Performance of Sorghum Grown on a Salt Affected Soil Manured with Dhaincha Plant Residues Using a 15N Isotopic Dilution Technique

A field experiment was conducted on a salt-affected soil to determine the effect of application of three types of Dhaincha (Sesbania aculeata Pers.) residues (R, roots; L, shoots; L+R, shoots plus roots) on the performance of sorghum (Sorghum bicolor L.) using the indirect ¹⁵N isotopic dilution technique. Results indicated that sesbania residues (L and L+R), used as green manures, significantly increased grain yield, dry matter production, N uptake, and water use efficiency of sorghum. Percentages of nitrogen (N) derived from residues (%Ndfr) in sorghum ranged from 6.4% to 28%. The N recoveries in sorghum were 52%, 19.6% and 19.7% of the total amount contained in sesbania roots, shoots and roots plus shoots, respectively. The beneficial effects of sesbania residues are attributed not only to the additional N availability to the plants, but also to effects on the enhancement of soil N uptake, particularly in the L+R treatment. The findings suggest that the use of Sesbania aculeata residues, as a green manure, can provide a substantial portion of total N in sorghum. In addition, the use of sesbania green manure in salt-affected soils, as a bio-reclaiming material, can be a promising approach for enhancing plant growth on a sustainable basis.     

Relative significance of soil and nitrogenous fertilizer in nitrogen nutrition and growth of wetland rice (Oryza sativa L.)

Summary A pot experiment was conducted to compare the yields from five commercially cultivated varieties (Bas-198, Bas-370, Bas-Pak, Bas-385, and IR-6) of rice (Oryza sativa L.) and to establish the relative significance of soil N and fertilizer N (¹⁵N-labelled ammonium sulphate) in affecting crop performance. Another aim was to study the interaction of fertilizer N and soil N as influenced by different rice varieties. Among the five varieties tested, Bas-Pak gave the maximum dry matter and N yield. The N-use efficiency (percentage of applied N taken up by the plants) of different varieties ranged between 33.7 and 43.7%, Bas-Pak being the most efficient. Significant losses of fertilizer N occurred from the soil-plant system. The maximum N loss (52.1% of applied N) was observed with IR-6 and the minimum loss (39.2%) with Bas-Pak. A substantial increase in the uptake of soil N following the application of fertilizer and an interaction between the two N sources were observed with all varieties except Bas-385. The interaction was attributed to greater root proliferation following the application of fertilizer. It was concluded that a varietey with greater potential to use soil N is likely to give a better yield and that, of the two N sources, the availability of soil N was more important in determining the yield performance of different varieties of rice.     

Translocation and recovery of 15N-labelled N derived from foliar uptake of 15NH3 by rice (Oryza sativa L.) cultivars

Foliar uptake of ¹⁵NH₃ applied at two growth stages (tillering and anthesis) and the subsequent ¹⁵N-labelled vegetative-N distribution in different plant components at maturity was investigated in three rice cultivars, IR-6, NIAB-6 and Bas-385. Rice plants absorbed 22–30% and 18–24% of the ¹⁵NH₃ applied at tillering and anthesis stages, respectively. Of the total ¹⁵NH₃ absorbed at tillering stage, IR-6 and Bas-385 showed higher recovery (71%) in different plant components at maturity as compared to NIAB-6 (48% recovery). At maturity, percent recovery of the ¹⁵NH₃ absorbed at anthesis stage was almost comparable in different cultivars, but it was lower (46–55%) than that absorbed at the tillering stage. Recovery of the absorbed ¹⁵NH₃-N in the soil was negligible and ranged from 0.3–1%. At maturity, the cultivars IR-6 and Bas-385 showed a higher loss (45–53%) of ¹⁵NH₃ absorbed at anthesis than at the tillering stage (29% loss), whereas for NIAB-6, the corresponding figures were comparable for the two growth stages (tillering, 51% loss; anthesis, 49% loss). Results indicated a variable potential of the tested rice cultivars for foliar uptake of atmospheric ¹⁵NH₃ and distribution of ¹⁵N-labelled vegetative-N in different plant components.     

