Leaf Color Chart Research Articles

Resource and environment conservation in smallholder rice production using leaf color chart based nitrogen application

Resource and environment conservation in smallholder rice production using leaf color chart based nitrogen application

Production and Profitability of Hybrid Rice Is Influenced by Different Nutrient Management Practices

The government of Nepal has recommended blanket fertilizer application for rice cultivation, which results in lower nutrient use efficiency (NUE) particularly under rainfed conditions. With the aim of finding an appropriate nutrient management practices concerning rice production and profitability, a field experiment was conducted during rainy season of 2017 and 2018 at Kavrepalanchowk and Dang district of Nepal. Altogether, five treatments comprising various nutrient management practices viz. Nutrient Expert Model (NE), use of Leaf Color Chart (LCC), Government Recommended Fertilizer Dose (GON), Farm Yard Manure (FYM), and Farmers’ Field Practice (FFP), were laid out in RCBD with four replications in farmers’ fields. The analysis of variance showed significant difference between treatments for test weight and grain yield in Kavrepalanchowk whereas all traits except number of effective tillers were significant in Dang. The significantly higher grain yield and harvest index were obtained in NE, followed by LCC; and the overall straw yield was highest in LCC, followed by NE in both the locations. Also, yield gap analysis suggested the NE had 44.44% and 23.97% increase in yield as compared to FPP in Kavrepalanchowk and Dang, respectively. The combined analysis with Best Linear Unbiased Estimator revealed the interaction of nutrient management and location significantly effects the straw yield and harvest index across both the locations. The estimated mean straw yield and harvest index were 10.93 t/ha and 34.98%, respectively. Both correlation study and biplot of principal component analysis signaled grain yield had positive correlation with all other traits. Furthermore, the net revenue was maximum for NE, followed by LCC in both the locations. The benefit: cost ratio was highest for NE which was 1.55 in Kavrepalanchowk and 2.61 in Dang. On the basis of these findings, NE and LCC can be effectively used as nutrient management practice by the farmers to obtain maximum production and profitability in Rice.

Arbuscular mycorrhizal fungi and proximal sensing for improving nutrient use efficiencies in wheat (Triticum aestivum L.)

A 4 years field study was conducted to improve nitrogen (N) and phosphorus (P) use efficiencies in wheat (Triticum aestivum L.) using arbuscular mycorrhizal fungi (AMF) and precision N management. Split plot design was employed to rationalize N and P fertilizer use in two different experiments with AMF in the main plot and fertilizer application practice in the subplots. The AMF seed coating improved mycorrhization, root dry weight and P uptake. AMF coating of wheat seeds improved mean grain yield and agronomic efficiency of applied P fertilizer (AEP) by 11% and 55.4%, respectively. However, AMF seed coating did not improve chlorophyll content, normalized difference vegetative index, grain yield and agronomic efficiency of applied N fertilizer (AEN). Precision N management using leaf color chart (LCC), chlorophyll meter (SPAD), and GreenSeeker optical sensor (GS) sustained wheat grain yield equivalent to the soil-test based N fertilizer recommendation with 20–31 kg ha−1 less fertilizer N. Proximal sensing guided N use improved AEN by 21.9%–39.6% while mitigating global warming potential by 16%–24%. Integrated use of AMF seed coating and precision N management provides a potential solution to improve N and P nutrition and reduce environmental footprints of fertilizer N use in wheat.

Influence of nutrient and weed management on weed dynamics and productivity of upland rice (Oryza sativa)

The field experiment was conducted during kharif 2019 at ICAR-CURRS-NRRI at Hazaribagh, Jharkhand. The experiment was conducted to evaluate precision nutrient management and weed management practices for achieving minimum weed menace and maximum crop productivity. Under precision nutrient management, Nutrient Expert ® guided NPK recorded lesser weed density (7.76, 8.07 and 8.62) at all three stages. Pendimethalin fb hand weeding resulted in comparatively lesser weed density (7.72, 7.29 and 7.34 at 25, 60 DAS and at harvest). Nutrient Expert ® guided NPK resulted in maximum grain yield (3.63 t/ha), followed by Leaf Colour Chart (LCC) guided N + Full P & K (3.41 t/ha), which was significantly higher over RDF. Among the weed management aspects, pendimethalin fb hand weeding and bispyribac-Na were observed with significantly higher grain yield (4.09 and 3.79 t/ha). Hence Nutrient Expert ® guided NPK and pendimethalin fb hand weeding can be recommended for better weed management and enhanced productivity.

