Wheat-maize Cropping System Research Articles

Long term impact of manuring, fertilization and liming on soil resilience, enzyme activities and productivity under maize-wheat system in an acidic Alfisol

Aim: This study was carried out to evaluate the long-term impact of manuring, fertilization and liming on soil resilience, enzyme activities and system productivity under changing climate scenarios. Methodology: The soil samples were collected from 67 year old long-term experiment going on, at Birsa Agricultural University, Jharkhand during 2022-23 under maize-wheat cropping system from seven treatments, viz. T1: control, T2: 100 % N, T3: 100 % FYM, T4: ½ (N+FYM) + PX/2 + KY/2, T5: 100 % NPK, T6: Lime + NPK, T7: Lime + FYM +P(A-X) + K(B-Y). To assess soil resistance and resilience, surface samples were subjected to with and without heat stress (48±2°C for 80 hrs) and substrate addition (0.02 g glucose g-1 soil). Results: Application of FYM/lime with NPK significantly improved bulk density, pH, SOC and system productivity. The highest enzyme activities and cumulative respiration were observed in lime + FYM + P(A-X) + K(B-Y) treatment. It exhibited the highest resistance index (0.92) and resilience index (0.34). Interpretation: The integrated use of inorganic, organic along with liming proved to be a useful management strategy for maintaining soil quality, resistance and resilience, and crop productivity in acid soil of Jharkhand. Key words: Enzyme, Heat stress, Maize-wheat system, Soil acidification, Substrate induced respiration, Wheat-maize

Rice straw biochar and NPK minerals for sustainable crop production in arid soils: a case study on maize-wheat cropping system

Maize and wheat are the main cereals grown in Egypt. However, the country relies on grain imports to meet its local demands. In order to improve their production, appropriate fertilization programs are needed. The present study investigates the effects of amending a clayey soil of an arid region with rice straw biochar and NPK mineral fertilizers, individually or in combination, for increasing growth and productivity of maize and wheat crops. Additionally, impacts of these additives on soil biological activities and carbon (C) transformations in soil were a matter of concern herein. To achieve this objective, a field research of a randomized block design was conducted during the summer (maize) and winter (wheat) seasons of 2020/2021. The following treatments were considered: unmodified control (CK), 100% N inputs in the form of biochar (reference organic treatment, RSB) (T1), 100% mineral treatment (reference inorganic treatment, T2), 75% RSB + 25% NPK minerals (T3), 50% RSB + 50% NPK minerals (T4) and 25% RSB + 75% NPK minerals (T5). Additional doses of mineral fertilizers were added to treatments from T3 to T5 to maintain NPK inputs within the recommended doses. Key results showed that all additives significantly enhanced plant growth parameters and productivity. They also increased soil organic carbon level by the end of the growing season hence reduced soil bulk density, even for the treatment that received only mineral NPK applications (T2). All additives also upraised soil cation exchange capacity (CEC), soil available nitrogen (N), and soil salinity. However, sole application of biochar recorded the least increase in soil salinity. Combined mineral-organic treatments not only recorded the highest increases in soluble and microbial fractions of organic carbon and nitrogen in soil; but also noted the greatest improvements in growth and grain productivity of maize and wheat versus sole applications of mineral fertilizers or biochar. The alkaline nature of biochar was buffered by soil while no significant differences were observed in harvest index among treatments. In conclusion, combined use of biochar and mineral fertilizers, especially T5 is recommended for increasing soil fertility and wheat and maize grain productvity.

