Lowland Paddy Research Articles

Agronomic performance of Ciherang near-isogenic lines for nitrogen use efficiency trait in irrigated lowland paddy field

Abstract Nitrogen (N) is an essential nutrient that affects plant growth and productivity. The consumption of N fertilizer is continuously increasing with the rapid demand for agricultural production. However, the rise in N fertilizer utilization causes higher production costs and leads to a negative impact on the environment. Improvement in nitrogen use efficiency (NUE) of rice plants is therefore important for sustainable rice production to reduce N fertilizer consumption while maintaining high grain yield. To improve the NUE of Indonesian elite cultivars, near-isogenic lines (NILs) with Ciherang genetic background have been developed by introducing genes related to N use efficiency, qRL6.1, and actpk1 through backcross breeding. Preliminary yield trials were conducted to evaluate the agronomic performance of CiherangNILqRL6.1 and CiherangNILactpk1 rice lines under optimum N fertilizer conditions in irrigated lowland fields for two seasons, wet season 2021/2022 and dry season 2022. Observations were performed on flowering time, biomass, yield, and yield component of NILs and Ciherang. The result from this preliminary observation indicated that under optimum N fertilizer, the agronomic performance of the NILs was comparable to Ciherang as the genetic background. Some NILs showed higher grain yield compared to Ciherang and were selected for further experiments to evaluate their performance under different N fertilizer conditions.

Alternative Agronomic Management Practices Through Fertilizer, Irrigation, and Plant Density Adjustments for Hybrid Fodder Sorghum (<em>Sorghum bicolor</em> L. Moench)

Purpose: The basal fertilizer recommendation for growing hybrid fodder sorghum varieties in uplands involves relatively high quantities of Urea, TSP, and MOP, with rates of 100:90:65 kg/ha for SX-17 and 150:62:37 kg/ha for Dairy green. For both initial and ratoon crops, it is recommended to apply 150 kg/ha of urea as a top dressing. This study investigated the impact of reducing the fertilizer application rate to 75% and employing alternative agronomic practices on hybrid fodder sorghum varieties grown in lowland fallow paddy fields in the dry zone during the Yala and third seasons.Research Method: The agronomic management practices, including four basal fertilizer rates (Urea:TSP: MOP) of 100:90:65 (BD1), 150:62:37 (BD2), 75:68:49 (BD3), and 113:47:28 (BD4); two top-dressing urea fertilizer rates of 150 (TD1) and 112.5 kg/ha (TD2); two plant spacing configurations of 45x30 (WS) and 45x15 cm (NS); and two irrigation interval regimes, 5 days up to 30 days followed by 8 days (SI) and 7 days up to 30 days followed by 10 days (LI) were investigated. These factors were combined into four agronomic management packages: AMP1 (BD1, TD1, WS, SI), AMP2 (BD2, TD1, NS, SI), AMP3 (BD3, TD2, WS, LI), and AMP4 (BD4, TD2, NS, LI). The study used a split-plot design with three replicates and assessed various parameters, including plant height, stem diameter, plant weight, leaf area index (LAI), number of tillers, and fodder yield in both the initial fodder sorghum crop and the first ratoon crop. The crops were harvested when 50% of the panicles on the plants were at the milk and dough grain stages.Findings: The initial crop exhibited significantly heavier plants having wider stems when grown with higher fertilizer rates, wider plant spacing, and shorter irrigation intervals in AMP1. Irrespective of fertilizer rate and irrigation interval, the initial crops tended to have higher LAI with narrow plant spacing in AMP2 and AMP4. In the ratoon crops, wider plant spacing in AMP1 and AMP3 resulted in clumps with a greater number of tillers and heavier plants. However, the ratoon crops also exhibited higher LAI with narrow plant spacing in AMP2 and AMP4. Total fodder dry matter yield (DMY) in AMP2 and AMP4 with narrow plant spacing was significantly greater for both varieties. Furthermore, the DMY was not affected by fertilizer rate and irrigation interval.Value: Hybrid fodder sorghum varieties (SX-17 and Dairygreen) cultivated at higher plant density, along with reduced fertilizer (75%) and irrigation, can produce comparable fodder yield (21.1 and 26.1 MT/ha, respectively) to those grown at lower plant density with more fertilizer and irrigation (24.6 and 28.1 MT/ha, respectively) in lowland paddy fields during Yala and third seasons in the dry zone.