Rule-of-Thumb Instructions to Improve Fertilizer Management: Experimental Evidence from Bangladesh

Heavy government subsidies have led to inefficient application and overuse of fertilizer in Bangladesh. This results in above-optimal costs to farmers as well as to the environment and the public. In a randomized controlled trial, we provide farmers with a simple tool (a leaf color chart) and basic, rule-of-thumb instructions to guide the timing and quantity of urea (nitrogen) application. Treatment farmers reduce urea use by 8% without compromising yield, suggesting significant scope for improving urea management. The results are mainly driven by farmers delaying urea application as returns to urea are low early on in the season and urea applied is likely to be wasted. Cost-effectiveness estimates suggest that each dollar spent on this intervention produces a return of US$2.8 due to reduction of urea use over three seasons, as well as significant environmental benefits. We also find suggestive evidence that optimizing the timing of urea application affects farmers’ yields, plausibly as the intervention allows farmers to reallocate urea application to times when returns to urea are highest.

Fixed-time corrective dose fertilizer nitrogen management in wheat using atLeaf meter and leaf colour chart

AbstractFertilizer nitrogen (N) management in any region following standard general recommendations discount the fact that crop response to N varies between sites and seasons. To devise field-specific N management in wheat at jointing stage (Feekes 6 growth stage) using atLeaf meter and leaf colour chart (LCC), eight field experiments were conducted in three wheat seasons during 2017–2020 in the West Delta of Egypt. In the first two seasons, four experiments consisted of treatments with a range of fertilizer N application levels from 0 to 320 kg N ha−1. Monitoring atLeaf and LCC measurements at Feekes 6 growth stage in plots with different yield potentials allowed formulation of different criteria to apply field-specific and crop need-based fertilizer N doses. In the four experiments conducted in the third season in 2019/20, different field-specific N management strategies formulated in 2017/18 and 2018/19 wheat seasons were evaluated. In the atLeaf-based fertilizer N management experiment, prescriptive application of 40 kg N ha−1 at 10 days after seeding (DAS) and 60 kg N ha−1 at 30 DAS followed by application of an adjustable dose at Feekes 6 stage computed by multiplying the difference of atLeaf measurements of the test plot and the N-sufficient plot with 42.25 (as derived from the functional model developed in this study), resulted in grain yield similar or higher to that obtained by following the standard treatment. The LCC-based strategy to apply field-specific fertilizer N at Feekes 6 stage consisted of applying 150, 100 or 0 kg N ha−1 based on LCC shade equal to or less than 4, between 4 and 5 or equal to or more than 5, respectively. Both atLeaf- and LCC-based fertilizer N management strategies not only recorded the highest grain yield levels but also resulted in higher use efficiency with 57–60 kg N ha−1 in average less fertilizer use than the standard treatment.

Effect of Different N Management on Improving N Efficiency in Rice- tarom Variety

The chlorophyll meter (SPAD) and leaf colour chart (LCC) are simple, portable diagnostic tools that can measure the crop N status in situ in rice fields to determine the timing of N top dressingAn experiment was carried out in Rice Research Institute in Mazandaran, in 2019. A test material has been evaluated in a Randomized Complete Block Design with three replications. Tarom variety were grown under eight treatments at plant density of 25*25 cm. Eight treatments included a zero-N control, o splits, chlorophyll meter 35, 37, 40, LCC 4 and 5. Result showed that Both LCC and SPAD can be used to improve N management for rice. The optimal SPAD threshold for determining the timing of N-application was 35. LCC treatments indicated that N-management based on LCC shade 4 helped avoid over application of N. Critical value of LCC 4 was more beneficial in enhancing the growth and agronomic, physiologic and internal efficiency. It is suggested that when N-management technology such as real time N-management (SPAD and LCC) were used, would avoid to over application of N fertilizer by rice farmers. The objective of this study is to determine critical threshold SPAD and LCC value of Tarom variety of rice(Oyiza Sativa L).