Effects of long-term saline water irrigation on soil salinity and crop production of winter wheat-maize cropping system in the North China Plain: A case study

Fresh water shortage is a major problem for grain production in the low plain around Bohai Sea in the North China Plain. Relative abundance of shallow saline groundwater could serve as an alternative water resource for use during dry seasons. A continuous 8-year field study was conducted from 2015 to 2023 to assess the effects of salt content in irrigation water on soil salt accumulation and crop production. Fresh water (FW) with electrical conductivity (EC) at 1.6 dS/m and three levels of saline water (SW) with EC at 4.7 (SW1), 6.3 (SW2) and 7.8 dS/m (SW3) were used for irrigation. Results showed that a single irrigation event at the jointing stage of winter wheat increased grain production averagely by 18.6 %, 22.5 %, 12.9 % and 9.5 % compared with a rain-fed treatment (RF) under FW, SW1, SW2 and SW3, respectively. With an additional irrigation applied at flowering stage, both irrigations using FW increased the yield by 28.6 %, and both irrigations using SW2 increased the yield by 19.3 % compared with RF. Negative effects of salt on winter wheat overshadowed the positive effects of increased water supply under two irrigations both using SW. With an irrigation at maize sowing and the subsequent summer rainy season, the yield of maize following winter wheat was not affected by a one-time SW irrigation to the previous crop, but showed a 5.3 % yield reduction when two irrigations of SW were applied. There was no apparent salt accumulation in the top 1 m of the soil profile, but a slight increasing trend in the salt content in the 1–2 m layer of the soil profile under SW2 and SW3 irrigation. No apparent changes in soil physical properties were observed for continuous application of SW. It was suggested that SW with EC not exceeding 6.3 dS/m should be applied for a single irrigation during the winter wheat season. This practice could alleviate the fresh water shortage in this region and allow for the maintenance of a relatively stable yield of winter wheat and maize without the risk of salt accumulation in the soil.

Impact of conservation agriculture and weed management on carbon footprint, energy efficiency, and sustainability in maize-wheat cropping systems

This study assesses the impact of conservation agriculture (CA) and weed management practices on the productivity, profitability, energy use, and carbon sustainability of a maize-wheat cropping system. Fifteen treatment combinations, incorporating five tillage methods (conventional-till maize and wheat [CT-CT], conventional-till maize and zero-till wheat [CT-ZT], zero-till maize and zero-till wheat [ZT-ZT], zero-till maize and zero-till plus residue in wheat [ZT-ZTR], and zero-till plus residue maize and wheat [ZTR-ZTR]) and three weed management practices (recommended herbicide [H-H], integrated weed management [IWM-IWM], and hand weeding [HW-HW]), were tested in a strip plot design. The results showed that ZTR-ZTR significantly increased system productivity (6.90 Mg ha−1), net returns, and benefit-cost ratio (BCR; 2.69), compared to CT. However, CT systems had 173 % higher energy use efficiency (EUE) and 170 % higher energy intensity (EI) than CA systems. CA-based treatments used about 15 % direct renewable energy and 85 % indirect renewable energy, while CT systems used 15–20 % direct non-renewable energy and 85–86 % indirect non-renewable energy. Among weed management practices, recommended herbicides (H-H) led to the highest productivity (6.71 Mg ha−1), EUE (9.80), net returns (3003 US$ ha−1), and BCR (3.08), but also higher carbon footprints. This underscores the balance between productivity, energy efficiency, and carbon in agriculture.

Effect of Different Approaches of Nutrient Application on Soil Quality Index Under Maize-Wheat Cropping System in Mollisol Region of Uttarakhand

ABSTRACT A field experiment was conducted at GBPUA&T, Pantnagar, to study the effect of different approaches of nutrient application on soil fertility and soil quality under maize-wheat cropping system. Nine treatment combinations were compared namely, Recommended Doses of Fertilizers (RDF), Soil Test Crop Response (STCR), and various combinations of organic and inorganic fertilizers. This paper aims to develop Soil Quality Index (SQI) based on Minimum Data Set (MDS) using Principal Component Analysis (PCA). Different indicators were employed to formulate the SQI, derived from surface soil layer measurements (0–15 cm). Each MDS indicator was then converted into a dimensionless score using linear scoring function and then integrated into SQI. Results showed that the key soil quality indicators identified as MDS using PCA under maize-wheat cropping system were Water Holding Capacity, organic carbon, available N and dehydrogenase activity. These soil quality indicators were found to be best for monitoring soil health status. After rabi wheat 2019–2020, SQI varied from 1.22 to 2.21 across the treatments whereas, after rabi wheat 2020–2021, SQI varied from 1.13 to 2.23 across the treatments. Among different approaches of nutrient application, STCR-based use of fertilizers along with FYM (T4) helped in maintaining better soil physical, chemical and biological properties and ultimately sustaining soil quality, which was followed by the treatment receiving 75% STCR dose of N (inorganic mode) + full P and K (T5). Integration of organics with inorganic fertilizers maintained soil quality, environmental health and reduced greater dependency on chemical fertilizers.

