emission and water productivity were estimated in an experiment conducted during wet (rainy) season of 2010 at the research farm of Indian Agricultural Research Institute, New Delhi, India. Treatments comprising three methods of crop establishment viz., conventional transplanting (CT), system of rice intensification (SRI) and double transplanting (DT) were laid out in randomized block design with four replications. Scented rice (Oryza sativa L) variety ‘Pusa Basmati 1401’ was transplanted in puddle field. In CT and SRI 21 and 12-day-old seedlings, respectively, were transplanted while in DT overall 45-day-old seedlings were transplanted. In CT and DT flooded conditions while in SRI saturated conditions were maintained. Results indicated that among the methods of crop establishment, CT had maximum cumulative CH4 emission (32.33 kg ha?1) followed by DT (29.30 kg ha?1) and SRI (19.93 kg ha?1). Temporal CH4 flux fluctuated between 79.7 and 482.0 mg m?2 day?1 under CT; 46.0 and 315.0 mg m?2 day?1 in SRI and 86.7 and 467.3 mg m?2 day?1 in DT. Considerable temporal variations in the individual CH4 fluxes were observed. Flux of CH4 was generally higher in early stage of crop and peaked about 21 days after transplanting coinciding with tillering stage of crop. CH4 flux declined gradually from 75 days after transplanting and stabilized at the harvest stage of rice in all the three methods of transplanting. Global warming potential was highest in CT (807.4 kg CO2 ha?1) and lowest in SRI (498.25 kg CO2 ha?1). However, a reverse trend was observed with carbon efficiency ratio. The water savings to the extent of six irrigations was recorded in SRI over CT. A saving of 27.4 % irrigation water and 18.5 % total water was recorded in SRI over CT while the corresponding values of DT over CT were 14.5 and 9.8 %. Water productivity of SRI (3.56 kg/ha mm) was significantly higher as compared to DT (2.87 kg/ha mm) and CT (2.61 kg/ha mm).  相似文献   

6.
A field experiment was conducted during rainy seasons of 2009 and 2010 at New Delhi, India to study the influence of varieties and integrated nitrogen management (INM) on methane (CH4) emission and water productivity under flooded transplanted (FT) and aerobic rice (AR) cultivation. The treatments included two rice (‘PB 1’ and ‘PB 1121’) varieties and eight INM practices including N control, recommended dose of N through urea, different combinations of urea with farmyard manure (FYM), green manure (GM), biofertilizer (BF) and vermicompost (VC). The results showed 91.6–92.5 % lower cumulative CH4 emission in AR compared to FT rice. In aerobic conditions, highest cumulative CH4 emission (6.9–7.0 kg ha?1) was recorded with the application of 100 % N by organic sources (FYM+GM+BF+VC). Global warming potential (GWP) was significantly lower in aerobic rice (105.0–107.5 kg CO2 ha?1) compared to FT rice (1242.5–1447.5 kg CO2 ha?1). Significantly higher amount of water was used in FT rice than aerobic rice by both the rice varieties, and a water saving between 59.5 and 63 % were recorded. Under aerobic conditions, both rice varieties had a water productivity of 8.50–14.69 kg ha?1, whereas in FT rice, it was 3.81–6.00 kg ha?1. In FT rice, a quantity of 1529.2–1725.2 mm water and in aerobic rice 929.2–1225.2 mm water was used to produce one kg rice. Thus, there was a saving of 28.4–39.6 % total water in both the rice varieties under AR cultivation.  相似文献   

