Nanofertilizers and their role in sustainable agriculture

Enhancing nutrient use efficiency (NUE) with minimal threat to environment has become critical for our agriculture food production systems (FPS) to sustain the burgeoning population. Nanotechnology with nanoscale inputs for production of nano agri-inputs (NAIPs) has emerged as an innovative solution for addressing issue of low or declining nutrient use efficiency (NUE) with minimal environment footprint. Nanotechnology is a promising field of research which has the potential to offer sustainable solutions to ever pressing challenges confronting our modern intensive agriculture. Nanotechnology employs nanomaterials which typically have small size (1–100 nm) which imparts unique characteristics and benefits. In addition to numerous other benefits, large surface area to volume ratio offers opportunity for better and effective interaction of nanoparticles to target sites. Nano-fertilizers hold potential to fulfil plant nutrition requirements along with imparting sustainability to crop production systems and that too without compromising the crops yield. Indian Farmers Fertilizer Cooperative Limited (IFFCO) - the farmers’ own fertilizer cooperative has been in the forefront for promotion of agro-technologies and novel agri-inputs to mitigate problems faced by the farmers. It has indigenously innovated at its Nano Biotechnology Research Centre (NBRC) at Kalol, Gujarat and succeeded in R& D and manufacturing of proprietary nano-fertilizers viz. nano urea, nano zinc, and nano copper. These nano-fertilizers utilize the dynamics of shape, size, surface area and bio-assimilation. There efficacy was evaluated on the basis of multi-location multi-crop trials under varying crop seasons, both by the research institutes and also on the progressive farmers’ fields across 11,000 locations on 94 crops across India. Independently, nano nitrogen, nano zinc, and nano copper have also been tested for bio-efficacy- bio safety- toxicity and environment suitability. IFFCO nano-fertilizers meet alll the current national and international guidelines related to nano technology or nano scale agri-inputs.They are in sync with OECD testing guidelines (TGs) and “Guidelines for Testing of NAIPs and Food Products” released by the Department of Biotechnology, Government of India. Harvested produce of crops applied with IFFCO nano-Urea, nano-zinc, and nano-copper have been found fit for consumption with no adverse effect. This paper reviews the benefits of nanofertilizers (Nano N, Nano Zn and Nano Cu) towards increasing nutrient use efficiency and crop productivity and produce quality in general and the journey of IFFCO nano-fertilizers (IFFCO’s Nano Urea, Nano Zn and Nano Cu) from conception to PILOT to PLANT stage has also been covered in this paper.

Rising levels of soil acidity in Meghalaya: Evidences and Imperatives

In order to examine the current status of soil acidity in Meghalaya, representative soil samples (n= 497) were collected (during 2015-2016) from across the state and analyzed for soil acidity and associated parameters. Averaged across the samples, pH of the soils was found to be very strongly acidic (4.94). Nearly 20 % of the soils had pH below 4.50, 59% below pH 5.0 and 80% below pH 5.50. Only 3.4% of the samples recorded pH more than 6.0. East Khasi Hills District had the maximum percentage (95.1%) of strongly acidic soils (pH ≤ 5.50) while Garo Hills had the least (50.2%). All other districts recorded more than 85% of the strongly acidic soils. Average exchangeable acidity, exchangeable Al and effective CEC were found to be 1.60, 1.27 and 3.86 meq/100g soil, respectively. Mean base saturation was recorded below 60%. Aluminium saturation (percentage of effective CEC being occupied by exch. Al) ranged from 1.5 to 79.7% with its mean value being as high as 33%. Principal component analysis provided three PCs with Eigen values >1 and together they explained 83.2 % of the variance in total dataset. The soil acidity in Meghalaya is on rise, with 80.2% of its soils being strongly acidic (pH ≤ 5.50) in contrast to the previous reports of 53% soils being strongly acidic. This calls for widespread adoption of soil acidity ameliorative measures in agriculture of Meghalaya, Northeast India.

Soil test based fertilizer prescriptions under integrated plant nutrient management system for carrot in an Inceptisol

A field experiment was conducted at Agricultural Research Farm, Banaras Hindu University, Varanasi in an Inceptisol during rabi 2020-21 to develop a targeted yield equation for carrot crop. After developing three levels of fertility gradient with respect to available NPK in soil, the main experiment was conducted by taking carrot as a test crop. Initial soil data, carrot yield and NPK uptake by carrot crop were used for obtaining four important basic parameters, viz., nutrients required to produce a quintal of carrot roots (NR%), contribution of nutrients from fertilizers (CF%), contribution of nutrients from soil (CS%) and contribution of nutrients from organic matter (%C-OM). It was found that 0.65, 0.11 and 0.83 kg of N, P2O5 and K2O, respectively were required for producing one quintal carrot yield. The per cent contribution of nutrients from soil, fertilizer and FYM were 45.33, 65.91 and 67.26 for N; 58.45, 67.86 and 108.12 for P2O5 and 5.54, 3.35 and 10.53 for K2O, respectively. The ready reckoner for fertilizer doses with NPK alone and integrated use of NPK and FYM was also made using developed basic parameters for varying soil test values and desired yield targets of carrot yield.