Modeling and simulation of sulfur availability in paddy soils under reducing environment considering heavy metal content

ABSTRACT Insufficient sulfur (S) can reduce rice yield under certain soil conditions. The availability of S in paddy soils is determined by the concentrations of inorganic S and some heavy metals that react with sulfide ions to form sparingly soluble sulfides. In order to evaluate the S fertility of paddy soils, a predictive model was formulated to simulate the formation of sulfides and the effect of heavy metal content on the concentration of sulfate ions (SO4 2-) in the soil solution under reducing conditions. The basic computational algorithm of the model was an iterative method incorporating the equilibria of major aqueous species, sparingly soluble salts, and soil adsorption. A field survey was also conducted to evaluate S availability in actual rice paddy soils. SO4 2- and heavy metal contents were measured in 250 paddy fields located in central Japan. The model calculation using the field survey results showed that as the redox potential (Eh) decreases from −80 to −170 mV, sulfide-forming metals (Ni, Cu, Zn, Cd, and Pb) take precedence over iron (Fe) in sulfide formation. The major sulfides present were chalcocite (Cu2S), greenockite (CdS), sphalerite (ZnS), galena (PbS), chalcopyrite (CuFeS) and α-NiS, Due to their predominance in paddy soil, zinc (Zn) and copper (Cu) have a strong influence on the reduction of SO4 2- concentration. The formation of metal sulfides increases the Eh value corresponding to the critical SO4 2- concentration and decreases the S availability under the individual Eh condition. The model calculation also showed that an increase in sulfide-forming metal content leads to S deficiency, even if the SO4 2- content is not exceeded. Model calculations for each geographical division against the field survey results suggest that S deficiency is more likely to occur in lowland paddy fields formed by river sediments than in Andisols on terraces.

Impacts of soil, water source, and agro-climatic conditions on exchangeable sodium in rice-cultivated lowland soils of Sri Lanka

Rice is sensitive to salt stress, commonly caused by high concentrations of sodium (Na) in soils. However, the concentration and spatial variability of exchangeable Na in lowland paddy fields of Sri Lanka are not known. This study examined the interactive effects of the agro-climatic zones (ACZs), soil orders, and water sources on exchangeable Na in lowland paddy fields in Sri Lanka using 8566 soil samples. Exchangeable Na was extracted using 0.01 mol/L CaCl2 solution and detected using inductively coupled plasma-mass spectrophotometry. Exchangeable-Na concentration ranged from 0.05 to 4814 mg kg−1 with a mean concentration of 140.7 mg kg−1, and these values were within the optimal range reported for tropical paddy soils. The distribution of exchangeable Na was right skewed with 44%, 35%, and 9.3% of samples falling into 0–100, 100–200, and 200–300 mg kg−1, respectively. Samples from the Low country Dry zone had the highest (157 mg kg−1) Na concentration while that in the Upcountry Intermediate zone was the lowest (13 mg kg−1) ( p < 0.05). Vertisols recorded the highest (255 mg kg−1) and Ultisols recorded the lowest (81 ± 5.0 mg kg−1) among soil orders. Soils receiving supplementary irrigation in Low country Dry zone had lower Na than that in rainfed systems. Exchangeable-Na concentration was positively correlated with soil pH ( p < 0.05). Even though the concentrations of Na in soil samples were within the optimal range, agronomic decisions based on ACZ, soil order, and water source need to be made to minimize the potential development of saline–sodic soils in the study areas.