Long Term Effect of Residue Management, Nitrification and Urease Inhibitor on Non-target Soil Bacterial Community in Rice–Wheat and Maize–Wheat Cropping Systems

Long Term Effect of Residue Management, Nitrification and Urease Inhibitor on Non-target Soil Bacterial Community in Rice–Wheat and Maize–Wheat Cropping Systems

Effect of continuous FYM and fertilizer applications over nine years utilizing STCR based targeted yield equations on transfer and uptake of micronutrients in an acid Alfisol under a maize-wheat cropping system

The present study was conducted to investigate the effect of long-term Soil Test Crop Response (STCR) based nutrient management in regulating soil micronutrient status and optimizing crop productivity under a maize-wheat cropping system in an acid Alfisol. The experiment was initiated during monsoon 2007, consisted of eight treatments viz., control, farmers’ practice, general recommended dose, soil test-based, STCR based targeted yield of 25 (wheat)/30 (maize) and 35 (wheat)/40 (maize) q ha−1 with FYM @ 5 t ha−1 and without FYM. Results revealed that the soil available Fe, Cu, Zn and Mn exhibited depletion in unfertilized plots over initial status. However, the STCR (Integrated Plant Nutrient Supply; IPNS) based targeted yield approach of fertilizer application maintains higher values of DTPA extractable micronutrients in comparisons to all other treatments. After nine continuous years, the highest DTPA- extractable Fe (27.6 mg kg−1), Mn (25.1 mg kg−1), Zn (1.25 mg kg−1) and Cu (0.75 mg kg−1) were recorded in treatment where, FYM was added along with fertilizers for targeted yield of 35 q ha−1. The micronutrient uptake by wheat was higher in STCR (IPNS) treatments. Low SRC values of Zn, Cu, Fe, and Mn indicated that long-term prescription based chemical fertilizers and FYM application can meet the plant nutritional requirement of wheat crop. Hence long-term STCR based integration of FYM (with NPK fertilizers) has an advantage in regulating the supply of micronutrients in soil-plant system and addressing the micronutrient deficiencies.

Long-term combined application of organic and inorganic fertilizers increases crop yield sustainability by improving soil fertility in maize-wheat cropping systems1

