Soil and Water Management for Sprinkler Irrigated Rice in Southern Brazil

Abstract

Rice is grown in lowland paddies, which is lood irrigated. In the most undulating areas, continuous looding is diicult and some farmers seek alternative irrigation methods. Grain yield in sprinkler irrigated rice ranges between 80 and 100% of that obtained under looding, but for this, fertilizer and water should be properly managed. For sprinkler irrigated rice, fertilizer should be corrected by adding 10 kg/ha of P 2 O 5 and 15 kg/ha of K 2 O for every expected additional ton of grains, over the standard recommendation. Regarding nitrogen fertilizer, it is recommended to be applied about 20 kg/ha of N at planting and the rest as topdressing. This can be done via soil, split into two applications: 50-60% of the topdressing dose at tillering start and the rest at panicle initiation. When N is applied by fertigation, 25% of the recommended topdressing N should be applied at tillering start; the remainder of the dose may be partitioned into four to six weekly applications through irrigation water. For water management, soil water tension should be kept below 10 kPa. At the vegetative stage, irrigation can be applied aiming to avoid water tensions in soil above 30 kPa at any moment.

October 2021

“…Theoretically, this would allow five extra days for rice before reaching significant water stress levels, compared to fields with no soil mulching. This is particularly important for rice fields grown under alternative irrigation schedules and/or methods, as intermittent or sprinkler irrigation (Parfitt et al, 2017b). While soil mulching is important for keeping adequate soil moisture levels as depicted in Figure 1, it also provided adverse rice establishment (Figure 2).…”

Rice Yield Components under Water Stress Imposed at Different Growth Stages

“…This supplies evidence that rice grown under water stress (sprinkler or intermittent flooding irrigation) should be planted in higher density compared to continuous flooding as the grain abortion rate is not higher under this irrigation system, but the whole kernel grains are reduced-it should be compensated by a higher tiller (and panicle) density, which may be achieved in the field by using higher seeding rates (Ahmed, Salim, & Chauhan, 2014) and accurate nitrogen topdressing management (Cai et al, 2006;Parfitt et al, 2017).…”

Effect of the irrigation method and genotype on the bioaccumulation of toxic and trace elements in rice

“…in SA conditions) to −25 kPa (i.e. a condition roughly midway to SA and SP, being the latter condition correlated to a soil water tension typically between −35 and − 38 kPa (Parfitt et al, 2017)). Also Orasen et al (Orasen et al, 2019) evidenced, on three different rice genotypes cultivated in two consecutive years, an average increase of the Ni concentration in rice grain between +300 and + 700% passing from CF irrigation to alternate wetting and drying irrigation.…”