Experimental comparison of continuous and intermittent flooding of rice in relation to methane, nitrous oxide and ammonia emissions and the implications for nitrogen use efficiency and yield

Intermittent flooding (IF) of rice has been encouraged as an approach to reduce water use and methane emissions compared with continuous flooding (CF), but may involve trade-offs. This study compared the contrasting effect of IF and CF flooding regimes on emissions of methane (CH4), nitrous oxide (N2O) and ammonia (NH3), nitrogen use efficiency (NUE) and yield. A split plot design was used which assessed the effects of four different fertiliser types. The results suggest that converting from CF to IF irrigation does lower CH4 emissions (by approximately 18%); however, this comes at a cost. IF irrigation resulted in a significant decrease in grain yield, regardless of fertiliser type (6.1% in this study) and also a significant decrease in NUE (a drop of 22.5% when compared to CF). IF irrigation also resulted in a small, but statistically significant (t-test p < 0.01) increase in N2O emissions. Difference in NH3 emission between the flooding regimes was not statistically significant. Our study concludes that conversion from CF to IF irrigation methods may well reduce overall global warming potential of greenhouse gas emissions from rice production; however, yield penalties and nitrogen pollution are likely to increase as a result. Leaf colour chart based application of Neem coated urea may lower the yield scaled GHG emissions under CF irrigation and NH3 loss in IF irrigation.

Nitrogen management for wheat (Triticum aestivum L.) intercropped with variable aged poplar (Populus deltoides Bartr.) plantations in North-Western India

Agroforestry system (AFS) is considered to be sustainable agricultural practice delivering wide range of ecosystem services. Nutrients and light are principal limiting resources for understorey crops. To optimize productivity, recommendation is to use well adapted tree–crop–fertilizer combinations. Nitrogen (N) management for wheat poplar is essential for maximizing synergies but the data is scarce. Therefore, current study addressed the issue by monitoring wheat performance fertilized with N: control (N1), 60 (N2), 90 (N3), 120 (N4), 150 (N5), 180 (N6) and leaf color chart (LCC) based-115 (N7) kg ha−1 under 2-, 3-, 5- and 6-year poplar. Tree age and N levels were key determinants of yield with reduction in growth (number of tillers m−1, plant height, ear length), yield parameters (1000-grain weight, number of grains ear−1), yield and NUE of wheat with advancing tree age, maximum reduction under 6-year plantation. However, fertilization with N7 −115 kg N ha−1 showed highest increase in grain yield (95.1%), harvest index (20.1%), NUE (agronomic efficiency (AE) 53.5% and recovery efficiency (RE)-91.1%). Nutrient uptake by grains showed maximum decrease of 32.1 (N), 13.6 (P) and 22.8 (K)%, respectively under 6-year-poplar. Averaged over poplar age, the N fertilizer treatment N7 lead to maximum increase of 2.3-, 2.9- and 2.3-folds in N, P, K uptake by grains, respectively. Therefore, the N management of wheat with N7 −115 kg N ha−1 (LCC-based treatment) under poplar tree canopies show the potential to mitigate the risk of poor crop yield and contribute to food security.

Sugarcane nutrition for food and environmental security/ Nutrição da cana-de-açúcar para segurança alimentar e ambiental

Sugarcane is an important cash crop cultivated globally from temperate to tropical regions. Improving cane yield and recovery sustainably is an important research area for improving livelihoods of the cane farmers. Among different approaches sill judicious and integrated use of nutrients as per plant needs holds the special place. Further, applying need based N management through optical gadgets viz. Leaf color chart (LCC), SPAD, Green seeker, integrated nutrient management, fertigation, special focus on for improving the efficiency of different fertilizers through different state of art technologies. For having higher fertilizer use efficiency in sugarcane, some aspects of fertilization especially How much? What type of? When to add? Is it worth? Number of splits? Mode of action? must be considered both for seed or ratoon. Further, soil textural class and climatic conditions on one side while on changing climatic conditions also affected it a lot. Further, inherent fertility status of the soils is also an important factor which affects the fate of applied fertilizers. There is a need to create awareness in between the farmers for not to applying huge quantity of different fertilizers as per their neighboring farmers, rather farmer should be smart enough to adopt different technologies in a smart way for having better benefits and thus livelihoods as the purpose is to fed the canes but not the soil. In the present review an attempt being made to compare the comparative performance of sugarcane with respect to fertilization for finally guiding the sugarcane cultivars. Idea is to enlighten them regarding need based sustainable fertilization with an aim to improve the fertilizer use efficiencies for having improved yield and quality parameters instead of loading the soil with much of fertilizers which further have environmental concerns.