Zeolite application coupled with film mulched drip irrigation enhances crop yield with less N2O emissions in peanut field

Zeolite has been previously reported to increase nitrogen (N) use efficiency in lowland paddy fields. However, few results are available regarding its effect on N2O emissions from upland field, especially with mulched drip irrigation. In present study, two-year peanut field experiments were conducted utilizing a split-plot design to assess the impact of zeolite application and irrigation regimes on plant dry weight and N accumulation, soil inorganic N content, peanut yield, N2O emissions, and soil physicochemical properties. Different irrigation regimes (MD, mulched drip irrigation; RF, rain-fed) as well as zeolite application rates (0 t ha−1 (Z0, control), 5 t ha−1 (Z5), and 10 t ha−1 (Z10)) were applied. Results showed that the MD treatment increased plant dry weight, N accumulation, soil NH4+-N, NO3−-N content and mean soil temperature compared to the RF control. Furthermore, cumulative N2O emissions and peanut yield were raised by 24.3% and 15.8%, respectively, with the MD treatment. The increased peanut yield by mulched drip irrigation might be resulted from the promoted soil inorganic N, soil temperature, and plant N accumulation. Regardless of irrigation, zeolite addition increased dry weight and N accumulation during all measured stages except seedling, mean soil NH4+-N, NO3−-N content, mean soil pH, and peanut yield. In contrast, cumulative N2O emissions were decreased compared to the non-zeolite control. Moreover, findings showed that Z10 performed better in increasing peanut yield by 12.7% and decreasing N2O emissions by 35.7% than Z5. Increasing soil inorganic N content with zeolite addition contributed to improve plant N accumulation and promote dry weight and peanut yield. Furthermore, the reduction of N2O emissions by zeolite was related to improved soil inorganic N and pH. Though MD increased N2O emissions, the MDZ10 treatment had 20.6% of cumulative N2O emissions lower than the conventional practice (RFZ0), indicating that zeolite application alleviated the adverse effect of mulched drip irrigation on N2O emissions. It was concluded that zeolite dose at 10 t ha−1 coupled with mulched drip irrigation gave a high peanut yield with less N2O emissions. Our findings could be adopted in arid areas to enhance peanut production and mitigate environmental risk induced by N2O emissions.

Enhancing phosphorus use efficiency and soil quality indicators in lowland paddy ecosystem through Azolla, rice straw, and NPKS fertilizers

PurposeThis study investigates the influence of incorporating Azolla, rice straw, and NPKS fertilizers on phosphorus use efficiency (PUE) and rice productivity in lowland paddy fields. Despite Azolla’s well-known role as a nitrogen-fixing aquatic fern in rice production, its specific impact on PUE remains unclear. The primary objective is to explore diverse treatment combinations to identify synergies that enhance both PUE and overall rice productivity.MethodsThe study was conducted at Mkula Irrigation Scheme in the Kilombero Valley, Tanzania; the field experiment employed a randomized complete block design with 13 treatments and three replications. Treatments comprised various combinations of Azolla, rice straw, and chemical fertilizers, incorporating 50% and 100% rates of nitrogen (N) applied with phosphorus (P), potassium (K), and sulfur (S).ResultsThe study reveals the substantial impact of Azolla application on total nitrogen, available phosphorus, and exchangeable potassium levels in the soil. Particularly noteworthy were treatment combinations involving Azolla, rice straw, and reduced rates of synthetic nitrogen, along with specific P, K, and S applications, which exhibited the highest phosphorus uptake and PUE. Specifically, combining rice straw and Azolla with reduced N rates, alongside 30 kg P ha−1 + 30 kg K ha−1 + 20 kg S ha−1, resulted in the highest phosphorus uptake (73.57 kg/ha) and PUE (46.24%).ConclusionIntegrated nutrient management, incorporating rice straw and Azolla alongside synthetic fertilizers, demonstrates synergistic effects on phosphorus uptake and efficiency while maintaining soil quality. The study underscores the potential of such integrated strategies to optimize PUE and contribute to sustainable rice production in lowland paddy fields.

