K.S. Rana

Greenhouse gases emission, soil organic carbon and wheat yield as affected by tillage systems and nitrogen management practices

ABSTRACT Agricultural activities are responsible for greenhouse gases (GHGs) emission in the environment. Strategies are required to enhance the soil organic carbon (SOC) and nitrogen (N) sequestration to adapt and mitigate the climate change. We investigated GHGs emission, SOC and N enhancement under conventional tillage (CT) and zero tillage (ZT) with N management in wheat (Triticum aestivum L.). Seasonal carbon dioxide (CO2) emission and global warming potential (GWP) reduced for ZT treatments over CT without residues and 100% of required N with a blanket split application (CT – R + 100N). The ZT with 5 t ha−1 maize (Zea mays L.) residues retention and 75% of required N and GreenSeekerTM (GS)-aided N management (ZT + R + 75N + GS) reduced yield-scaled GHGs emission and increased total organic carbon (C) stock over CT – R + 100N. However, nitrous oxide (N2O) emission was lower in CT. The GS-based N management saved 26–35 kg N ha−1 in different tillage systems in both years over blanket application with higher N uptake and associated reduction in N2O emission. The study recommends that ZT with residues retention and GS-based N management can minimize the GHGs emission and improve the SOC.

AM Fungi Lead to Fertilizer Phosphorus Economy and Enhanced System Productivity and Profitability in Okra (Abelmoschus esculentus L.) – Pea (Pisum sativum L.) Cropping System in Himalayan Acid Alfisol

ABSTRACT The present investigation was carried out at CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh, India, during 2009–2011 to economize inorganic phosphorus (P) and enhance profitability of okra (Abelmoschus esculentus)–pea (Pisum sativum) cropping system through arbuscular mycorrhizal fungi (AMF). A field experiment was replicated thrice in a randomized block design comprising 14 treatments involving AMF (Glomus mosseae) at varying inorganic P (50%, 75%, and 100% of recommended soil test-based P dose) and irrigation regimes (40% and 80% available water capacity] in a Himalayan acid Alfisol. In okra, AMF inoculation at varying P and irrigation regimes registered higher P response ratio (PRR), net returns (10–18%), and benefit:cost (B:C) ratio (17–49%) compared to “generalized recommended P dose (GRD)” and their non-AMF counterparts. Similarly in pea, AMF inoculation at varying P and irrigation regimes again registered higher PRR, net returns (14–23%), and B:C ratio (10–58%) compared to GRD and non-AMF counterparts. Higher system productivity (7–16%) and profitability in terms of net returns (9–23%) and B:C ratio (10–54%) were also registered in AMF-imbedded treatments compared to non-AMF counterparts. Further, “AMF + 75% soil test-based P dose” at either of these irrigation regimes registered statistically similar okra–pea system productivity and profitability as that obtained under “100% soil test-based P dose” at either of two irrigation regimes, thus indicating an economy of soil test-based applied P dose by about 25%. Overall, the current study suggests that practice of AMF inoculation has great potential in enhancing system productivity and profitability besides cutting down about 25% inorganic P requirement in okra–pea production system in the Himalayan acid Alfisol.

Resource Conserving Techniques for Improving Nitrogen-Use Efficiency

The use of nitrogen fertilisers has played an instrumental role in enhancing agricultural productions the world over including India. Currently, about 83 million tons N is used in agriculture globally. A large portion of applied N is lost through leaching, volatilisation and runoff, and only 50 % of applied N is assimilated by the crop plant. Recently, there have been serious concerns about environmental footprints of N fertilisers, particularly greenhouse gas emissions from the rice fields and escalating costs of fertilisers beyond farmers’ reach. To meet the growing need for N fertilisers due to the rise in food requirement for ever multiplying population on the one hand and an increasing environmental and atmospheric pollution on the other, improving nitrogen-use efficiency (NUE) appears to be a viable solution. Certain resource conserving techniques, such as laser land levelling, zero or minimum tillage (save fuel), direct seeding, permanent or semi-permanent residue cover, new varieties that use plant nutrients more efficiently, furrow irrigated raised bed (FIRB) technology, system of rice intensification (SRI), direct seeded rice (DSR), precision farming techniques, use of leaf colour chart (LCC), chlorophyll meter, GreenSeeker, etc. have been shown to increase crop yields and NUE. For example, the use of optical sensors like GreenSeeker, chlorophyll meter and FIRB saved 25–50 % N. Even laser levelling has been reported to increase NUE by 6–7 % in India. Hence the use of such resource conserving technologies should be facilitated and supported for the sustainability of agricultural production and the natural resource base (land and water).