Effect of nitrogen scheduling in early and late planted medium duration rice (Oryza sativa L.)

A field experiment on rice (Oryza sativa L.) crop was conducted at Rice Research Station, Kaul (Kaithal), India during kharif season of 2017 and 2018 to evaluate the optimum schedule of nitrogen application in the rice grown under early and late planting conditions. The treatments consisted of three timings of transplanting (3rd week of June, 1st week of July and 3 rd week of July), four levels of N (90, 120, 150 and 180 kg Nha-1) and four timings of N fertilizer application (½ at transplanting + ½ at 21 DAT, ½ at 21 DAT + ½ at 42 DAT, 1/3 at transplanting + 1/3 at 21 DAT + 1/3 at 42 DAT and LCC based N supply) and were laid out in split-plot design with transplanting time and N levels in main plots and N application time in sub-plots. The growth parameters (plant height, number of tillers/m2 and dry matter accumulation/m2), yield attributing characters (number of panicles/m2 and grains/panicle) and yield (grain and straw yield) of rice crop reduced significantly under late planting (3rd week of July) as compared to that under the two earlier plantings (3rd week of June and 1stweek of July) whereas the two earlier plantings were at par in respect of these parameters. The growth, yield attributes and the yield increased with every increase in N application rates but the increase was significant up to 150 kg Nha-1. The highest yield was (7.33 tha-1), however, obtained with the crop transplanted early (up to1st week of July) and supplied with 150 kg Nha-1.Application of N in three equal splits (at 0, 21 and 42 DAT or as per LCC schedule), being at par, resulted into higher yield (grain and straw) than the N application in two equal splits. The net returns and B: C ratio increased appreciably with increase in N application levels upto 150 kg Nha-1 obviously due to increase in crop yield.

Spatial variability of fertility status in soils of Dima Hasao district of Assam

Two hundred fifty geo-referenced surfaces (0-15 cm) soil samples were collected and analysed for macronutrients and micronutrients to study fertility status in soils of Dima Hasao district of Assam and their relationship with some important soil properties. Soils of the district were found to be extremely acidic to slightly acidic in reaction with a low to high organic carbon content and low in cation exchange capacity. The soil of the district indicated that the available nitrogen, phosphorus and potassium status was observed to the tune of 14.0 %,7.2% and 67.2% under low and 86.0 %, 92.8 % and 32.8 %under medium categories, respectively. The overall percent deficient of exchangeable calcium, magnesium and available sulphur in soils was 25.6, 30.4 and 6.8 %, respectively. Based on critical limit, all soils were adequately supplied with DTPA-extractable Fe, Mn and Cu content. In respect of zinc and boron, soils exhibited 90.4 and 73 per cent under sufficient, while, 2.4 and 12 per cent were found deficient in DTPA -Zn and HWS-B, respectively. Soil pH and EC showed positive correlation with macro nutrients and negative correlation with micronutrients. The macro- and micronutrient showed significant positive relation with soil organic carbon and cation exchange capacity.

Combining ability analysis for seed yield and its attributes in Indian mustard [Brassica juncea (L.) Czern and Coss]

The experimental material comprised of forty eight genotypes consisting of five Mori based CMS lines and seven Mori based fertile lines crossed in line x tester mating design. The resultant thirty five hybrids along with their twelve parents and standard check (GDM 4) were evaluated in randomized block design at Castor-Mustard Research Station, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar during, rabi 2018-2019. The analysis of variance for combining ability revealed that variance due to gca was significant for all the characters except number of seeds per siliqua, seed yield per plant and 1000 seed weight. Whereas, variance due to sca was significant for all the traits. This indicates significant contribution of hybrids for specific combining ability variance component. The ratio of σ2gca/σ2sca below than unity for days to maturity, siliqua length, number of seeds per siliqua, seed yield per plant, 1000 seed weight and oil content which suggested greater role of non-additive gene action in the inheritance of these traits. Among the parents, female SKM 9928 and Kranti were good general combiner for seed yield per plant, total number of branches per plant and total number of siliquae per plant. Whereas, male parent Mori 'R' 1-18 was good general combiner for seed yield per plant, total number of branches per plant and total number of siliquae per plant. Best three hybrids which possessed significant positive SCA effects for seed yield per plant were SKM 301 x SKM 303, SKM 9928 x Pusa Agrani and Kranti x Mori ‘R’ 1-18.

