Green manuring–system of rice intensification–rice fallow pulses cropping system for enhancing the crop productivity and soil health: a sustainable farming solutions

Abstract

Rice cultivation in Tamil Nadu, a southern state of India, is a vital component of its agricultural landscape and economy. It holds historical significance and contributes significantly to the state's food security. Green manuring–system of rice intensification (SRI)–blackgram (rice fallow pulses) cropping system is novel, and this integrated system appears to be holistic and sustainable approach, combining innovative farming techniques to optimize yields, improve soil health, and minimize environmental impacts. To evaluate this, field demonstrations were conducted at a farmer's field through the National Pulses Research Centre, Vamban, Pudukkottai, Tamil Nadu, within the kharif rabi and summer seasons of 2019–20 under the Tamil Nadu Irrigated Agriculture Modernization project. The experimental site was medium deep clay with soil pH of 8.51, EC of 0.26 d S m⁻¹, low in available nitrogen (212.02 kg ha⁻¹), high in P₂O₅ (23.24 kg ha⁻¹), and medium in K₂O (300.46 kg ha⁻¹). Initially, farmers were given the awareness about the improved production technologies (IPT), and then, demonstration was conducted in 50 hectares with 92 locations of Ponnaniyar sub-basin. The demonstration results showed that the improved practice of SRI recorded higher plant height and other yield attributes. Notably, the SRI cultivation method exhibited a range of yields from 7580 to 9400 kg ha⁻¹ of rice across various locations, with the highest recorded at Avoor village. Concurrently, within the IPT framework for the GM–SRI–Rice fallow pulses cropping system, the recorded yields for Rice fallow Blackgram ranged from 590 to 730 kg ha⁻¹. Comparative analysis indicated a remarkable 39.9 percent enhancement in system productivity through the adoption of IPT practices compared to conventional farmer practices. Moreover, the IPT framework showcased significantly higher water productivity, recording 0.7087 kg ha⁻¹ m⁻³ compared to the conventional method, which yielded 0.2512 kg ha⁻¹ m⁻³. Soil nutrient observations highlighted that these cropping systems positively impacted soil fertility parameters, compared to the initial available nutrient status. This augmentation in soil fertility could be attributed to the incorporation of green manures. Consequently, the green manure–system of rice intensification–rice fallow pulses crop sequences emerged as more productive and sustainable option, displaying the potential to enhance soil productivity and fertility status compared to conventional rice–blackgram/groundnut cropping sequences. These systems present promising alternatives for farmers within the Ponnaniyar sub-basin area of Tamil Nadu.