Selection for representative environment to identify high yielding and sweetness levels of sweet potato (Ipomoea batatas L.) in Indonesia

Abstract. Solihin E, Santosa DA, Nugroho B, Purwono, Sudirja R, Maulana H, Kamaluddin NN, Karuniawan A, Anwar S. 2024. Selection for representative environment to identify high yield and sweetness levels of sweet potato (Ipomoea batatas) in Indonesia. Biodiversitas 25: 386-391. Sweet potato is one of the important and commercial agricultural commodities in the world. Yield and sweetness levels are important traits that can influence consumer preferences. Environment is an important factor in the development of sweet potatoes. A suitable environment will provide high yields and good quality. The objectives of this study were to examine the significance and relevance of sweet potato yield and sweetness levels in two locations (Sumedang and Bandung District) and to select representative environments for sweet potato yield and sweetness levels. The research was conducted in Sumedang and Bandung districts on lowland paddy field and dry land. The field experiment used a factorial randomized completed block design with three repetitions. The significance and relevance of sweet potato yield and sweetness levels was analysis using T-test. Representative environments were identified by GGE biplot. The results showed that the Bandung and Sumedang environments showed significant differences in yield but not in sweetness. The Bandung paddy field is the most representative environment for yield, while the Sumedang dry field and Bandung dry field are the most representative environments for sweetness. The results of this research can be used by researchers, farmers and industrial users in the sweet potato development program, especially the yield and yield quality.

Evaluation of nutrition status and fertilization recommendations for lowland paddy (Case study in Merigi Kelindang District, Bengkulu Central Regency)

Farmer fertilization doses are generally insufficient compared to the recommended doses therefore causing low productivity of rice plants. This study aims to evaluate soil nutrient status to determine site-specific fertilization recommendations in Merigi Kelindang District, Central Bengkulu Regency. This study was carried out in February-April 2022 in Merigi Kelindang District, Central Bengkulu Regency, Bengkulu Province. Data was collected by taking composite soil samples at random after harvesting or before the first tillage. Determination of nutrient levels of N, P, K, and soil pH using the at Paddy Soil Test Kit. Data were analyzed descriptively comparatively. The results showed that the nutrient status of paddy fields in Merigi Kelindang District was low N 72%, medium N 14%, high N 7%, and very high 7%. P nutrient status was medium at 93% and low at 7%. High K nutrient status 100%. Meanwhile, pH status is acidic at 7% and slightly acidic at 93%. Recommendations for fertilizer usage in the Merigi Kelindang sub-district as follow; Urea 300 kg/ha for sandy soil (clay content < 20%) or 250 kg in clayey soil (clay content >20%); SP-36 fertilizer (100 kg/ha); KCl (50 kg/ha) without the use of paddy straw as compost and no KCL needed if 5 t/ha paddy straw compost used. Recommendations for soil management with a soil pH value of 5-6 (slightly acidic) are conventional drainage systems and the application of urea as N fertilizer.

Effects of climate, soil and water source on determining exchangeable copper concentration in lowland paddy fields in Sri Lanka

Effects of climate, soil and water source on determining exchangeable copper concentration in lowland paddy fields in Sri Lanka

Exchangeable molybdenum concentration in lowland paddy fields of Sri Lanka as affected by the differences in agro-climatic zones, soil orders, and water sources

Exchangeable molybdenum concentration in lowland paddy fields of Sri Lanka as affected by the differences in agro-climatic zones, soil orders, and water sources

Effect of Change of Agronomic Practices on Nutritive Value of Hybrid Fodder Sorghum Cultivated in Lowland Paddy Fields of the Dry Zone of Sri Lanka