Classification of rice plant nitrogen nutrient status using k-nearest neighbors (k-NN) with light intensity data

&lt;span&gt;Crop management including the efficient use of nitrogen (N) fertilizer is important to ensure crop productivity. Human error in judging the leaf greenness when using the leaf color chart (LCC) to estimate the rice plant N nutrient status has encouraged numerous researchers to implement a machine-learning algorithm but experienced some issues in calibration and lighting. The datasets are created at 6.00-7.00AM (consistent lighting) and including light intensity, so each dataset contains RGB value and light intensity as inputs, and LCC value as a target. A system consists of a smartphone with an application that prevents user from taking an image if the light intensity is not in 2000-3500 lux, and a computer for preprocessing and classification purposes were developed. The preprocessing included cropping, splitting the rice leaf images, and calculating the average RGB values. A k-NN classifier is implemented and by using a cross-validation method is found k=5 gives the best accuracy of 97,22%. The in-site test of the system also works with an accuracy of 96.40%. &lt;/span&gt;

Real-time nitrogen management using decision support-tools increases nitrogen use efficiency of rice

Several decision support tools have been proposed for precision nitrogen (N) fertilizer application in rice (Oryza sativa L.) to increase nitrogen use efficiency (NUE) and grain yields. However, a comparison of their effectiveness has not been well documented. A field experiment was conducted in western Terai of Nepal during 2017–2018 to identify the appropriate decision support tool for improving NUE and grain yields. Nine N fertilizer management treatments were laid out in a randomized complete block design with three replications. The treatments included a GreenSeeker (GS) optical sensor, soil plant analysis development (SPAD) meter, leaf color chart (LCC), each of these treatments with basal application of N at 25 kg ha−1, urea briquette deep placement (UDP), and the existing government-recommended practice (RP, 100 kg N ha−1). N fertilizer application guided by decision support tools had a significant (p < 0.05) effect on grain yields. UDP produced the highest grain yield (6.80 Mg ha−1) among the treatments. Grain yields were not significantly different among GS, LCC (in combination with basal 25 kg N ha−1), RP, and UDP treatments. However, GS, UDP, and LCC saved N input by 54%, 22%, and 21%, respectively, compared to RP. In addition, GS produced a significantly higher agronomic N use efficiency (ANUE), partial factor productivity of N (PFPN), apparent N recovery (ANR), and utilization efficiency of N (UEN) compared to RP. These results suggest that application of N fertilizer guided by the GS decision support tool can save significant amount of N fertilizer compared to the current RP without compromising grain yield.

Improving nitrogen use efficiency using precision nitrogen management in wheat (Triticum aestivum L.)

AbstractBackground: Excessive application of nitrogen (N) fertilizer in cereal crops not only decreases the N use efficiency but also accelerates greenhouse gas (GHG) emission.Aim: To improve N use efficiency in wheat (Triticum aestivum L.) using precision N management and coating seeds with arbuscular mycorrhizal fungi (AMF).Methods: Field experiment laid out in split‐plot design was conducted to study the role of AMF consortia (four species) seed coating and different precision N management strategies in rationalizing fertilizer N use.Results: The AMF seed coating improved mycorrhization but did not improve N assimilation, grain yield, root weight, N uptake, chlorophyll value, normalized difference vegetative index, and physiological efficiency (PEN) of applied N fertilizer. The benefits of AMF seed coating in improving N assimilation were not visible even in no‐N treatment. Precision N management using leaf color chart (LCC), chlorophyll meter (SPAD), and GreenSeeker optical sensor (GS) sustained wheat grain yield equivalent to the soil‐test based N fertilizer recommendation with the average savings of 20% N fertilizer. Precision N management strategies improved mean recovery efficiency (REN) and partial factor productivity (PFPN) of applied N fertilizer, respectively by 26.0% and 26.4% over the soil‐test based N management. Spectral properties measured with LCC, SPAD and GS showed good correlation (R2 &gt; 0.71) with grain yield, depicting great potential of optical sensing tools in predicting grain yield and inferring need‐based fertilizer N topdressings decisions in wheat.Conclusions: Precision N management provides a potential solution to improve N nutrition in wheat while reducing nitrous oxide (N2O) and total GHG emissions by 23.2 and 23.6%, respectively, in comparison to soil‐test based N application.

Consumer preference for some genotypes of ornamental chili (Capsicum spp.) population F2

The experiment was conducted to determine the characteristics of ornamental chili plants from several genotypes in the F2 population by consumer desires. This research performed using a single plant method. The planted community consists of all the elders (P) and crossing results. This study uses survey techniques and questionnaires as research aids in obtaining ornamental chili character information that is the public likes. Consumer preference test results (I) against 14 genotypes show that the average consumer most wants TR 23 x TR 25U (1) in some of the characters tested: the leaf color, habitus, and fruit color characters. Genotype TR23 x TR 25U (1) has a dark green leaf color character with a scale of 5 based on the IRRI Leaf Color Chart, a compact habitus, and has two color changes in the fruit, green-red and purple-red. Based on the results of the consumer preference test (II) on four genotypes, it shows that there is no difference in the average value of consumer preferences in the genotypes TR 23B x Ayesha (3), TR 25U, and TR 25 x Ayesha (2) in the characters tested.