Response of flooded rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) to nitrogen application at two root-zone temperature regimes in a pot experiment

In a greenhouse experiment, the response of three cultivars of rice to N application was studied at two root-zone moisture regimes. The response was measured in terms of dry matter yield, uptake of N from applied fertilizer and soil organic matter, loss of fertilizer N, and interaction of applied N with the native soil N. Nitrogen was applied as ¹⁵N-labelled ammonium sulphate and two temperature regimes in the root-zone were established by digging one set of pots into the soil, while keeping the other set on the surface. This setup created and maintained a temperature difference of 5–7°C in the rhizosphere, temperature being lower in the buried pots throughout the growth period. The rice cultivars included a coarse-grain and high-yielding cultivar (IR-6) and two aromatic fine-grain cultivars (Bas-198 and Bas-Pak). IR-6 showed a negative response to higher root-zone temperature with resultant reduced efficiency of soil N and fertilizer N. The other two cultivars were relatively insensitive. The effect of temperature was more pronounced for N yield than dry matter accumulation. Loss of applied N occurred in all cases, but it was more pronounced in IR-6 at the higher temperature regime. Application of labelled fertilizer N led to an increase in the uptake of unlabelled N due to a real "added nitrogen interaction" which was attributed mainly to an increase in root biomass.     

Nutrients transport through variably structured soils

Abstract

Contribution of sesbania green manure, rice straw, and FYM (farm yard manure) was studied along with that of urea and A/SO₄ (ammonium sulphate) for the cultivation of lowland rice and for the residual soil fertility. The results revealed that A/SO₄ application resulted in a larger number of productive tillers, higher straw production, and higher grain yield compared to urea. Among the organic manures, sesbania green manure and FYM exerted almost similar effects on the number of productive tillers and paddy yield while the yield increase compared to the incorporation of rice straw. A similar affect of these organic manures on nitrogen uptake by rice straw, grain, and straw + grain was observed. Additional uptake of N due to the application of sesbania green manure, FYM and rice straw amounted to 15, 13, and 2.85 kg ha^?1, respectively. Residual N fertility was the highest when of sesbania green manure was applied followed by FYM and rice straw. Residual P fertility was higher in the case of FYM than other treatments whereas the residual K fertility was the highest in the case of rice straw incorporation.     

Effect of addition of organic residues,farmyard manure and fertilizer nitrogen on soil fertility in rice‐wheat cropping system

A field experiment was conducted for 3 crop years (July‐June) at the Indian Agricultural Research Institute, New Delhi to study the effects of Sesbania and cowpea green manuring (GM) and incorporation of mungbean residues after harvesting grain, Leucaena loppings, FYM and wheat straw incorporation before planting rice and application of 0,40,80 and 120 kg N ha^?1 to rice on the soil organic carbon (SOC), alkaline permanganate oxidizable N (APO‐N), 0.5 M sodium bicarbonate extractable P (SBC‐P) and 1N ammonium acetate exchangeable K (AAE‐K) in surface 0–15 cm soil after the harvest of rice and wheat grown in sequence. Green manuring and addition of organic residues prevented the decline in SOC. On the other hand addition of N fertilizer tended to decrease SOC after rice harvest. On the contrary application of green manures, organic residues, FYM and fertilizer N increased APO‐N, which indicates the benefit of these treatments to a more labile soil organic N pool. Also application of green manures, organic residues, FYM and fertilizer N increased SBC‐P. Not much change was observed in AAE‐K by the treatments applied.     

Influence of Sesbania Brown Manuring and Rice Residue Mulch on Soil Health,Weeds and System Productivity of Conservation Rice–Wheat Systems

The sustainability of rice–wheat cropping system (RWCS) is threatened by increasing labor, water, and energy crises in the region. Conservation RWCSs offers an ecofriendly alternate option. This study was aimed to evaluate the impact of sesbania brown manuring in direct‐seeded aerobic rice (DSAR) and of rice residue mulch in no‐tilled wheat (NTW) on soil health, weed dynamics and system productivity. The experiment was composed of five RWCS systems: (i) DSAR‐NTW; (ii) DSAR + sesbania brown manuring‐NTW; (iii) DSAR‐NTW + rice residue mulch; (iv) puddled transplanted flooded rice (PudTR)‐NTW; and (v) PudTR‐plow‐tilled wheat. Sesbania brown manuring in direct‐seeded rice decreased the weed density and dry biomass 41–56% and 62–75%, respectively, than the sole direct‐seeded rice crop. At rice harvest, better soil health, in terms of total nitrogen (N), soil organic carbon, soil microbial biomass carbon, and soil microbial biomass nitrogen, was noted with DSAR + sesbania brown manuring‐NTW. Rice residue mulch retention in NTW decreased weed density and dry weight by 60 and 69%, respectively, than those under NTW with no mulch. At wheat harvest, highest total N, soil organic carbon, and soil microbial biomass carbon were recorded with DSAR‐NTW + rice residue mulch, followed by DSAR + sesbania brown manuring‐NTW. Overall, NTW grown after DSAR + sesbania brown manuring produced more grain yield than PudTR‐NTW and PudTR‐plow‐tilled wheat systems. In conclusion, sesbania brown manuring in DSAR and residue mulch retention in NTW may be opted to improve soil properties, suppress weeds, and to harvest better grain yield and achieve higher system productivity in conservation RWCSs. Copyright © 2016 John Wiley & Sons, Ltd.     