7.
In order to increase the efficacy of water and control the losses of fertilizer, it is necessary to assess the influence of level of fertilization on crop responses, movement and balance of water and solutes from fertilizers in the root zone. With this goal, the reported study was undertaken to determine the effect of fertilization on crop responses and fertilizer solute transport in rice crop field in a sub-humid and sub-tropical region. Field experiment was conducted on rice crop (cultivar IR 36) during the years 2003, 2004, and 2005. The experiment included four fertilizer treatments comprising different levels of fertilizer application. The fertilizer treatments during the experiment were: F1 = control with N:P2O5:K2O as 0:0:0 kg ha?1; F2 = fertilizer application of N:P2O5:K2O as 80:40:40 kg ha?1; F3 = fertilizer application of N:P2O5:K2O as 120:60:60 kg ha?1 and F4 = fertilizer application of N:P2O5:K2O as 160:80:80 kg ha?1. The results of the investigation revealed that the magnitudes of crop parameters such as grain yield, straw yield, and maximum leaf area index increased with increase in fertilizer application rate. The levels of fertilization had very little effect on water loss via deep percolation and water use by the crop. The levels of fertilization had considerable effect on N leaching loss and uptake of N whereas it had no significant impact on leaching loss of water-soluble phosphorus. This indicated that PO4-P leaching loss was very low in the soil solution as compared to nitrogen due to fixation of phosphorus in soils. The results also revealed that increase in level of fertilization increased water use efficiency considerably by increased crop yield. From the observed data of nutrient use efficiency, crop yield and environmental pollution, the fertilization rate of N:P2O5:K2O as 80:40:40 kg ha?1 (F2) was the most suitable fertilizer treatment for rice crop among studied treatments.  相似文献   

8.
System of rice intensification (SRI) is an alternate method of conventional puddled, transplanted, and continuously flooded rice cultivation for higher yield, water saving, and increased farmer’s income. The SRI may also have considerable impact on greenhouse gas emission because of difference in planting, water and nutrient management practices. A field experiment was conducted with three planting methods: conventional puddled transplanted rice (TPR), conventional SRI with 12-days-old seedling (SRI) and modified SRI with 18-days-old seedling (MSRI) to study their effect on methane and nitrous oxide emission. Seasonal integrated flux (SIF) for methane was highest in the conventional method (22.59 kg ha?1) and lowest in MSRI (8.16 kg ha?1). Methane emissions with SRI and MSRI decreased by 61.1 and 64 %, respectively, compared to the TPR method. Cumulative N2O–N emission was 0.69, 0.90, and 0.89 kg ha?1 from the TPR, SRI, and MSRI planting methods, respectively. An average of 22.5 % increase in N2O–N emission over the TPR method was observed in the SRI and MSRI methods. The global warming potential (GWP), however, reduced by 28 % in SRI and 30 % in MSRI over the TPR method. A 36 % of water saving was observed with both SRI and MSRI methods. Grain yield in the SRI and MSRI methods decreased by 4.42 and 2.2 %, respectively, compared to the TPR method. Carbon efficiency ratio was highest in the MSRI and lowest in the TPR method. This study revealed that the SRI and MSRI methods were effective in reducing GWP and saving water without yield penalty in rice.  相似文献   

9.
The effect of controlled irrigation and drainage on N leaching losses from paddy fields was investigated by controlling root zone soil water content and water table depth using a lysimeter equipped with an automatic water table control system. Three treatments that combined irrigation and drainage managements were implemented: controlled irrigation (CI) + controlled water table depth 1 (CWT1), CI + controlled water table depth 2 (CWT2), and flooding irrigation (FI) + actual field water table depth (FWT). Controlled irrigation and drainage had significant environmental effects on the reduction of NH4 +–N and NO3 ?–N leaching losses from paddy fields by decreasing water leakage. The NH4 +–N leaching losses from CI + CWT1 and CI + CWT2 were 3.68 and 4.45 kg ha?1, respectively, which significantly reduced by 59.2 and 50.7 % compared with FI + FWT (9.02 kg ha?1). The NO3 ?–N leaching losses from CI + CWT1 and CI + CWT2 were 0.88 and 0.43 kg ha?1 with a significant reduction of 45.2 and 73.2 %, respectively, compared with FI + FWT (1.61 kg ha?1). The application of CI + CWT1 can be a pollution-controlled water management method of reducing N leaching losses from paddy fields.  相似文献   

