•N application extends the growth period of direct sown oilseed rape.•Pre-sowing N application improved seed yield most significantly.•Fast biomass accumulation of the growth centers is conducive to ...high seed yield.•Gompertz’ model can be used to simulate plant biomass production of the crop.
Direct sown oilseed rape has been rapidly developed in recent years due to increasing shortage of labor force in the winter oilseed rape (Brassica napus L.) region of Yangtze River Basin. However, the appropriate nitrogen management of the crop has not yet been established, resulting in poor seed yield. Two experiments were conducted, including a pot trial to elucidate the N utilization in different growth periods under sufficient supplies of N and other nutrients, and a field experiment to study the effects of N application rates at different stages on plant development, biomass production, seed yield and N use efficiency of direct sown oilseed rape. The results showed that N applications at different stages extended the growth period of the crop. The vegetative growth was extended more than the reproductive growth by N applied at early stages. Nitrogen application promoted the plant growth center/s leading to high biomass accumulations in different periods. Higher pre-sowing N rates prolonged the fast biomass accumulation period and increased the fastest accumulation speed. The seed yield and NUE of the crop were improved by N applied prior to sowing and at the initiation of stem elongation. The results suggest that, relatively high N rate but not exceeding 135kgNha−1 applied at pre-sowing, 67.5–90kgNha−1 at the initiation of stem elongation, and appropriate rates depending on the seedling growth at 5-leaf stage were optimum N fertilizer strategies to achieve high production for the direct sown winter oilseed rape in Yangtze River Basin.
The unsustainable use of nutrients such as nitrogen (N) and phosphorus (P) has resulted in the straining of the environment to excess. To improve this situation, a better knowledge of the nutrient ...flows is necessary. Even though nutrient balances and emissions have been calculated, an illustrative calculation method for the efficient use of nutrients use is still lacking.
This article presents a novel methodology for a nutrient footprint, which takes into account 1) the amount of nutrients taken into use as virgin or recycled nutrients and 2) the efficiency of these nutrients utilized in that particular production chain. At the same time, nutrient losses at each life cycle phase are identified. Hence, the nutrient footprint is an indicator which combines the amount of captured nutrients kg of N and P for use in the production chain and the share of nutrients utilized % either in the product itself or in the entire production chain, accounting also for side-products.
The nutrient footprint method is tested using oat flakes and porridge as a case product. The case calculation results reveal a relatively efficient use of the nutrients, as the nutrient use efficiency (NUE) of the production chain for N is 71% and for P 99%. When examining only the NUE of the oat flakes and porridge and excluding the side-products, the nutrient use efficiency is 55% for both N and P. The case calculation also reveals the hotspots for nutrient losses, which were located in the wastewater and food waste treatment.
The nutrient footprint methodology seems to have potential in assessing the nutrient balances of food chains as well as other bio-based production chains. It offers information about the nutrient usage and utilization efficiency in a simple and comparable form. This information can not only be used in improving the production chains but also in communicating the importance of the sustainable use of nutrients to decision makers.
•We propose a novel method for calculating a nutrient footprint.•Combined indicator of the amount and use efficiency of virgin and recycled nutrients.•Case calculation for oat flakes had a good nutrient use efficiency (NUE) overall.•The hotspots in the case were in the waste treatment processes with low NUEs.•Aim of the method is to improve the NUE of bio-based materials and energy chains.
Nutrient use efficiency (NuUE), comprising nutrient uptake and utilization efficiency, is regarded as one of the most important factors for wheat yield. In the present study, six morphological, nine ...nutrient content and nine nutrient utilization efficiency traits were investigated at the seedling stage using a set of recombinant inbred lines (RILs), under hydroponic culture of 12 treatments including single nutrient levels and two- and three-nutrient combinations treatments of N, P and K. For the 12 designed treatments, a total of 380 quantitative trait loci (QTLs) on 20 chromosomes for the 24 traits were detected. Of these, 87, 149 and 144 QTLs for morphological, nutrient content and nutrient utilization efficiency traits were found, respectively. Using the data of the average value (AV) across 12 treatments, 70 QTLs were detected for 23 traits. Most QTLs were located in new marker regions. Twenty-six important QTL clusters were mapped on 13 chromosomes, 1A, 1B, 1D, 2B, 3A, 3B, 4A, 4B, 5D, 6A, 6B, 7A and 7B. Of these, ten clusters involved 147 QTLs (38.7%) for investigated traits, indicating that these 10 loci were more important for the NuUE of N, P and K. We found evidence for cooperative uptake and utilization (CUU) of N, P and K in the early growth period at both the phenotype and QTL level. The correlation coefficients (r) between nutrient content and nutrient utilization efficiency traits for N, P and K were almost all significantly positive correlations. A total of 32 cooperative CUU loci (L1–L32) were found, which included 190 out of the 293 QTLs (64.8%) for the nutrient uptake and utilization efficiency traits, indicating that the CUU-QTLs were common for N, P and K. The CUU-QTLs in L3, L7, L16 and L28 were relatively stable. The CUU-QTLs may explain the CUU phenotype at the QTL level.