Real-time application of neem-coated urea for enhancing N-use efficiency and minimizing the yield gap between aerobic direct-seeded and puddled transplanted rice

Abstract An appropriate nitrogen (N) management strategy is required for minimizing the yield loss incurred in aerobic direct-seeded rice (ADR) due to moisture stress. Field experiments for two consecutive years were conducted to evaluate comparative performance of real-time application of neem-coated urea (NCU) and prilled urea (PU) using a customized leaf color chart (CLCC) on growth, yield and N use efficiency of both ADR and puddled transplanted rice (PTR). Six treatments were tested with cultivar ‘Apo’:0 N (T1) as control, 100 kg N ha−1 as prilled urea (PU) applied conventionally (T2), 100 kg N ha−1 as NCU applied conventionally (T3), 100 kg N ha−1 as PU applied on the basis of CLCC recommendation (T4), 100 kg N ha−1 as NCU applied on the basis of CLCC recommendation (T5), and 50 kg N ha−1 as PU and 50 kg N ha−1 as farm yard manure (FYM) (T6). Results of the field experiments showed significant effects (p ≤ 0.05) of both cultivation method and N management on yield. The ADR produced 22.5–46.0% less yield as compared to PTR mainly due to substantial reductions in leaf area, biomass and sink size. As compared to PU, the conventional application of NCU increased yields by 7.1–13.4 % and 6.8–10.0 %,in ADR and PTR, respectively and the differences were significant (p ≤ 0.05). But when applied using CLCC, yield enhancements from PU increased to 21.2–22.9 % and 14.6–15.9 %, respectively. The NCU resulted in 6.6–8.9 and 6.2–6.5 % higher N recovery efficiency as compared to PU, which was further increased to 16.3–18.0 and 11.4–14.6 % in ADR and PTR, respectively when applied using CLCC. Hence, our results indicate that optimization of N application combining both a real-time N management tool (CLCC) and enhanced efficiency N fertilizer (NCU) could help minimize yield losses, which was more visible under ADR by improving growth and yield parameters. The findings of the present study can be proposed as a suitable alternative to the existing N-fertilizer management for rice farmers of both aerobic dry-seeded and puddled transplanted conditions, while more yield advantage was realized in the former.

Prediction of spring maize yields using leaf color chart, chlorophyll meter, and GreenSeeker optical sensor

SummaryPredicting in-season crop yield is a unique tool for drawing important crop management decisions for precision farming. Field experiments were conducted at two locations in northwestern India under different agro-climatic zones to predict and validate spring maize yield using various in-season spectral indices. The spectral properties measured with leaf color chart (LCC), chlorophyll meter (SPAD meter), and GreenSeeker optical sensor were used to predict grain yield. A power function based on the Normalized Difference Vegetative Index (NDVI) measured with GreenSeeker optical sensor at V9 growth stage (9th leaf with fully exposed collar) presented higher values of coefficient of determination and explained 61% of the variability in spring maize grain yield, whereas NDVI measured at early and late growth stages were not reliable for the purpose. The spectral properties recorded with the SPAD meter and LCC rendered better grain yield estimates at VT growth stage (tasseling) and were respectively able to explain 75 and 76% variability in grain yield. The developed models were validated on an independent data set from another field experiment on spring maize. The normalized root mean square error (NRMSE) was &lt;10% for LCC and SPAD at all the growth stages and at V9 growth stage for NDVI. The LCC, SPAD, and NDVI values adjusted with cumulative growing degree day were not helpful to improve NRMSE.

Farmers’ perception towards water and soil management in the irrigated paddy field in North Sumatera, Indonesia

Integrated Crop Management (ICM) had been introduced in North Sumatra Province since 2002. This study aimed to explore how farmers’ perception on intermittent irrigation and balanced fertilization of ICM. The assessment was obtained using cross-sectional and field survey in Serdang Bedagai and Deli Serdang Regency. Primary data were initially collected through observation toward community surrounding the watershed. The farmer respondents were selected purposively based on their roles as innovators or early adopters. Secondary data was collected from the review of previous studies. The results showed that after its first introduction in 2002, most farmers had not applied intermittent irrigation and balanced fertilization such as the use of compost and leaf colour chart (BWD) in farming practice. Farmers perception was low regarding technological characteristics that did not correspond with adoption level. High understanding on complexity, comparative advantage, and compatibility were not followed by high level of adoption, resulting innovation dissonance to occur. Farmers in downstream area were unsatisfied of irrigation institution (P3A) particularly in dry season. Therefore, it is recommended to consider institutional (P3A) approach to stimulate behaviour changes among farmers in surrounding watershed area despite hard effort to do so.