Organic material combined with inorganic fertilizer has been shown to greatly improve g crop yield and maintain soil fertility globally. However, it remains unclear if crop yield and soil fertility can be sustained in the long term under the combined application of organic and inorganic fertilizers. Three long-term field trials were conducted to investigate the effects of organic amendments on the grain sustainable yield index (SYI), soil fertility index (SFI) and nutrient balance in maize-wheat cropping systems of central and southern China during 1991-2019. Five treatments were included in the trials: 1) no fertilization (control); 2) balanced mineral fertilization (NPK); 3) NPK plus manure (NPKM); 4) high dose of NPK plus manure (1.5NPKM); and 5) NPK plus crop straw (NPKS). Over time, the grain yields of wheat and maize showed an increasing trend in all four fertilization treatments at the Yangling (YL) and Zhengzhou (ZZ) locations, while they declined at Qiyang (QY). The grain yield in the NPKM and 1.5 NPKM treatments gradually exceeded that of the NPK and NPKS treatments at the QY site. The largest SYI was recorded in the NPKM treatment across the three sites, suggesting that inorganic fertilizer combined with manure can effectively improve crop yield sustainability. Higher SYI values were recorded at the YL and ZZ sites than at the QY site, possibly because the soil was more acid at QY. The key factors affecting grain yield were soil available phosphorus (AP) and available potassium (AK) at the YL and ZZ sites, and pH and AP at the QY site. All fertilization treatments resulted in soil N and P surpluses at the three sites, but soil K surpluses were recorded only at the QY site. The SFI was greater in the 1.5NPKM, NPKM and NPKS treatments than in the NPK treatment by 13.3-40.0 and 16.4-63.6% at the YL and ZZ sites, respectively, and was significantly higher in the NPKM and 1.5NPKM treatments than in the NPK and NPKS treatments at the QY site. A significant, positive linear relationship was found between SFI and crop yield, and SYI and nutrient balance, indicating that grain yield and its sustainability significantly increased with increasing soil fertility. The apparent N, P and K balances positively affected SFI. This study suggests that the appropriate amount of manure mixed with mineral NPK fertilizer is beneficial to the development of sustainable agriculture, which effectively increases the crop yield and yield sustainability by improving soil fertility.

Impact of Nutrient Management Practices on Exchangeable K, Ca, Mg, CEC and Correlations with Soil Properties Under Maize-wheat Cropping System

In order to study the impact of nutrient management practices on exchangeable K, Ca, Mg, CEC and its correlations with soil properties in two depths (0-15 cm and 16-30 cm) under maize-wheat cropping system, a long term experiment was conducted at farm research centre of department of soil science falling under the jurisdiction of Birsa Agricultural University. The experiment consisted of nine treatments replicated thrice in a randomized block design were selected for the study. The selected treatments were T1-control, T2-100% N only where 100% N was applied through Urea fertilizers,T3- FYM where 100% N was supplied through FYM (full dose 22 t/ha), T4-100% NP here 110 and 90 kg ha-1were supplied through Urea and SSP fertilizers, respectively, T5-100% NPK here 110:90:70 kg ha-1 were supplied through Urea: SSP: MOP fertilizers, T6- ½ (N+FYM)+P (A-X/2)+K (B-Y/2) (INM) where 50% of the nutrient need was supplied through Urea, SSP & MOP fertilizer and the rest 50% need through FYM and T7-100% NPK + Lime where NPK applied through Urea, SSP & MOP fertilizer along with lime application in LR once in 4 years, T8-Lime+ FYM+ P (A-X)+K (B-Y), the 100% N need of the crop was met by application of FYM whereas the P & K need was met by the application of SSP & MOP fertilizer, T9-Lime+N the 100% N dose was supplied through Urea along with lime. The results indicated that exchangeable K was found to be significantly highest in T8 than rest of the treatments followed by T7 and T5 while lowest was in T4 treatment in both depths respectively. The exchangeable Ca2+ was found to be highest in treatment T7 followed by T8 and T3 than rest of the other treated plot while lowest amount was found in T2 in both the depths. The trend of exchangeable magnesium was found to be significantly different in 0-15 cm and 15-30 cm soil depths as the highest amount was observed in treatments such as T8 followed by T3 and T6 in surface depths (0-15 cm) while in sub-surface depths (15-30 cm) the highest amount was found in treatments T3 followed by T8 and T6 while the lowest amount was found in T2 treated plot in both depths. Cation exchangeable capacity (CEC) is one the vital soil parameters concerning to soil fertility measured in terms of c mol (p+) kg-1 of soil and it is significantly varied in surface soils as well as in sub-surface soil depths. The CEC was significantly higher in FYM treated plot as compared to Non-FYM treated plot. Therefore, the highest CEC was recorded in T3 treated plot than rest of the other treatment while the lowest one was recorded in T2 plot in surface soils as well as sub-surface soils. The correlation coefficient (r) values worked out among the various soil parameters at these depth of soil where pH was significantly and positively correlated with exchangeable Ca2+ and exchangeable Mg2+. Similarly organic carbon shows positive correlation with exchangeable Mg2+ and exchangeable K+. Whereas EC and CEC shows non-significant but positive correlation with the parameters taken under study. The result of the present study will be highly useful for improving the soil fertility by using suitable and judicious combination of nutrient management with various cropping system side by side and hence provides a scientific scope for further research work.

