Precise nutrient management for enhancing crop yield is possible through delineating soil management zones. Generally, the fertilizer recommendations followed use a blanket application for a larger area without considering the soil spatial variability. This may lead to low fertilizer application in pockets of less nutrient content and vice versa. Therefore, this study aims to develop soil management zones (MZs) adopting geostatistical and fuzzy clustering techniques in the Alwarthirunagiri block of the Thoothukudi district in Southern India. One hundred and seventy-one surface samples were collected from a study area of 2760 ha. The collected soils were processed and characterized by available macronutrients and micronutrients. The coefficient of variation of the soils varied from low (9.72%) to high (74.60%). Ordinary kriging and semivariogram analysis showed wide variation in the soil characteristics within the study site, with a spatial dependence ranging from moderate to strong. Four management zones were demarcated based on fuzzy performance index and normalized classification entropy using PCA and fuzzy K-means clustering. The study results indicated that the soil properties differed significantly under different management zones and provided potential site-specific fertilizer management options. The management zone map could be useful to the farmers to adopt precise management of nutrients for different zones.

Plants are found to remove toxic gases in the indoor atmosphere. It is well documented that plants in indoor space not only add aesthetic value but contribute and promote the improvement of indoor air quality (IAQ). Hence, this present study was taken up with an objective to study the impact of foliage ornamentals on IAQ in digital printing unit. In this experiment, three indoor foliage ornamentals viz., garden croton (Codiaeum variegatum), dumb cane (Dieffenbachia bowmannii) and song of India (Dracaena reflexa) were tested in the digital printing unit. Six plants of each genus were separately placed in the experimental unit (15 x 15 x 12 ft printing unit) for a week. A control experiment was done on the adjacent printing unit without plants and kept as control. The IAQ was monitored on an hourly basis by uHOO smart air monitor and the mean data on humidity, carbon dioxide (CO2), PM 2.5, carbon monoxide (CO) along with ozone (O3) were recorded and analyzed. It is evident from the experiment that all three foliage ornamentals viz., C. variegatum, D. reflexa and D. bowmannii improved the IAQ placed in the digital printing unit. However, among the three genus, Dieffenbachia recorded a more positive effect in modifying the indoor air during the experimental period.

Soil is an important source of available nutrients. Either shortage or surplus of available nutrients in the soil would limit growth of crops. Understanding the spatial variability and distribution patterns of soil available nutrients is essential for soil management with respect to fertilizer application. A total of 111 geo-referenced soil samples were collected on 300 m x 300 m grid at a depth of 0–15 cm, processed and analyzed for pH, EC, soil organic carbon (SOC), available nitrogen (AN), available phosphorus (AP), available potassium (AK), available sulphur (AS), available iron (Fe), available manganese (Mn), available zinc (Zn) and available copper (Cu). Soil properties coefficients of variation (CVs) of soil properties widely varied from low (5.22%) to moderate (49.28%). The geostatistics and geographic information system (GIS) techniques were applied. Ordinary kriging and semivariogram analysis showed differed spatial variability patterns for the studied soil properties with spatial dependence ranged from moderate to strong. The semivariograms for the soil properties were best fitted with spherical model. The range of influence for available N, P, K and S were 268, 287, 497 and 706 m, respectively. The spatial ranges of available Fe, Mn, Zn and Cu were 1050, 1150, 1470, and 1430 m, respectively. The spatial dependence class was strong for EC, SOC, available P, K and was moderate for available N, S, Fe, Mn, Zn and Cu. The available N and P is categorized as low (<280 kg ha^-1) and low (<11 kg ha^-1) to medium ( 280 kg ha ^-1). The soil nutrient maps generated would help to provide precise fertilizer recommendations for sustainable production and environmental conservation.

In direct seeded rice cultivation, weed is the major constraint mainly due to absence of puddling in field. The yield loss due to weed interference is huge, may be up to 100 %. In this perspective, the present experiment was conducted to study the effect weed management on nutrient uptake, grain yield, economics of direct seeded rice. The dry weight and density of weeds were recorded at different growth stages and consequently herbicide efficacy was evaluated. Experimental results revealed that pre-emergence herbicide effectively controlled the germination of grass weeds. Application of bispyribac-sodium as post-emergence following pre-herbicides plus hand weeding effectively reduced the density and biomass accumulation of diverse weed flora in Direct Seeded Rice (DSR). Herbicidal treatment improved the plant height, yield attributes and economics over weedy check. Besides early control of weeds is a better prescription to improve rice yield. Based on the grain yield and Weed Control Index (WCI), it can be concluded that the combined application of pre followed by post plus hand weeding effectively control different weed flushes throughout the crop growth period in DSR.