J Bhuvaneswari

Conservation agriculture (CA) is an approach to optimize farm and watershed performance. It integrates local and national economic systems while considering societal, environmental and institutional frameworks. This approach engages value chains supported by public, private and civil sectors. CA seeks to harmonize the use of natural resources with population needs, employing sustainable intensification to meet human demands effectively and preventing the loss of arable land. Conservation agriculture directly influences all sustainable development goals (SDGs) by leveraging the core principles of minimum soil disturbance, permanent soil cover and crop rotation. Conservation agriculture can prove to be a viable option for meeting the targets of the sustainable agenda. This practice supports environmental, social and economic justice, which creates a holistic developmental route that supports the burgeoning population. Conservation agriculture relies on a knowledge-based strategy to reduce production costs, enabling farmers to adopt new technologies more readily. While CA demonstrates significant benefits across scales, its adoption remains constrained by socioeconomic factors and limited mechanization in the smallholder context. Advancing CA requires a multidisciplinary, participatory research paradigm coupled with policy support, institutional support and capacity building for farmers. CA offers a sustainable framework that ensures sustainable intensification and environmental stewardship in the long term.

A field experiment was conducted at Agricultural College and Research Institute, Madurai during 2022 to study the effect of supplemental nutrition on different varieties under drip fertigated aerobic rice (Oryza sativa L.). The experiment was laid out in a split plot design with twelve treatment combinations and three replications. The treatment consisted of two varieties such as CO-54 and ADT-53 as the main factor and the sub-plot treatments included foliar application of 1% urea + 2% diammonium phosphate (DAP) + 1% potassium chloride at panicle initiation (PI) and 10 days later (F1), foliar application of 0.5% zinc sulphate and 1% ferrous sulphate at tillering and PI stages (F2), foliar application of 2% mono ammonium phosphate (MAP) + 1% potassium chloride at heading and grain filling stages (F3), foliar application of 1.5% fermented egg extract at tillering, PI and flowering stage (F4), foliar application of 1% ferrous sulphate at 25-30 days after sowing (DAS) (F5) and control - No spray (F6). The results of the study indicated that rice variety CO-54 coupled with application of recommended dose of fertilizers (RDF) of nitrogen (N), phosphorus (P) and potassium (K) through drip fertigation along with foliar application of 1% urea + 2% DAP + 1% potassium chloride at panicle initiation and 10 days later registered higher values for yield traits, total yield and zinc (Zn) and iron (Fe) partitioning of aerobic rice.

An experiment was conducted during 2021 and 2022 in Anbil Dharmalingam Agricultural College and Research Institute, TNAU, Tiruchirappalli, to know the overall allelopathic impact of horse purslane on the germination and seedling growth of rice, ragi, maize, green gram and sunflower. A Completely Randomised Design (CRD) was used to test 6 treatments, including a control and 1%, 2%, 3%, 4% and 5% concentrations of horse purslane whole-plant extract, with 4 replications. Seed germination and subsequent growth and development of selected crops were negatively affected by the extract of horse purslane. The minimum germination was recorded in 5% horse purslane extract, while maximum germination was recorded in control. A consistent decline in germination percentage was observed with increasing extract concentrations. The extract of horse purslane significantly reduced the root length, shoot length, seedling length and seedling vigour index (SVI) of the tested crops. The highest seedling mortality rates were observed at the 5% extract concentration, with values of 83.8%, 78.9%, 47.3%, 51.6% and 81.3% for rice, ragi, maize, sunflower and green gram respectively. The study indicates that horse purslane needs to be controlled effectively in the cropped fields, otherwise, it could reduce the growth and development of field crops. The allelochemicals in horse purslane present significant opportunities for further research on their impact on other weed species, which could contribute to the development of effective weed management strategies in field crops.

A field experiment was conducted on aggregatum onion (Allium cepa L. var. aggregatum Don.) under a drip irrigation system to evaluate the water productivity, nutrient use efficiency, nutrient dynamics and yield of onion in order to optimize the best fertigation level. The experiment was designed in a Randomized Block Design (RBD), with treatments replicated 3 times. The treatment details are as follows: T1-100 % nitrogen (N) through fertigation with100 % phosphorus (P) and potassium (K) applied as basal; T2 - 100 % N and K through venturi as fertigation and basal application of 100 % P; T3 - 100 % N, P and K through fertigation; T4 – 75 % N, P and K through fertigation with basal application of 25 % N, P and K; T5 – 75 % N through fertigation with 75 % P and K applied as basal; T6 - 75 % N and K through venturi as fertigation with basal application of 75 % P; T7 - 75 % N, P and K through fertigation; T8 – 75 % of N, P and K through fertigation and 25 % of 75 % N, P and K applied as basal; T9 - 50 % N 100 % P and K applied as basal and 50 % N applied on 30 DAT; T10 - absolute control (no fertilizer). The results indicated that the bulb yield of aggregatum onion was significantly higher in 100 % N, P and K through fertigation (23.24 to 23.47 t ha-1). Among the different fertigation treatments, the 100 % N, P and K through fertigation recorded higher water use efficiency (75.08 to 78.44 kg/ha mm), water productivity (7.841 to 7.508 kg m-3) and nutrient use efficiency, which was comparable to the 75 % N, P and K through fertigation.