Impacts on Various Management Practices on Crops Yield and Soil Biology in Maize-Wheat Cropping System

Aims: Integrated approaches that consider the synergies and trade-offs among tillage, residue, and nitrogen management are essential for optimizing agricultural sustainability to highlight the complex interplay between agronomic, environmental, and biological factors. We intended to evaluate the impact of tillage, residue, and nitrogen management on crop growth and soil biological properties under a maize-wheat cropping system in an inceptisol. Study Design: Split-split plot design. Place and Duration of Study: ICAR-IARI research farm, New Delhi, since 2014. Methodology: We collected soil samples at the anthesis stage of wheat crop and silking stage of maize crop at 0-5, 5-15, and 15-30 cm soil depth. Soil properties, namely soil organic carbon, dehydrogenase, acid, and alkaline phosphatase, soil microbial biomass carbon, soil microbial biomass phosphorus, and glomalin content by using standard procedures. Results: We observed that the soil organic carbon, enzyme activities, microbial biomass carbon and phosphorus, and glomalin content were significantly (P<0.05) higher under no-tillage and residue treatment at 0-5 and 5-15 cm soil depth. Enzyme activity and microbial biomass carbon (MBC) were significantly higher by application of 100 and 150% RDN, respectively, at 0-5 and 5-15 cm soil depth. The effect of nitrogen treatment on biomass yield was significant (P<0.05) and found to be higher at 150% Recommended dose of Nitrogen (RDN). The biomass yield of maize was 15.3% and 44.5%, and wheat was 7.8% and 20.4%, significantly increased by applying 150% RDN over the 100% and 50% RDN respectively. Conclusion: Farmers can successfully adopt NT with 5 t ha-1 crop residue mulch with 150% RDN to attain better soil health and higher biomass yield under the maize-wheat cropping system.

Optimization of inter-seasonal nitrogen allocation increases yield and resource-use efficiency in a water-limited wheat–maize cropping system in the North China Plain

Winter wheat–summer maize cropping system in the North China Plain often experiences drought-induced yield reduction in the wheat season and rainwater and nitrogen (N) fertilizer losses in the maize season. This study aimed to identify an optimal interseasonal water- and N-management strategy to alleviate these losses. Four ratios of allocation of 360 kg N ha−1 between the wheat and maize seasons under one-time presowing root-zone irrigation (W0) and additional jointing and anthesis irrigation (W2) in wheat and one irrigation after maize sowing were set as follows: N1 (120:240), N2 (180:180), N3 (240:120) and N4 (300:60). The results showed that under W0, the N3 treatment produced the highest annual yield, crop water productivity (WPC), and nitrogen partial factor productivity (PFPN). Increased N allocation in wheat under W0 improved wheat yield without affecting maize yield, as surplus nitrate after wheat harvest was retained in the topsoil layers and available for the subsequent maize. Under W2, annual yield was largest in the N2 treatment. The risk of nitrate leaching increased in W2 when N application rate in wheat exceeded that of the N2 treatment, especially in the wet year. Compared to W2N2, the W0N3 maintained 95.2% grain yield over two years. The WPC was higher in the W0 treatment than in the W2 treatment. Therefore, following limited total N rate, an appropriate fertilizer N transfer from maize to wheat season had the potential of a “triple win” for high annual yield, WPC and PFPN in a water-limited wheat–maize cropping system.

