Integrated crop–livestock systems in paddy fields: New strategies for flooded rice nutrition

Abstract

Integrated crop-livestock systems (ICLSs) appear as a good alternative to increase nutrient use efficiency (NUE) in rice (Oryza sativa L.) through the improvement in nutrient cycling and soil chemical attributes in paddy fields. The objective of this study was to evaluate the impact of an ICLS on soil chemical attributes and on the fertilization requirement of N, P, and K by flooded rice in the Brazilian subtropical region. Nutritional status, yield, and NUE of flooded rice were evaluated by fertilization trials through rice response to different fertilization rates of N, P, and K. Soil chemical attributes were evaluated at the beginning of the experiment and 30 mo later.Different fertilization rates were applied in two systems: (a) a conventional system (CS), based on intensive tillage, rice monocropping and winter fallow, and (b) ICLS, characterized by no-tillage and winter cattle grazing in annual ryegrass (Lolium multiflorum Lam.) pasture. Rice shoot accumulation of N, P, and K was greater under CS than ICLS at all fertilization levels. On the other hand, higher rice yields were observed under ICLS at almost every fertilization level, suggesting higher NUE than CS. In addition, rice yield was increased by 40% by fertilization of P and K under CS, whereas no response was observed under ICLS. These benefits were possibly related to greater nutrient cycling and greater synchronism between rice's nutrient uptake and nutrient release of the soil. Our results indicate that the adoption of ICLS ensures greater NUE becoming a system less dependent on external inputs.Abbreviations: CEC, cation exchange capacity; CS, conventional system; ICLS, integrated crop-livestock system; NUE, nutrient use efficiency; SOM, soil organic matter.

Sheep Dung Composition and Phosphorus and Potassium Release Affected by Grazing Intensity and Pasture Development Stage in an Integrated Crop-Livestock System

“…In addition, we have shown that not only nutrient cycling from one phase to another (pasture to crop) in the annual ICLS cycle is important, but also nutrient recycling in the pasture phase is a relevant process, both with potential to improve systems' nutrient-use efficiency. Recent studies [8,29] recommended that most of the P and K fertilizer should be applied prior to the grazing season in ICLS (i.e., at the beginning of the pasture phase) instead of the traditional fertilization in the crop phase. This change in the logic of fertilization management results in greater pasture yields and animal live weight gains (as a result of improved sward structures and stocking rates) with the same amount of nutrient input to the system.…”

“…Residue diversity also benefits soil microbial diversity, which is greater under moderate grazing intensities [7]. As a consequence, increased biodiversity has been recently acknowledged as the responsible for higher grain yields and nutrient use efficiencies under ICLS, ultimately reducing fertilizer requirements and increasing systems' self-sufficiency [8].…”

Soybean Yield Does Not Rely on Mineral Fertilizer in Rotation with Flooded Rice under a No-Till Integrated Crop-Livestock System

“…However, during the 2015/2016 cropping season, soybean yield did not respond to P and K fertilization with average yield across treatments of ~4.5 Mg ha −1 (Figure 1). The lack of soybean yield response could be related to the greater cycling of P and K under an ICLS, favored by fertilized pasture residues and cattle manure [8,10]. The high pasture fertilization rates could have led to an accumulation of nutrients in the soil, contributing to a reduction in the response to mineral fertilizer in soybean.…”

“…The benefits of legumes in rotation are not only caused by biological nitrogen (N) fixation but also by increased nutrient availability through higher microbial carbon use efficiency from legume residues that increase the soil organic matter content, which could help to sustain the long-term productivity of cereal-based cropping systems [6,7]. In addition, both rice and soybean benefit in this environment, which can be achieved under an integrated crop-livestock system (ICLS) [8,9]. These systems enhance the nutrient cycling process and increase both soil phosphorus (P) and potassium (K) supplies [10].…”

“…These systems enhance the nutrient cycling process and increase both soil phosphorus (P) and potassium (K) supplies [10]. Under a no-till ICLS, the flooded rice efficiently utilizes N, P, and K; therefore, the flooded rice under a no-till ICLS does not respond to P and K fertilization [8].…”