Different growth rates of grasses from South American natural grasslands are adaptations to soils of low fertility. Grasses with fast growth rate are species with an accumulation of nutrients in ...soluble forms, with a high metabolic rate. This work aimed to study whether grasses with different growth rates have different phosphorus (P) uptake and efficiency of P use with high and low P availability in soil, as well as whether phosphatase activity is related to the species growth rate and variations in P biochemical forms in the tissues. Three native grasses (Axonopus affinis, Paspalum notatum, and Andropogon lateralis) were grown in pots with soil. Along plant growth, biomass production and its structural components were measured, as well as leaf acid phosphatase activity and leaf P chemical fractions. At 40 days of growth, leaf acid phosphatase activity declined by about 20–30% with an increase of P availability in soil for A. affinis and P. notatum, respectively. Under both soil P levels, P. notatum showed the highest plant total biomass, leaf dry weight and highest P use efficiency. A. affinis presented the higher P uptake efficiency and soluble organic P concentration in the leaf tissues. A. lateralis showed P-Lipid concentration 1.6 and 1.3 times higher than A. affinis and P. notatum, respectively. In conclusion, acid phosphatase activity in grass of higher growth rate is related to higher remobilization of P due to higher demand, as in A. affinis, and higher growth rates are associated with higher P uptake efficiency.
Nitrogen is quantitatively the most essential nutrient for plants and a major factor limiting crop productivity. One of the critical steps limiting the efficient use of nitrogen is the ability of ...plants to acquire it from applied fertilizer. Therefore, the development of crop plants that absorb and use nitrogen more efficiently has been a long-term goal of agricultural research. In an attempt to develop nitrogen-efficient plants, rice (Oryza sativa L.) was genetically engineered by introducing a barley AlaAT (alanine aminotransferase) cDNA driven by a rice tissue-specific promoter (OsAnt1). This modification increased the biomass and grain yield significantly in comparison with control plants when plants were well supplied with nitrogen. Compared with controls, transgenic rice plants also demonstrated significant changes in key metabolites and total nitrogen content, indicating increased nitrogen uptake efficiency. The development of crop plants that take up and assimilate nitrogen more efficiently would not only improve the use of nitrogen fertilizers, resulting in lower production costs, but would also have significant environmental benefits. These results are discussed in terms of their relevance to the development of strategies to engineer enhanced nitrogen use efficiency in crop plants.
► We model soil water flow and nitrogen transport in furrow irrigated systems. ► Nitrogen fertilizer placement and soil surface management strategies are analysed. ► Using a plastic cover or ...compacting the furrow results in significant water savings. ► Results highlight opportunities for improving water and nitrogen use efficiency. ► Improved efficiencies lead to significant reductions in deep drainage/leaching.
Inappropriate soil, water and fertilizer management in irrigated agriculture can result in environmental problems, including groundwater pollution with nitrates. Furrow irrigation is widely used around the world and is considered as a major source of nitrate leaching. Improved soil, water and fertilizer management practices are needed to improve the production and environmental performance of furrow irrigated agriculture. This paper describes results of a simulation study using HYDRUS-2D to assess opportunities to improve irrigation efficiency and reduce the risk of nitrate leaching from furrow irrigated systems. It focuses on the commonly used practice in Pakistan where irrigation water supply is turned off once the water level in the furrow has reached a pre-determined depth. The study involved analysing the impact of fertilizer placement on nitrate leaching from a loamy soil subjected to three different soil surface treatments. Fertilizer placements included placing the fertilizer on the bottom of the furrow (P1), sides of the furrow (P2), bottom and sides of the furrow (P3), on the sides of the furrow near to the ridge top (P4), and on the surface in the middle of the ridge top (P5). The soil surface management treatments included the original soil (So), compacting the bottom of the furrow (Sc) and placing a plastic sheet on the bottom of the furrow (Sp). Results showed water savings varied with application rate and soil surface management, with soil surface management strategies Sc and Sp yielding water savings of 17% and 28% relative to So for a water application rate of 1800Lh−1 for a 100m long furrow. Leaching of nitrogen for this case was reduced from 33% for So with fertilizer placement P1 to 1% by compacting the bottom of the furrow (Sc) and to zero loss by placing a plastic sheet on the bottom of the furrow (Sp). By changing the fertilizer placement for So from P1 to P2, P3, P4, and P5, nitrogen leaching was reduced from 33% to 2%, 15%, 0%, and 0%, respectively. Results of this study demonstrate that placing nitrogen fertilizer on the sides of the furrow near the ridge top (P4) or on top of the furrow at the centre of the ridge (P5) maximize the retention of nitrogen fertilizer within the root zone. Results of this study also demonstrate that enhancements in irrigation efficiency, particularly in coarser soils with high infiltration rates can be achieved through compacting the bottom of the furrow or by placing a plastic sheet on the bottom of the furrow before applying irrigation.
