Effect of Post-emergence Herbicides on Paddy Ratoon Management for Successful Zero-Till Maize Establishment
E. Priyankabai *
Department of Agronomy, S.V. Agricultural College, Tirupati, ANGRAU, Andhra Pradesh, India.
G. Karuna Sagar
University of librarian, ANGRAU, Lam, Guntur, India.
D. Subramanyam
Department of Agronomy, S.V. Agricultural College, Tirupati, ANGRAU, Andhra Pradesh, India.
M. Sreenivasa Chari
Soil Science & Agricultural Chemistry, Agricultural Research Station, Kadiri, India.
B. Sandhya Rani
Crop Production, DAATTC, Chittor, ANGRAU, India.
*Author to whom correspondence should be addressed.
Abstract
Maize is traditionally cultivated as a rainy season crop in India; however, in recent years, its cultivation during the winter season has expanded considerably. This shift is largely driven by the need for crop diversification and better utilization of residual soil moisture, particularly in rice fallow areas. Paddy ratoons, which regenerate from leftover rice stubbles after harvest, behave as weeds and compete aggressively with maize for essential resources such as nutrients, moisture, light, and space, ultimately affecting crop growth and yield. A field experiment was conducted at S.V. Agricultural College's wet land farm in Tirupati during the rabi seasons of 2022-23 and 2023-24 to evaluate the effect of nutrient levels and weed management practices on paddy ratoon density in zero-till maize. The study aimed to identify effective strategies for suppressing paddy ratoons to ensure better establishment of maize under conservation agriculture systems. The treatments comprised three nutrient levels, viz., 125% recommended dose of fertilizers (RDF), 100% RDF, and 75% RDF, along with six weed management practices including different post-emergence herbicide applications followed by hand weeding, manual weeding and an unweeded control. The results revealed that nutrient levels significantly influenced paddy ratoon density at both 20 and 40 days after sowing (DAS). The lowest ratoon population was recorded with 125% RDF (185 and 193 no. m⁻² at 20 and 40 DAS, respectively), while the highest was observed under 75% RDF (246 and 232 no. m⁻²), indicating that higher nutrient availability favored better crop competitiveness and reduced ratoon survival. Weed management practices showed non-significant differences at 20 DAS but had a significant impact at 40 DAS. Among the treatments, post-emergence application of mesotrione + atrazine followed by hand weeding recorded a substantial reduction in ratoon density (139 no. m⁻²), which was comparable to hand weeding twice (127 no. m⁻²). In contrast, the unweeded control exhibited the highest ratoon population (279 no. m⁻²). Other herbicidal treatments exhibited a moderate degree of efficacy in suppressing ratoon density, although their performance was comparatively inferior to the most effective options evaluated. Statistical analysis further indicated that the interaction between nutrient application levels and weed management practices was non-significant, suggesting that the influence of herbicide treatments on ratoon control operated independently of the nutrient regimes imposed. Moreover, the post-emergence herbicides applied under zero-tillage maize conditions did not exhibit any observable phytotoxic effects on the crop. No symptoms such as chlorosis, necrosis, or growth inhibition were recorded throughout the assessment period. This absence of crop injury clearly demonstrates that all herbicides, when applied at their recommended dosages, were highly selective and safe for maize cultivation under the given experimental conditions.
Keywords: Paddy rations, nutrient levels, post-emergence (PoE), zero-till maize, hand weeding.