Wheat genotypes evaluated for GxE interactions in Central Zone of the country by AMMI analysis

Highly significant effects of environments, GxE interaction and genotypes were observed for cropping years 2017-18 and 2018-19. Further analysis of interactions sum of squares bifurcated into seven significant multiplicative interactions principal components to assess the performances of genotypes as per AMMI based measures. For the first year of study wheat genotypes (G5, G6, G7) had top ranked by EV2, D2, ASV, ASV1 and ASTAB2 measures. MASV & MASV1 pointed towards G7, G8, G6 wheat genotypes. Association among these measures displayed graphically in a biplot analysis. Largest cluster comprised of D2, D3, D5, D7, ASV, ASV1, ASTAB2, EV2, EV3, EV5, ASTAB3, ASTAB5, ASTAB7 measures. Wheat genotypes (G1, G11, G3) pointed by EV2, D2, ASV, ASV1 and ASTAB2 values for the second year. MASV settled for G11, G7, G13 whereas MASV1 pointed towards G11, G7, G2. Biplot analysis based on first two PC’s observed largest group had clubbed measures D2, ASV, ASTAB2, EV5, MASV, MASV1, EV3, D3, D5, D7, EV7, ASTAB3 ASTAB5, ASTAB7. AMMI based measures would be useful to identify and recommend genotypes with high, stable and predictable yield across environments.

Elevated CO2 and temperature effect on growth and physiology of Chenopodium album L.

A study was conducted in open top chambers (OTCs) to understand the effect of elevated temperature (ambient+2±0.5oC) and elevated CO2 (550±50 ppm) individually and in combination on Chenopodium album. Impact of the climate variables was studied in terms of selected plant attributes, viz., leaf area, RGR etc. Study showed that elevated temperature as well as elevated CO2 individually and in combination had significant positive effect on growth and development, rate of photosynthesis, and water use efficiency of the Chenopodium album. Rate of transpiration and stomatal conductance increased marginally in plants grown at elevated temperature, but a marked decrease was evident at elevated CO2 individually and in combination with elevated temperature as compared that in plants grown in ambient conditions in the Chenopodium album. No significant changes were observed in relative water content and relative stress injury under any of the Chenopodium album. Treatments changes were evident with respect to the activity of antioxidant enzymes and nitrate reductase and peptide banding pattern using SDS-PAGE. This research was conducted to examine the joint effects of increased temperature and elevated CO2 level onChenopodium album (C3 weed). Results from this experiment suggested that rising (CO2) could alter physiochemical response for growth and development of Chenopodium album and it is well defined competitors with different crops in current changing climate conditions.

Nitrogen use efficiency in crops with new and available technologies

Among fertilizers, nitrogen (N) is the one that is used in the largest amounts mainly due to immediate response to the fertilizer-N application. However, the N use efficiency (NUE) is very low leading to high production costs and also a threat to the environment. Therefore, improving NUE is imperative. The 4 R’s (right quantity, right time, right method and right source) should be considered as the first step for enhancing NUE. Best management practices (BMP’s) of production and protection need to be adopted in order to achieve high NUE. Integration of novel N sources and nanofertilizers and better N fertilization products would lead to high NUE. Furthermore, novel techniques such as Precision Nutrient Management and Variable Rate Application to time nutrient application with crop need, and remote sensing are upcoming technologies that will bring about considerable savings in fertilizer-N. Further we should also account for plant physiological processes, including the diversity of mineral nutrient uptake mechanisms, their translocation and metabolism in order to breed and develop crop cultivars that are efficient N users.

Productivity and water use efficiency of kinnow mandarin (citrus reticulate blanco) as influenced by drip trickle irrigation and hydrogel

An experiment was conducted to find out the effect of drip trickle irrigation and hydrogel with black polyethylene mulch on productivity and water use efficiency of Kinnow mandarin. The two years pooled data revealed that highest available nitrogen, phosphorus and potassium (244, 20 and 164 kgha-1), porosity and maximum water holding capacity (34.5 and 40.9 %) and percent increase height, spread and canopy volume (13.6, 14.8 and 44.5 %), respectively, were obtained with the application of 3 days drip trickle irrigation and 90 g hydrogel with black polyethylene mulch materials of tree. The drip trickle irrigation and hydrogel with black polyethylene mulch produced a significantly (p=0.05) maximum improve in soil moisture content over control treatment. The 3 days drip trickle irrigation and 90 g hydrogel with mulch showed highest fruit yield (9404.7 kg ha-1), length (6.5 cm), weight (116.5 g) and quality of fruit volume (113.9 cc), Juice content (54.1 %) and TSS (13.3 0Brix). The specific gravity and titratable acidity showed reverse trend. The water use efficiency and benefit cost ratio were better in 3 days drip trickle irrigation and 90 g hydrogel with mulch materials of tree.