Onion yield as a function of soil tillage system and soil water content

Jardênia R Feitosa,Filipe M T Nery,Haroldo C Fernandes,Janielle S Pereira,Paulo R Cecon,Daniel M Leite

doi:10.1590/1807-1929/agriambi.v24n2p115-120

Abstract

ABSTRACT Excessive tillage operations under inadequate conditions can raise the cost of agricultural production and lead to soil degradation without adequate crop response. The objective of this study was to evaluate the onion crop response to soil water contents and tillage systems. Three tillage systems were evaluated: P1 (plowing + two harrowings + two seedbed raising operations), P2 (two harrowings + one seedbed raising operation), P3 (one harrowing + one seedbed raising operation); and four soil water contents: 12, 15, 23 and 26%. The experiment was conducted in the irrigated perimeter of Tourão, Juazeiro, BA, Brazil (9° 24’ 7.3” S; 40° 26’ 8.7” W and altitude of 368 m), in 2017, and was installed in split plots, in a randomized block design, with four repetitions. Water contents were arranged in the plots and tillage systems in the subplots. Crop response to the applied treatments was evaluated through the determination of the emergence speed index of the seedlings, regularity of the longitudinal distribution of seedlings, final stand, total and marketable yields of the crop and yield per bulb transverse diameter class. The variation of soil water content had a quadratic effect on the variables emergence speed index, final stand and total onion yield. The treatments did not significantly affect the longitudinal distribution of plants and marketable yield. The tillage system composed of one harrowing and one seedbed raising operation showed to be the most appropriate for onion cultivation by direct seeding.

Highlights

Soil tillage may interfere with characteristics that determine the commercial quality of onion (Allium cepa L.), such as shape, size and health of the bulbs.Onion cultivation by means of the conventional tillage system is characterized by excessive turning of the soil, which is subjected to plowing and subsequent breaking of aggregates with rotary hoe
Crop response to the applied treatments was evaluated through the determination of the emergence speed index of the seedlings, regularity of the longitudinal distribution of seedlings, final stand, total and marketable yields of the crop and yield per bulb transverse diameter class
The variation of soil water content had a quadratic effect on the variables emergence speed index, final stand and total onion yield

Summary

Introduction

Soil tillage may interfere with characteristics that determine the commercial quality of onion (Allium cepa L.), such as shape, size and health of the bulbs. Onion cultivation by means of the conventional tillage system is characterized by excessive turning of the soil, which is subjected to plowing and subsequent breaking of aggregates with rotary hoe. These operations cause soil pulverization and, physical, chemical and biological degradation (Loss et al, 2015). There are doubts regarding the expected yield, bulb quality, time of cultivation and production cost of onions in these systems (Factor et al, 2012). Rós et al (2014) stated that the main argument contrary to the use of conservation systems in vegetable cultivation is that crops whose part of commercial interest develops completely or partially below the soil surface are sensitive to compaction, inadequate aeration or poor drainage, which may result in low yield

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Conclusion