International Journal of Plant Production最新文献

Leaf gas exchange plays a critical role in determining crop final yield, and there is a threshold response of leaf gas exchange to water stress. It is of great significance to quantify crop water stress severity by using the response characteristics of leaf gas exchange to drought. However, it is currently unclear whether leaf gas exchange serve as a reliable indicator for predicting crop final yield in response to drought, which affects the accuracy of monitoring agricultural drought using physiological indicators during the crop growing season. This study determined the response threshold of leaf gas exchange to drought for spring wheat through a serials of soil dry-down experiments and used the threshold characteristics to construct and parameterize a spring wheat growth model. Spring wheat were designed to be irrigated with five treatments (with supplementary irrigation at 230 mm, 165 mm, 115 mm, 50 mm and 0 mm). Crop model were used to simulate and analyze the threshold response characteristics of grain yield to drought and compare them to the thresholds of leaf gas exchange indices for spring wheat. The results showed that the response threshold of stomatal conductance of spring wheat to fraction of transpirable soil water was 0.5, which was greater than that of transpiration rate and net photosynthetic rate, 0.4. The parameterized spring wheat growth model with the response threshold of net photosynthetic rate to fraction of transpirable soil water accurately simulated the aboveground biomass and final yield of spring wheat. The response threshold of spring wheat final yield to fraction of transpirable soil water was significantly smaller than that of leaf gas exchange parameters to fraction of transpirable soil water (0.18 versus 0.4). This indicates that there are certain problems in using physiological indicator such as leaf gas exchange indices during crop growing season to determine the agricultural drought severity and reflect the reduction of final crop yields due to drought.

Ratooning of rice (Oryza sativa L.) is process of obtaining grain from tillers that grow from crop stubbles that have already been harvested. Ratooning has gained attention since it has a potential for obtaining yield with conventional techniques. Field experiment was conducted during 2021–2022 at the research farm, Institute of Agronomy, Bahauddin Zakariya University Multan, Punjab, Pakistan. The response of various nitrogen (N) levels (0, 25, 50, 75, and 100 kg ha^− 1) was studied on the growth and yield of three rice cultivars (Guard Lp-02, Guard Lp-18, and Super Fine) grown as ratoon rice. In cultivars, Guard Lp-02 and Guard Lp-18 were hybrid but Super Fine was a non-hybrid cultivar. The hybrid cultivars showed a significant response to N levels. The cultivar Guard Lp-18 with higher level of N 100 kg ha^− 1 resulted in more plant height, total tillers, fertile tiller, panicle length, and biological yield while the higher number of branches and grains per panicle, 1000-grain weight, and grain yield was achieved by Guard Lp-18 with the application of 75 kg N ha^− 1. Maximum agronomic nitrogen use efficiency (ANUE) and economic nitrogen use efficiency (ENUE) was observed at cultivar Guard Lp-18 with N level of 50 kg ha^− 1. Likewise, water use efficiency (WUE) was recorded maximum at cultivar Guard Lp-18 with N level 75 kg ha^− 1. The highest gross income, net income, and benefit cost ratio (BCR) were noted at 75 kg N ha^− 1 among all cultivars but Guard Lp-18 with 75 kg N ha^− 1 respond better in ratoon rice. Among rice cultivars, hybrid rice performed better and out yielded non-hybrid cultivars in ratoon rice. The findings of this study revealed that growing ratoon rice will be helpful for increasing farm income; enhancing resources use efficiency and ensuring food security under prevailing agro-climatic conditions of Punjab, Pakistan.

In the no-tillage system in Brazil, grasses are commonly grown for grain production or soil cover in the soybean off-season with no or low nitrogen (N) fertilization rates. The soybean sowing in soil containing high amounts of grass straw can lead to mineral N temporary immobilization at the beginning of the crop cycle. Some farmers apply N fertilizers at soybean sowing, often combined with seed inoculation with Bradyrhizobium spp. to circumvent that limitation. The objective of this work was to evaluate the effects of N fertilization at soybean sowing cultivated after different off-season crops or after fallow on soybean yield and grain protein and oil concentrations. The field experiment installed in Londrina, Paraná, Brazil, lasted seven years. The treatments were plots unfertilized or fertilized with 30 kg ha⁻¹ N at soybean sowing with five land uses in the off-season: (i) corn for grain production with N (80 kg ha⁻¹) broadcasted, (ii) corn for grain production without N fertilization, (iii) wheat for grain production without N fertilization, (iv) ruzigrass (Urochoa ruziziensis) as a cover crop, and (v) unplanted fallow. Results showed no interaction between soybean N fertilization and off-season crops on any variable. Soybean N fertilization did not affect grain yield (mean of 4064 kg ha⁻¹ without N and 4136 kg ha⁻¹ with N fertilization) in any of the seven seasons, including when the yield average was higher than 4500 kg ha⁻¹, which implies a high N demand for grain production. N applied at soybean sowing did not influence grain protein or oil concentration. Off-season cultivation of ruzigrass and wheat resulted in higher soybean yields (4354 and 4304 kg ha⁻¹, respectively) than off-season cultivation of corn with or without N and fallow (4058, 3942, and 3843 kg ha⁻¹, respectively). Soybean protein concentration (367 g kg⁻¹) was highest after ruzigrass and lowest (354 g kg⁻¹) after fallow. Soybean cultivated after N-fertilized corn yielded the maximum oil concentration (222 g kg⁻¹) and rendered the minimum (216 g kg⁻¹) after wheat. The results indicate that the mineral N application at soybean sowing was unnecessary, even in plots with high amounts of grass straw produced during the off-season.

To clarify the effect of plant spacing on the growth, yield formation, and quality of sugar beet taproot. We designed field experiments in 2021–2022, and sugar beet variety KWS1176 was used as experimental material, and 9 plant spacing treatments from 8 to 32 cm were set up. The morphological indicators, photosynthetic characteristics, and the nutrient contents were determined at the stages of the leafage growing period (V1), sugar increase period of taproot (V2), sugar accumulation period I of taproot (V3), and sugar accumulation period II of taproot (V4), and the root yield and quality parameters were measured at the harvest. The results showed that in the plant spacing treatments of 11 and 14 cm, sugar beet had a suitable canopy structure and space for taproot growing. The canopy photosynthetic activity was higher, which provided sufficient photosynthetic products for root growth, and appropriate root size could balance root growth and sucrose accumulation. The highest root yield and sugar content were also obtained in the treatment of 14 cm plant spacing. With the increase of plant spacing, the yield of sugar beet decreased, and the content of α-amino N, K⁺, and Na⁺ in the root increased, which had a disadvantageous influence on the processing quality of the root. It was found that the number of cambial rings and the average distance between cambial rings could be used as qualitative indicators of the sugar content of taproot and the processing quality. Therefore, 11-14 cm was recommended as a reasonable planting spacing to obtain higher taproot and sugar yield with better quality.