This study was conducted to investigate the effect of low fertilizer rate and irrigation along with increased plant density on nutritive value of hybrid fodder sorghum cultivated in lowland fallowed paddy fields in dry zone during May to September. Seeds were sown in Yala season and continued as a ratoon crop to inter-monsoonal (Third) season. Four agronomic management packages (AMP1, AMP2, AMP3 and AMP4), which differ in fertilizer application rates, plant spacing, and irrigation intervals were tested with two fodder sorghum varieties (SX-17 and Dairygreen) in a split-plot design. The initial and first ratoon crops were harvested at dough grain stage. High fertilizer rate in combination with short irrigation interval, resulted in high (P&lt;0.05) crude protein content in the initial harvest. AMP2 and AMP4 produced equally high (P&lt;0.05) total dry matter yield (DMY) for SX-17 (24.7 and 20.9 MT/ha, respectively) and Dairygreen (27.7 and 25.7 MT/ha, respectively) varieties. Total digestible organic matter, crude protein and metabolizable energy yields were higher under AMP2 and AMP4 compared to other two packages for both varieties. Nutritive value was high in SX-17 under AMP1 for ratoon crop. In conclusion, AMP4 with plant spacing of 45 x 15 cm, low fertilizer rate (338-47-28 kg/ha, urea-TSP-MOP) and extended irrigation interval, could be recommended for cultivation of hybrid fodder sorghum in lowland paddy fields in the dry zone during Yala season. However, for cultivating SX-17 targeting to produce fodder with high nutritive level, AMP1 with spacing of 45 x 30 cm, high fertilizer rate (400-62-37 kg/ha of urea-TSP-MOP) and frequent irrigation could be recommended.

Distribution of Exchangeable Magnesium in Lowland Rice-Cultivated Soils of Sri Lanka as Affected by the Differences in Climate, Soil, and Water Source

Magnesium (Mg) is an essential macronutrient for plants. Even though Sri Lankans consume rice as the staple food, the Mg status in Sri Lankan paddy soils as affected by its climate, soils, and water sources used are not well understood. This study was conducted to (i) determine the distribution of exchangeable Mg (ex-Mg) concentration, and (ii) examine the interactive effects of agro-climatic zones (ACZs), soil order, and water source in determining the ex-Mg concentra-tion in lowland paddy fields of Sri Lanka. A total of 9,038 soil samples representing six ACZs, six soil orders, and three water sources were collected using a stratified random sampling approach. The ex-Mg concentration was determined after extracting in 0.01 M CaCl2 and detected using inductively coupled plasma-mass spectrometry. The range of ex-Mg was within 0.01-1,610 mg kg-1, with a mean of 210.4 mg kg-1. From the tested soil samples, 66% were Mg-deficient (&lt;240 mg kg-1), 32% were Mg-optimal (240-730 mg kg-1) and 2% were Mg-excessive (&gt;730 mg kg-1). Among the ACZ, the Dry zone Low country had the highest ex-Mg concentration (p&lt;0.05). Among the soil orders tested, Vertisols had the highest and Histosols had the lowest ex-Mg concentration (p&lt;0.05). Irrigated rice fields had higher ex-Mg than the rainfed systems (p&lt;0.05). Soil ex-Mg concentration was positively correlated with soil pH (p&lt;0.05) and crop productivity (p&lt;0.05). As most rice-growing soils of Sri Lanka are Mg-deficient, it is important to implement strategies specific to ACZs, soil orders, and water sources to improve the soil-Mg status.

