Establishment and performance of rainfed corn (Zea mays L.) and soybean (Glycine max (L)Merrill) in the dry season after puddled flooded rice

Date

1-1979

Abstract

Efforts are being carried out to increase cropping intensity and productivity of rainfed rice areas.

Six field and one greenhouse experiments were conducted on a Lipa clay loam soil at IRRI, Los Banos, Philippines. The objective was to evaluate tillage, establishment, mulching and fertilization methods that improved soil chemical and physical conditions for rainfed corn and soybean grown after puddled flooded rice in the dry season. Corn and Soybean were grown from late November to late April, 1978. The monthly rainfall for December to April was 21.1, 21.5,8.9, 6.4, and 28.7 mm, respectively. The waterable during this time was about 60cm below the soil surface.

Immediately after rice harvest soil moisture contents and levels of available P, NH4-n, water soluble Fe and Mn were higher in the puddled flooded rice plots than in the unpuddled plots. In unpuddled soils these chemical measures were higher in flooded than in non flooded than in non-flooded plots. Available zinc showed the reverse trend and no differences in exhangeable K contents were observed between rice management treatments. At 40 days after rice harvest these differences disappeared. Although the establishment of corn was similar in all rice management treatments, the performance of corn grown after puddled flooded rice was poorer than that grown after unpuddled flooded rice, but did not differ much from that grown after unpuddled non-flooded rice. This was mainly due to higher moisture content and more compact of soil in puddled flooded plots than in unpuddled plots which interfered with root growth and nutrient uptake of corn.

An experiment comparing rates and placement of N and P fertilizer in presence and absence of rice straw mulch showed that corn grown after puddled flooded rice responded strongly to N and P. Lack of N or P decreased the beneficial effect of other cultural practices. In the absence of mulch, deep placement of fertilizer resulted in 50-90% yield increase over shallow (5cm) placement of fertilizer. The effect of deep placement was small under mulch, particularly at high fertilizer rates. Fertilizer rates, particularly phosphorus, deep placement and mulching increased rooting depth of corn as measured by 32p enrichment and direct sampling and improved nutrient uptake and corn yield. Corn yields ranged from 381 to 3,150 kg/ha using and 80-day variety. The highest yield was obtained in treatments receiving complete tillage, rice straw mulch and deep placement (20cm) of 120-60-60 rate of fertilizer.

The soil moisture content at planting affected soybean establishment. A lack of excess of soil moisture reduced percent stand establishment and maximum stands were obtained at moisture contents of 50-56% (oven dry weight basis) in the 0-5 cm soil layer. Soil moisture deficiencies at later stages reduced soybean yields. Soybean planted on beds immediately after rice harvest germinated and grew poorly because of lack of soil moisture while those planted in 10cm deep furrows appeared to suffer from Mn deficiency. These treatments yielded less than those that received three rotovation treatments. The later, however, resulted in low soil moisture contents of the 0 to 5cm layer. This reduced crop stand to about 50% of the no-tillage plots but also provided a mulch to reduce further moisture loss from lower zones, so that growth of established plant was better than that in the no tillage treatments. Yields in three rotovations plots were, however, slightly less that those of no tillage plots. A single rotovation did not reduce topsoil moisture to the extent that it affected stand establishment. It provided sufficient weed control and soil mulch to avoid crusting and cracking of the soil. These treatments had similar stands but a slightly higher yields than the no-tillage treatments.

Relay planting of soybean into puddled rice field showed promise. The usual low stand and yields of this method could be improved 35-32% by increasing the seeding rate from 60 kg/ha to 120 kg/ha, 9-31% by soaking seeds for 24 hours and 11-35% by drilling in alternate rice inter-rows instead of broadcasting. Row drilling facilitated weeding and improved crop distribution.

Mulching with 8 t rice staw/ha inhibited soil crusting and cracking and reduced soil moisture loss and weed growth. This allow to delay planting time up to 10 DARH without substantially reduced crop stand and performance. It did not affect corn and soybean stands, but increased dry matter and seed yields. Mulching increased corn yield by 45-90% and 4-61% where fertilizer was placed shallow and deep, respectively. It increased soybean yield by 20-100%. The highest soybean yield obtained was 2,160 kg/h. It was obtained by drilling soaked soybean seeds in alternate rice inter-rows two days before harvest at a rate of 120 kg seed/ha. These plots received a 30-60-60 fertilizer rate, band-placed at seeding time and a rice straw mulch immediately after rice harvest.

Document Type

Dissertation

Degree

Doctor of Philosophy in Agronomy

College

Graduate School (GS)

Adviser/Committee Chair

Dr. Hubert G. Zandstra

Committee Member

Dr. Kwanchai A. Gomez, Dioscado A. Carandang, Dr. Adolfo C. Necesito

Language

English

LC Subject

Corn--Climatic factors, Soybean

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 996 1979 A42 K37

Notes

Doctor of Philosophy ( Agronomy - Crop Management)

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