Optical sensing for precision Nitrogen management in wheat

Fertilizer nitrogen (N) is the major input for food production. Excessive and untimely fertilizer N topdressings to achieve high yields are common among the farmers in the major food producing regions of Asia. A four year field study was conducted to validate precision N management strategies in wheat (Triticum aestivum L.; variety PbW 550) through optical sensing with leaf colour chart (LCC), chlorophyll meter (SPAD), and GreenSeeker (GS) optical sensor for achieving high N use efficiencies. The study consisted of five treatments--no-N control, soil test based N application, and precision N application using LCC, SPAD meter and GS optical sensor. The precision N management techniques sustained grain yield, N assimilation and root dry weight equivalent to the soil test based fertilizer N application with 16.7 to 25.8 percent less use of fertilizer N during different years. The optical sensing techniques improved agronomic and recovery efficiency of applied N up to 40.5 and 35.3 per cent, respectively in comparison with the soil test based fertilizer N recommendation. The optical sensing based N topdressings promisingly synchronized fertilizer N supply with the plant N demand and are thus more useful in improving N use efficiency, reducing cost of production and mitigating escape of reactive N from soil system to atmosphere.

Effect of different mitigation options on growth, productivity and economics of wheat (Triticum aestivum)

Wheat (Triticum aestivum L.) is second most important food grain after rice and is consumed in different forms. The production of wheat in India is currently facing new challenges due to increasing population and adverse impacts of climate change. The production of wheat has increased significantly after the introduction of high yielding varieties. Modern wheat cultivars require adequate amount of nitrogen (N) fertilizer and several irrigations for economical production. The amount and type of nitrogen fertilizers not only affect the production of wheat but also has impact on climate change due to emission of nitrous oxide. A field experiment was conducted in 2016-17 to study the impact of water management (3 and 5 irrigations) and nitrogen fertilizer (urea, neem coated urea (NCU), urea with thiourea, and leaf colour chart (LCC) based N application) on wheat production and profitability. The nitrogen-management practices and irrigation practices significantly influenced the yield parameters, cost of cultivation, net returns and benefit to cost ratio of wheat crop. Grain yield was increased by 15.89% (p ≥ 0.05) in 5 irrigations compared to 3 irrigations. The grain yield increased by 3.0%, 3.4% and 5.9% in treatments where N was applied using NCU, LCC based N application and urea + thiourea respectively, over urea treatment. Grain yield per kg of N applied was highest in LCC based N application treatment followed by thiourea + urea, NCU and urea N treatments. Highest gross returns was from thiourea treatment however the net returns and B: C ratio were highest in LCC based urea N application due to higher biological yield and saving of 20 kg nitrogen per ha. The study revealed that the economic performance of greenhouse gas mitigation technologies where N was applied based on the plant requirement using leaf colour chart and 5 irrigations was the best followed by application of nitrification inhibitor thiourea with urea and 5 irrigations.

Nitrogen management practices for improving yield and nitrogen use efficiency in rice (Oryza sativa)

A field experiment was conducted on rice (Oryza sativa L.) during kharif season of 2017 at Crop Research Centre of Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut (U P) to assess the nitrogen (N) use efficiency and performance of rice under different nitrogen management practice. Management practices included N levels with modified application through leaf colour chart (LCC) and chlorophyll meter (SPAD). The study shows that treatment T6 (LCC (50 kg N/ha) with basal N @50 kg/ha)gave highest yield and N-use efficiency which were comparable to T9 (SPAD (67 kg N/ha) with basal N @33 kg/ha). The total biological yield (grain + straw) of rice was significantly higher in T6 (114.4 q/ha) as compared to control (66.9 q/ha). The SPAD and LCC-treated plot showed higher N-use efficiency in rice over fixed-scheduling N treatments. Highest N content(1.88% (grain) and 0.76% (straw)) and uptake (128.14 kg/ha) was recorded in T6 treatmentin all stages (tillering, PI and harvest) which was comparable with T8 and T9 treatment.