Prediction of Yield and Nitrogen Uptake of Wheat from Net Nitrogen Balance after Rice in Rice–Wheat Cropping System

Net nitrogen (N) balance after rice (Oryza sativa L.) and its relationship with yield and N uptake of succeeding wheat crop was studied in a greenhouse. Three urea-enriched green manures, namely dhaincha (Sesbania aculeata L.), cowpea (Vigna unguiculata L.), and guar (Cyamopsis tetragonoloba L.) were compared with split application of urea in a rice–wheat cropping sequence. After rice, a negative N balance was measured in all treatments; however, the N balance values were greater with urea than with green manures. The N balance was positively correlated with the N content but negatively correlated with lignin content and carbon (C)–N ratio of the green manures. Lignin content was a better index than C/N ratio for predicting the net N balance, which described 82.3% of the total variations. Efficiency of residual N utilization by wheat could be determined by estimating the N balance after rice. Net N balance after rice can be used as a yardstick for the prediction of yield and N uptake by wheat crop.     

Nitrogen contribution to wetland rice by green manuring with Sesbania spp. in an alkaline soil

Summary Two annual species of Sesbania, S. aculeata and Sesbania sp. PL Se-17, were field evaluated as green manure for wetland rice in an alkaline soil. The two species were raised as a catch crop during summer in a wheat-rice rotation, and added as 24.7 and 20.8 t ha^–1 of green matter, 116 and 98 kg N ha^–1, respectively, after 45 days of growth. For the optimum green manuring effect on rice grain yield and N uptake, S. aculeata required 5 days of decomposition (after turning in and before rice transplantation), whereas no decomposition period was necessary for Sesbania sp. PL Se-17. The effect on grain yield and N uptake of rice was equivalent to an application of 122 and 78 kg ha^–1 of chemical N, for the two species, respectively. There was no residual effect of the green manuring on the soil N status after rice harvest.     

Modern wheat cultivars have greater root nitrogen uptake efficiency than old cultivars

The availability of nitrogen (N) contained in crop residues for a following crop may vary with cultivar, depending on root traits and the interaction between roots and soil. We used a pot experiment to investigate the effects of six spring wheat (Triticum aestivum L.) cultivars (three old varieties introduced before mid last century and three modern varieties) and N fertilization on the ability of wheat to acquire N from maize (Zea mays L.) straw added to soil. Wheat was grown in a soil where ¹⁵N‐labeled maize straw had been incorporated with or without N fertilization. Higher grain yield in three modern and one old cultivar was ascribed to preferred allocation of photosynthate to aboveground plant parts and from vegetative organs to grains. Root biomass, root length density and root surface area were all smaller in modern than in old cultivars at both anthesis and maturity. Root mean diameter was generally similar between modern and old cultivars at anthesis but was greater in modern than in old cultivars at maturity. There were cultivar differences in N uptake from incorporated maize straw and the other N sources (soil and fertilizer). However, these differences were not related to variation in the measured root parameters among the six cultivars. At anthesis, total N uptake efficiencies by roots (total N uptake per root weight or root length) were greater in modern than in old cultivars within each fertilization level. At maturity, averaged over fertilization levels, the total N uptake efficiencies by roots were 292?336 mg N g^?1 roots or 3.2?4.0 mg N m^?1 roots for three modern cultivars, in contrast to 132?213 mg N g^?1 roots or 0.93?1.6 mg N m^?1 roots for three old cultivars. Fertilization enhanced the utilization of N from maize straw by all cultivars, but root N uptake efficiencies were less affected. We concluded that modern spring wheat cultivars had higher root N uptake efficiency than old cultivars.     