•A reduction of nitrogen by 1/3 mitigates N2O emission in one of the two years.•Nitrogen use efficiency was negatively and non-linearly correlated with N2O emission.•N2O and NO fluxes were best ...explained by a dual Arrhenius and Michaelis–Menten model.
Given the common problem of fertilizer overuse, agronomists are calling for a reduction of the high nitrogen dose by 1/3. We carried out a field experiment over two full winter wheat–summer maize rotations in the North China Plain (NCP) to determine whether this degree of nitrogen reduction will significantly reduce the emissions of nitrous oxide (N2O) and nitric oxide (NO). Three treatments were investigated in the field trial: a control with no nitrogen application, the conventional practice with nitrogen over-application and the optimal practice with a reduced dose of nitrogen by 1/3. Our observations across all treatments over the experimental period reveal significant correlations of the fluxes of either gas with soil temperature and moisture as well as the concentrations of soil ammonium, nitrate and dissolvable organic carbon. There were strong correlations within the functions of the dual Arrhenius and Michaelis–Menten kinetics, giving apparent activation energy values of 40–97 and 59–92kJmol−1 for N2O and NO fluxes, respectively. Our results provide annual direct emission factors of 0.48–0.96% for N2O and 0.15–0.47% for NO and demonstrate a significant correlation between N2O emission induced by fertilization and fertilizer nitrogen use efficiency (NUE). The correlation indicates a significant potential of N2O mitigation via enhancing NUEs. A reduction in the nitrogen dose did not obviously mitigate either the annual NO emission in both rotations or the annual N2O emission in the second one. However, nitrogen reduction significantly decreased the annual total N2O emission by 38% during the first rotation. These inconsistencies in the responses of N2O emission to the reduced nitrogen dose can be attributed to improper fertilization practices, such as broadcasting urea prior to heavy rainfalls or irrigation events during the maize season, which implies a need for further fertilization practice options/techniques in addition to the reduction of nitrogen doses.
Nutrient use efficiency is reported as a strong indicator of the buildup soil nutrient status for nutritional security of crops through an integrated nutrient management approach under a rice-wheat ...system. The data revealed that integrated application of manures and fertilizers reported maximum organic carbon (0.39%) in the treatment receiving 100% of the recommended dose of fertilizers (RDF) + farmyard manure and lowering the pH to 6.39. The maximum available N (360.8 kg ha−1) was found in 100% RDF + press mud treatment; available P (66.30 kg ha−1) was found in 75% RDF + poultry manure; and available K, Zn, Cu, and Fe (226.3 kg ha−1 and 2.220, 0.732, and 36.87 mg kg−1, respectively) in 100% RDF + farmyard manure treatments. Similarly, total macro- and micronutrient content in soil increased with the addition of organic manures alone or in combination with chemical fertilizers. The highest agronomic efficiency and utilization efficiency of nitrogen (41.83 and 102.55 kg kg−1, respectively) and phosphorous (83.57 and 204.9 kg kg−1, respectively) were recorded in the treatment receiving 75% RDF + poultry manure. This study concluded that the integrated application of manures and chemical fertilizers is a must for improving soil nutrient status and nutrient use efficiency and ultimately enhances nutritional security under a rice-wheat system.
▶ A good correlation between leaf N content per unit leaf area versus SPAD reading and SPAD readings versus LCC readings was observed for continuously flooded and AWD treatments. ▶ A combination of ...AWD
−10 and SPAD-based N management, using critical value 38, can save irrigation water and N fertilizer while maintaining high yield as in CF conditions with fixed time and rate of nitrogen application of 180
kg
ha
−1. ▶ The findings show that SPAD can be used under AWD conditions and that LCC can also be a practical tool for N-fertilizer management of rice grown under AWD, but this needs further field validation.