10.
Tropical highland conditions in Mwea Kenya, ensure the high radiation and the large day–night temperature differences. Such conditions are generally believed to promote rice growth and yield, but the current grain yield is lower than the expectation. In the current standard N fertilizer practice in Mwea, 75 kg nitrogen (N) ha?1 is applied in three splits at fixed timing. The effects of increases in N fertilizer amount (125, 175, and 225 kg N ha?1) on rice growth and yield were evaluated to test the hypothesis that unachieved high rice grain yield in Mwea is due to insufficient amount of N fertilizer. Two popular lowland varieties in Mwea (Basmati 370 and BW196) and two varieties reported as high yielding in other countries (Takanari and IR72) were used. Shoot dry weight (DW) increased with increases in the amount of N fertilizer applied in three splits at fixed timing, irrespective of variety. It reached approximately 20 t ha?1 under increased N conditions (>75 kg N ha?1) in several cases, indicating that high biomass production could be achieved by increasing N application rate. However, the increased biomass did not increase grain yield, due to decreased grain filling under high N conditions in all varieties. Thus, N amounts above 75 kg ha?1 were ineffective for increasing grain yields in Mwea, where N fertilizer was applied in three splits at fixed timing. Increasing influence of low temperature under high N conditions may be one of the reasons for the decreased grain filling in Mwea.  相似文献   

11.
As the challenges toward increasing water for irrigation become more prevalent, knowledge of crop yield response to water can facilitate the development of irrigation strategies for improving agricultural productivity. Experiments were conducted to quantify maize yield response to soil moisture deficits, and assess the effects of deficit irrigation (DI) on water productivity (water and irrigation water use efficiency, WUE and IWUE). Five irrigation treatments were investigated: a full irrigation (I1) with a water application of 60 mm and four deficit treatments with application depths of 50 (I2), 40 (I3), 30 (I4), and 20 mm (I5). On average, the highest grain yield observed was 1008.41 g m?2 in I1, and water deficits resulted in significant (p < .05) reduction within range of 6 and 33%. This reduction was significantly correlated with a decline in grain number per ear, 1000-grain weight, ear number per plant, and number of grain per row. The highest correlation was found between grain yield and grain number per ear. The WUE and IWUE were within range of 1.52–2.25 kg m?3 and 1.64–4.53 kg m?3, respectively. High water productivity without significant reduction in yield (<13%) for I2 and I3 compared to the yield in I1 indicates that these water depths are viable practices to promote sustainable water development. Also, for assessing the benefits of irrigation practices in the region crop water production functions were established. Maize yield response to water stress was estimated as .92, suggesting the environmental conditions are conducive for implementing DI strategies.  相似文献   

12.
Rice–wheat (RW) production system, which covers over 13.5 million ha in the Indo-Gangetic Plains of south Asia, is vital for food and nutritional security and livelihood of millions of poor people in this part of the region. Availability of irrigation water under projected climate change scenarios is a great concern, and demonstration of the impact of different irrigation regimes on rice, wheat, and system yields is essential to adopt suitable water saving technologies to minimize risk. This study tested the ability of the agricultural production systems simulator (APSIM) model to simulate the effects of different irrigation regimes on yield, irrigation water requirement, and irrigation water productivity (WPi) of rice, wheat, and RW system in upper-gangetic plains of India. The long-term simulated rice yield showed a steadily declining trend at an average rate of 120 kg ha?1 yr?1 (R 2 = 0.94, p < 0.05), while long-term simulated wheat yields showed a lower declining trend at an average rate of 48 kg ha?1 yr?1 (R 2 = 0.48, p < 0.05). The highest WPi of 8.31 kg ha?1 mm?1 was observed under RW system with the rice irrigation (IR) regime of 8 days alternate wetting and drying (AWD) and five irrigations for wheat with a yield penalty of 25.5 %. The next highest WPi was observed in the treatment with a 5-day AWD regime in rice and five irrigations for wheat, with a yield penalty of 20.1 %. Thus, we can suggest that a 5-day AWD irrigation regime for rice combined with five irrigations during wheat could be the best option under water limiting situations.  相似文献   