Effects of climate, soil and water source on the distribution of bioavailable iron in low-land paddy soils of Sri Lanka

Iron (Fe) is an essential mineral element of plants. However, the current status of bioavailable Fe in lowland paddy fields in Sri Lanka is not known. This study was conducted to examine the (i) spatial distribution of bioavailable Fe concentration, and (ii) interactive effects of agro-climatic zone (ACZ), soil order, and water source in determining the bioavailable Fe concentration in lowland paddy fields in Sri Lanka. A total of 6003 soil samples representing six ACZs, six soil orders, and three water sources were collected using a stratified random sampling approach. Bioavailable Fe was extracted using 0.01 M CaCl2 and measured using Inductively Coupled Plasma Mass Spectrophotometry. Bioavailable Fe concentration ranged between 0.0003 and 339 mg kg−1 with a mean of 49.4 mg kg−1. Samples collected from the Wet zone, particularly the Wet zone Low country, had higher Fe concentrations than those reported in other ACZs (p < 0.05). Among the soil orders, Histosols, Inceptisols and Ultisols had higher Fe concentrations while Entisols, Alfisols and Vertisols reported lower values (p < 0.05). Paddy fields receiving water from major irrigation systems in Wet zone Low country had more Fe. Moreover, Fe concentration was not correlated with rice crop productivity (p > 0.05). The spatial maps of bioavailable Fe generated in this study could be useful for making area-specific agronomic and administrative decisions based on ACZs, soil orders and water sources used in paddy cultivation in Sri Lanka.

Root endophyte Piriformospora indica significantly affects mechanisms involved in mitigating drought stress in rice (Oryza sativa)

An experiment was conducted during the summer season of 2020 at College of Agriculture, Kerala Agricultural University, Vellayani to study the potential of a beneficial root endophyte Piriformospora indica Sav. Verma, Aj. Varma, Rexer G. Kost &amp; P. Franken in mitigating drought stress in rice (Oryza sativa L.). The field experiment was undertaken in the lowland paddy fields with sandy clay loam texture in randomized block design. Treatments were Piriformospora indica colonized and non-colonized rice seedlings under 3 irrigation intervals of 30 mm, 35 mm and 40 mm cumulative pan evaporation and 2 irrigation depths of 1.5 cm and 3 cm. Plants colonized with P. indica significantly enhanced the yield attributes and root parameters. This symbiotic association alleviated the negative effects of drought stress by maintaining higher proline content (71.8 μmole/g) and relative leaf water content (74%) irrespective of interval and depth of irrigation. Colonization boosted the uptake of phosphorus and maintained higher chlorophyll stability index (79.20%). Yield attributes of P. indica colonized plants subjected to severe stress, were observed to be equivalent to those of non-colonized plants under moderate stress and association with the endophyte resulted in saving of 30 mm water and could help rice to combat drought stress. Higher phosphorus uptake enhanced the root volume (29.1cm3 ) under severe water stress facilitated improved nutrient uptake (10.6 kg/ ha) from deeper layers of soil for colonized plants compared to the control plants and acted as a mitigating mechanism against drought stress.

Carbon Sequestration in Low Land Paddy Soils: Effect of Certain Cultural and Nutrient Management Practices: A Review

Carbon(C) is the only key to running in this worldly life and without carbon, nothing can be ensured, but the amount and form of C in different spheres of the earth make numerous changes. Changes in the carbon levels cause the lives of all living things. Soil carbon flux directly or indirectly affects the global climate and thus agriculture productivity. To ensuring the human rations, protection is intended for the rising populace worldwide, where the critical challenges in the agriculture sector are inevitable. Improved soil and nutrient supervisions and cultural practices are very imperative to tackling these troubles. Augmenting the productivity of various agro-ecosystems, soil productiveness, and carbon accretion via certain approaches become a must concern towards sustainable food production. “Paddy soils form the huge area of artificial swamplands on the earth, and serves as food basket for the world population also responsible for sequestering soil organic carbon potentially”. Rice accounts for around 9-10 % of the total cropland area globally, and their environmental conditions are responsible for storing organic carbon in soil, methane (CH4) production, and emit nitrous oxide (N2O) in meager amount. The present review signifies the present and future potential agricultural management practices, particularly soil and plant nutrition and their effects on soil organic carbon storage (SOCS) and carbon sequestration (CS) by paddies grown under submerged conditions compared to other crops. Increasing carbon inputs and reducing SOC losses in low land paddy soils need attention as its concern with GHGs that implies direct causes of global climate. As future direction, life-cycle assessments of certain practices in low land paddy soils helps in assessing the carbon footprints and sustaining the crop productivity consequently mitigating climate change. With this view, this review study was taken to the life of carbon in the terrestrial ecosystem and its accumulation in low land paddy soils moderated by cultural and nutrient management practices adapted for rice production in low lands.