Farmers have adopted alternate wetting and drying (AWD) irrigation to cope with water scarcity in rice production. This practice shifts rice land away from being continuously anaerobic to being partly aerobic, thus affecting nutrient availability to the rice plant, and requiring some adjustment in nutrient management. The use of a chlorophyll meter (also known as a SPAD meter) has been proven effective in increasing nitrogen-use efficiency (NUE) in continuously flooded (CF) rice, but its use has not been investigated under AWD irrigation. This study aimed at testing the hypotheses that (i) SPAD-based N management can be applied to AWD in the same way it is used in CF rice, and (ii) combining chlorophyll meter-based nitrogen management and AWD can enhance NUE, save water, and maintain high rice yield. Experiments were conducted in a split-plot design with four replications in the 2004 and 2005 dry seasons (DS) at IRRI. The main plots were three water treatments: CF, AWD that involved irrigation application when the soil dried to soil water potential at 15-cm depth of −20
kPa (AWD
−20) and −80
kPa (AWD
−80) in 2004, and AWD
−10 and AWD
−50 were used in 2005. The subplots were five N management treatments: zero N (N
0), 180
kg
N
ha
−1 in four splits (N
180), and three SPAD-based N-management treatments in which N was applied when the SPAD reading of the youngest fully extended leaf was less than or equaled 35 (N
SPAD35), 38 (N
SPAD38), and 41 (N
SPAD41). In 2005, N
SPAD32 was tested instead of N
SPAD41. A good correlation between leaf N content per unit leaf area and the SPAD reading was observed for all water treatments, suggesting that the SPAD reading can be used to estimate leaf N of rice grown under AWD in a way similar to that under CF. SPAD readings and leaf color chart (LCC) values also showed a good correlation. There were no water
×
nitrogen interactive effects on rice yield, water input, water productivity, and N-use efficiency. Rice yield in AWD
−10 was similar to those of CF; yields of other AWD treatments were significantly lower than those of CF. AWD
−10 reduced irrigation water input by 20% and significantly increased water productivity compared with CF. The apparent nitrogen recovery and agronomic N-use efficiency (ANUE) of AWD
−10 and AWD
−20 were similar to those of CF. The ANUE of N
SPAD38 and N
SPAD35 was consistently higher than that of N
180 in all water treatments. N
SPAD38 consistently gave yield similar to that of N
180 in all water treatments, while yield of N
SPAD35 about 90% of that of CF. We conclude that a combination of AWD
−10 and SPAD-based N management, using critical value 38, can save irrigation water and N fertilizer while maintaining high yield as in CF conditions with fixed time and rate of nitrogen application of 180
kg
ha
−1. Treatments AWD
−20 and N
SPAD35 may be accepted by farmers when water and N fertilizer are scarce and costly. The findings also suggested LCC can also be a practical tool for N-fertilizer management of rice grown under AWD, but this needs further field validation.
Background
Chemical fertilization helped modern agriculture in grain yield improvement to ensure food security. The response of chemical fertilization for higher hybrid rice production is highly ...dependent on optimal fertilization management in paddy fields. To assess such responses, in the current work we examine the yield, root growth, and expression of related genes responsible for stress metabolism of nitrogen (N) and phosphorus (P) in two hybrid-rice cultivars Deyou4727 (D47) and Yixiangyou2115 (Y21).
Methods and results
The experiment followed four nitrogen (N) (N
0
, N
60
, N
120,
and N
180
kg/ha) and phosphorus (P) (P
0
, P
60
, P
90
, and P
120
kg/ha) fertilizer levels. The grain yield in D47 was more sensitive to nitrogen application, while Y21 was more sensitive to phosphorus application, which resulted in comparatively higher biomass and yield. Our findings were corroborated by gene expression studies of glutamine synthetase
OsGS1;1
and
OsGS1;2
and phosphate starvation-related genes
PHR1
and
SPX
, confirming sensitivity to N and P application. The number of roots was less sensitive to nitrogen application in D47 between N
0
and N
60
, but the overall nutrient response difference was significantly higher due to the deep rooting system as compared to Y21.
Conclusions
The higher yield, high N and P use efficiency, and versatile root growth of D47 make it suitable to reduce unproductive usage of N and P from paddy fields, improving hybrid rice productivity, and environmental safety in the Sichuan basin area of China.
PDF