Evaluation of urea loaded nanoclay biopolymer composites with Zn and P solubilizing microbes for nitrogen uptake and use efficiency in maize (Zea mays)-wheat (Triticum aestivum) cropping system

A field experiment was conducted during rainy (kharif) 2022 (July 2022–October 2022) and winter (rabi) 2022–23 (November 2022–March 2023) seasons at ICAR-Indian Agricultural Research Institute, New Delhi to evaluate a series of Zn and P solubilizing microbial culture enriched nanoclay biopolymer composite (NCBPC) loaded with nitrogenous fertilizer (urea) and the efficiency of the products for maize (Zea mays L.) and wheat (Triticum aestivum L.). Experiment consisted of 10 treatments, viz. T1, Control; T2, 100% N though urea; T3; T5; T7; and T9, 75% N as urea loaded NCBPC-A (prepared using acrylic acid + acrylamide + mango kernel flour) alone or along with P or Zn or P + Zn solubilizers; T4; T6; T8 and T10, 75% N as urea loaded NCBPC-B (prepared using acrylic acid + acrylamide + maize flour) alone or along with P or Zn or P + Zn solubilizers in a randomized block design (RBD) and replicated thrice. In both maize and wheat crop, highest grain (5.09 and 5.32 t/ha) and straw yield (6.56 and 7.45 t/ha), apparent N recovery (51.26 and 47.26%) and agronomic efficiency (12 and 13.3 kg grain yield obtained/kg N application) were obtained in treatment T10 followed by T9. In addition, total N uptake significantly enhanced by 20.1–28.4% in maize and 22.1–30.8% in wheat (T9 and T10); apparent nitrogen recovery (ANR) improved by 12.9–18.2 and 15.2–21.1% and agronomic efficiency (AE) triggered by 19.5–21.2 and 15.4–20.8% in maize and wheat crops respectively, under T9 and T10 treatments over standard urea fertilization (T2). Thus, the study concludes that, 25% N requirement could be cut down through application of 75% N (urea) loaded NCBPCs in conjunction with Zn or P or Zn + P solubilizing microbial culture as compared to sole urea application under maize-wheat cropping system.

Substitution of Inorganic Nitrogen with Organic Amendments for Improvement of Soil Properties, Microbial Community, and Enzymatic Activity in Maize-Wheat Cropping System Under Sub-temperate Ecology

Substitution of Inorganic Nitrogen with Organic Amendments for Improvement of Soil Properties, Microbial Community, and Enzymatic Activity in Maize-Wheat Cropping System Under Sub-temperate Ecology

Nutrient Balance and Soil Fertility of Rainfed Maize-Wheat Cropping System Under Different Seed Priming, Tillage and Nutrient Management Practices

ABSTRACT Crop productivity, soil quality and fertility have been degraded due to intensive conventional tillage and poor crop management practices. Conservation tillage along with proper crop establishment methods (including seed priming, integrated nutrient management) helps in sustaining the productivity of crops, especially under rainfed conditions. A field experiment was carried out to evaluate the effect of seed priming, tillage and nutrient management practices on nutrient balance; chemical and microbial properties of soil; and productivity of maize-wheat cropping system in rainfed conditions. The experiment was laid out in factorial randomized block design with three factors (tillage, seed priming and nutrient management) and control as independent treatment for general comparison of results. The findings showed that chemical and microbial properties of soil were enhanced under zero tillage+ mulch as compared to other tillage practices. However, crop productivity was higher in conventional tillage+ mulch (70.28 q/ha (maize), 35.27 q/ha (wheat)). Under nutrient management practices, integrated nutrient management proved to be better as compared to recommended dose of fertilizers. Highest production efficiency (32.8 kg ha−1 day−1) was found under CT+M,Hydro,Int. Nutrient balance (N, P, K) was found higher in treatments with integrated nutrient management.