Effect of zinc and silicon nanoparticles on yield, quality and economics of lowland paddy

An investigation to know the effect of nano zinc and silicon on quality and yield of rice was conducted at AHRS, Bavikere, KSNUAHS, Shivamogga. The experiment consisted 12 treatments replicated thrice and was laid in completely randomized block design. The different treatment combinations of seed treatment of nano zinc and silicon, foliar spray of zinc and silicon nanoparticles were compared with conventional sources and the control. Application of both zinc and silicon (T6) in nano form as foliar @ 40 ppm each at 40 DAT registered significantly higher no. of productive tillers (18.72), protein content (11.41 %), starch content (75.70 %) grain yield (6034 kg/ha), straw yield (6693 kg/ha) with higher economic net returns (98631 Rs ha-1), foliar spray of zinc nano particles alone @ 40 ppm at 40 DAT showed next best results.

Knowledge improvement of agricultural extender through technical guidance of paddy soil test kit

Paddy Soil Test Kit is one of the appropriate instruments to determine the nutrient status of lowland paddy and preparation of site-specific fertilization recommendations to increase rice productivity. Agriculture extension agents as technology transfer agents have a strategic role. Technical Guidance is needed to improve knowledge of agriculture extension. This study aims to analyze the level of knowledge of agricultural instructors on Technical Guidance use of Paddy Soil Test Kit and Preparation of Site-Specific Fertilization Recommendations. Data collection was carried out before and after implementation of Technical Guidance through direct interviews with a questionnaire guide. The evaluation was carried out on all participants of technical guidance, totaling 32 extension workers from representatives of 11 sub-districts throughout Bengkulu Selatan Regency by providing pretest and posttest to determine the increase in knowledge of Technical Guidance participants. The level of knowledge of participants is calculated using index % formula. The significance of increasing knowledge of technical and technical training participants was analyzed using non-parametric Wilcoxon Match Pairs Test statistical analysis. Correlation test to determine level of knowledge on age, experience, and education. Results of the analysis showed that there was a very significant increase (&lt;0.05) in the knowledge of officers after the implementation of technical guidance from an index of 52.58% (low category) to 84.83% (high category). There is no correlation between increasing knowledge about Paddy Soil Test Kit with age (sig &gt; 0.05) which is 0.571, experience 0.661, and education 0.130.

Impact of Cultivation Practices and Varieties on Productivity, Profitability, and Nutrient Uptake of Rice (Oryza sativa L.) and Wheat (Triticum aestivum L.) Cropping System in India