13.
Three methods of rice cultivation were compared in a field experiment at New Delhi, India during 2012 for their water use and changes in nutrient availability of soil. The experiment was laid out in a split plot design with conventional transplanting (CT), system of rice intensification (SRI), and aerobic rice (AR) cultivation technologies. Five doses of nitrogen included 100 % (120 kg N ha?1), 125, and 150 % recommended dose of N(RDN) through urea, 75 % of RDN through urea (90 kg N ha?1) + 25 % of RDN (30 kg ha?1) through farm yard manure (FYM), and 100 % of RDN through FYM. Results revealed that status of available N in soil under rice at 45 and 90 days after sowing (DAS) was significantly higher in CT and SRI compared to AR method. Application of the highest dose of nitrogen through urea resulted in the highest availability of N (188.9, 174.2, and 135.2 kg ha?1 for 45 and 90 DAS and at harvest stage, respectively). The soil under AR recorded significantly low availability of phosphorus and iron. However, availability of K in soil was not affected significantly under adopted production techniques and nitrogen management. The recorded irrigation water productivity was maximum in AR cultivation (9.16 kg ha mm?1) followed by SRI (7.02 kg ha mm?1) with irrigation water saving of 54 and 36 %, respectively compared to CT.  相似文献   

14.
Water shortage threatens agricultural sustainability in the Huang-Huai-Hai Plain of China. Thus, we investigated the effect of supplemental irrigation (SI) on the root growth, soil water variation, and grain yield of winter wheat in this region by measuring the moisture content in different soil layers. Prior to SI, the soil water content (SWC) at given soil depths was monitored to calculate amount of irritation water that can rehydrate the soil to target SWC. The SWC before SI was monitored to depths of 20, 40, and 60 cm in treatments of W20, W40, and W60, respectively. Rainfed treatment with no irrigation as the control (W0). The mean root weight density (RWD), triphenyl tetrazolium chloride reduction activity (TTC reduction activity), soluble protein (SP) concentrations as well as catalase (CAT), and superoxide dismutase (SOD) activities in W40 and W60 treatments were significantly higher than those in W20. The RWD in 60–100 cm soil layers and the root activity, SP concentrations, CAT and SOD activities in 40–60 cm soil layers in W40 treatment were significantly higher than those in W20 and W60. W40 treatment is characterized by higher SWC in the upper soil layers but lower SWC in the 60–100-cm soil layers during grain filling. The soil water consumption (SWU) in the 60–100 cm soil layers from anthesis after SI to maturity was the highest in W40. The grain yield, water use efficiency (WUE), and irrigation water productivity were the highest in W40, with corresponding mean values of 9169 kg ha?1, 20.8 kg ha?1 mm?1, and 35.5 kg ha?1 mm?1. The RWD, root activities, SP concentrations, CAT and SOD activities, and SWU were strongly positively correlated with grain yield and WUE. Therefore, the optimum soil layer for SI of winter wheat after jointing is 0–40 cm.  相似文献   

15.
Intermittent and prolonged dry spell during growth of transplanted rice is an important abiotic problem in north eastern region (NER). However, the productivity of rice in the region is very low, and this is mainly associated with reduced plant population, growth, and yield attributes with lower relative water content and leaf rolling with formation of soil cracks by erratic and aberrant rainfall. Keeping this in view, a field experiment on transplanted rice was conducted during two consecutive years 2011 and 2012 at NER of India, to evaluate the imposition of forced surface drainage (SD) at various growth stages (continuous drainage, SD at tillering, SD at panicle initiation, SD at booting, SD at flowering, SD at milking, and 15 days intermittent SD) and was compared with continuous flooding on growth and yield attributes, yield, relative water content, leaf rolling, and formation of soil cracks. Results revealed that continuous flooding has significant (p < 0.05) improved the plant population, growth and yield parameters, rice grain yield (3,406.7 kg ha?1) and straw yield (4,683.3 kg ha?1), relative water content maintained >90 %, no leaf roll, and soil crack. However, imposition of SD at tillering has lower tillers hill?1, but yield was compensated by improvement in yield attributes. As per the availability of water, growers of the region can utilize the water for scheduling of water and most critical stages can be avoided by moisture stress to obtain higher productivity.  相似文献   