Productivity and sustainability of mustard (Brassica juncea L.) and lentil (Lens culinaris L.) intercropping system as affected by moisture conservation practices and fertility levels under rainfed conditions

Field experiments were carried out at the research farm of the Indian Agricultural Research Institute, New Delhi, during the 2003–2004 and 2004–2005 winter seasons, to investigate the effect of moisture conservation practices and fertility levels on the performance of a mustard (Brassica juncea) and lentil (Lens culinaris) intercropping system under rainfed conditions. Moisture conservation practice farmyard manure (FYM) + organic mulch + kaolin spray (6%) produced significantly higher numbers of siliquae per plant leading to significantly higher seed yields of mustard, whereas in lentil it produced significantly higher numbers of pods per plant and seed weight per plant. The 100% recommended doses of fertilizers (RDF) fertility level produced significantly higher values of yield attributes and yield of mustard and lentil over control, but it remained statistically on a par with 50% RDF. The maximum increment in seed yield of mustard and lentil was observed with 100% RDF fertility level by 6.6 and 13.3% higher over 50% RDF and control, respectively; whereas it increased significantly with moisture conservation practices and the application of fertility levels. The consumptive use, moisture use rates and moisture use-efficiency were the highest under mustard-paired row (30/90 cm) and lentil (two rows) intercropping system. Moisture conservation practices and fertility levels also increased the consumptive use.

Bio-fortification potential of global wild annual lentil core collection

Lentil, generally known as poor man’s’ meat due to its high protein value is also a good source of dietary fiber, antioxidants and vitamins along with fast cooking characteristics. It could be used globally as a staple food crop to eradicate hidden hunger, if this nutritionally rich crop is further enriched with essential minerals. This requires identification of essential mineral rich germplasm. So, in the present study, a core set of 96 wild accessions extracted from 405 global wild annual collections comprising different species was analyzed to determine its bio-fortification potential. Impressive variation (mg/100 g) was observed for different minerals including Na (30–318), K (138.29–1578), P (37.50–593.75), Ca (4.74–188.75), Mg (15–159), Fe (2.82–14.12), Zn (1.29–12.62), Cu (0.5–7.12), Mn (1.22–9.99), Mo (1.02–11.89), Ni (0.16–3.49), Pb (0.01–0.58), Cd (0–0.03), Co (0–0.63) and As (0–0.02). Hierarchical clustering revealed high intra- and inter-specific variability. Further, correlation study showed positive significant association among minerals and between minerals including agro-morphological traits. Accessions representation from Turkey and Syria had maximum variability for different minerals. Diversity analysis exhibited wide geographical variations across gene-pool in core set. Potential use of the identified trait-specific genetic resources could be initial genetic material, for genetic base broadening and biofortification of cultivated lentil.

Tillage and nitrogen management effects with sequential and ready-mix herbicides on weed diversity and wheat productivity

ABSTRACT In this experiment, weed management was studied in zero tillage (ZT) and conventional tillage (CT) wheat with and without crop residue and nitrogen (N). The treatment ZT with crop residue retention (R) and 75% of required N plus GreenSeeker™ (GS)-aided N management (ZTRNGS) resulted in a reduction of density and dry weight of weeds compared to CT and ZT without residue. Sequential application of pendimethalin and sulfosulfuron (PMT-SSF) reduced the weed density and dry weight compared to the weedy check (WC). Importantly, the richness and diversity indices were high in ZTRNGS and in WC treatments. Greater wheat grain (5.11 t/ha) and biomass yield (13.31 t/ha) were observed in ZTRNGS than CT without residue and blanket split application of N (CTN). The treatment ZTRNGS recorded 14.1% and 16.9% higher gross and net returns, respectively, over CTN. This study demonstrates that surface retention of crop residue in ZT is more useful than residue incorporation under CT for effective weed control, improving crop yield and profitability.

Changes in physico-chemical and biological properties of soil under conservation agriculture based pearl millet – mustard cropping system in rainfed semi-arid region

ABSTRACT Poor soil health and low soil water content during crop growing period are major factor for low productivity of pearl millet – mustard rotation under rainfed semi-arid regions. The authors evaluated five different tillage and residue management practices for improving physico–chemical and biological properties of soil. Results showed that conservation agriculture (CA) practice (zero tillage (ZT) with 4 t ha–1 residue retention) exhibited higher proportion of soil macro-aggregate. It also increased infiltration rate of about 15.2% over conventional tillage without residue but ZT increased soil penetration resistance in surface soil layer. In the residue applied plots, ~2–4% (w/w) higher soil water content was maintained throughout the season than the no-residue plots. CA practice had the highest soil organic carbon (4.96 g kg–1) and microbial biomass carbon (188.3 μg g–1 soil). Significant and positive correlation was also found between soil organic carbon with infiltration rate (r = 0.73**), mean weight diameter (r = 0.80**) and microbial biomass carbon (r = 0.86**). Thus, this study suggests that ZT with residue retention can be advocated in pearl millet – mustard rotations for improving, productivity, soil health and maintaining higher soil water content in rainfed semi-arid regions.