Optimizing tillage and fertilization practices to improve the carbon footprint and energy efficiency of wheat-maize cropping systems

To make agricultural systems sustainable in terms of their greenness and efficiency, it is essential to optimize the tillage and fertilization practices. To assess the effect of tilling and fertilization practices in the wheat-maize cropping systems, we carried out a three-year field experiment designed to quantify the carbon footprint (CF), and energy efficiency of the cropping systems in the North China Plain. As the study parameters, we used four tillage practices (no tillage (NT), conventional tillage (CT), rotary tillage (RT) and subsoiling rotary tillage (SRT)), and two fertilizer regimes (inorganic fertilizer (IF), and hybrid fertilizer with organic and inorganic components (HF)). Our results indicated that the most prominent energy inputs and greenhouse gas (GHG) emissions could be ascribed to the use of fertilizers and fuel consumption. Assuming the same fertilization regime, ranking the tillage patterns with respect to the value of the crop yield, the profit, the CF, the energy use efficiency (EUE) or the energy productivity (EP) for either wheat or maize always gave the following result: SRT>RT>CT>NT. For the same tillage, the energy consumption associated with HF was higher than IF, but its GHG emissions and CF were lower while the yield and profit were better. In terms of the overall performance, tilling is more beneficial than NT, and reduced tillage (RT and SRT) are more beneficial than CT. The fertilization regime with the best overall performance was HF. Combining SRT with HF has significant potential for reducing CF and increasing EUE, improving the sustainability. Adopting measures promoting these optimizations can help overcome the challenges posed by lack of food security, energy crises and ecological stress.

Releasing Patterns of Potassium and its Relationship with Different Forms of Potassium in Acid Alfisols Soils of Ranchi, Jharkhand, India

A study was conducted during 2017-2018 at the Experimental Farm of Birsa Agricultural University, Kanke, Ranchi, Jharkhand, India to assess the releasing patterns of potassium and its relationship with different forms of potassium in surface (0-15 cm) and sub-surface (16-30 cm) soils of acid alfisols from the selected 9 treatments under long-term nutrient management practices in maize-wheat cropping system. The releasing power of soil potassium is an index of the availability of the nutrient to the crops over a longer duration and in general, it indicates the sum of water-soluble K, exchangeable K, and a fraction of non-exchangeable K which is not immediately available to the growing plants, but will be slowly available over a longer period. Repeated extraction with boiling 1N HNO3 has been suggested as one of the methods to assess the potassium-releasing capacity of soils. In this context, cumulative K, constant rate K, and step K as a part of non-exchangeable potassium proposed by Haylock (1956) measure the potassium-releasing capacity of soils more effectively under intensive crop cultivation. The amount of K release in successive extraction with boiling 1N HNO3 decreased consistently and reached a plateau at the 8th and 9th extraction steps in both depths of soils. Cumulative K is highest in INM (T6) while constant rate K and step K are highest in Lime, FYM, P2O5, and K2O treated plots (T8). The lowest contribution of potassium release patterns is generally observed in the control plot (T1). Also, the K release was found to be maximum in surface soils than in sub-surface soils concerning various selected treatments. Cumulative K, Constant- rate K, and Step K had highly significant and positive correlations with different forms of potassium (Water soluble K, Exchangeable K, Non-Exchangeable K, Total K, and Lattice K) in both depths. The potassium-releasing patterns evaluated through cumulative K, constant rate K, and step K could be meaningful for making fertilizer recommendation programmes, especially in intensively cultivated areas. Hence, the importance of study in terms of the possible contribution to plant available pool of soil K through potassium release patterns in two depths of given soil has been pointed out.