Interest in conservation measures, including reduced tillage, zero tillage, and crop residue retention, is growing in major rice growing areas of the world; particularly in the Indo-Gangetic plains. Of late, research interest is increasing in India for a specialised method of cultivation known as natural farming, which aims at maintain the functional biodiversity of the farm with little or no use of external inputs. With the increasing water crisis at a global level, it became imperative to develop technologies that can reduce the water use, particularly in water-guzzling low land paddy, by developing alternate cultivation methods; direct seeded rice is one such technology. A two-year field experiment was carried out at two locations during 2019–2020 and 2020–2021 to find out the impact of different cultivation and varieties on the productivity and profitability of the rice–wheat cropping system. The experiments were conducted in split plot design, replicated thrice, with cultivation practices in the main plot and varieties of both wheat and rice in the sub plot. The results so obtained reveal that conventional tillage significantly out yielded other methods of cultivation in both the crops at both the locations, while significantly lower grain yield in both crops was observed from natural farming. Adoption of reduced tillage, zero tillage and natural farming reduced the grain yield of wheat by 4.6%, 10.9%, and 59.4% over conventional tillage, while the corresponding decline in grain yield of rice was 10.8%, 16.1%, and 34.0% with reduced tillage, zero tillage, and natural farming, respectively. Among the varieties tested, HPW 368 and Him Palam Lal Dhan 1 (HPR 2795) produced significantly higher grain yield of wheat and rice, respectively, at both the locations during both years. Conventional tillage among cultivation practices and HPW 368 and Him Palam Lal Dhan 1 (HPR 2795) among wheat and rice varieties also proved to be better in terms of various economic indicators, including gross return, net return, and ratio benefit cost ratio (B:C ratio).

Zeolite enhances phosphorus accumulation, translocation, and partitioning in rice under alternate wetting and drying

Zeolite can increase fertilizer use efficiency in rice production. Zeolite’s positive effect on nitrogen (N) and phosphorus (P) utilization has been validated in lowland paddy fields, but little information is available on its effect on P accumulation, translocation, and partitioning in lowland rice, especially under water stress. We conducted a two-year field experiment to evaluate the effect of zeolite and irrigations on soil P availability, dry matter accumulation, and P accumulation, partitioning, and translocation. Regardless of irrigation, zeolite application accumulated greater dry matter (DM) across growth stages than the non-zeolite control (Z 0 ). A zeolite application rate of 10 t ha −1 (Z 10 ) increased soil available P, plant P accumulation, stem and leaf P translocation, and panicle P partitioning across growth stages compared to Z 0 . Z 10 increased grain yield, water use efficiency (WUE), and economic benefit by 21.4%, 35.5%, and 20.9%, respectively, compared to Z 0 . For the irrigation treatments, alternate wetting and drying irrigation (AWD) increased DM and shoot P accumulation at all stages (except DM at tillering and shoot P accumulation at tillering and yellow ripening) relative to continuous flooding (CF). AWD produced similar grain yields but higher WUE than CF. Significant correlations between grain yield, shoot P accumulation, and soil available P indicated that zeolite enhanced grain yield by improving soil P availability and plant P uptake. These results showed that 10 t ha −1 zeolite combined with AWD irrigation achieved the highest soil available P, plant P accumulation, grain yield, WUE, and economic benefit, and could be an alternative management option for improving fertilizer P utilization, increasing rice production, and enhancing farmer profits in water-deficient regions. • Zeolite application increased soil P availability and plant P accumulation. • Zeolite application (10 t ha −1 ) increased P translocation in stems and leaves and P partitioning in panicles. • Grain yield positively correlated with shoot P accumulation and soil P availability. • Zeolite application (10 t ha −1 ) combined with AWD achieved the highest grain yield, WUE, and economic benefit.

Mapping Productivity-related Spatial Characteristics in Rice-based Cropping Systems in Sri Lanka

Accurate and timely information on the productivity-related spatial characteristics in paddy fields will facilitate accurate decision-making to achieve food security needs. The aim of the present study was to map rice-cultivating regions in Sri Lanka based on crop productivity and related agronomic decisions made. A grid-based map coupled with a paddy land map of the country was used for the sampling protocol, and the generated data were mapped using ArcGIS software. The study revealed the spatial heterogeneity in the productivity of lowland paddy lands, rice varieties cultivated according to their age classes and breeding stations, water sources used for cultivation, and crops grown in lowlands during the water-limited cropping seasons. The constructed maps carrying the productivity-related spatial characteristics of rice across the country could facilitate agricultural decision support systems. The maps could be used to develop novel approaches for the management of rice productivity in rice-based cropping systems in the country.