16.
Farmers' participatory field trials were conducted at Madhuban, and Taraori, the two participatory experimental sites/locations of the Cereal Systems Initiative for South Asia (CSISA), a collaborative project of IRRI and CIMMYT in Karnal district of Haryana, India, during Kharif (wet season) 2010 and 2011. This research aimed to evaluate preemergence (PRE) and postemergence (POST) herbicides for providing feasible and economically viable weed management options to farmers for predominant scented rice varieties. Treatments with pendimethalin PRE fb bispyribac-sodium + azimsulfuron POST had lower weed biomass at 45 days after sowing (DAS). At Madhuban, highest grain yield of scented basmati rice (3.43 t ha−1) was recorded with the sequential application of pendimethalin PRE fb bispyribac-sodium + azimsulfuron POST. However, at Taraori, yields were similar with pendimethalin or oxadiargyl PRE fb bispyribac-sodium and/or azimsulfuron POST. Applying oxadiargyl by mixing with sand onto flooded field was less effective than spray applications in non-flooded field. The benefit-cost ratio of rice crop was higher with herbicide treatments at both sites as compared with the non-treated weed-free check except single PRE and POST applications and sequential application of oxadiargyl PRE fb oxadiargyl PRE. In a separate experiment conducted at Nagla and Taraori sites, scented rice cultivars' ('CSR 30′ and 'Pusa 1121′) tolerance to three rates of azimsulfuron (15, 25, and 35 g ai ha−1) was evaluated over two years (2010 and 2011). CSR 30 (superfine, scented) was more sensitive to higher rates (35 g ai ha−1) of azimsulfuron as compared to Pusa 1121 (fine, scented). Crop injuries were 8 and 28% in case of CSR 30; 5 and 15% in Pusa 1121 when applied with azimsulfuron 25 and 35 g ai ha−1, respectively. Azimsulfuron applied at 35 g ai ha−1 reduced yield in both cultivars but in CSR 30 yield reduction was twofold (11.5%) as that of Pusa 1121 (5.2%).  相似文献   

17.
Manganese (Mn) deficiency is prevalent in rice-growing regions resulting in poor paddy yield and human health. In this study, role of Mn, applied through various methods, in improving the productivity and grain biofortification of fine grain aromatic rice was evaluated. Manganese was delivered as soil application (SA) (0.5 kg ha?1), foliar spray (FA) (0.02 M Mn), seed priming (SP) (0.1 M Mn) and seed coating (SC) (2 g Mn kg?1 seed) in conventional (puddled transplanted flooded rice) and conservation (direct seeded aerobic rice) production systems at two different sites (Faisalabad, Sheikhupura) in Punjab, Pakistan. Manganese application, through either method, improved the grain yield and grain Mn contents of fine grain aromatic rice grown in both production systems at both sites. However, Mn application as SC and FA was the most beneficial and cost effective in improving the productivity and grain biofortification in this regard. Overall, order of improvement in grain yield was SC (3.85 t ha?1) > FA (3.72 t ha?1) > SP (3.61 t ha?1) > SA (3.36 t ha?1). Maximum net benefits and benefit–cost ratio were obtained through Mn SC in flooded field at Faisalabad, which was followed by Mn SP in direct seeded aerobic rice at the same site. However, maximum marginal rate of return was noted with Mn SC in direct seeded aerobic rice at both sites. In crux, Mn nutrition improved the productivity and grain biofortification of fine grain aromatic rice grown in both conventional and conservation production systems. However, Mn application as seed treatment (SC or SP) was the most cost effective and economical.  相似文献   