Growth and Nitrogen Fixation in Dhaincha/Sorghum and Dhaincha/Sunflower Intercropping Systems Using 15Nitrogen and 13Carbon Natural Abundance Techniques

A field experiment on dhaincha, sunflower, and sorghum plants grown in monocropping and intercropping systems was conducted to evaluate growth and nitrogen (N₂) fixation using ¹³carbon (C) and ¹⁵N natural abundance techniques. Intercropping of sesbania/sorghum showed a greater efficiency than monocropping in producing dry matter during the entire growth period, whereas the efficiency of producing dry matter in the sesbania/sunflower intercropping was similar to that in the monocropping system. Moreover, sorghum plants (C4) were more competitive than sesbania (C3) for soil N uptake, whereas sesbania seemed to be more competitive than its associated sunflower (C3). Nitrogen uptake in the mixed stand of sesbania/sorghum was improved as a result of the increase in soil N uptake by the component sorghum and the greater root nodule activity of component sesbania without affecting the amount of N₂ fixed. The Δ ¹³C in plant materials was affected by plant species and the cropping system.     

Performance of rice ( Oryza Sativa L.) cultivars to integrated application of fertilizer n and farmyard manure in acid laterite soil

Varietal adaptability in exploiting the natural resources is important. Field experiments were conducted during the wet seasons of 1998 and 1999 at the Regional Research Substation, Sekhampur. The aim was to evaluate the performance of locally popular IR-36 (high yielding, photo-insensitive) and Khejurthari (local land race, photosensitive) rice cultivars with variable proportions of N management through inorganic and organic supplements separately or combined. The cv. IR-36 produced the highest number of panicles/m 2 but the cv. Khejurthari had significantly higher number of grains/panicle and test weight. Fertilizer N and farmyard manure rates influenced the yield attributing characters. The cv. IR-36 produced 10% more grain yield than Khejurthari. Combined application of inorganic (urea) and organic (farmyard manure) sources increased the grain yield by 72% over no input (control). Nitrogen uptake by cv. IR-36 and Khejurthari was statistically similar. Application of 60 kg N/ha with 4 t farmyard manure/ha increased the N uptake by 1.88 times compared to control. Apparent N recovery was higher in cv. IR-36 at higher doses of N and in cv. Kejurthari at lower doses.     

Prospects of using leguminous green manuring crop Sesbania rostrata for supplementing fertilizer nitrogen in rice production and control of environmental pollution

Abstract

Modern rice cultivation relies on chemical nitrogen (N) fertilizer that ultimately degrades soil health and creates environmental pollution. The increasing concerns about environmental pollution, restoring soil health, and conservation of energy, public attention is now towards green manures as supplement for N fertilizer. Sesbania rostrata is a popular leguminous green manuring crop that fixes atmospheric N₂, improves soil health, and rice productivity through incorporation of its biomass in to soil. About 40–60?days plants provide 5–6 tons dry biomass that can supplement 50–100% N requirement. In world, it is adapted as pre-rice or post-rice green manuring crop. Long-term use of S. rostrata improves soil health and increased rice yield by 9–11% over chemical fertilizer. Use of S. rostrata in large scale for rice production can reduce environmental pollution problems as it can cut down chemical N requirement and thus reduction dispersal of Nr to the environment.     

Effect of presubmergence and green manuring (Sesbania aculeata) on nutrition and yield of wetland rice (Oryza sativa L.) on a sodic soil

Summary A field experiment was conducted to evaluate the effect of 0, 1 and 2 weeks' submergence prior to the transplantation of rice (presubmergence), with and without Sesbania aculeata green manure, on the yield and nutrition of rice in a highly sodic soil [pH 10.3, exchangeable sodium percentage (ESP) 86.4]. Green manuring significantly enhanced the yield of rice and contributed 112 kg N/ha. One week's presubmergence with incorporated green manure improved the yield of rice significantly over that obtained with no previous flooding, giving a yield on a par with that obtained with 2 weeks' submergence. The beneficial effect of presubmergence without green manure on rice yield was of lesser magnitude and was significant only when it was continued for 2 weeks. Cultivation of rice under submerged conditions improved the sodic soil, and green manuring enhanced the process of reclamation by further decreasing the pH value and the exchangeable Na of soil. Green manuring considerably improved organic C, available N, P, and K status of the soil and enhanced the uptake of N, P, Ca, Mg, S, Fe, Mn, and Zn by the crop. Effects of submergence and green manuring on the availability of Fe, Mn, Zn, and P in soil and their role in the nutrition of rice are discussed.     