Physico-chemical properties, available nutrient content and their inter-relationship in soils under rain fed maize-wheat cropping system, district Reasi (J&K)

Composite soil samples representing rain fed maize-wheat cropping system in district Reasi of Jammu and Kashmir were analyzed for important physico-chemical properties and available nutrients. These soils were found to be sandy loam in texture with pH, EC and OC varying from 5.89 to 8.73, 0.04 to 0.47 dS/m and 3.5 to 21.9 g/kg, respectively. Content of available major nutrients viz. N, P, K and S varied from 207.6 to 663.6, 0.89 to 78.0, 22.71 to 349.45 kg/ha and 0.50 to 52.30 mg/kg, respectively, while that of available micronutrients viz. Fe, Zn and B varied from 0.89 to 30.20, 0.18 to 3.85 and 0.11 to 0.70 mg/kg, respectively. As per Nutrient Index values, these soils fell in high category of available Fe, medium category of available N, P, Zn, B and low category of available K and S. Soil pH, EC and OC were significantly and positively correlated with each other as well as with available N, K and B; and negatively with available Zn. Soil pH was also significantly negatively correlated with available Fe whereas, EC was positively correlated with available S and P. Further, available P was significantly positively correlated with OC, available N, K, S, Fe and B. Available N had a synergistic relationship with available K and B; and antagonistic relationship with available Zn. Available Zn showed significant and positive correlation with available Fe; however its correlation with available K and B was significantly negative. Available B had a significant positive correlation with available K and negative correlation with available Fe. The step down regression analysis indicated that nearly whole of variability in available N could be attributed to OC alone. About 28% of total variability in available P could be attributed to pH and EC together; while 13% of that in available S could be attributed to EC alone. Nearly 58 and 82% of the respective variability in available K and B could be due to OC and EC together. Soil pH and OC together contributed about 80 and 86% of the total variability towards available Fe and Zn in order.

Estimation of ET and Crop Water Productivity in a Semi-Arid Region Using a Large Aperture Scintillometer and Remote Sensing-Based SETMI Model

With the increasing water scarcity and the demand for sustainable agriculture, precise estimation of crop evapotranspiration (ET) is crucial for effective irrigation management, crop yield assessment, and equitable water distribution, particularly in semi-arid regions. In this study, a large aperture scintillometer (LAS) was used to validate the remote sensing-based ET model SETMI (Spatial Evapotranspiration Modeling Interface) in an irrigated maize-wheat cropping system in a semi-arid region at the ICAR-Indian Agricultural Research Institute, New Delhi. Results obtained by the SETMI model depicted modeled surface energy fluxes compared well with LAS field data, showing a very high R2 (0.83–0.95) and NRMSE (8–29%). The SETMI model performed better in the case of the maize crop than the wheat crop in field experiments. Further, the SETMI model was employed at the regional level using high-resolution Sentinel-2 to estimate the regional water productivity of wheat crops over a semi-arid region in India. The estimated regional, seasonal wheat actual ET mainly ranged between 101 mm and 325 mm. The regional wheat water productivity varied from 0.9 kg m−3 to 2.20 kg m−3. Our research reveals that the SETMI model can give reliable estimates of regional wheat water productivity by examining its spatial and temporal fluctuations and facilitating the creation of regional benchmark values.

Microbially mediated mechanisms underlie soil carbon accrual by conservation agriculture under decade-long warming

Increasing soil organic carbon (SOC) in croplands by switching from conventional to conservation management may be hampered by stimulated microbial decomposition under warming. Here, we test the interactive effects of agricultural management and warming on SOC persistence and underlying microbial mechanisms in a decade-long controlled experiment on a wheat-maize cropping system. Warming increased SOC content and accelerated fungal community temporal turnover under conservation agriculture (no tillage, chopped crop residue), but not under conventional agriculture (annual tillage, crop residue removed). Microbial carbon use efficiency (CUE) and growth increased linearly over time, with stronger positive warming effects after 5 years under conservation agriculture. According to structural equation models, these increases arose from greater carbon inputs from the crops, which indirectly controlled microbial CUE via changes in fungal communities. As a result, fungal necromass increased from 28 to 53%, emerging as the strongest predictor of SOC content. Collectively, our results demonstrate how management and climatic factors can interact to alter microbial community composition, physiology and functions and, in turn, SOC formation and accrual in croplands.

Soil health and microbial network analysis in a wheat-maize cropping system under different wheat yields

Soil health and microbial network analysis in a wheat-maize cropping system under different wheat yields