18.
Improper application of nitrogen (N) has led to high N losses and low N use efficiency in the lower reaches of Yangtze River in China. An effective method to solve such problems is the deep fertilized N in root zone (RZF). Limited information is available on the effect of RZF on the uptake of macronutrients (N, P and K) and rice yield. Field experiments, conducted from 2014 to 2015, compared the farmer fertilizer practice (FFP, with 225 kg ha?1 of N, split into three doses) and RZF using the same rate but placing N 5 cm away from rice roots in holes 10 cm deep (RZF10) or 5 cm deep (RZF5) as a single application. The highest mean yield (10.0 t ha?1) was obtained in RZF10, which was 19.5% more than that in FFP. Root zone fertilization of urea (whether 10 cm deep or 5 cm deep) resulted in greater accumulation of N, P and K in stem, leaf sheaths, leaf blades and grains compared to that in FFP in sandy and in loam soils. The uptake of N, P and K was the highest in RZF10 (average at 176.7, 66.2 and 179.1 kg ha?1, respectively), higher than that in FFP by 45.0, 17.0 and 22.6%, respectively. N apparent recovery efficiency was markedly higher in RZF10 (53.1%) than in FFP (27.5%). RZF10 significantly increased the N, P, K uptake compared with FFP under different N rates in both sandy and loam soils. These results suggest that the N, P and K input amount should be re-determined under RZF.  相似文献   

19.
Application time of nitrogen (N) fertilizer can significantly influence the yield and quality of potato tubers. The objective of this experiment was to assess the effects of N application time on dry matter accumulation in foliage and tubers, as well as on marketable tuber ratio, dry matter concentration, and specific gravity of the Chinese cultivar KX 13. The four treatments were as follows: all the 150 kg?N?ha?1 applied at planting (T1); 100 kg N ha?1 applied at planting and 50 kg N ha?1 applied 1 week before tuber initiation (20 days after emergence, DAE) (T2); 100 kg N ha?1 applied at planting and 50 kg N ha?1 applied 1 week before tuber bulking stage (35 DAE) (T3); and 100 kg?N?ha?1 applied at emergence and 50 kg N ha?1 applied 1 week before tuber bulking stage (35 DAE) (T4). For all treatments, 90 kg P2O5 ha?1 ((NH4)2HPO4) and 150 kg K2O ha?1 (K2SO4) were applied at planting. Thirty tons per hectare of marketable tuber yield was achieved with T3, while 23 t ha?1 marketable yield was achieved by applying all 150 kg N ha?1 at planting (T1). Relative to treatment T1, T3 also significantly increased harvest index (HI) from 0.76 to 0.86 and marketable tuber ratio from 64.8% to 79.2%. Applying N at planting in conjunction with dressing at 20 DAE (T2) gave a high marketable tuber ratio (74%) and HI (0.86), but the lower total tuber yield led to a lower marketable tuber yield. Without N application at planting (T4), N dressing did not increase the yield and HI. Treatments with N dressing had no significant effect on specific gravity or dry matter concentration of tubers.  相似文献   

20.
Sugarcane is a crop of great economic, social, and environmental relevance in Brazil. The country is the largest sugar producer and the second largest bioethanol producer in the world. The goal of this study was to evaluate the efficiency of a sugarcane inoculant composed of five diazotrophic bacterial strains, as well as nitrogen fertilization of two sugarcane varieties. Two experiments were carried out on two varieties using an experimental design composed of complete randomized blocks in a factorial of two varieties and three treatments with four replicates. The treatments can be described as: inoculation with the consortium of five diazotrophic strains, or N fertilization with 120 kg ha?1, and one control treatment. The following parameters were then evaluated: stem yield, accumulation of total dry matter, nitrogen content, quality of the sugarcane juice, and 15N natural abundance on flag-leaves. Inoculation and N fertilization on the Sapucaia plantation promoted increases of stem yield equivalent to 22.3 and 26.5 Mg ha?1 in the RB867515 variety, in comparison to the control, respectively. Inoculation and N fertilizer used for the Coruripe plantation increased stem yield of 38.0 and 42.4 Mg ha?1, respectively, with the RB867515 variety, while RB72454 showed increases of 16.7 and 37.5 Mg ha?1, both compared to the control. Biological nitrogen fixation was not affected by the treatments, however, both treatments increased the total recoverable sugar yield. Benefits from inoculation appeared to promote plant growth due to the plant–bacteria interaction.  相似文献   

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