Assessment of nitrogen uptake and utilization in drought tolerant and Striga resistant tropical maize varieties

Maize (Zea mays L.) is an important food crop in the Guinea savannas of Nigeria. Despite its high production potential, drought, Striga hermonthica parasitsim, and poor soil fertility particularly nitrogen deficiency limit maize production in the savannas. Breeders at IITA have developed drought- and Striga-tolerant cultivars for testing, dissemination, and deployment in the region. Information on the response of these cultivars to N fertilization is, however, not available. This study evaluated grain yield, total N uptake (TNU), N uptake (NUPE), N utilization (NUTE), and N use efficiency (NUE) of selected maize cultivars along with a widely grown improved maize cultivar at two locations in the Guinea savannas of northern Nigeria. Maize grain yield increased with N application. The average grain yield of the maize cultivars was 76% higher at 30, 156% higher at 60, and 203% higher at 120 kg N ha^?1 than at 0 kg N ha^?1. This suggests that N is a limiting nutrient in the Nigerian savannas. Five drought-tolerant cultivars produced consistently higher yields when N was added at all levels. These cultivars had either high NUPE or NUTE confirming earlier reports that high N uptake or NUTE improves maize grain yield. The study also confirms earlier reports that maize cultivars that are selected for tolerance to drought are also efficient in uptake and use of N fertilizer. This means that these cultivars can be grown with application of less N fertilizer thereby reducing investment on fertilizers and reduction in environmental pollution.     

Enhancing nutrient translocation,yields and water productivity of wheat under rice–wheat cropping system through zinc nutrition and residual effect of green manuring

Abstract

Efficient nutrient and water use are two important considerations to obtain good harvests of wheat. This necessitates the development of an effective nutrient management technique that not only increases yield, but simultaneously can save nutrient and water use. In this context, a field experiment was conducted at Indian Agricultural Research Institute, New Delhi, India to evaluate the residual effect of sesbania and rice bean (in-situ), subabul (ex-situ) green manuring and Zinc (Zn) fertilization, using chelated Zn-ethylenediaminetetraacetic acid (Zn-EDTA) on nutrient use, yields and water productivity of wheat under rice–wheat cropping system. Among residual effects of green manure crops and Zn fertilization, sesbania and foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 days after sowing (DAS) recorded significantly higher nutrient content and uptake and yields than other green manure crops and Zn treatments. Residual effect of sesbania saved about 46.5?×?10³ and 30.5?×?10³ L irrigation water per tonne of wheat over subabul and rice bean, respectively. Foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 DAS saved about 55.5?×?10³, 47?×?10³ and 13?×?10³ L irrigation water per tonne wheat over residual effect of 5?kg Zn ha^?1 through chelated Zn-EDTA as soil application, 2.5?kg Zn ha^?1 through chelated Zn-EDTA as soil application + 1 foliar spray of 0.5% chelated Zn-EDTA at flowering and foliar spray of 0.5% chelated Zn-EDTA at active tillering?+?flowering?+?grain filling, respectively. Correlation analysis showed positive correlation between Zn uptake and grain yield.     

Impact of growing maize (<Emphasis Type="Italic">Zea mays</Emphasis>) on the decomposition of incorporated fresh alfalfa residues

In this study, the effects of growing maize plants on the microbial decomposition of easily degradable plant residues were investigated in a 90-day pot experiment using a sandy arable soil. Four treatments were carried out: (1) untreated control, (2) with freshly chopped alfalfa residues (Medicago sativa L.) incorporated into soil, (3) with growing maize plants (Zea mays L.), and (4) with growing maize plants and freshly chopped alfalfa residues incorporated into soil. The amount of alfalfa residues was equivalent to 1.5 mg C g⁻¹ soil and 120 μg N g⁻¹ soil. At the end of the experiment, only the combination of growing maize plants and alfalfa residues significantly increased the contents of microbial biomass C, microbial biomass N, and ergosterol in soil compared to the non-amended control. The dry weight of the maize shoot material was more than doubled in the treatment with alfalfa residues than without. In treatment (2), 6% of the alfalfa residues could be recovered as plant remains >2 mm. In treatment (4), this fraction contained 14.7% alfalfa residues and 85.3% maize root remains, calculated on the basis of δ ¹³C values. This means that 60% more alfalfa-C was recovered than in treatment (2). The reasons for the retardation in the breakdown of alfalfa residues might be water deficiency of soil microorganisms in the increased presence of maize roots. Assuming that the addition of alfalfa residues did not affect the decomposition of native soil organic matter, only 23% of the alfalfa residues were found as CO₂ monitored with a portable gas analyzer with a dynamic chamber. The discrepancy is probably due to problems in measuring peak concentrations of CO₂ evolution in the two alfalfa treatments at the beginning of the experiment and in the two maize treatments at the end, especially in treatment (4).     

