Nutrient cycling of different plant residues and fertilizer doses in broccoli cultivation

Abstract

The decomposition and release of nutrients from plant residues that precede the cultivation of vegetables can positively affect the morphological parameters and crop productivity. The objective of this study was to evaluate the effects of plant residue decomposition and the cycling of macro and micronutrients of four cover crops preceding the broccoli production (single head Avenger hybrid). A 4x3 factorial scheme was implemented including four cover crops: signal grass (SG), pearl millet (PM), sunn hemp (SH), mixture PM+SH; and three doses of mineral fertilizer: 0, 50 (200 kg ha-1 of P2O5, 50 kg ha-1 of K2O, 75 kg ha-1 of N) and 100% of the recommended fertilizer dose (400 kg ha-1 of P2O5, 100 kg ha-1 of K2O and 150 kg ha-1 of N). Fresh (FB) and dry biomass (DB), residue decomposition, nutrient cycling of cover crops, the number of leaves, head height (HH), stem diameter (SD), head diameter (HD), head fresh-biomass (FB), head dry biomass (DB) and broccoli yield were evaluated. The FB production from PM (25.9 t ha-1), SG (23.3 t ha-1) and mixture PM+SH (23.9 t ha-1) were similar, while the largest production of DB occurred in the SG (11.9 t ha-1). The lowest rate of decomposition and the greatest half-life time of residues occurred where PM was present. The accumulation and nutrient cycling follow the sequence K>N>Ca>Mg>P>S and Mn>Zn>B>Cu for all cover crop treatments evaluated. The highest SD (51.95; 51.44 and 50.67 mm), HD (187.97; 187.41 and 183.48 mm), FB (1.01; 1.00 and 0.97 kg), DB (0.08; 0.07 and 0.07 kg) and broccoli yield (25.3; 24.9 and 24.7 t ha-1) was observed in the 100% dose of mineral fertilizer and on the residues of SH or PM+SH mixture, respectively.

Green and sweet corn grown under different cover crops and phases of the no-tillage system

“…When comparing the implantation phases of the system, the transition phase stood out concerning the others, with the highest DM production (Figure 1). The production of DM from SG, PM, and SH in isolated cultivation in this study ranged, respectively, from 4.2 to 7.7 Mg ha -1 , 6.8 to 10.1 Mg ha -1 , and 8.7 to 15, 3 Mg ha -1 , which are close to the ranges of 6.0 and 11.0 Mg ha -1 for SG, 7.0 and 12.0 Mg ha -1 for PM, and 4.0 and 9.0 Mg ha -1 for SH reported in other studies conducted in the Cerrado (Collier et al, 2018;Mazetto Júnior et al, 2019;Torres et al ., 2021).…”

“…The quantity and quality of dry matter produced by cover crops are essential parameters to be considered when producing straw in the Cerrado, as the decomposition and nutrient cycling of plant residues is more accelerated in this region (Pacheco et al, 2017;Ceballos et al, 2018;Torres et al, 2021). According to Lal & Logan (1995), the decomposition rate of waste is up to 10 times faster than temperate climate regions.…”

“…In the Brazilian Cerrado, pearl millet, signal grass, and sunn hemp are the cover crops most used in isolated or mixed cultivation, as they have high straw production and nutrient cycling, thus improving soil quality (Pacheco et al, 2017;Mazetto Júnior et al, 2019;Torres et al, 2021).…”