Impact of Locally Derived Organic Materials and Method of Addition on Maize Yields and Nitrogen Use Efficiencies in Major and Minor Seasons of Tropical South Asia

Maize is the most important highland cereal grown in the tropics, generally cultivated under rainfed smallholder conditions in Asia. Field experiments were carried out in Sri Lanka with the objective of determining the impact of three types of organic matter applied as mulch or incorporated on the yields and nitrogen uptake by maize cultivated under rainfed conditions in the South Asian major and minor seasons. The organic matter used was leaves of Gliricidia sepium, Tithonia diversifolia, or rice straw, with the full compliment of recommended mineral fertilizers. Organic matter, especially the two green manures, enhanced yields and nitrogen (N) uptake of maize, and the impact was more prominent in the minor dry season where the yields were lower. Incorporation of organic matter had a greater positive impact in the dry season in terms of N utilization efficiency and seed yields. The beneficial impact of organic matter with low carbon (C):N ratios in enhancing N nutrition and seed yields of rainfed maize in major and more importantly in the minor seasons is presented.     

Changes in soil properties and their effects on maize productivity following<Emphasis Type="Italic"> Sesbania sesban</Emphasis> and<Emphasis Type="Italic"> Cajanus cajan</Emphasis> improved fallow systems in eastern Zambia

Improved fallows with leguminous trees have been developed in Southern Africa as a viable alternative to inorganic fertilizers but the changes in soil properties that are responsible for crop productivity improvement and implications of mixing litter and fresh leaves from the same tree species on soil fertility are not fully understood. Our objectives were to quantify (1) some changes in soil properties that are responsible for crop production improvement under improved fallow systems; (2) the N mineralization patterns of mixtures of litter and fresh leaves from the same tree species. The treatments used in the study were 2-year planted Sesbania sesban (sesbania) and Cajanus cajan (cajanus) and controls of natural fallow, continuous fertilized and unfertilized maize. At fallow clearing sesbania contributed 56 kg N ha^–1 through litter and fresh leaves. Sesbania (fresh leaves + litter) showed high N mineralization after 10 weeks compared to the mixture of cajanus fresh leaves with litter. Maize yields were significantly correlated with preseason NO₃^–-N and total inorganic-N content of the top 20-cm soil layer. Soil penetrometer resistance at 4 weeks after planting was lowest in the sesbania land-use system (2.2 Mpa), whereas the highest percentage of water-stable aggregates at fallow clearing and crop harvest was in sesbania (83%) and cajanus (77%), respectively. The improved soil conditions and N contribution of sesbania and cajanus fallows to the subsequent maize crop was evidenced by increased maize yields of between 170–200% over maize without fertilizer.     

Water Use and Soil Fertility under Rice–Wheat Cropping System in Response to Green Manuring and Zinc Nutrition

ABSTRACT

Soil fertility and water use are two important aspects that influence rice productivity. This study was conducted to evaluate the performance of in-situ (sesbania and rice bean) and ex-situ (subabul) green manuring along with zinc fertilization on water productivity and soil fertility in rice under rice–wheat cropping system at Indian Agricultural Research Institute, New Delhi, India. Sesbania incorporation recorded higher total water productivity (2.20 and 3.24 kg ha^?1 mm^?1), available soil nutrients, organic carbon, alkaline phosphatase activity, microbial biomass carbon and increased soil dehydrogenase activity by 39.6 and 26.8% over subabul and rice bean respectively. Among interaction of green manures and zinc fertilization, subabul × foliar application of chelated zinc-ethylenediaminetetraacetic acid at 20, 40, 60 and 80 days after transplanting recorded highest total water productivity (2.56 and 3.79 kg ha^?1 mm^?1). Foliar application of chelated Zn-EDTA at 20, 40, 60 and 80 days after transplanting recorded significantly higher water productivity than other Zn treatments, however it was statistically similar with foliar application of zinc at active tillering + flowering + grain filling. Sesbania × 5 kg Zn ha^?1 through chelated Zn-EDTA, recorded highest available nitrogen, phosphorus, potassium, zinc, manganese, copper and iron than other green manure and Zn fertilization interactions, although it was statistically similar with rice bean × 5 kg Zn ha^?1 through chelated Zn-EDTA as soil application. Sesbania × foliar application of 5 kg Zn ha^?1 through chelated Zn-EDTA as soil application recorded highest soil enzymatic activities and microbial biomass carbon.